BIOLOGY AND HEALTH PHYSiCS DIViSJON October 1 to … · Biology and Health Physics Division...

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AECL 5108

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BIOLOGY AND HEALTH PHYSiCS DIViSJON

October 1 to December 31, 1974

PR.B-104

Chalk River Nuclear Laboratories

Chalk River, Ontario

ATOMIC ENERGY OF CANADA LIMITEDChalk River Nuclear Laboratories

PROGRESS REPORT


Biology and Health Physics Division

PR-B-104

Chalk River, Ontario

AECL-5108

PREVIOUS REPORTS IN THIS SERIES

AECL-5018 July 1 to September 30, 1974 PR-B-103

AECL-4911 April 1 to June 30. 1974 PR-B-102

AECL-4833 January 1 to March 31, 1974 PR-B-101

AECL-4765 October 1 to December 31, 1973 PR-B-100

PROGRESS REPORT


Biology and Health Physics Division

Director - Dr. A.M. Marko

Secretary - Mrs. B.L. Phillips

Staff reporting to Divisional Office . . - Mr. M.I. GibsonMr. L.G. Hunter

CONTENTS

1. Summar y - Dr . A.M. Marko 1 - 9

2. Health Physics Branch - Mr. G. Cowper 1 1 - 3 9

3. Environmental Research Branch - Mr. I .L. Ophel . . 4 1 - 7 2

4. Population Research Branch - Dr. H.B. Newcombe . . 73 - 88

5. Biology Branch - Dr. W.F. Baldwin , 89-111

BIOLOGY AND HEALTH PHYSICS DIVISION SUMMARY

A.M. Marko

Health Physics

Radiation monitoring in health physics is the first step in assessing

the doses received by those exposed to various forms of ionizing radiation.

In many instances when conservative assumptions arc made the conversion

of the measured output of a radiation detector to a radiation dose is often

no more than a simple arithmetic process. A well-known example is the

assumption that a worker wears his personal gamma dosimeter on the most

likely exposed portion of his body and the dosimeter reading is taken to be

the whole body radiation dose.

Such approximations and assumptions are generally acceptable

when the radiation absorption characteristics of the detector are similar

to those of tissue and when the exposure occurs in generally uniform radia-

tion fields, often the case when exposure to gamma radiation is involved.

However, in the case of fast neutron dosimetry the situation is much

more complex. No convenient detectors of fast neutrons have responses to

neutrons of different energies which match those of tissue and the conver-

sion step from the estimate of neutron flux by any detector to the estimate

of the dose received by a person is far from simple. Nevertheless, in the

event of an incident involving a large radiation exposure there would be a

considerable interest in establishing with the least delay a credible value

u! t h r d o s e r i 'Ci ' ivoi l ,

To this end much effort has gone into the analysis of typical ra

tion exposure situations to provide relationships between neutron flux and

dose for a variety of neutron detectors having a limited energy response

and a range of probable neutron spectra likely to be encountered in real

situations where the primary neutron source either from an accelerator or

a fi-jsion process is shielded or scattered to some extent by materials such

an water, heavy water, concrete or iron.

In another situation where the handling of plutonium could result in

a contaminated puncture wound and it would be a matter of some urgency

to determine the amount of plutonium present, recently developed amplify-

ing semiconductor junction detectors show considerable promise. These

detectors developed in industry under contract have been found capable of

resolving the L X-rays of plutoniuin so that by comparing the magnitudes

of the measured X-ray intensities an estimate of the thickness of tissue

covering the activity could be made.

The unambiguous detection of one source of radiation or radio-

activity in the presence of others of less critical effect is another important

requirement in health physics. Th's situation is well represented in the

requirement to detect tritium which may escape from a heavy water power

reactor into an environment which is contaminated also with radioactive

rare gases and is subject to external gamma radiation fields. Instruments

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now being completed for tritium monitoring at the Bruce Generating Station

have been designed to meet these requirements. In one design, pairs o:

gamma compensated ion chambers and a drying column permit the separa-

tion of the signal due to tritum from competing sources and in the other,

the separation in achieved by transferring the HTO of Interest in air into a

water stream from which dissolved rare gases are scrubbed with a clean

air stream. In this case gamma radiation interference is suppressed by

the combination of shielding and a detector with inherently small gamma

sensitivity.

Environmental Research

A program has been initiated to study some beneficial uses of waste

heat on food chains. Microscopic algae (phytoplankton) are being screened

to find protein-rich species which will gvow rapidly at elevated water

temperatures. An attempt will be made to mass-culture these organisms

in heated, nutrient-rich water and use the harvested material as the basis

of a diet for pond-cultured fish.

A group from the Department of Etiology, Universite du Quebec a.

Trois-Rivieres under the direction of Professor Guy Vaillancourt completed

another year of contract research on the effects of heated water effluent

from the Gentilly Nuclear Generating Station on the St. Lawrence River.

Their third annual report has recently been issued. It deal i wi'-h the

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observed distribufion of water temperatures in the river and discusses

them in relation to a mathematical model of diffusion which has been

developed by the ^roup. Biological research included studies of the distri-

bution, reproduction and food supply of the 19 .species of molluscs (water-

sruiil?^ found in the d-scharge area. These animals are the most important

local food supply for fish and wildlife.

The Perch Lake Evaporation Study, which was a participating pro-

ject of the Canadian contribution to the UNF.'SCO International Hydrological

Decade, was completed with a Symposium/Workshop held at the Chalk

River Nuclear Laboratories (CRNLj, 9-11 December 1974. Approximately

35 participants from Environment Canada, University of Waterloo and

AECL presented 16' papers for discussion and subsequent publication in a

proceedings. An irtercomparison and evaluation of methods is the main

subject of the final summary statement which was prepared in draft form

during the Symposium /Workshop.

In co-operation with Dr. J.M. Bewers, Bedford Institute of

Oceanography, Nova Scotia, a study of some 35 trace elements in precipita-

tion of the Ottawa Valley is under way. Trace element concentrations in

rain and snow storms are determined by neutron activation analysis. The

aim of the joint project is to model the trace element cycling in the Ottawa

River watershed.

The distribution and variability of natural deuterium concentrations

in the St. Lawrence River and tributaries in the vicinity of Gentiiiy are

being studied to gain information on concentrations to be expected in the

feed-water to the LyaPrade Heavy Water Plant. -Results indicate there will

be a springtime low in the deuterium content of water ta'.cen from the south

channel of the river. It mi^ht be possible to avoid this by extending the

intake pipe out to the deep waters of tVv. main charvriel but thL = would pro-

bably not be economically advantageous.

Indications have been found of the flow of slightly contaminated

surface water out of the Perch Lake drainage basin into an adjoining drain-

age basin. The cause appears to be a change in relative wa(er levels at the

divide caused by beaver dams. The amounts of radioactivity involved are

very small but previous conditions will be restored, by live-trapping of

the beaver and destruction of the dams, as soon as possible.

Population Research

The first stage of a study of the possible "multiplicaiive effect"

of radiation in combination with chemical carcinogens on the induction of

skin cancers in rats, i.e. involving irradiation alone, was completed in

October. The second stage, which involves chemical treatment alone, was

begun in August; the backs of 200 animals have now been painted with

cigarette tar a total of 54 times, the amount used being equivalent to 350

cigarettes each. The third and final stage, involving combined treatment,

will be started towards the end of stage two; each stage takes approxi-

mately 18 months.

In the development of record sources to study human disease that

might increase with irradintion, a sample file of 35,000 records of ill

health among children (from hospital discharges, registrations of handicap-

ping conditions, a surveillanc <- scheme for congenital anomalies, and death

registrations) has been linked tu the appropriate birth registration files.

Th\s sample linkage is being used to improve the procedures by which

individual and family histories may be obtained for diseases of special

Lnte.'est.

Magnetic tape files of British Columbia records held at CRNL are

being transmitted to the University of British Columbia as part of a colla-

borative undertaking to study hereditary and congenital disease, and radia-

tion induced cancer. Altogether these data represent 11 million magnetic

tape records; 40 per cent of this material has now been processed and

sent to UBC.

A study of cancer following multiple fluoroscopy, originally plan-

ned at CRNL and being carried out at National Cancer Institute of Canada

in collaboration with University of Toronto and CRNL, received in December

a grant of $231, 300 from Health and Welfare Canada.

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Biology

In an effort to understand and measure the harmful effects of

radiation, studies of the consequences of both ionizing and ultraviolet

radiation are being carried out in the Biology Branch. The biological sys-

tems under study include simple forms such as bacteria as well as more

complex forms such as insects and rats. Studies on human cells in tissue

culture are also in progress.

In the bacteria Micrococcus radiodurans, previous evidence

indicated that radiation-produced hydroxyl radicals were the cause of the

release of proteins from the cell walls. Hydroxyl ions produced chemically,

rather than by radiation, have exactly the same effect, i .e. release of

proteins, lending further support to our conclusions. The exact chemical

nature of the reaction caused by hydroxyl radicals is not known, but tests

aimed at determining the nature of the damage are in progress.

In insects, environmental stress in the form of heat during irradia-

tion has caused drastic increases in the production of eye colour mutations

in Dahlbom'nus. In a recent study, the heat treatments have been given at

different periods up to and including 24 hours after irradiation. At this

time interval the mutation frequency has receded to the level caused by

radiation alone, indicating that repair can take place when the Iwo agents,

heat and radiation, are separated with time. This result has important

implications in the interpretation of the hazards arising from the reaction

of ,u> i-nv.runmental factor on radiat .un-induc ed mutations.

In rats, experiments to determine whether the effects of radiation

,iiui chi-mieals in producing tumours are simply additive or are synergistic

in action are in progress. In one group of tests, rats of the Sprague-

PawLey and Long-Evans strains developed very few leukemias and few skin

tumours but a large number of mammary tumours after treatment with

either urethane or X-radiation. However, no evidence of synergism

between X-radiation and urethane was found with any of the tumours, and

it can be concluded that the total carcinogenic stimulus of urethane is

additive and not synergistic with that of X-irradiation in rats.

Several projects have now been initiated in the new tissue culture

facilities in Biology. In one study, stock cultures of human fibroblast

strains obtained in Holland froir ten different patients suffering from the

hereditary skin disease Xeroderma pigmentosum have been established.

Each of these strains is deficient in its ability to overcome damage in DNA

from ultraviolet radiation. Also fibroblasts from chick embryos have been

cultivated in the laboratory. Finally, the sensitivity and specificity of

highly purified enzymes for detecting certain lesions in irradiated DNA

have been studied. These projects together will form the basis of a highly

sensitive method of detecting repair of DNA in animal cells damaged

during irradiation.

1.1 VERBAL PRESENTATIONS

1.1.1 Lectures or Seminars

Marko, A.M. - "Radiation Hazards", Queen's University, Kingston,Ontario, 16 April 1974.

Marko, A.M. - "Objectives of Radiation Biology in an Atomic EnergyEstablishment", Ontario Radiobiology Group Meeting, OntarioCancer Foundation, London, Ontario, 15-16 May 1974.

Marko, A.M. - "Radioactive Absorbed Dosage Due to InternallyLocated Radioisotopes", University of Toronto, Toronto,Ontario, 27 & 28 May 1974.

1.1.2 Local talks

Marko, A.M. - "Environmental and Biological Considerations" .Summer student lecture series, CRNL, 24 May 1974.

Marko, A.M. - "Principles of Radiation Protection". Presentedat 16th Annual Health Physics Course held at CRNL,10-14 June 1974.

1.1.3 Panel meetings

Marko, A.M. - Working Group on "The Ocean Dumping of Radio-active Wastes". Held at the International Atomic EnergyAgency, Vienna, Austria, 8-12 July 1974.

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HEALTH PMYSICS BRANCH

G. Cowoer

2.1 Staff2.2 Directional Dependence of the Sensitivity of Damage

Track Neutron Dosimeters2.3 Neutron Dosimetry by Measurement of Electrolyte

Conductance in Damaqe Tracks2.4 Spectra and Dosimetry of Neutrons from Various Sources

Shielded by Iron2.5 Dose Measurements Relatsd to Meutron Irradiations of

the Human Body2.6 The Decay of 8.0-min 7"Ga2.7 Modifications of the 05R Program Library2.8 Analytical Representation of Fast Neutron Cross Sections

Used in Dosimetry2.9 Spectra and Dosimetry of Beams of Fission Neutrons

Penetrating Water2.10 Therir.oluminescence Dosimetry2.11 Amplifying Radiation Detectors2.12 Life Testing of Geiger Counters2.13 A Linear Counting Rate Circuit with Variable Time

Constants2.14 Application of the Analog to Digital Converter to

Radiation Dosimetry2.15 Spectroscopy of Environmental Gamma Radiation2.16 Measurements of the Efficiency of the Plutonium-In-Air

Monitor2.17 Miscellaneous Instrument Developments

2.17.1 Thin Window Portable Contamination Monitor2.17.2 Multichannel Area Monitor AEP-52392.17.3 Geiger Counter Laundry Monitor2.17.4 Hide Range BY Survey Meter AEP-52382.17.5 Fuel Element a Monitor2.17.6 Digital Warning Dosimeter AEP-52782.17.7 Uranium Oxide Level Monitor

2.18 Tritium Monitoring2.18.1 AEP-52752.18.2 AEP-52842.18.3 AEP-52702.18.4 AEP-52152.18.5 Miscellaneous Instruments for Tritium Detection

2.19 Electron Energy Loss In Thin Organic Films

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2.20 Detection of : ' ' I In Air2.21 Detection of 1 ?"I In Air2.22 Analysis of Sucrose Gradient Centrifugation Data2.2J Analysis of Arqon-41 Concentration Data from Meteoro-

logical Records2.24 Argon-41 Detection in Air2.2 5 Routine Dose Monitoring2.26 Publications2.27 Verbal Presentations

2.2 7.1 Lectures or Seminars

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2. 1 STAFF

Branch Head

Secretary

G. Cowper

B. Lucas (Miss)

W.G. CrossH. Ing

Assistants P.J. BungeD.J. Robertson

A.R. Jones Assistants A.H. OhnoW.F. RichterJ. Akister :D

R.V. Osborne Assistants A.£. CoveartA.P. PriniN.W. Tepley

(3)

R.M. Kolford Assistant J. Plato

Personnel Monitoring L.S. LarkinR.M. Rondeau (Miss)J.M. Vincent (Mrs.)

Draftsmen B.A. MacDonald (2)J.H. Sneddon (2)L. Spear (2)

(1) Jim Akister, Waterloo University Co-op Student,working with A.R. Jones terminated December 20,1974.

(2) On loan from the drawing office.

(3) Armando Prini, terminated December 27, 197 4.

2.2 DIRECTIONAL DEPENDENCE OF THE SENSITIVITY OF DAMAGETRACK NEUTRON DOSIMETERS - W.G. Cross and H. Ing

Recent measurements by Mijnheer1 on fissiontrack detectors indicated that their sensitivitydiffers by a factor of 1.6 when 14.6 MeV neutrons areincident normal or parallel to the plane of the detec-tor, for botr. "'''Th and ' 17Np radiators. The ratiosof sensitivities in the forward and backwarddirections were 1.2 and 1.3 for the same detectors.Such a larqe directional variation would reduce theusefulness of these dosimeters in neutron therapy andpersonal dosimetry.

We have calculated the directional variation ofthe sensitivity of these dosimeters as a function of(1) the radiator thickness, (2) the detector foilthickness (which the tracks must penetrate) (3) theanisctropy of fission fragment emission and (4) theneutron energy. The sensitivity ratio between 0° and90° incidence is determined mainly by the first threefactors, while the forward/backward ratio (0°/180°) isinsensitive to the emission anisotropy. For our Npand Th radiators and 10-um thick polycarbonate detec-tor foils, the calculated 0a/900 ratios were 1.15 and1.33. Measurements with these radiators, using 14.6-MeV neutrons, gave respectively 1.15 tn.05 and 1.30t0.05 for the 0°/90° ratios and 1.07 +0.04 and 1.09'0.04 for the 0°/180° ratios. While our radiator anddetector thicknesses were somewhat different Mijnheer's,theory suggests that our ratios and his should differby only a few percent. The two sets of results areapparently in disagreement, our lower values suggestingthat the clixectional dependence of Np dosimeters, atleast, is not enough to affect their usefulnessseriously.

2.3 NEUTRON DOSIMETRY BY MEASUREMENT OF ELECTROLYTECONDUCTANCE IN DAMAGE TRACKS - W.G. Cross and H. Ing

The determination of fission fragment damage trackdensities in neutron dosimeters, by measuring the con-ductance of electrolyte filling the tracks, was des-cribed in AECL-4765, PR-B-100. An investigation of thecapabilities and limitations of this method and of thefactors that affect reproducibility and accuracy hasbeen made.

!3.J. Mijnheer, Int. J. App. Rad. and Isotopes, 25,337 (1974)

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For tracks in Makrofol, 10 pm thick, etched inKOH at 40°C, the foil conductance was found to beproportional to the square of the etching time, downto 10 minutes or less. Thus the mean track radiusincreases uniformly with etching time and the etchantinitially penetrates the track core in much less than10 minutes. For 90 rainute etch timo.s, conductancewas proportional to neutron dose up to 1000 rads (for23*Th radiators and 14-MeV neutrons) and the aboveresults imply that doses as high as 10 u rads can bemeasured by decreasing the etching time to 30 minuter.Times shorter than this give poorer reproducibi]ity.While a single track can also be detected, conductancemeasurements are less reliable than spark counting forlow doses.

Typical reproducibility of Makrofol foils irradiatedtogether and etched in the same solution is + 3%(standard deviation). Foils etched at different timesusually vary by less than 10% but occasionally vary bylarger amounts. These differences are not due to theconductance measurement but to variations in either thefoil or the etching. Repeated measurements of a foilthat is washed and dried between measurements givereadings that are constant to within 2%.

Exposure of unetched foils to UV light was foundto have two separate effects; (1) tracks existing beforeexposure were more rapidly penetrated by the etchant,as has been observed elsewhere; (2) diameters of tracksproduced after UV exposure increased more slowly withetching times than those in unexposed foils. Thisappears contrary to experience on other foil materialsfor which the bulk etching rate is increased by UV.Ambient light will not affect etching rates significantlyunless the foils are left exposed for several days.The use of a surfactant (Benax 2A1) in the etchant, foundby Price to increase track etching speed in NaOH solutions,did not significantly alter etching rates in KOH.

2.4 SPECTRA AND DOSIMETRY OF NEUTRONS FROM VARIOUS SOURCESSHIELDED BY IRON - H. Ing and W.G. Cross

Spectra from 14.7 MeV neutrons, fission neutrons,H20-moderated fission neutrons and D20-moderated fissionneutrons escaping from Fe spheres and transmitted throughFe slabs of various thicknesses were computed using amore exact treatment of inelastic neutron scattering thanused previously (AECL-4610, PR-B-98, p. 57). The thicknessof an Fe shield has dramatic effects on the spectral shapeof the escaping neutrons while shielding geometry anddetector location only introduce minor spectral differences,For 14.7 MeV source neutrons, dose attenuation in Feresults primarily from neutron scattering to unresolvedlevels above 4.2 MeV and the (n,2n) reaction. Both

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processes transfer neutrons to a broad distributionbetween 0.1 and 2 MeV, similar in shape to a fission-spectrum. After 20 cm of Fe, this distribution accountsfor about 20% of the dose delivered by all neutrons. Forfission and moderated neutron sources, dose attenuationresults primarily from inelastic neutron scattering tothe first excited state in 56Fe at 847 keV. Thisinteraction causes the peak to decrease quickly in energywith increasing shield thickness so that after 50 cm,the average energy of the resulting peak is only about0.3 MeV. A large number of 24-keV neutrons accompanvmost Fe-filtered spectra, but only few neutrons arefound below this energy. These two features make itimpossible to represent the intermediate energy region(1 eV to 100 keV) by functions of the form 1/En, where Eis the neutron energy and n is a parameter.

Average cross sections (a) for various activation_and danage track dosimeters, kerma (k), maximum dose (D)and dose equivalent (D.E.) were calculated for all escapespectra, Investigations of o/k, and o/D, and a/D.E.Indicated that none of the detectors displayed a doseresponse that was nearly independent of Fe thickness.Detectors with high energy thresholds (such as S, U orTh) were particularly poor for criticality accidentdosimetry involving Fe-filtered neutrons since they weremost sensitive to spectral changes. Response curvesversus Fe thickness were calculated so that correctionfactors can be obtained to convert the apparent dose read-ing of a particular dosimeter to the actual dose when thethickness of the Fe shield is known.

2. 5 DOSE MEASUREMENTS RELATED TO NEUTRON IRRADIATIONS OF THEHUMAN BODY - H. Ing and W.G. Cross

Neutron spectra, calculated by Monte Carlo, wereobtained at various regions in a phantom (represented byan elliptic cylinder containing appropriate amounts of H,C, N and 0) irradiated by beams of 14.7 MeV neutrons andneutrons from Po-Be and 252Cf sources. Although thesespectra have other applications, we regard them asprimarily providing an indication of the spectral distortionswithin the body on neutrons from sources used in medicaldiagnosis and cancer therapy.

These spectra were used in the investigation of thedependence of the dose response of several activation anddamage track detectors with location in the body irradiatedby a collimated neutron beam. The response of the Rhdosimeter was rather independent (<20%) of spectralchanges for 252Cf and Po-Be irradiations, but it showedlarge variations (> factor of 3) for 14 MeV irradiations.The Np detector h^d the most favourable response of the 6detectors studied - varying by less than ±10% for all threeneutron sources and all locations.

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2.6 THE DECAY OF 8.0-min 7l4Ga - H. Ing in collaboration withH.W. Taylor, R.L. Schulte and P.J. Tivin (Physics Dept.University of Toronto)

A source of 7"Ga was produced by bombarding GeO2(95% enriched in 7l<Ge) with 14.7 MeV neutrons and itsdecay was followed with Ge-Li gamma-ray spectrometers.The cross section of the 7 uGe (n,p) 7''Ga reaction, measuredagainst the 56Fe(n,p)5GMn and the 63Cu(n,2n)e2Cu reactions,was 10.7 +1.5 mb. The half-life of 7"Ga was 8.00 ± 0.05min. Over 100 gamma rays, extending to about 4 MeV, wereidentified. From the measured energies and intensities ofthe gamma rays, a revised level scheme for 7l*Ge wasconstructed and beta branching ratios to the variouslevels along with their log ft values were .determined.Good agreement with the work of Camp et a_l was obtainedfor levels below 2700 keV, but the level scheme above thisenergy was different from this and other schemes establishedby (n,y), (Y»Y') and(p,p') experiments.

2.7 MODIFICATIONS OF THE 05R PROGRAM LIBRARY - H. Ing andW.G. Cross

The KINNY sub-routine which handles inelastic neutronscattering in the 05R program was modified to treatscattering to unresolved levels where the secondary neutron

.,/ distributions are given :,n the form of tabulated histogramsin the ENDF/B neutron cross-section data files. Work is inprogress which would enable KINNY to handle anisotropicinelastic scattering as well. This additional modificationwill allow the treatment of such interactions withconsiderably less core storage than the existing methodwhere the angular distribution information is interwovenwith (and has the same format as) similar but more detaileddata for elastic scattering.

Programs have been written to extract neutron crosssections for inelastic scattering, tabulated neutrondistributions and angular distribution data from the ENDF/Bfiles in a format compatible with the input requirementsof KINNY.

A program "REDANC" was written to process card outputfrom the 05R and calculates average cross sections for thefollowing reactions: * ° 3Rh (n,n! ) * ° 3mRh, u5In(nfn')

] ' 5mIn,32S(n,p)i2P, 5BNi(n,p)SBCo, 237Np(n,f), 238U(n,f) and232Th(n,f). REDANC also provides average kermas, maximumdoses and dose equivalents and ratios of cross sections tothese quantities as well as plots of spectra in versatileformats which can be used directly in publications.

.C. Camp, D.R. Fielder and B.P. Foster, Nucl. Phys.A163 (1971) 145.

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2.8 ANALYTICAL REPRESENTATION OF FAST NEUTRON CROSS SECTIONSUSED IN DOSIMETRY - W.G. Cross and H. Ing

In determining average fast neutron cross sectionsover distributed spectra - e.g. or fission neutrons thathave passed through moderating material - it is convenientto work with analytical expressions of the cross sectionas a function of energy. We find that sums of "smoothedstep functions" (1/(1+(E/Ei)

n) and Gaussian functions aremor^ useful for this purpose than polynomial series,mainly because each term of the sum varies only over ar^ctricted energy region, making it easy to adjust the fitnear a particular energy without affecting agreement inother parts of the spectrum. Such series have been usedto fit the fission cross sections of 23BU, z3'Th and 237Np,the (n,n') cross sections of 1°3Rh and 115In and the (n,p)cross sections of 58Ni, 32S and 61tZn. Data were selectedfrom recent evaluations and experimental results.Expressions that fit well within the accuracy of the data,from the threshold to 15 MeV, are simple enough for usewith programmable desk calculators.

2.9 SPECTRA AND DOSIMETRY OF BEAMS OF FISSION NEUTRONSPENETRATING WATER - W.G. Cross and H. Ing

Spectra of neutrons at various depths in a water"slab", 30 cm thick, when a beam of fission neutrons isincident normally on one face, have been calculated usingthe 05R Monte Carlo code. About 500,000 neutronhistories were followed. Spectra of fluence and currentwere obtained at 5 cm intervals in depth, for neutronsdirected in both the forward and backward hemispheres.Angular distributions of 3 energy groups were alsoobtained. In comparison with spectra of fission neutronsescaping from H20 spheres having a central point source(AECL-4765 (PR-B-100)), spectra of neutron beams containfewer low energy neutrons - the difference at 30 cmpenetration approaching a factor of 2 below 10 keV - butthe same number of neutrons above 3 MeV. Cross sectionsof threshold detectors used in dosimetry, averaged overthese spectra, differ in sphere and beam geometry by 10to 25%, for the same distance of penetration in H20.However the ratios of cross section to dose, which determinethe accuracy of dose measurements with these detectors,differ by a maximum of 17% (for Ni and S) and by less than5% for Rh, In and Np detectors.

2.10 THERMOLUMINESCENCE DOSIMETRY - A.R. Jones

The TLD reader AEP-5256 has been redesigned to suitthe requirements of Ontario Hydro and Health and WelfareCanada. The major changes are

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- the replacement of a mechanical hole-codereader by a photo-electric ona which identifies a 10digit plaque to allow the use of Social Insurance Numbersas well as the 5-digit plaque used by AECL. The photo-electric reader is also faster.

- the replacement of an electromagnetic proximityswitch (made by a singla manufacturer) by a photo-electric one available from several sources.

- The replacement of the existing thermo-electriccooler by a simpler and cheaper one employing airrather than water cooling.

These and the accompanying changes to electroniccircuits have been cested in the laboratory prototypeand in a conversion performed on the TLD reader belongingto Ontario Hydro.

A 10 digit plaque has been designed and tested inthe modified readers. In addition to mechanical changesthe new plaque is provided with a 0.015" thick TLD formeasuring skin doses rather than the original 0.010"thick ones. The change was introduced because the thickerTLDs are cheaper, more uniform and less fragile. Inaddition the availability of the 0.010" TLDs is uncertain.Because the thicker TLDs are more sensitive, they areless affected by contamination. However their sensitivityis more dependent on beta radiation energy.

Samples of the new plaques have been made usingaluminum (used previously) and ABS plastic. Both kindswere subjected to more than 100 cycles of readings,including 10 cycles of exposure. The plastic plaquedosimeters were less sensitive (10 - 20%) and exhibiteda detectable decline (20% in 50 cycles) in sensitivityduring cycling. The aluminum plaques showed no detectabledecline as compared with controls which were not cycled.These results agree with a previous comparison made withTLDs mounted on aluminum or phenolic plaques. It ispossible that the difference in performance may lie inthe different cooling rates for TLDs mounted in plasticand aluminum plaques.

The variation in sensitivity between dosimeters wasless for aluminum than for the ABS plastic ones. Despitetheir advantage of lightness, the plastic plaques wereshown to have poorer performance and for this reasonaluminum plaques will continue to be used.

Non-radioactive contamination of TLDs has posed themost serious problem in the operation of the TLD servicesince its introduction in January 1972. Dirt can causeover estimates of small doses and fouling of the TLDreader optics. TI a problem has been attacked in twodifferent ways.

- an effective and harmless ultrasonic cleaningtechnique has been developed.

- the design of a new TLD dosimeter holder hasbegun. A laboratory prototype holder was made whicheffectively excluded dirt. Also it was easily openedwith a special tool while it was difficult to openwithout the tool, either accidentally or otherwise.Woodbridge Moulded Products Ltd., have contracted todesign a similar TLD holder together with the toolingneeded to mould it from high impact styrene. A secondmodel has been fabricated from the drawings uiade underthe contract and it was found inferior to the originalwith respect to dirt exclusion and the locking mechanism.Further work by Woodbridge Moulded Products is in progress.

A detailed manual for the use and maintenance of theTLD reader and dosimeter system has been finished.

Environmental y monitoring continues at CRNL andCommercial Products on a quarterly basis and a commitmenthas been made to extend this service to McMasterUniversity using packages of 4 TLD-100 solid dosimeterspreannealed according to the manufacturer's instructions.This technique is satisfactory, from the view point ofperformance, but is time consuming so an alternativetechnique is under study where two 0.035" TLDs aremounted on the plaque used for personnel dosimetry andthen rend in the automatic TLD reader operated at highgain. The following advantages are gained: less effortis spent in reading; the readings are identified bynumber; because each dosimeter is identified it isconvenient to apply automatically individual responsecorrections. The first problem to overcome is fading.Because of the materials used in the plaque the TLDscannot be preannealed according to the manufacturer'sinstructions. In fact the personnel dosimeters are notpreannealed at all. However a modified preanneal at 80°Cfor 16 hours (i.e. overnight) has been tried and comparedwith unannealed plaques and separate TLDs annealedaccording to the manufacturer's instructions. Fading testswere done at 4 temperatures between 50 and 100°C and ineach case the annealed plaques faded least, the unannealedplagues the most and the separate annealed TLDs were inbetween. This does not prove that the annealed plaqueswill fade the least at room temperature (although it is astrong indication that this is so) and longer roomtemperature tests will be performed.

The second question to be settled was that of theprecision attainable at the low levels of exposuremeasured in 90 days of environmental y monitoring. Thestandard deviations of a group of the pairs of TLDs weremeasured at exposures in the range 10 - 100 mR. Theseresults are given in the table below.

- 21 -

Percent Standard Deviation

Exposure mR Calibrated Uncalibrated

100 3.1 4.950 4.0 5.325 5.3 6.510 8.4 8.9

The standard deviations in the first column wereobtained by correcting for individual dosimeter variation.It can be seen that a small improvement results and thatthe precision is adequate for low-level monitoring.

TLD packages, similar to those for environmentalmeasurements, were exposed at the University of Texasas part of an intercomparison between different TLDmonitoring systems. One group of TLDs were exposed toa known exposure in the laboratory and a second groupwere exposed for 90 days to environmental y"raYs, out ofdoors. The exposed TLDs have been received and theexposures determined. However the promised data on theknown exposures and on results obtained by other participantshave not yet been received.

2.11 AMPLIFYING RADIATION DETECTORS - A.R. Jones

A contract was awarded to RCA for the production of15 sample detectors and for their life testing. Thepurposes of the contract were

- to determine the yield of satisfactory detectorsper wafer, out of a possible twelve. This yield has amajor influence on the production costs and hence theapplication of the detectors.

- to demonstrate the reliability and life of thedetectors.

- to devise suitable tests by the manufacturer whichwould guarantee adequate performance of the detectors.

Fifteen detectors which meet the required specificationfor gain (between 10 and 20 and at 200 V bias) and noise(less than 0.1 count/second above a discriminator levelof 120 keV) have been received. The manufacturer'sperformance has been verified and further tests on thedetector sensitivities to high and low energy y-rays andft-rays have been measured. These sensitivities do not varymuch from one detector to another.

Ten detectors have been returned to RCA where fivewill be kept at an elevated temperature, while biassed,for 90 days and the other five controls will be biassedat room temperature. The five remaining at CRNL will bo

- u -cycled 10 times between - 30 and +50°C. After the15 detectors have been subjected to these tests thesame performance measurements will be repeated todetermine any changes.

One unexpected result noted with the detectorsis good resolution at room temperature (-1 keV at 5.9keV X-ray energy) which implies both low noise andhigh gain uniformity over the sensitive area. Althoughthe detectors were developed for dosimetry the resultsshow that the detectors could be used for spectrometry,or counting in restricted energy bands to discriminatebetween X-rays of different energies, in the energyrange 5-20 keV. One possible application is X-rayfluorescence analysis. A second is the determinationof the tiesue depth of a plutonium source by comparisonof the intensities of the three X-rays at 14, 17 and 21keV which are well resolved.

2.12 LIFE TESTING OF GEIGER COUNTERS - A.R. Jones

A series of life tests on large area organicquenched counters and on small halogen-quenched counterswere completed. They demonstrated a potential longworking life for organic-quenched counters under certainrestricted conditions i.e. - low duty cycle or lowbackground operation.

Conversely the tests demonstrated a limited life(-lO11 counts or -103 hours at 100 R/hour) for one typeof counter (Philips type 18529) widely used in portableand area monitors. This hardly poses a problem for portableinstruments since a user's life would be even more limitedbut it is important in area monitors placed in areas ofhigh exposure rate from which personnel are excluded duringreactor operation. The damage does not occur if thecounters are unbiassed so that this problem can be solvedby switching off the monitors.

The results also showed that ITT counters, ofsimilar sensitivity were not so sensitive to radiationdamage and neither were amplifying radiation detectors.

2.13 A LINEAR COUNTING RATE CIRCUIT WITH VARIABLE TIMECONSTANTS - A.R. Jones

For radiation monitoring, it is desirable that theRC smoothing time constants vary inversely with thecounting rate. Then, the statistical fluctuation,expressed as a percentage of the mean value, is independentof the counting rate. The speed of response is rapid athigh counting rates (which are generally associated witha high hazard) and is slower at low counting rates.

- 23 -

This is particularly useful when many decades arecovered with a single scale. This principle is embodiedin the logarithmic rate meters used in the Portable AreaMonitor AEP-5233 and the Environmental Gamma MonitorAEP-5247.

With the advent of 3-and 4-digit, digital panelmeters it is now practicable to span several decades witha single linear count rate circuit. A linear countingrate circuit has been designed for measuring random ornon-random repetition rates up to 10 kHz. A choice ofstatistical precision is achievable (3 or 12% standarddeviation) by changing the smoothing capacitor. Theseprecisions were verified over the range 10 Hz to 1 kHz butat 10 kHz the standard deviations both decreased becauseof the presence of a short fixed time constant. This isa useful modification of the principle because there islittle point in reducing the response time much belowhuman response times and the added precision is welcomeat very high count rates. In addition, the dynamicresponse of the circuit to changing repetition rates wasalso verified.

2.14 APPLICATION OF THE ANALOG TO DIGITAL CONVERTER TORADIATION DOSIMETRY - A.R. Jones

An analog to digital converter (ADC) was designedfor converting the photomultiplier current of the TLDreader to a train of pulses whose frequency is proportionalto the current over a wide range (10" - 10"''A). Thecircuit, in principle, could be usefully employed withradiation detectors such as a photo-multiplier-scintillatorcombinations and ion chambers. The pulse rate andintegrated pulse count would be in a convenient form formeasuring dose rate and dose respectively. Furthermorethe signal level is raised and the pulses could be trans-mitted over long cables.

To miniaturize the circuit, the Electronics Branchrepackaged it in hybrid form. Tests performed on thehybrid versions showed that the hybrid circuits functionedin the same way as the original discrete circuit whenallowance was made for different stray capacities. Thesample hybrid circuits performance verified over thetemperature range -20 to +20°C.

The ADC was then tested with a photomultiplier andplastic scintillator operated with only five dynodes, andwas found to be linear up to an exposure rate of 2,400 R/h.Since the detector was useful at quite high exposure rates,the ADC was tested for sensitivity to radiation damage.For this test it was fed with a stable input current andits output frequency (which could be measured quiteaccurately) was monitored as a function of exposure. Ashift in frequency of about 0.1% was detected after anexposure of 10R and after 3,000R the frequency had decreasedby 15%.

- 24 -

These results showed that the ADC was unsuited tothis application. An examination of the circuit showedthat the change was due to a shift in the thresholdvoltage of the metal-oxide-semiconductor transistor usedin the circuit input and the shift appears to be permanent.The same phenomenon was also noticed in two other circuitsusing MOS transistors. These transistors are widely usedin radiation monitors because of their high independanceand low power consumption but it is clear that this highsensitivity to radiation damage must be kept in mind. Thelack of stability of the ADC can be useful for studyingradiation damage and also raises the possibility of usingit as a passive radiation dosimeter since the change infrequency is proportional to exposure.

2.15 SPECTROSCOPY OF ENVIRONMENTAL GAMMA RADIATION - A.R. Jones

If we are required to monitor small increases inannual background radiation (less than 10 mR/year)conventional methods of radiation dosimetry will beseverely taxed because of the requirements of long-termstability and precision and because of fluctuation dueto natural causes. If any increases in dose rate can bebroken down into intervals of photon energies theserequirements may be considerably relaxed. A program hasbeen started to evaluate scintillation and germaniumspectrometers from the view point of sensitivity andstability. In addition it is intended to evaluate silicondetectors used as compton spectrometers.

2.16 MEASUREMENTS OF THE EFFICIENCY OF THE PLUTONIUM-IN-AIRMONITOR - A.R. Jones

The plutonium-in-air monitors are calibrated andtested with a prepared plutonium-source and measurementsare being made with uranium oxide powder collected onfilter paper to establish the safest energy window forcounting plutonium-239. At present the window is set at4-5 MeV which is satisfactory for a prepared plutonium-source. Measurements with the uranium show that a 2-5MeV window would permit counting even with a spectrumhighly degraded by burying in dust, filter papers or inbig particles. However further tests are needed todemonstrate that the wide window will cause an unacceptablehigh rate of spurious trips from radon daughters.

2.17 MISCELLANEOUS INSTRUMENT DEVELOPMENTS - A.R. Jones

2.17.1 Thin Window Portable Contamination Monitor

The existing portable contamination meter AEP-5227and portable contamination rate meter AEP-2160 can beequipped with either small area end window counters, withthin windows (~4 mg/cm2) or with larger side wall counters

- Z5 -

("30 mg/cm^). Development of the personal contaminationmeter has demonstrated the usefulness of a larqe area(50 cm2) counter with a thin window (7 or 13 mg/cm2).

A portable monitor using this counter is beingdeveloped which could permit more rapitf and efficientmonitoring of large surfaces. It is equipped with adigital display and makes use of the count rate circuitwith variable time constant, described in Section 2.13.A laboratory prototype is being built.

2.17.2 Multichannel Area Monitor AEP-5289

A laboratory prototype has been built and tested andis ready for mechanical design using modules whosemechanical components are commercially available. Themonitor has been tested with a low sensitivity counterpermitting operation over the range 10 mrad/h to 100 rad/hinstead of the original range of 1 mrad/h to 100 rad/h.

A source which can be attached to the head unit andoperated remotely from a control room to test the alarmcircuits and calibrate all head units is being designed.

2.17.3 Geiger Counter Laundry Monitor

The laboratory-built monitor is being evaluated byusers at CRNL.

2.17.4 Wide Range By Survey Meter AEP-5288

The laboratory prototype has been field tested atCRNL and Pickering Generating Station and is presently beingtested at Bruce Generating Station.

2.17.5 Fuel Element a Monitor

The monitor has been assembled/ tested and calibrated.It is being reassembled in the plutonium laboratory afterwhich final tests will be carried out.

2.17.6 Digital Warning Dosimeter AEP-5278

The dosimeter was completed in the first quarterof 1974 and eight are being made by Canadian Admiral. Amanual is in preparation.

2.17.7 Uranium Oxide Level Monitor

This monitor now completed detects the absence ofuranium oxide in the feed line of a fuel pelletisingmachine.

2.18 TRITIUM MONITORING - R.V. Osborne, A.S. Coveart,N.W. Tepley and A.P. Prini

Detailing of designs has been the major task during

the year in the development of the set of instrumentsfor monitoring tritium that were described in the lastsummary (AECL-4765, PR-B-100). Drawings formanufacturing the tritium-in-air monitor AEP-5275 havebeen completed and a contract for the manufacture of thefi.vst five units for Bruce Generating Station has beenplaced by Power Projects. Associated with this monitoras a self-contained unit is the calibrator AEP-5284; thedesign of this has been detailed and engineering drawingsare complete. The other tritium-in-air monitor, AEP-5270,that is designed to be moved between places not sampledby a central AEP-5275 monitor has nearly reached the stageof a laboratory prototype. Two changes to the design ofthe portable air monitor AEP-5215 have been made in responseto problems experienced by users of manufactured instrumentsof this type.

2.18.1 AEF-5275

The monitor AEP-5275 collects a sample of tritiatedwater vapour from air in a stream of water that subsequentlyflows through a stack of scintillator sheets in ascintillation counter. This method has been chosen toallow tritium to be detected when radioactive noble gasesare also in the sample air. To attain the desiredinsensitivity to the noble gases, purging of the tritiatedwater stream is needed to reduce their concentration in thewater flowing to the detector. The main changes made tothis sample handling technique in the prototype monitorhave been to allow a small fraction of the purge air topass through the detector and to use individual pumps forthe sample aii. and water istreains. The former change, althouglreducing the effectiveness of the purge stage, results ina more rapid and stable transfer of water from purger todetector than was attained with the previous gravity feedmethod. Pumps, as items needing frequent maintenance, hadnot been included in the prototype monitor since water andpurge air were supplied at high enough pressures for flowcontrol by pressure regulators and needle valves, andsuction at the outlet provided the 'head' for sample flowcontrol. However long-term stability of the sample anr1

water flows were inadequate. A metal bellows air pump anda positive displacement water metering pump have thereforebeen included.

Other changes made in the process system have beenthe inclusion of buffers to prevent water reaching pressuregauges and switches during alsnormal flow conditions, theaddition of purge and water flow sensors as part of thefault monitoring system and the addition of a manual 'reset'on solenoid valves that isolate the instrument if abnormalpressures are sensed at inputs or outputs. The last changeensures that transient excursions are noticed and preventson/off oscillations if the cause of the oscillation is ablockage within the instrument.

The control and signal processing circuitry has been

- 27 -

laid out on plug-in printed circuit boards. Two of thesecircuits that have similar functions to two in the othertritium monitor, AEP-5270, have been modified so that theyare interchangeable between the two instruments. Thisreflects the general approach in all the current designs oftritium monitor, to minimize the number of differentcomponents and assemblies. Other examples of common unitsin these two instruments are in the use of similar digitaldisplays, pressure sensors and air pumps.

Design for the remote display units has been completed.An analog meter relay indicates the measured tritiumconcentration and provides for an independent tritium alarmset-point. Occurrence of an instrument fault is alsoindicated on the unit.

2.18.2 AEP-5284

The output from a calibrator, AEP-5284, is sampledperiodically by the sampling system of AEP-5275. Thetritiated water vapour is provided at a dew point of 10°C+

0.05°C for an ambient temperature range from 13°C to 40°C.It is obtained by bubbling air through a water bubblerwhich is cooled by a frigistcr. A bridge circuit containinga thermistor sensing the temperature inside the containerprovides an error signal to drive the frigistor. Ratherthan use a linear amplifier to drive the frigistor whichwould necessitate providing the capability for heatdissipation in the output stages similar to that r>f thefrigistor, a variable duty saturating switch is used. Thisis accomplished by controlling with the error signal thewidth of the pulses, and hence the duty cycle, of a constantfrequency pulse train. The smoothed output derived fromthe output switching transistor drives the frigistor. Awarning signal, indicating loss of temperature control isavailable and, in this application, is linked to theinstrument fault circuits of the AEP-5275.

2.18.3 AEP-5270

h laboratory prototype of the tritium-in-air monitorAEP-5270 is completed. This instrument determines thetritium concentration by measuring the difference inionization current in two identical chambers, one samplingthe air directly, the other after the (tritiated) watervapour has been removed. The value of the net ionizationcurrent is converted to a pulse frequency so that subsequentsignal processing is digital and is with circuits similarto (identical in two cases as noted above) those in theAEP-5275. As with all the currently designed instruments,controls accessible to the casual user are kept to aminimum and only affect the circuits while a user isoperating the controls. For example alarm test switcheswhen released cause the circuits to revert to the normaloperating modes. Although this restriction complicatescircuit design, control of the instruments is simplified forthe user and incorrect operation or adjustment is inhibited.

- IS -

The monitor AEP-5279 has been designed to be portablein the sense that although normally line-operated, it canbe readily wheeled from place to place without interruptinqits operation. All power supplies are therefore derivedfrom a single 12V battery which has sufficient capacity tomaintain operation for at least 30 minutes without charging.The vacuum pump that maintains the continuous purge of theair drying system operates directly from line but the dryershave sufficient drying capacity to remove water vapour forthis time without purging.

Nickel-plated aluminum has been used for the ionizationchamoer electrodes. Absorption of water on this type ofsurface appears to be much lower than on aluminum as usedin the lightweight portable air monitor AEP-5215. As aresult the "memory" when measuring changes in concentrationof tritiated water vapour has been reduced as has theenhanced sensitivity at low relative humidities when tritiumin the absorbed water contributes disproportionately to thetotal ionization. The latter effect is now only a fewpercent even at relative humidities in the 2-5% range. Rapidchanges in relative humidity are expected, theoretically, toresult in transient current pulses from ionization chambersbecause of the rate of change of dielectric constant and,hence, of chamber capacity. The magnitude of this effect hasbeen verified experimentally and is equivalent to an averagereading of approximately 8 (MPC)a for a change from 80% to10% relative humidity in 10 s. This transient effect isunlikely to be of practical concern in normal monitoringapplications.

2.18.4 AEP-5215

The portable monitor AEP-5215 is now being manufacturedand feedback from users has prompted two changes. The biascurrent at the input of the electrometer has the oppositepolarity to that of the ionization current from the tritiummeasuring chamber. Although this is generally less than 5fAit is sufficient to take the output meter reading below zeroand just off scale. Changing the chamber polarity wouldresult in a more acceptable on-scale reading (of less than0.5(MPC)a) but would necessitate reversal of the polarity ofthe logarithmic conversion circuit. The simpler solutionfollowed has been to extend the output linear scale to -1(MPC)a.

The second change is in the time constant of the electro-meter. After selection of the most sensitive range on thecurrent model a reading cannot be obtained for about 15 swhile the electrometer recovers from the switching transient.This recovery time has been reduced an order of magnitude bychanging the feedback resistor from 5T0 to lTfi, halving thefeedback capacitance, and adding a voltage gain of 5 tomaintain the same sensitivity. The penalties are an increasedzero drift and increased noise. The former does not presenta practical problem; the latter can be reduced by capacitivedamping of the meter. The operating time of the meter protectioncircuit that isolates the meter after range changing can now

- 29 -

be reduced to about 3 s.

2.18.5 Miscellaneous Instruments for Tritium Detection

Users of other tritium monitors have been u ;lped invarious ways; recomissioning of the central monitoringsystem at Douglas Point Generating Station has been directed.Also at Douglas Point an additional water effluent monitorhas been commissioned and technical staff there trained inits operation.

The requirements for future autourinalysers (AEP-5216)have been discussed with current users and assistance givenin drawing up specifications for units suitable for BruceGenerating Station and subsequent stations.

A review of methods for measuring tritium has beencompleted as a contribution to an NCRP report on tritiun.One of the most sensitive methods is the mass spectrometricmeasurement of 3He accumulated in a confined tritiatedsample IClark, W.B. and Kugler, G; Economic Geology 6J , 243-251) and possible applications of this technique have alsobeen reviewed. The method appears very well suited forlaboratory measurements of environmental samples, beingcapable of detecting concentrations in water down to theorder of 100 fCi/H , although sample storage times of severalmonths are needed to reach this sensitivity. "On-line"sampling with effective sample storage time of only a fewminutes in principle gives greater sensitivity than attainablewith current monitors. However capital costs would, certainlybe higher and the practical problems in preparing on-linesamples are not yet known.

2.19 ELECTRON ENERGY LOSS IN THIN ORGANIC FILMS - R.V. Osborneand A.P. Prini

Performance of the 1 keV electron gun, filter lensanalyser, faraday cup and phase sensitive amplifier arenow reproducible and peak half-widths less than 0.7 V areattained. A technique for preparing formvar films of theorder of 10 nm has been developed but so far the life-timeof those films in the beam has been too short for measurements.This is probably due to absorption of the periphery of thebeam spot by the edge of the specimen aperture. A beam-defining aperture for the specimen holder may be needed;initially however, improvement in the beam focussing is beingattempted.

2.20 DETECTION OF 131I IN AIR - R.M. Holford

The engineering drawings for the Iodine-in-air monitor,AEP-5217 are being revised. Further operating experience inthe vicinity of an operating reactor will be gathered usingthe modified instrument.

- .JO -

2.21 DETECTION OF 1 2 5I IN AIR - R.M. Holford

Design of the electronic part of a monitor designedspecifically for 1 2 5 I , AEP-5285, has now been completed anddrafting work is in progress. It is intended for use witha scintillation detector, chosen to suit the type of samplesencountered in a specific application, and a commercial high-voltage power supply. Two detectors which have beenobtained for evaluation are a 6.2 5 cm diameter, 3 mm thick,planar sodium iodide crystal intended for general applications,and a thin-window well-counter for counting of charcoal filledcapsules.

The range of 1 2 5I activities is from 10 to 10G dps(27 uCi) for sources counted at high efficiency. Even higheractivities can be estimated by using spacers between thesource and a planar detector to lower the counting efficiency,but in this case the automatic compensation for countingefficiency and self absorption, which is a special feature ofthe instrument, is not useable.

2.22 ANALYSIS OF SUCROSE GRADIENT CENTRIFUGATION DATA -R.M. Holford

A measurement of the rate of sedimentation of nucleicacid molecules through an aqueous solution is often used inmolecular biology as a way of estimating the relative sizesof molecules. To obtain reproducible results the solutionhas to be stabilized against convection by the addition ofsucrose, and this is usually done in such a way that thereis a linear increase in sucrose concentration from the top tothe bottom of the centrifuge tube. At the end of an experimentthe total distance travelled by various groups of moleculesis measured, and the experimenter needs to determine fromthis the standard sedimentation co-efficient for each group.Since the rate of sedimentation is not constant and themathematical procedure for this is fairly involved, a programhas been written to carry it out on a HP Model 9820programmable calculator. This has resulted in a large savingin time, and also probably, an increase in accuracy, althoughthis is difficult to estimate with certainty.

2.2 3 ANALYSIS OF ARGON-41 CONCENTRATION DATA FROM METEOROLOGICALRECORDS - R.M. Holford

Simple models for the dispersion of radio-nuclides froma stack into the environment are useful both as a way ofsummari zing experimental results and as a means for predictingthe effects of a major release of activity. A large body ofexperimental data has been collected at CRNL over the past10 years giving the ground-level Argon-41 concentration inair at a number of sampling points a mile or so from the stackfrom which it is released, and also associated meteorologicaldata. The current analysis has the aim of explaining theobserved probability distribution of the results, which is anexponential one with an excess of zero values, and of

- 31 -

suggesting the most efficient way in which additionalsamples could be used.

Since dispersion of the Argon-41 is obviously determinedby the properties of the wind, its direction, speed anddegree of turbulence, these have been examined as a firststep. At CRNL there is strong channelling of the wind intothe direction of the Ottawa River, approximately NW to SE.If the wind is treated as a vector and split into componentsparallel and perpendicular to the river, then these twocomponents fit a bivariate normal distribution fairly closely.Another property of the wind, which is of interest whendifferent sampling and averaging periods are compared, is theauto-correlation function (coherence), or its Fourriertransform, the power spectral density. For intervals of afew hours the auto-correlation is approximately a decreasingexponential function with a time constant of about 10 hours.For longer periods a positive concentration tends to persist,along with a strong 24 hour periodicity. To reach a truezero a very long period would be required since, for instance,a significant correlation at an interval of a year might beexpected. This persistence of correlation explainsqualitatively why quite long perieJs without detection of anysignificant amount of Argon-41 can be found in the records,but an exact mathematical expression of this relationship hasnot yet been obtained.

In the literature, a Gaussian model is usually used todescribe the structure of a plume for a given set of windconditions. Such a model cannot explain exactly the observedprobability distribution of Argon concentration since itpredicts a mathematically non-zero concentration for any setof wind conditions. If the Gaussian model is replaced by arectangular one, the zeros can be produced, and the observed. distribution should be a result of the probabilitydistribution of the parameters of the model. This isinsufficient to explain,however, why the observed type ofdistribution is found in almost all situations.

2.24 ARGON-41 DETECTION IN AIR - R.M. Holford

Argon-41 concentrations are measured by the detectionof the beta radiation in sheets of thin scintillator mountedin a closed volume through which the air is circulated. Thedesign has been reviewed in an attempt to improve theperformance of the detector at low argon concentrations.Changes in scintillator area and thickness and volume of theenclosed air sample are possible factors that could bechanged. However since background interactions are theresult of secondary electrons generated in the containerrather than in the scintillator itself changes in scintillatorthickness are not effective. Increases in scintillator areaand volume of contained air could be productive but expensivesince the apparatus already uses a 23 cm dia. photomultiplier.An upper limit of dimensions set by the range of beta particlesin air is unlikely to be reached since a counter of suchdimensions would impose severe pumping power requirements ina situation where batterv operations mav be reeded.

- 32 -

2.25 ROUTINE DOSE MONITORING - R.M. Rondeau and L.S. L-arkin

Body Radiation Doses

In the calendar year and in the fourteen week periodup to November 22 there was the following distributions ofradiation exposure.

- 33 -

Penetrating Radiation Doses - CRNL

DoseRangerems

No radiationless than 0.490. 50 - 0.991.00 - 1.491.50 - 1.992.00 - 2.492.50 - 2.993.00 - 3.493.50 - 3.994.00 - 4.494.50 - 4.99

Average doseper monitoredperson

Average doseper exposed

| person

Fourteen Weeks

No. ofmonitoredpersons

392525103153

TotalDose

Man-rem

0157.7567.9017.775.03

9 3 mrem

94 mrem

Calendar Year

No ofmonitoredpersons

23221919511260381911431

303

306

TotalDose

Man-rem

0229.68140.76136.80103.4484.1151.5735.7914.9312. b-4.31

mrem

mrem

Penetrating Radiation Doses - CP

DoseRangerems

No radiationless than 0.490.50 - 0.991.00 - 1.491.50 - 1.992.00 - 2.492.50 - 2.99


Average Doseper exposedperson

Fourteen Weeks


21202101

TotalDose

Man-rem

017.356.171.02

105 mrem

115 mrem

Calendar Year


12178278522

TotalDose

Mar.-rem0

20.7617.649.933.444.075.13

232 mrem

297 mrem

- 34 -

Penetrating Radiation Doses - PP

DoseRangerems

Nfo radiationless than 0.490.50 - 0.991.00 - 1.491.50 - 1.992.0 0 • 2.492.50 - 2.99o.00 - 3.493.50 - 3.994.00 - 4.49


I Average doseper exposed

1 person

Fourteen Weeks


63543213211

TotalDose

man-rem

04.275.642.091.956.895.253.103.85

2 36 mrem

4 59 mrem

Calendar Year


278879123201

TotalDose

man-rern

08.535.19

11.261.534.898.076.3504.13

357 mrem

4 42 mrem

- 35 -

Surface Radiation Doses - CRNL

Dose

Rangerems

No radiationless than 0.490.50 - 0.991.00 - 1.491.50 - 1.992.00 - 2.492.50 - 2.993.00 - 3.493.50 - 3.994.00 - 4.494.5 0 - 4 995.00 - 5.495.50-5 996.00 - 6.496.50 - 6.997.50 - 8.00


Average doseper exposedperson

Fourteen


39244715239512

Weeks

TotalDose

man-rem

0159.108.46825

12 3 mrem

125 mrem

119934732431

Calendar Year

No, ofmonitored •persons

23213018611184354531219412111

TotalDose

man-rem

0226.134.138.143.78.122.100.78.38.19.5.

11.6.6.7.

417 mrem

4 20 mrem

304520945183386136074452508871

- 36 -

Surface Radiation Doses - CP

DoseRangeretis

No radiationless than 0.490.50 - 0.991.00 - 1.491.50 - 1.992.00 - 2.492.50 - 2.993.00 - 3.493.50 - 3.99



; Fourteen Weeks

! No. ofmonitoredpersons

0189176

i;

1

, 179

197

j Total! Dose

man-rem

' 019.9012.596.68

2.76i

j

mrem

mrem

Calendar Year


1215339984351

460

485

TotalDose

man-rem

017. 3728.1211.0213.709.268.32

16.173.71

mrem

mrem

Surface Radiation Doses - PP

DoseRangereras

No radiationless than 0.490.50 - 0.991.00 - 1.491.50 - 1.992.00 - 2.492.50 - 2.99

i 3.00 - 3.493.50 - 3.994.00 - 4.49

Average doseper monitored

; person


Fourteen


68529213311

Weeks

TotalDose

man-rem

04.355.982.411.556.748.313.253.97

261 mrom

508 mrem

Calendar Year

No. of |monitored 'persons

27C5105413401

404

500

TotalDose

man-rem

08.837.166.826.552.217.9412.7704.24

mrem

mrem

In the fourteen week period ending November 22the 60 0 mrem control limit for 2-wsekly whole bodyradiation exposure was exceeded on five occasions byCRKL workers and on fourteen occasions by Power Pro-jects workers. The 1600 mrem control limit for surfaceradiation exposure was exceeded on ten occasions byPower Projects workers.

Hand Radiation Doses

In the Calendar year and in the fourteen weekperiod up to November 22 there was the followingdistribution of extremity doses as measured by fingertip TLDs.

Persons ExposedCalendar Year

:RNL

2411812681

CP Ii" ~ r ~1724512

in

PP

810---—

Persons Exposed inFourteen Weeks

Dose range rems CRNL CP PP

less than 0.49 11 3 00.50 - 1.99 41 9 42.00 - 3.99 5 2 -4.00 - 5.99 5 3 -6.00-11.99 1 112.00 - 19.99 -20.00 - 29.00 -

2.26 PUBLICATIONS

W.G. Cross, Canadian Progress Report to the NEANDC,EANDC(Can)-47L

W.G. Cross an 3 H. Ing, Prediction of Fast NeutronSpectra in Criticality Accidents; in NeutronMonitoring for Radiation Protection Purposes;Vol. I, IAEA, Vienna 1973, p. 73

W.G. Cross and L. Tonunasino, Factors Affecting theAccuracy of Spark Counting of Fission FragmentDamage Track Detectors. Proceedings of theInternational Conference on Nuclear Photographyand Solid State Track Detectors. Bucharest.1972, M. Nicolae, Ed., Vol. II, p. 440.

W.G. Cross, Canadian Progress Report to the INDC,INDC(Can)-14G.

H. Ing, Mathematics in Health Physics in Proc. ofMathematics in Today's World (Science Council ofCanada, Ottawa, 1974) p. 171.

H. Ing and W.G. Cross, Informal Report to IAEA; ResearchAgreement RC/920-CAN, Atomic Energy of CanadaLimited Unpublished Internal Report, CRNL-1130.

A.R. Jones, Measurement of Low Level Environmentaly-Doses with TLDs and Geiger Counters, AECL-4786,IEEE Transactions on Nuclear Science, NS21,February 1974

- 39 -

A.R. Jones and P. Webb, Large Area Reach-ThroughAvalanche Diodes for Radiation Monitoring,AECL-4787, February 1974.

A.R. Jones, A Manual for the Use and Repair of thePersonal Contamination Monitor AEP-5276, CRNL-1163, August 1974.

R.V. Osborne, Measurement of Tritium by Detecting3Ke in a Mass Spectrometer, CRNL-1142, 1974.

R.V. Osborne, SI Units in Radiology and RadiationMeasurements. Brit. Jour, of Radiology, 47,296, 1974.

R.V. Osborne, Methods for Measuring Tritium, CRNL-1178, 1974.

2.2 7 VERBAL PRESENTATIONS

2.27.1 Lectures and Seminars

W.G. Cross and H. Ing, Neutron Dose Measurement byElectrolytic Conductance in Fission FragmentDamage Tracks, Health Physics Society AnnualMeeting, Houston, Texas, July 1974.

H. Ing and W.G. Cross, Dosimetry Associated withNeutron Irradiations of the Human Body, CAPAnnual Congress, St. John's, Newfoundland,June 1974.

H. Ing and W.G. Cross, Spectra and Dosimetry of FastNeutrons Transmitted Through Fe Shields, HealthPhysics Society Annual Meeting, Houston, Texas,July 1974.

H. Ing, Application of Neutron Spectra to CriticalityAccident Dosimetry, Eleventh Dosimetry Inter-comparison, Oak Ridge National Laboratories,July 29-August 9, 1974.

A.R. Jones, Application of Large Area Organic QuenchedGeiger Counters to Radiation Monitoring, IEEENuclear Science Symposium and 14th Scintillationand Semiconductor Counter Symposium, Washington,D.C., December 11-13, 1974.

R.V. Osborne, Central Tritium Monitor for CANDU NuclearPower Stations, IEEE Nuclear Science Symposiumand 14th Scintillation and Semiconductor CounterSymposium, Washington, D.C., December 11-13, 1974.

- 41 -

ENVIRONMENTAL RESEARCH BRANCH

I.L. Ophel

3.1 Staff3.2 Studies on Sub-Lethal Effects of Heated Water on Aquatic

Organisms3.3 Chemistry of Lake Sediments3.4 Beneficial uses of "waste Heat3.5 Experimental Studies with Radionuclides3.6 Aquatic Radioecology and Freshwater Biology

3.6.1 Stable Element Analysis3.6.2 60Co and 90Sr in Perch Lake3.6.3 Effects of Water Chemistry and Food Composition on

the Accumulation o£ Calcium and Strontium by Fish3.7 St. Lawrence River Studies3.8 Radiation Effects

3.8.1 Effects of Internally Deposited Radionuclides in Fishon the Incipient Lethal Level of Dissolved Oxygen

3-9 Culture of Zebra Fish3.10 Perch Lake Evaporation Study3.11 cross-Canada Evaporation Experiment3.12 Atmospheric Diffusion Studies3.13 Neutron Activation Analysis3.14 waste Management3.15 Perch Lake International Hydrological Decade program3.16 Cooperative Programs

3.16.1 Chalk River Environmental Authority3.16.2 Hydro-Quebec3.16.3 Environmental Protection Service of Environment Canada

3.17 Tritium in Vegetation of the Perch Lake Disposal Area3.18 Natural Deuterium Concentrations in the vicinity of the

LaPrade Heavy Water Plant3.19 Mixing of Waters in the St. Lawrence Estuary3.20 Evaporation-Exchange in the Emergency Holding Basin

3 . 2 1 Environmental isotope Hydrology of Ground Water Systems3.21.1 East Side of Perch Lake Basin3.21.2 Camp Borden, Ontario, Sanitary-Fill Study3.21.3 Mayne Island, British Columbia

3.22 Gamma Dose Rates at the CRNL Boundary3.2 3 Gamma Dose Rates in the Exclusion Area3.24 Off-Site Monitoring3.25 Liquid Effluent Monitoring3.26 Liquid Disposal Area3.2 7 water Leakage from Perch Lake Basin3.28 Tritium Survey3.2 9 Land Gamma Survey3.30 Survey Summary3.31 Publications3.32 Verbal Presentations

3.32.1 Presented Papers3.32.2 Lectures or Seminars3.32.3 Local Talks

3.33 Invited Speaker

For Figures 1, 2, 3 and 4 see end of Section.

- 43 -

3.1 STAFF

Branch Head - I.L. Ophel

Environmental Chemistry and Meteorology

P.J. Barry Assistants: P.C. JayR.E. LegereD.P. Wildsmith

Natural Isotope Studies

R.M. Brown Assistants: C D . FraserE. Robertson

Radiochemistry and Terrestrial Radicecology

W.E. Grummitt Assistants: G. LahaieL.A. MaskH.M. McLaughlinW.J. PiersonJ. L. Young

Biology and Aquatic Radioecology

J.W. McMahon Assistants: A.E. Docherty

S-R. Gentner

I.L. Ophel Assistant: J.M. Judd

Hydrology and Trace Element? AnalysisW.F. Merritt Assistant: B.A. Risto

Secretarial

D.J. TerMarsch

- 44 -

3.1 STAFF (cont'd)

Attached Staff

R.E. Jackson - Working under a research contractbetween AECL and the University ofWaterloo with W.F. Merritt.

I. Suyama - Arrived 9 October 1974 for approxi-mately one year from the NationalInstitute of Radiological Sciences,Chiba-shi,Japan, supported by a JapaneseGovernment Fellowship. Working withI.L. Ophel.

3,2 STUDIES ON SUB-LETHAL EFFECTS OF HEATED WATER ON AQUATICORGANISMS - J.W. McMahon and A.E. Docherty

On-site construction of an insulated building tohouse the 500 kw boiler and support facilities is cur-rently under way.

In preparation for proposed heated water experi-ments in Maskinonge Lake, techniques are being evaluatedin the laboratory for measuring photosynthetic pigmentconcentrations (an indirect measure of biomass) andnitrogen.

Studies were carried out during the summer toidentify problems associated with handling fish fry incages immersed in the lake. While the heating facilityused in this study (a 6 kW hot water heater) proved un-reliable, considerable experience was gained in manipu-lating these organisms in the field.

Problems associated with fabrication and installa-tion in the lake of the polyethylene enclosure (approxi-mately 9 m dia.) have been resolved.

- 45 -

3.3 CHEMISTRY OP LAKE SEDIMENTS - J.W. McMahon and A.E.Docherty

Studies were completed on concentrations of ironand phosphorus in Upper Bass Lake water and sediments.During this period a report was prepared and submittedfor publication.

3.4 BENEFICIAL USES OF WASTE HEAT - J.W. McMahon, A.E.Docherty and S-R. Gentner

A program has been initiated to study the influenceof heated water on the growth of phytoplankton. Oncesuitable species of phytoplankton are selected, on thebasis of growth and protein composition, an attempt willbe made to mass-culture these organisms in a heated mix-ture of nutrient rich sewage effluent and lake water.The harvested material will be used to feed fish frygrowing in heated waters.

EXPERIMENTAL STUDIES WITH RADIONUCLIDES - I.L. Ophel andS-R. Gentner

The study of the uptake of iron ( Fe+++) and phos-phate (32po4) by Vallisneria spiralis was concluded anda paper on the results is being prepared for possiblepublication.

Factors influencing the adsorption of ferric ionson paper strips were studied to compare the behaviour ofthe adsorption on to non-living surfaces with that ofliving aquatic plant surfaces.

3.6 AQUATIC RADIOECOLOGY AND FRESHWATER BIOLOGY - I.L. Opheland J.M. Judd

3.6.1 Stable Element Analysis - Methods were developed for theanalysis of aluminum and potassium at environmental con-centrations using atomic absorption spectrophotometry.

3.6.1 Stable Element Analysis (cont'd)

A series of water and sediment samples from Perch Lakewere analyzed for the two elements. The main body ofPerch Lake water was found to contain approximately0.2 5 p.g Al/m-f. and 0.8 ug K/m-t. Sediment and core sam-ples contained approximately 20 mg Al/g and 1.5 mg K/gin the upper 0-6 m layers reaching 100 mg Al/g and20 mg K/g sample at 10 m. Aluminum/Potassium ratioswere obtained for all samples which were taken as partof a larger study of the water chemistry of the PerchLake system being carried out by Dr. I. Gacs.

3.6.2 Co and Sr in Perch Lake - samples of fish, plantsand water from Perch Lake were analyzed for stable cobalt.Sediment samples, taken with a modified core sampler,were analyzed for ^Co. Results show that most of the60(20 ( n contrast to ^Sr) is in the upper 6 cm of sedi-ment.

Gamma-ray spectrometry showed that the ^37Cs con-tent of Perch Lake water and sediments does not differfrom those in an uncontaminated lake (Maskinonge).

3.6.3 Effects of Water Chemistry and Food Composition on theAccumulation of calcium and Strontium by Fish - Resultsof previous work on the effects of water chemistry andfood composition on the accumulation of Ca and Sr byfish is being prepared for publication.

3.7 ST. LAWRENCE RIVER STUDIES - I.L. Ophel

The group from the Department of Biology at theUniversite du Quebec a Trois-Rivieres under the directionof Professor G. Vaillancourt. continued its research onthe effects of the heated water from Gentilly G.S. on thebiota of St. Lawrence River.

- 47 -

3.7 ST. LAWRENCE RIVER STUDIES (cont'd)

Their third report entitled "Rapport Thermopol III"details their results on temperature distribution inthe river during the period May 197 3 to April 1974 anddiscusses them in relation to a mathematical model ofeffluent diffusion developed from observations of pre-vious years. Biological research included studies ofthe food supply, reproduction variation in abundance,recolonization and association with plants and bottomsediments of the mollusc fauna in the discharge areaduring a period when the generating station was shutdown.

3.8 RADIATION EFFECTS - I. Suyama, I.L. Ophel and J.M. Judd

3.8.1 Effects of Internally Deposited Radionuclides in Fish onthe Incipient Lethal Level of Dissolved Oxygen - previouswork at CRNL showed that fish which contained body burdensof radionuclides often exhibit*'1', a marked increase inmean survival time when compared with that of uncontaini-nated fish. This increase in survival time was thoughtto have been produced by differences in the metabolicefficiency, and thus O2 consumption, of the two groups.The experiments now being undertaken will measure theminimum level of oxygen required for fish to survive("incipient lethal level") in groups of fish with andwithout internally deposited sOsr. An apparatus whichdelivers a continuous flow of temperature-controlled wa-ter containing O2 concentrations in the range 0.3 to10 mg 02/-?- has been constructed.

:.9 CULTURE OF ZEBRA FISH - I. Suyama

A culture of Zebra fish (Brachydanio rerio) is be-ing established in the radioecology laboratory for scudieson the embryonic development of eggs cultured in radioac-tive solutions.

- 48 -

3.10 PERCH LAKE EVAPORATION STUDY - P.J. Barry

This international Hyrirological Decade study wascompleted at the end of the year with a Symposium/Workshop held at CRNL, 9-11 December 1974. Several pa-pers summing up the results of the wcrk at Perch Lakevere presented by all participants. Daily evaporationestimates were prepared for the three years, 1970, 1971and 1972 to serve as a standard against which evapora--tion predicted by various other methods were comparedand evaluated. Daily net ground water inflow was esti-mated from daily water budgets for the same three years.These estimates also serve as standards for the compari-son and evaluation of other methods for estimating groundwater inflow.

These intercomparisons and evaluations of methodsform the main subject of the final summary statementwhich was prepared in draft form daring the Symposium/Workshop.

It is hoped that the final summary will be publishedearly next year together with the prepared papers fromindividual participants.

3.11 CROSS-CANADA EVAPORATION EXPERIMENT - P.J. Barry

This experiment was started in June (See PR-B-102)and continued throughout the summer until low tempera-tures caused the water in the pans to freeze (September-October) . Results will be analyzed during this winterwhen the meteorological data for the period becomesavailable.

3.12 ATMOSPHERIC DIFFUSION STUDIES - P.J. Barry

These studies, which include measuring Ar concen-trations around CRNL and meteorological variables, ter-minated this year though it is expected that working upof all the data gathered and preparation of a final re-port will take up to half of 1975 to complete.

- 49 -

3.13 NEUTRON ACTIVATION ANALYSIS - W.P. Merritt

The concentration of some 3 5 trace elements in snowcollected during eight different snowfalls in 1973-1974have been measured- Data on the storm tracks are beingprovided by the Atmospheric Environment Service of En-vironment Canada. Using the precipitation data, and thetrace element concentrations measured in the OttawaRiver, it is hoped to model the trace element cyclingin the Ottawa River watershed. Dr. J.M. Bewers of theBedford institute of Oceanography, Dartmouth, Nova Scotiais cooperating in this program.

Rain water samples were collected during 1974 andare being prepared for analysis.

3.14 WASTE MANAGEMENT - W . F . Merritt and B.A. Risto

90

Investigation of the underground movement of Srfrom the 195 5 test disposal h~-a been completed. it ap-pears that the "plume" from J hia experiment has joinedwith the one from the 1954 ;;est. At present the movementof ^37Cs from these two experimental disposals is underinvestigation.

3.15 PERCH LAKE INTERNATIONAL HYDROLOGICAL DECADE PROGRAM -W.F. Merritt and B.A. Risto

Two contracts were negotiated in 1974 with theDepartment of Earth Sciences, University of Waterloo.The first was a continuation of the study of the groundwater contribution to the water budget of Perch Lake.The second contract was for work aimed at developing athree-dimensional digital model of ground water flowutilizing data generated in the first contract.

3.15 PERCH LAKE INTERNATIONAL HYDROLOGICAL DECADE PROGRAM(cont'd)

In support of these contracts, more wells andpiezometer nests have been installed in and around PerchLake. In addition, the churn drill was reactivated forsetting larger well-screens. The Parsons undisturbedsoil sampler was redesigned (so that the samples couldbe taken in a plastic tube for visual inspection ratherthan a metal one) and placed into service, not withoutconsiderable trouble, since the present drilling crewwas not famililar with its operation.

A new borehole dilution apparatus, designed to workinside 4 in. (10 cm) plastic well-screens was constructedwith improved electronics. Three wells with continuousscreening down to the clay layer, which separates theupper and lower sands, were installed to a depth of ap-proximately 10 m. A coarse sand pack was used aroundthe screen to prevent silt from entering the well. Thetwo wells installed naar Inlet #2 and "F nest" (piezo-meter group) on the edge of the dyke proved unsatisfac-tory for dilution studies since vertical ground watercurrents up to 10 m/h were measured in these wells.The well at "O nest", 500 m from the lake, gave resultsthat agreed reasonably well with results from dye andisotope studies made in 1960. Only mild vertical cur-rents existed in this well. Studies in wells near thedyke with single 2 m long veil-screens also showed theeffect of vertical currents. Future work will entailusing shorter well-screens, and omitting the coarse sandpack, since this negates the use of packers inside thescreen in preventing vertical currents. The presentwork points up the izact that, speaking in a hydrologicalsense, we are dealing with an extremely inhomogeneoussystem.

- 51 -

3.16 COOPERATIVE PROGRAMS

3.16.1 Chalk River Environmental Authority - W.F. Merritt andB.A. Risto

An investigation of the ground water in the vicinityof the storage tanks at Building 240 indicated thateither the larger tank or its associated plumbing wasleaking.

A survey of the water table around a set of tileholes in the B Disposal Area was only partially success-ful. On one side till was found at a shallow depth. Onthe second side an old burial trench was encountered.The water table was finally determined to be well belowthe bottom of the tile holes by drilling close to the endset of holes in the original excavation.

3.16.2 Hydro-Quebec - W.F. Merritt

Further dye studies off the Gentilly G.S. site, insupport of the Gentilly-2 reactor and the LaPrade HeavyWater plant, indicate that dilution of the effluents froma nearshore discharge channel will be minimal for thefirst 10 km. The dye studies do not agree in severalparticulars with results from hydraulic model tests con-ducted for Hydro-Quebec.

3.16.3 Environmental Protection Service of Environment Canada -W.F. Merritt

Advice and some equipment were made available tothe Environmental Protection Service of EnvironmentCanada in support of dilution studies carried out in thebay off the town of Yellowknife, Northwest Territories.

3.17 TRITIUM IN VEGETATION OF THE PERCH LAKE DISPOSAL AREA -R.M. Brown and E.S. Lloyd

The distribution of organically bound tritium inthe wood of annual growth rings of several poplar treesgrowing in the Perch Lake Disposal Area has been measuredin a continuing study of the history of tritium in thewaters and vegetation of the area.

Trees growing in the main drainage path from theDisposal Pits show a major peak of tritium concentrationin the 1963-1964 rings, a minimum in 1967-1968 and asecond lesser peak in 1969-1970. Two trees growing onthe east side of Reactor Pit #2, south of the ChemicalPit, suggest a peak of tritium in this area in the period1951-1954.

The distribution of tritium in soil waters near oneof the above trees growing in Perch Lake Swamp has beenfound to be very variable. The ground water is the sourceof the HTO but infiltrating precipitation, relatively freeof tritium, lowers the concentration in the upper soillayers. Below the water table, tritium concentrationsvaried considerably within the metre of depth sampled withno correlation of pattern from one profile to another inspite of their being only 3-6 m apart-

The tritium content of the free water of fresh greenvegetation growing at this site was significantly lowerthan that of surface soil waters, particularly in thecases of fern, suggesting that a significant portion ofthe moisture of these leaves has come from direct absorp-tion of low-tritium precipitation.

Concentrations of organically bound tritium in theseleaves was similar to that in the 1973 ring of the nearbytree, but significantly lower than their free HTO. Thismay be explained by most of the organic material beingformed in the spring just after infiltration of the winter'sprecipitation has lowered the tritium content of the soilmoisture.

- 5 5 -

3.18 NATURAL, DEUTERIUM CONCENTRATIONS IN THE VICINITY OF THELAPRADE HEAVY WATER PLANT - R.M. Brown

The distribution and variability of natural deuter-ium concentrations in the St. Lawrence River and tribu-taries in the vicinity of Gentilly are being studied togain information on concentrations to be expected in thefeedwater to the LaPrade Heavy Water Plant.

Initial measurements showed concentrations in thesouthern part of the St. Lawrence River offshore of theGentilly Reactor to be quite uniform regionally on aspecific date (Figure 1) but rather lower than expected.These low concentrations proved to be a temporary condi-tion probably resulting from spring runoff of snowmelthaving low deuterium content. By late July, the deuter-ium concentration had risen to 148.5 ppm in both thesouth channel (Site 10, Figure 1) and the mainstream(Site 21). Concentration at Site 10 remained at thislevel through the fall but that at Site 21 continued torise, reaching a value of 149.2 ppm in November. Nocorrelations of deuterium concentration with tidal orwind conditions were observed. Profiles at Sites 10,11,21 taken in July showed, no variation of concentrationwith depth. However, there is some evidence that thelow springtime concentrations do not extend to the deepwaters of the main channel.

Concentrations in tributary streams near Gentillyare significantly lower than in the St. Lawrence River.Water from the St. Maurice River (143 ppm in June)streams along the north shore of the St. Lawrence andinfluences concentrations out to the middle of the navi-gational channel at the Becancour jetty. The south shoretributaries, the Becancour and Gentilly Rivers, have some-what higher deuterium content (145-147 ppm) but are toosmall to have a significant effect on concentrations inthe St. Lawrence River near the Gentilly reactor site.

- 54 -

3.18 NATURAL DEUTERIUM CONCENTRATIONS IN THE VICINITY OF THELAPRADE HEAVY WATER PLANT (cont'd)

Evidently there will be a springtime low in thedeuterium content of water taken from the south channelof the St. Lawrence River for the LaPrade Heavy WaterPlant at Gentilly. It might be possible to avoid thisby extending an intcike pipe out to the deep waters ofthe main channel but this probably would not be economi-cally advantageous.

3.19 MIXING OF WATERS IN THE ST. LAWRENCE ESTUARY - R.M. Brownand C D . Fraser

The Oceanographic Section of the University duQuebec a Rimouski is studying water-mass exchange in theestuary of the St. Lawrence River. In collaboration withthis group, deuterium and tritium variations are beingstudied to help differentiate river and ocean water.Tritium concentrations (0-50 Tritium Units) are at thelimit of measurement without isotopic enrichment. Deu-terium and oxygen-18 measurements (the latter done bythe Department of Earth Sciences, University of Waterloo)are more promising in view of the ease of analysis oflarge numbers of samples and high precision attainable.The high salinity samples have presented no problem withthe "Thurston" water inlet system of the AECL D/H massspectrometer. Samples from a cross section of the St.Lawrence River near Rimouski show deuterium concentra-tions of 154 ppm in south shore shallow waters, 155-156ppm in north shore waters and 157 ppm in deep mid-streamwaters.

3.20 EVAPORATION-EXCHANGE IN THE EMERGENCY HOLDING BASIN -R.M. Brown and C D . Fraser

Evaporation and exchange of isotopic water moleculesin the Emergency Holding Basin are being studied in col-laboration with personnel from the Department of EarthSciencas, University of Waterloo. The plastic lined basin

- 55 -

3.2 0 EVAPORATION-EXCHANGE IN THE EMERGENCY HOLDING BASIN(cont'd)

contains accumulated precipitation of the past year anda half to a depth of about 5 m and a surface area ofabout 2 300 m . The deuterium and oxygen-18 concentra-tions rose from early June to the end of August and thenstabilized through the fall months until freeze-up.During the period of rising concentrations, the surfacewater showed a very slight but consistent enrichment re-lative to that at 1.2 m depth. Tritium concentrationsin the basin rose from 750 to 830 Tritium Units (2.3 to2.6 pCi/m-t.) from early June to early September.

3.21 ENVIRONMENTAL ISOTOPE HYDROLOGY OF GROUND WATER SYSTEMS -R,M. Brown and C D . Fraser

Isotopic forms of the water molecule occurringnaturally in the environment constitute tracers that arecompletely conservative and have been introduced intothe whole hydrological system in an undisturbing manner.Study of the distribution of deuterium, tritium andoxygen-18 in several ground water systems in differentparts of Canada are under way in collaboration with per-sonnel of the Department of Earth Sciences, Universityof Waterloo.

3.21.1 East Side of Perch Lake Basin - This is a study of theground water chemistry and isotope behaviour in a re-charge area that has not been disturbed by waste waterinjection as is the case in the Waste Management Area tothe north of the lake. Some boreholes have shown abnor-mally high tritium contents which have gradually declined,indicating the slow flushing from these systems of sur-face waters necessarily used in the drilling. The hightritium content of precipitation and surface waters inthis area resulting from waste disposal and reactor oper-ations (about 600-800 Tritium Units compared to 100-2 00Tritium Units at off-site locations) facilitates useof this tracer as a marker of recently infiltrated

•1.2 1.1 East Side of Perch Lake Basin (cont'd)

water. There is some evidence of tritium and stableisotope fluctuations unrelated to drill-water injec-tions and presumably reflecting seasonal fluctuationof the isotopic content of infiltrating water. Deu-terium concentrations of 142-144 ppm indicate that re-charge occurs principally in the cool periods of theyear.

3.21.2 Camp Borden, Ontario, Sanitary-Fill Study - Tritiummeasurements are particularly useful in studying exist-ing or proposed sanitary-fill sites. The presence orabsence of fallcut tritium gives information on thetime-scale of water movement through the area and thepossibility of penetration of waters from the shallowfill-site to deeper aquifers which may be used forwater supply purposes at significant distances. Sucha study is under way at Camp Borden where a new siteis being selected and an existing site is being equippedfor long-term study.

3-21.3 Mayne Island, British Columbia - The origin of waterand salts in the ground water system of Mayne Island,British Columbia is being investigated. Tritium, deu-terium and oxygen-18 serve to relate different watersand differentiate between leached salts and intrudingsea water.

3.22 GAMMA DOSE RATES AT THE CRNL BOUNDARY •- W.E. Grummitt

TLDs placed at the perimeter of the CRNL exclusionarea are used to measure mean dose rates and the annualintegrated dose. Results for 1973 and for the thirdquarter of 1974 give the sum of contributions from CRNLand natural gamma-radiation. The CRNL portion can beestimated by subtracting the dose due to natural gamma-radiation from the values given below. Natural back-ground varies throughout the year due to shielding fromsoil moisture and snow cover. Measurements with a dose

- 57 -

3.2 2 GAMMA DOSE RATES AT THE CRNL BOUNDARY (cont'd)

rate meter give an average value of 5.7ten sites for the third quarter of 19747.4

at the(range 5.4 to

Argon-41 dose rates at the boundary of the exclu-sion area range from 0.2 to 11.2 pH/h with highestvalues being observed at sites along the Ottawa River.Argon output was up by 27%, averaged over the threemonths, due to startup of NRU on 3 August after a two-year shut-down.

TLD Gamma Dose Rates in Public Area(MB/h)

Location(See Figure 4)

1

2

3

4

5

6

7

8

13

Deep River

Third Quarter1974

12.6

6.9

5.3

7.0

6.1

5.7

8.8

10.1

16.9

•7.5

1973Average

9.5

5.8

-

5.1

5.3

4.7

-

6.3

9.1

8.13

Sum of natural background and airborne contaminationfrom CRNL. The dose from cosmic radiation has beenestimated by exposing controls in a shielded castle inthe basement of Bldg. 513 and subtracting the readingon the controls from the total observed at other sta-tions. This method may underestimate the cosmic raycomponent by ~< 1 |iR/h.

!Inside brick building in 1973.

- 58 -

1.2"? OAMMA DOSE RATES IN THE EXCLUSION AREA - W.E. Grummitt

Shielded (indoor) and unshielded (outdoor) gamma-ray dose rates in the CRNL exclusion area are givenbelow. The 12-fold reduction in dose rate observed inBldg. 513 is due to 35 cm of concrete in the floorsabove the detector.

TLD Gamma Dose Rates in Exclusion Area(L!B/h)

Location(See Figure 4)

9

10

11

12

9 office1

FirstQuarter

33.9

-

11.0

-

17.0

SecondQuarter

20.9

-

12.6

-

14.1

ThirdQuarter

30.3

-

15.4

-

16.2

1973Average

20.2

12.7

10.7

8.8

-

First floor office in Bldg. 513. Shielding factor for4lAr gamma-ray is 12. Background in the room due tobrick and concrete construction materials is 13 jiR/h.The dose rate from Argon averages 2

3.24 OFF-SITE MONITORING - W.E. Grummitt

Precipitation samples collected from the areaaround the Nuclear Power Demonstration (NPD) Station,Rolphton, and from Deep River were analyzed radio-chemically for 90sr and spectrometrically for l37Csand other gamma-emitters. Monthly cc ,posite samplesof water from the Ottawa River, collec; 3. at Rolphton,Deep River and Pembroke, were also ane.-.-;aed for gamma-emitting nuclides, tritium and 90Sr. Gamma-ray spectro-metry is being used wherever possible, eliminating

3.24 OFF-SITE MONITORING (cont'd)

radiochemical separation of elements other than stron-tium, sulphur, phosphorus and plutonium. The resultsare shown in Figure 2. The main source of activity inthese samples continues to be weapons' fallout.

3.2 5 LIQUID EFFLUENT MONITORING - W.E. Grummitt

At CRNL, four liquid effluent streams dischargeradioactivity to the river from the Inner Area. Theyare the Process and Sanitary Sewers plus the 04 StormSewer and 04A Seepage Drain. Each of these is sampledregularly and is analyzed for individual nuclides. Themean daily release from the Process Sewer is given inthe table for the third quarter of 1974. Several ad-ditional radionuclidfes are now being analyzed for bygamma-ray spectrometry.

Perch Creek ;, draining Perch Lake and the dis-posal areas, also flows into the river and is sampledregularly. The total amount of radioactivity dis-charged from CRNL per day is calculated from the mea-sured flow rates and radionuclide concentrations inindividual streams (See Figure 3).

At no time did the average concentrations ofradioactivity in any of the effluents exceed 1% ofthe ICRP 40-hour occupational MPC for drinking water.

See map. Figure 4.

- 60 -

3.2 5 LIQUID EFFLUENT MONITORING (cont'd)

Mean Daily Release from the Process Sewer(mci/day)

Radionuclides

90^Sr

137Cs

144Ce

106Ru

140Ba

131].

239Np

Zr

54Mn

46Sc

59Fe

Zn

Co

Daily Release

3.1

2.5

1.6

0.1

2.8

3.9

228.0

1.6

11.6

13.4

5.4

24.1

3.9

- 61 -

3.2 6 LIQUID DISPOSAL AREA - W.E. Grummitt

Weekly samples and flow readings were taken atweira on the surface streams carrying contaminatedseepaqe water from the Liquid Disposal Area into Perchand Maskinonge Lakes (^). samples were combined andanalyzed monthly for ^°Sr, -*5g and ^H as well as quar-terly for gamma-emitting radionuclides. Strontium-90,60Co and % are still the me in contaminants in thePerch Lake Basin.

3.27 WATER LEAKAGE FROM PERCH LAKE BASIN - W.E, Grummitt

90Slightly elevated levels of tritium and Sr have

been observed in Toussaint Lake since 1971. A recentfield survey indicated that radioactivity from B Dis-posal Area is being diverted from Inlet #1 to PerchLake by a beaver dam on the creek near the Hydro line(Figure 4). At the present time half the flow of thisstream is leaking out of the Perch Lake Basin intoChalk Lake via Toussaint Lake.

An estimate of the time of construction of thedam and extent of the leakage can be obtained fromwater flows into Perch Lake given in a report by J.E.Slater of the water Resources Branch, Environment Can-ada which indicates that 16.2% of the Perch Lake Basindrains through Inlet #1. Fractional flows at inlet #1and Inlet #2 are given in the table for the years 1968to 1973. It is apparent that the diversion started inlate 1971 or early 1972 and that about 6% of the PerchLake flow is escaping via Chalk Lake.

See map. Figure 4.

- 62 -

3.2 7 WATER LEAKAGE FROM PERCH LAKE BASIN (cont'd)

Water Plows into Perch L

Year

1968

1969

1970

1*71

1972

1973

Fraction ofFlow at Inlet #1

0.16

0.16

0, 16

0. 15

0.12

0.10

Fraction ofFlow at Inlet #2

0.60

0.59

0.59

0.61

0.58

0.59

3.28 TRITIUM SURVEY - W, E. Grummitt and G. Lahaie

Average concentrations of tritium in streams withinthe exclusion area are given in the table together withthe amount released during the third quarter of 1974.

Tritium in Streams in the Exclusion Area

Process Sewer

Sanitary Sewer

04 Storm Sewer

04A (building510 drainage)

Perch Creek

Duke Stream

Third Quarter 1974

Concentration[iCi/l

0.10

0.048

0.001

0.93

0.12

2.4

QuarterlyReleaseCuries

1060

5

0.3

4

24

70

1973TotalCuries

1490

16

3

51

1140

2 90

19741

TotalCuries

3400

13

2

16

800

2701

For the twelve-month period ending 1 December-2

Duke Stream discharges into Maskinonge Laker all otherstreams flow directly to the Ottawa River.

- 63 -

3.2 8 TRITIUM SURVEY (cont'd)

The amounts of tritium added to the disposal areaand leaving the Perch Lake system are listed in thefollowing table.

AmountB of Tritium Added to the Disposal Areaand Leaving the Perch Lake System

Transferred to theDisposal Pits

Entering Perch Lake

Leaving Perch Lake

Discharged to OttawaRiver

19721

1430

~1200

840

820

19731

18 02

940

1170

1150

19741

200

780

710

690

For the twelve-month period ending 1 December.

Corrected for total £~ in sanple at time of analysis.

Evaporative losses amount to ~ 350 Ci per yearfrom Perch Lake and ~ 20 Ci per year from the beaverdams between the lake and the Ottawa River. The amountof tritium transferred to the disposal pits is sub-stantially lower in 1973 and 1974 than in previousyears.

3.2 9 LAND GAMMA SURVEY - W.E. Gruinmitt

Routine surveys have been made of Highway 17 fromDeep River to Pembroke and of most of the roads insidethe plant boundary. Mean fields vary from 6 to 40 |iR/h;no increase in background levels has been observed.

- 64 -

3.30 SURVEY SUMMARY -W.E. Grummitt

No significant contamination of the environmentresulting from operations at CRNL has been detected inthese surveys.

3.31 PUBLICATIONS

Barry, P.J. - "Estimating dose commitments to popula-tions from radioactive waste disposals into largelakes", pp. 499-506 in Environmental Behaviour ofRadionuclides Released in the Nuclear Industry.IAEA, Vienna. [Atomic Energy of Canada LimitedPublication No. AECL-4741]

Barry, P.J. - Book Review "Survey of instruments formicrometeorology by J.L. Monteith" (I.B.P. Hand-book No. 22, Blackwell Scientific Publications1972). Boundary-Layer Meteorology 5(4): 517-518.

Barry, P.J. - "Energy for tomorrow - Nuclear power andthe environment". [Substance of an inv^.rd addressto the First World Congress of Environmental Medi-cine and Biology, Paris, France, 1-5 July 1974].AECL-5011.

Grummitt, W.E. and F.A. Prantl - "Use of thermolumines-cent dosimeters for studies of the snow cover",pp. 642-650 in Advanced Concepts and Techniques inthe Study of Snow and Ice Resources. Nat. Acad. ofSciences, Washington, D.C.

Grummitt, W.E. - "Retention of iodine on duct surfaces",pp. 857-8'J3 in Proc. of the 3rd Int'l Congress ofthe Intl Radiation Protection Association. USAEC.CONF-730907-P2.

Merritt, W.F. - Letter to Nature "No radioactive silverdetectable in silver-uranium ore". Nature 250(5464): 351. [Atomic Energy of Canada LimitedPublication No. AECL-4823]

- 65 -

3.31 PUBLICATIONS (cont'd)

Ophel, I.L. - "The environmental capacity of freshwa-ters for waste radionuclides", pp. 613-624 inEnvironmental Behaviour of Radionuclides Releasedin the Nuclear Industry. IAEA, Vienna. [AtomicEnergy of Canada Limited Publication No. AECL-4742]

Prantl, F.A., R.M. Koerner and E. Robertson - "Nucleartechniques for snow and ice studies in Canada sub-pol r regions (Devon Island)", pp. 632-641 in Ad-vanced Concepts and Techniques in the Study ofSnow and Ice Resources. Nat. Acad. of Sciences,Washington, D.C.

Prantl, F.A., W. Ambach and H. Eisner - "Alpine glacierstudies with nuclear methods", pp. 435-444 inProc. of Int'1 Symp. on the Role of Snow and Icein Hydrology. Beauregard Press Ltd., Ottawa,Ontario.

Prantl, F.A. - "Isotope balances for hydrological sys-tems. Part I. Isotope evaporation studies withtritiated water in the laboratory", J. of Pure &Applied Geophysics (Italy) 112; 209-218.


3.32.1 Presented Papers

Barry, P.J. - "Perch lake evaporation study - A briefhistory and review". Presented at Perch LakeEvaporation Study Symposium/Workshop, CRNL, 9-11December 1974. [To foe printed in proceedings]

Barry, P.J. and E. Robertson - "The water budget ofPerch Lake". Presented at Perch Lake EvaporationStudy Symposium/Workshop, CRNL, 9-11 December 1974.[To be printed in proceedings]

- 66 -

3.32.1 presented papers (cont'd)

Barry, P.J. and E. Robertson - "The energy budget ofPerch Lake". Presented at Perch Lake EvaporationStudy Symposium/workshop, CRNL, 9-11 December 197A.[To be printed in proceedings]

Merritt W.F. and B.A. Risto - "Calibration and historyof the Perch Lake weirs". Presented at Perch LakeEvaporation Study Symposium/Workshop, CRNL, 9-11December 1974. [To be printed in proceedings]

Merritt, W.F. - "Ground water conductivity measurementsby point dilution". Presented at perch Lake Evapor-ation Study Symposium/Workshop, CRNL, 9-11 December1974. [To be printed in proceedings]

MCMahon, J.W. and A.E. Docherty - "Effects of heat en-richment on species succession and primary produc-tion in freshwater plankton". Presented at IAEASymposium on the Physical and Biological Effectson the Environment of Cooling Systems and ThermalDischarges at Nuclear Power Stations, Oslo, Norway,25-30 August 1974. [To be printed in proceedings]


Grummitt, W.E. - "Monitoring of radioactive isotopes inthe environment". Presented at the 16th AnnualHealth Physics Course, CRNL, 10-14 June 1974.

Merritt, W.F. - "Permissible levels of radioactivity andreleases to the environment". Presented at the16th Annual Health Physics Course, CRNL, 10-14 June1974.

McMahon, j.w. - "Effects of heat enrichment on freshwaterplankton". Presented at University of Ottawa,Ottawa, Ontario, 27 March 1974.

Ophel, I.L. - "Studies on biologically important radio-miclides in aquatic ecosystems", presented atUniversity of Ottawa, Ottawa, Ontario, 20 March 1974,

- 67 -

3.32.2 Lectures or Seminars (cont'd)

Ophel, I.L. - "Studies on biologically important radio-nuclides in aquatic ecosystems". Presented atPetawawa Forest Experiment Station, Chalk River,Ontario, 2 9 March 1974.

Ophel, I.L. - panel of Experts on "The Effects of ioniz-ing Radiation on Aquatic Organisms and Ecosystems".Held at the International Atomic Energy Agency,Vienna, Austria, 22-26 April 1974.

Ophel, I.L. - Working group on "The Ocean Dumping ofRadioactive Wastes". Held at the internationalAtomic Energy Agency, Vienna, Austria, 8-12 July1974.

3.32.3 Local Talks

Ophel, I.L. - "Work of the Environmental Research Branch".Presented to University of Guelph, Guelph, Ontariostudents at CRNL, 11 January 1974.

Ophel, I.L. - "Ecology". Presented to Madawaska ValleyDistrict High School, Barry's Bay, Ontario studentsat CRNL, 17 January 1974.

Ophel, I.L. - "Nuclear power and the environment". Pre-sented at Canadian Forces Nuclear, Biological andChemical Staff Officer Course at CRNL, 12 March 1974.

Ophel, I.L. - "Work of the Environmental Research Branch".Presented at Summer Student Guides' Training Programat CRNL, 16 May 1974.

Ophel, I.L. - "Nuclear power and the environment". Pre-sented at Technical Familiarization Workshop atCRNL, 4 September 1974.

Ophel, I.L. - "Research programs of the Environmentctl Re-search Branch related to the nuclear power program" .Presented to Science Council Committee on EnergyScientific Policies at CRNL, 4 November 1974.

- 68 -

3 . 3 3 INVITED SPEAKER

Dr. 0- Vanderborght, Centre d1Etude de l'Energia Nucleaire,Kraaiboasen 25, B-2330 GEEL, Belgium - "The influenceof alginates on alkaline earth metabolism: calcium,strontium, barium, radium", CRNL, 12 July 1974.

Batture de Genti l lySt. Maurice River 146.815 mi. frcrc mouth , ._ , ,_ _

147^0 Exposedsvarrp at

147.17) 147.7145.8148.0

DEUTERIUM CONCENTRATIONS

1A6* 5i V§} Becancour River a t Highway 3 Top value - 28 May 74 - 3 'dep thBottom " - 19 June - 1 'depth

Becancour River 5 mi. further upstrea

Scale 1/20,0000.5

Figure 1.

- 70 -

R Q I P H T O H l 3 7 C s

pC i I

0 . 8 -

0 4

1.2 "

0.6

ROLPHTON 9 0 S r

i 1 I I I I I I I I I I ( i l l I I I I I I I t I

I F M A M I J A S O N O ) F M A M J ) A S O N O

p C i I

0 S

0.4

D E E P R I V E R 1 3 7 C s

i i i i i

1.2

0.6

D E E P R I V E R 9 0 S f

i i i i i i i i i I

I F M A i I I A S O N Q > F M A N ! 1 A S Q I | O

p C i / l

0.8

0.4

PEMBROKE 1 3 7 C s

i i i i i i i i i i I J

1 F M A H J J A S O N D

1.2

PEMBROKE 9 0 S

i i i i i

1 F M A M J J A S 0 H D

Figure 2. Ottawa River Water

- 7) -

m C i d

4 0 0 ~

2 0 0 "

MOMI

r—^_

• ki i t i i

HAL /315

12

m C i / d 9

6

3 ~

90 Sr

1 F M A M J J A S 0 N Di i i i i i i i i i l l

l F M A M I J A S O N D

m C i / d

15

12

9

6

3

137 Cs

m G t. ' ' d

P-

15

12

9

6

3

i i i i i i i i i t

1

I I I I I I I I

J F H A M 1 1 A S 0 N D J F M A M J J A S O N Q

m C i / d

10 -

8 -

6 ~

4 ~

2

106 Ru l O r

mg d

i i i l l

239 Pu

J F M A M J J A S O N D 1 F M A M J 1 A S 0 N D

Figure 3. Radionuclides Discharged to Ottawa River

Outer Area of AECL Chalk River

Nuclecr Laboratories

- 73 -

POPULATION RESEARCH BRANCH

Howard B. Newcombe

4.1 Staff

4.2 Aims of the Branch

TUMOUR INDUCTION IN MAMMALS

4.3 Additive versus multiplicative effects in radiation carcLnogenesis

METHODS FOR DERIVING HUMAN DATA ONDISEASES LIKELY TO BE INCREASED BYIRRADIATION - - DEVELOPMENT OF THE

INFORMATION SOURCES

4.4 Organization of birth and marriage records

4. 5 Linking ill-health records for children to birth summary records

4.6 Linking ill-health records into individual health histories

4.7 Ascertainment of congenital malformations through hospitalrecords

4.8 Conversion of G20 and Scope 3.2 computer programs andmagnetic tape files for use under the Scope 3.4.1 operating system

4. "i Sib risks for central nervous system defects in children

4. 10 Work with hereditary and congenital defects in children

4.11 Maternal irradiation and Down's syndrome

4. 12 AECL-UBC collaborative record linkage project

4. 13 Collaboration with outside agencies

- 74 -

4. 14 Publications

4.15 Verbal Presentations4.15.1 Presented Papers4.15.2 Lectures or Seminars

- 75 -

4.1 STAFF

Branch Head - H.B. Newcombe

Hereditary changes and tumour induction in vertqbr; tes

Assistant J .F . McGregor

Methods for deriving human data on diseases likely tobe increased by irradiation

M.E. Smith (Miss)

Secretarial - B.L. Phillips (Mrs.)

Attached Staff

Dr. B.K, Trimble, on a NRC postdoctoral fellowship,working with H. B, Newcombe.

4.2 AIMS OF THE BRANCH

The Branch attempts to obtain biological data with which toassess the consequences of exposing large numbers of people tolow levels of radiation. Information is derived from irradiatedand unirradiated populations of mammals and fish, and new com-puter methods are being developed at CRNL for extracting datafor man from existing records of procreation and health.

- 76 -

TUMOUR INDUCTION IN MAMMALS

4.3 ADDITIVE VERSUS MULTIPLICATIVE EFFECTS IH RADIATIONCARCINOGENESIS - H.B. Newcombe and J .F . McGregor.

A long-term experiment with laboratory rats has been underway since April of 1973, lo determine whether exposure to radia-tion in combination with cigarette tar or Z-anfhramine results ina yield of skin tumours substantially greater than the sum of theyields expected for the two agents separately. More specifically,the experiment is designed to test the assertion made byDrs. G of man and Tamplin that exposure to radiation enhances theyields of cancers from all other causes, both natural and artificial,by a factor that is essentially similar for all of them and for allmagnitudes of exposures to them. This implies a special kind ofsynergism in which radiation is said to have a multiplicative effectlather than an additive effect.

The experiment to test this theory is being carried out inthree phases, In the first phase, a dose-effect curve is obtainedfor the production of the skin tumours by beta radiation in doseswhich range in two-fold steps from 1, 600 to 12, 800 rad, for thepurpose of identifying the rising part of this curve. In the secondphawe, the yields of the tumours are determined for treatmentswith chemical carcinogens, i.e. for paintings three times a weekwith a 40% solution of cigarette tar in acetone, on intact skin andon skin irom which the dead surface layer is removed every twomonths by repeated stripping with Scotch tape, and for twice-weeklypaintings with 2-anthramine in 1% and 0.5% solutions in acetone.In the third phase, there are combined treatments with radiationand a chemical carcinogen. In all phases the final assessment oftumour incidence is made 18 months after the first treatment.

The first phase (irradiation alone) was terminated in Octoberof this year for doses in the range 1, 600 to 12, 800 rad, but asupplementary test using 800 rad is being carried out now to ensurethat the rising part of che dose-effect curve has been covered. Thetumours found in 400 irradiated animals were scored periodicallyduring the study, and the data are awaiting final analysis. Typicalgross tumours from ten of the irradiated animals are being testedfor malignancy a.s indicated by their ability to grow when trans-planted into recipient animals in which the immune response is

- 77 -

4. 3 continued

suppressed by prior combined treatment with whole body irradia-tion followed by a series of cortisone injections. These tests arecontinuing.

The second phase (chemical carcinogen alone) was begun inAugust of this year. To date, 54 paintings with cigarette tar havebeen carried out, on 200 animals. About 7 grams of tar have beenused so far, per animal, i.e. equivalent to 350 cigarettes each.No deaths have occurred from nicotine poisoning, as would havebeen expected for mice, but there has been a 10% reduction in bodyweight as compared with the unpainted controls. In addition, thecigarette tar has produced profuse rashes of tiny sores and pinkirritated patches of skin in 3% of the tarred-unstripped animalsand in 8% of the tarred-stripped animals. No skin tumours wouldbe expected as yet, and none has occurred, but a grossly tumourouskidney was found in one of the tarred-stripped group. This is nowbeing tested for malignancy.

Of the anthramine treated animals, 48% of those receiving the1% concentration have died from the toxicity; of those receivingthe 0.5% concentration all are still alive. No tumours have beenobserved as yet in these animals.

The third phase has not been started, but it was regarded asprudent to carry out in advance of this phase a small pilot test inwhich 30 rats were exposed to beta radiation (1, 600 rad) and, begin-ning two months later, painted repeatedly with cigarette tar (i. e.three times per week). Skin irritation occurred in 20 per cent ofthese animals after as few as four paintings, and has persisted for32 paintings with some additional animals becoming involved. Thus,prior irradiation of the skin appears to make it more sensitive tothe tar. It is unlikely that this will interfere with the execution ofpihase three, but conceivably the irritation might perhaps serve toenhance the yield of tumours from the combined treatment.

- 78 -

METHODS FOR DERIVING HUMAN DATA ONDISEASES LIKELY TO BE INCREASED BYIRRADIATION - - DEVELOPMENT OF THE

INFORMATION SOURCES

4.4 ORGANIZATION OF BIRTH AND MARRIAGE RECORDS -H.B, Newcombe and M . E . Smith

A file of 953, 311 magnetic tape records, relating to 1946-70British Columbia live births and stillbirths, was sorted into threesequences, under 1) single Soundex and birth date, 2) singleSoundex and forename, and 3) birth date and forename.

Two sample files of the 3-word summaries, one sorted inorder of single Soundex and birth date and the other in singleSoundex and forename sequence, were prepared and used in thedevelopment of methods for linking birth records to ill healthrecords. The sample files included all records on which appea. 1any one of 24 Soundex codes. These codes were selected asrepresenting the surnames most likely to give rise to difficultiesin a linkage operation, either because the names are common, suchas Smith, Jones, or Brown, or because they are of oriental origin.

This "difficult" sample would presumably necessitate thedevelopment of greater refinement in the matching rules, in orderto achieve an acceptable level of linkage accuracy, than would afile based on a random sample of surnames. Observations of thenumbers of linkage errors encountered when using this "difficult"sample should thus provide estimates of the upper limits to beexpected for the frequencies of similar errors in a large linkageoperation involving all surname codes.

4.5 LINKING ILL-HEALTH RECORDS FOR CHILDREN TO BIRTHSUMMARY RECORDS - H.B. Newcombe and M.E. Smith

A file of 35, 516 4-word ill-health records, relating to aselected "difficult" sample of all records on which appeared any oneof 24 selected Soundex codes, was prepared from a) the 1961-70hospital admission-separation records, b) the 1952-72 registra-tions of handicaps, c) the 1964-72 congenital anomaly surveillancerecords, and d) the 1946-70 death records. This "difficult" fileof ill health records was linked to the corresponding 1946-70

- 79 -

4. 5 continued

British Columbia 3-word birth and stillbirth summaries. Threesequences were employed in the linkage operation; 1) singleSoundex and birth date, 2) single Soundex and forename, and 3)birth date alone.

Our first linkage trial indicated that about 95% of the recordsin the ill-health sample that were potentially linkable to the 1946-70British Columbia live birth and stillbirth records could be linkedin the first of these three sequences. A further 4% linked in thesecond sequence and 1% in the third sequence. About 13% of the ill-health records did not link in any sequence; for 7% of them thiswas because the individuals were born outside the period coveredby the available birth records, and most of the remaining 6% maybe presumed to have been born outside the province. Manual testsshowed that a few false linkages and failures to link did occur withthe rules used in this first program, and indicated changes in therules that would reduce the errors.

Successive refinements of the linkage rules and of the binitweights require testing with a modified computer program, whichcan be used to li;ik the sample file again. Such linkage tests arecurrently being made and will be repeated until a favourablebalance is achieved between the linkage precision attained and thecomputer time needed to execute the modified computer program.

4.6 LINKING ILL-HEALTH RECORDS INTO INDIVIDUAL HEALTHHISTORIES - H.B. Newcombe and M.E. Smith

Procedures for preparing and linking 4-word ill-healthsummaries for persons not represented in the 1946-70 BritishColumbia live birth and stillbirth files into individual healthhistories were outlined and tested. The results of the first trialsof this computer program, which created individual health historiesusing the sample "difficult" file of Z4 selected Soundex codes,indicated that 99% of the potential links were achieved, that 0.9%were lost, and that 0. 1% of the linkages v/ere false linkages.

Because the formats and coding techniques used for BritishColumbia ill-health records have varied over the years, somestandardization is required before the records can be interfiled.

- 80 -

4. 6 continued

It is also desirable that the different types of ill health records becomparable in form. An "extended ill-health" format has thereforebeen designed which will standardize the fields in which informationmaybe stored, for 1946-70 deaths, 1952-72 handicaps, 1961-70hospital admission separations, 1946-70 stillbirths, and 1964-74congenital anomaly surveillance reports. This extended formatwill contain information from the name and statistical punchcardentries for events of ill health (where these are separately punched),and from the birth record for the individual concerned. Includedwill be a field which may contain information that identifies a recordto which it has been linked, such as the birth record or another ill-health record relating to the same person.

4.7 ASCERTAINMENT OF CONGENITAL MALFORMATIONS THROUGHHOSPITAL RECORDS - M.E. Smith and H.B. Newcombe

Documentation describing the design and performance of acomputer system for linking a sample file of 1961-63 BritishColumbia hospital admission-separation records into longitudinalhealth histories is near completion. In this study, linkages ofhospital insurance admission-separation records for children wereexecuted at a rate of 3,000 incoming records per minute using aCDC6600 computer. Empirical tests carried out manually afterthe computer operation showed that all of the pairs of recordslinked by computer (excluding twin pairs) were in fact linkedcorrectly.

The linkages of hospital records pertaining to twins presentspecial problems due to their common birth date and familyinformation. Sixty-six cases were investigated of record pairsthat were tentatively Ihought to pertain to different members of atwin pair. When suitable rules were adopted, the special problemsassociated with unnamed infants and twins were estimated to resultin losses of genuine linkages amounting to only 0.3% of thepotentially linkable pairs.

- 81 -

4.8 CONVERSION OF G20 AND SCOPE 3.2 COMPUTER PROGRAMSAND MAGNETIC TAPE FILES FOR USE UNDER THE SCOPE3.4.1 OPERATING SYSTEM - M.E. Smith and H.B. Newcombe(with L.E. Evans, Mathematics and Computation Branch)

Documentation of a revised version of FREAK has been com-pleted. This is a computer program which is used to obtain tablesof frequency distributions from files of individual records. It waswritten initially for the G20 computer and has now been re-designedand re-written in FORTRAN for use on the CDC6600.

During the month of May, the Scope 3.4. 1 operating system,along with up-to-date versions of the compilers and utilities, wereinstalled at CRNL's Computation Centre. All computer programshave had to be re-compiled. All permanent files have been trans-ferred to the 3.4. 1 system. Some file conversions have been madeand certain job control cards have been changed, so that ourexisting computer programs and tape files can be used under thenew operating system.

4.9 SIB RISKS FOR CENTRAL NERVOUS SYSTEM DEFECTS INCHILDREN - H.B. Newcombe and M.E. Smith

Data have been extracted from the British Columbia filesregarding sibling risks for central nervous system defects. Thelinked files are based on a defined birth population of more than200,000 children, born over a six-year period (1953-58), withcomplete information on sibship groups, and on the diagnoses fromall records of stillbirth, infant mortality, and registerable handi-caps. In all, there are 529 cases of central nervous systemdefects (anencephaly, spina bifida and hydrocephalus), in 518sibship groups.

Among later-born siblings of children with central nervoussystem defects the risk of similar defects occurring is shown tobe 3. 8%, as compared with 0.25% for the birth population as awhole.

- 82 -

4. 10 WORK WITH HEREDITARY AND CONGENITAL DEFECTS INCHILDREN - B.K. Trimble

Information on the natural incidence in human populations ofgenetic defects, and also of certain congenital malformations andcategories of malformations, is important in a number of contexts.It is useful as a starting point for research, for the detection ofpossible increases in specific types of disorders and for the planningof public health and rehabilitation services. As well, informationon the incidence of genetic defects is required for estimation of theeffects on human health of a radiation-induced change in the muta-tion rate in man.

The records from the British Columbia Registry of Handi-capped Children and Adults and the province-wide congenitalanomalies surveillance system have been revised by translating theoriginally assigned aetiology and ICDA malformation codes into anew system of coding that lends itself more readily to the abovepurposes and conforms to that used in a large prospective study ofcongenital malformations sponsored by WHO. The revised recordshave been tabulated separately by aetiology and by type of malforma-tion. These tabulations have been broken down according to place,year and month of birth, and by sex.

The results show that a total of 12 individuals out of every100 born alive suffer from an hereditary or congenital anomaly.Of this total, however, only the simple dominant diseases seemlikely to increase promptly (i.e. over just a few generations) andin direct proportion to a radiation-induced increase in the mutationrate. The present data indicate an incidence of these conditions ofonly 8 in every 10,000 live born, i.e. more than 10 times lowerthan a previously accepted estimate of one affected individual per100 born alive. It is generally agreed that, if the mutation ratewere permanently doubled, all of the simple dominant diseaseswould double in frequency. Accordingly, previous estimates of therisk to human health from these diseases, due to an artificiallyinduced increase in mutation rate in man, are at least 10 timestoo high.

The tabulations were also analyzed to obtain estimates, forall malformations and categories of malformations, of incidencevalues and sex ratios and to test for seasonal and secular varia-tions in the frequency of occurrence of malformations. The resultsare being prepared for publication.

- 83 -

4. 11 MATERNAL IRRADIATION AND DOWN'S SYNDROME -B.K. Trimble

A detailed proposal to study the relationship betweenmaternal irradiation and the risk of giving birth to a child withDown's syndrome has been drawn up at CRNL and submitted to theAtomic Energy Control Board for consideration for a grant in aidof research to be carried out in British Columbia.

The proposed project is designed to retrieve human epidemio-logical data which might help to indicate the magnitude of the pro-blem of genetic risks to man due to ionizing radiation. Large num-bers of relevant observations pertaining to the question of whethermaternal irradiation is a significant cause of human non-disjunctionleading to the birth of a child with Down's syndrome would beobtained through computer and manual linkages of existing vital,health and radiology clinic records. The study would be uniqueboth in terms of the number of cases of Down's syndrome ascer-tained and the fact that histories of maternal irradiations would bederived from existing vital and clinical records, rather than relyingsolely on the ability of a mother to recall irradiations that she mighthave received ten or more years previously.

The proposed study is designed to harmonize as closely aspossible with an experimental protocol recommended, by theNuclear Energy Agency of the Organization for Economic Co-opera-tion and Development, for a proposed international co-operativeprogram in radiation genetics. If funded, the study will be carriedout within the Department of Medical Genetics of the University ofBritish Columbia under the direction of Dr. B.K. Trimble andDr. J.R. Miller.

4.12 AECL-UBC COLLABORATIVE RECORD LINKAGE PROJECT -B.K. Trimble

The Population Research Branch of CRNL and the Departmentof Medical Genetics of the University of British Columbia arecurrently collaborating on a project to be initiated in BritishColumbia, that involves linking together vital and ill-health recordsinto individual and family histories to be used for studies relatingto the prevention, cause and treatment of ill-health.

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4.12 continued

The first stage of this collaborative project is the transferralto UBC of the data base already existing at CRNL. The BritishColumba files to be transferred include all B.C. records availablehere, relating to: marriages, births, deaths, hospitalizations andhandicaps. Altogether, these data represent about 11 millionmagnetic tape records. Approximately 40% of them have beenprocessed and sent to British Columbia.

The records for 1952-72 of the British Columbia Registry forHandicapped Children and Adults and those of the province-widecongenital anomalies surveillance system have been verified andrevised at Chalk River, so that they now contain uniform controlcodes and registration numbers, a modified aetiology code, a newmalformation code and a Soundex code. Copies have been createdof the original card images, Ln the sequence in which the recordswere received, and of the revised records, in control code -single Soundex - birth date sequence, for use at UBC.

The original death index and death statistics records havebeen converted from the now obsolete G20 compatible format toCDC Scope format, and sample listings obtained for each year ofdeaths. These listings serve to identify the various formats usedover the years. The index and statistics records have beenseparately validated, edited, "standard formatted" and sorted bydeath per year, province, and registration number. Correspondingstandardized inde« and statistics records were then merged intosingle records on the basis of the event registration number.Copies have been created of the standardized death index andstatistics records and of the merged death records, all for 1946-70,and transferred to UBC.

The 1961-70 hospital name and statistics card images havebeen converted from IBM compatible data tapes to CDC Scopecompatible form, verified and standard formatted. The standard-ized files have been sorted by hospital code and registration num-ber and copies have been made of these sorted name and statisticsrecords for use at UBC.

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4. 12 continued

The 1946-67 "marriage parental" cards (which identify theparents of grooms and brides) have been verified and sorted inorder of marriage year, province, and registration number. Thesorted files have been copied and transferred to UBC.

The original marriage index and statistics records for 1946-70have been converted from IBM compatible to Scope CDC compatibleform, and sample listings obtained for each year of marriages.These listings serve to identify the various formats in use over theyears. The index and statistics records have been separatelyvalidated and sorted by marriage year, province, and registrationnumber. Copies of the sorted files have been created for use atUBC.

In all, 44 data tapes relating to the above files have beencreated in a form suitable for use at UBC and sample listings ofthese tapes have been prepared. As a result of this, duplicatecopies of all of this material now exist at both CRNL and UBC.Work is in progress on processing in a similar manner the 1946-70birth name and statistics records prior to transferring these toUBC.

4. 13 COLLABORATION WITH OUTSIDE AGENCIES

The Historical Demography Department of the University ofMontreal has used methods of record linkage, similar to thosedeveloped at Chalk River, to link the 1681 census enumerations ofearly French settlers with records of marriages and births inQuebec during that period. At their invitation, the techniques ofrecord linkage which were being employed by the University ofMontreal were reviewed at a meeting of the Department withMiss Martha Smith in January of this year, and possible improve-ments were suggested.

Computer methods for linking all Canadian infant death recordsto the corresponding birth records were developed by Mr. Pio Uranand Miss Elizabeth Coppock of Statistics Canada, 11.1 collaborationwith CRNL. Much of the planning and some of the testing were doneduring a visit to this laboratory in July; the applicatioi will relateto the work of Statistics Canada. Such linkages will enable

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4.13 continued

statistics to be prepared for all perinatal deaths, in a form similarto that currently employed for stillbirth statistics. In particularthe linkage makes it possible to relate cause of death to informationrecorded at the time of birth, such as birth weight and mother'sage. A test sample of such linkages was listed, and these listingswere used at CRNL to verify manually the computer's decisionsrelating to linkage, and to refine the rules and weighting factorsused in the linkage process.

A major study, based in part on a design developed at CRNL,has been started at the National Cancer Institute of Canada to inves-tigate the cancer producing effects of repeated small doses ofradiation. Records of people treated for tuberculosis from 1930through 1953 with collapse therapy, which was controlled by multiplefluoroscopic examinations, will be linked to a consolidated indexof all deaths in Canada since 1950. This study is being carried outunder the direction of Dr. A.B. Miller of NCIC, with the collabora-tion of Professor David Hewitt of the School of Hygiene, Universityof Toronto, and H.B. Newcombe of CRNL. In December, a grantof $231, 300 was approved for this project under the National HealthResearch and Development Program of Health and Welfare Canada.

4.14 PUBLICATIONS

McGregor, J .F. - Possible Usefulness of Hypotrichotic Rats forStudies on Skin Tumorigenesis. Can. J. Genet. Cytol. lb_,341-348, 1974.

Newcombe, H.B. - Letter re. "Getting M.D's. and NumbersTogether". The Medical Post. (July 1974)

Newcombe, H.B. - Book Review "An Epidemiologist Takes aLook at Radiation Risks". Health Physics 26 (No. 4),370-371, 1974.

Newcombe, H.B. - Record Linkage - Its Role in Congenital DefectResearch. Pp. 95-111 in "Congenital Defects: New Directionsin Research", Academic Press, Inc., New York. (1974)(AECL-4801)

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4. 14 continued

Newcombe, H.B. - A Method of Monitoring Nationally forPossible Delayed Effects of Various Occupational Environ-ments. NRCC No. 13686. (AECL-4960)

Tri.mble, B.K. and J.H. Doughty - The Amount of HereditaryDisease in Human Populations. Ajin. Hum. Genet., Lond.(1974) 38, 199-223.

4. 15 VERBAL PRESENTATIONS

4.15.1 Presented Papers

Newcombe, H.B. and B.K. Trimble - "Criteria for AutomaticRecord Linkage - - Part I. Identifying the People". Invitedpaper presented at the 6th Buffalo Conference on 'Computersin Clinical Medicine: Computer-Based Obstetrical Records',Niagara Falls, New York, 17-19 June 1974.

Trimble, B.K. and H.B. Newcombe - "Criteria for AutomaticRecord Linkage - - Part II. A Product of Linkage". Invitedpaper presented at the 6th Buffalo Conference on 'Computersin Clinical Medicine: Computer-Based Obstetrical Records',Niagara Falls, New York, 17-19 June 1974.


Newcombe, H.B. - Record Linkage as a Means for Following -Up Large Study Populations. Department of Epidemiologyand Health, McGill University, Montreal, 11 April 1974.

Newt CT.be, H.B. - Genetic Effects of Radiation. Ontario HydroHealth Physicists, Pickering, 31 October 1974.

Newcomba, H.B. - Record Linkage as a Means for Following -Up Large Study Groups of Special Interest. Department ofEpidemiology and Community Medicine, University ofOttawa, 19 November 1974.

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4. 1 5. I continued

Trimble, B.K. - The Magnitude of the Genetic "Load" in HumanPopulations. Presented at the Organizing Meeting for the"As sociation of Genetic Counsellors of Ontario", Toronto,24 April 1974.

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BIOLOGY BRANCH

W.F. Baldwin

5.1 STAFF

BIOCHEMISTRY AND MOLECULAR BIOLOGY

5.2 Study of Long Pyrimidine Tracts (Polypyrimidines)in DNA from Eukaryotes

5.3 Study of Long Pyrimidine Tracts in Drosophila DNA

5.4 Pyrimidine Dimers in Polypyrimidines from Mouse DNA

5.5 Excision of pyrimidine dimers by several UV-sensitivemutants of a fission yeast, Sj_ pombe

5.6 Radiation-induced Tumors in Rats

5.7 Radiosensitivity of Micrococcus radiodurans toIodine-125

5.8 Ionizing Radiation Damage to M;_ radiodurans Cell Walls

5.9 Enzymology of DNA Repair in Micrococcus radiodurans

5.10 Synergism Between Heat and Radiation in Micrococcur:radiodurans

5.11 Activity Assay for DNA Polymerase in Disc Gels

5.12 DNA Repair in Cultivated Animal Cells

GENETICS, DEVELOPMENT ANDPOPULATION STUDIES

5.13 Radiation Sensitivity of Bacteriophage T4

5.14 Polyacrylamide Gel Electrophoresis of Bacteriophage T4

5.15 Radiation Genetics in Insects - Dahlbominus

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5.16 Radiation Studies on Biting Flies

5.17 PUBLICATIONS


5.18.1 Presented papers

5.18.2 Lectures or seminars

5.18.3 Local talks

5.19 INVITED SPEAKERS

5. 1 STAFF

Branch Head - W.F. Baldwin


RNA MoleculesH.C. Birnboim

Radiation BiochemistryD.K. Myers

Repair of DNA in BacteriaR.E.J. Mitchel

Enzymatic Repair of Radiation DamageN.E. Gentner

DNA Repair in Cultivated Animal CellsM.C. Paterson

Assistants J.M. Ostrom (MrsC.E. Grant (Miss

Assistant L.D. Johnson

Assistant K.M. Baird

Assistant M.M. Werner (Mrs

Assistant B.P. Smith


Radiation Repair in InsectsW.F. Baldwin

Bacteriophage T4 GeneticsJ.D. ChiIds

Assistants G.D. ChantP.A. KnightA. G. Knight

Assistant L.A. Chant (Mrs.

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SecretarialA.S. Burton (Ms.)

Laboratory AttendantsM.A. Jones, R.M. Bechamp and D.R. Ezeard


5.2 STUDY OF LONG PYRIMIDINE TRACTS (POLYPYRIMIDINES) INDNA FROM EUKARYOTES -H.C. Birnboim, J.M. Ostrom, C.E. Grant and N.A. Straus*(•University of Toronto)

In recent years, numerous unusual components havebeen found in the DNA of higher organisms. Thesecomponents are special sequences in DNA whose precisefunction has not been identified, but they are presumedto have developed during evolution as organismsbecame more complex. It may be that they play arole in the control and/or expression of geneticinformation.

In this laboratory, another unusual DNA componenthas been detected. It consists of long runs ofpyrimdine nucleotides (polypyrimidines). Runs ofpyrimidine nucleotides of this length (25-150 residues)would not be expected to occur in DNA solely on arandom basis, so these polypyrimidine sites have beenpresumed to be involved in some important cell functionfor which the sequences have been conserved. Supportingthis argument is our observation that polypyrimidineshave been found in several organisms, including mouse,human, hamster, rabbit and other cell types, in whichthey comprise about 0.1 - 1% of the total DNA. Further-more, cross-hybridization experiments involvingC3H7 polypyrimidines from mouse cells and unlabelledDNA from sevsral other organisms (rat, rabbit, human,cow, pigeon and others) have indicated that thenucleotide sequences in mouse polypyrimidines aresimilar to those found in other cell types.

In order to gain further insight into the functionof polypyrimidines, we have attempted to obtain moreprecise information about ttieir base sequence. Methodsfor directly sequencing C3l0 DNA fragments, such aspolypyrimidines, are not available, largely becauseenzymatic or chemical cleavage at a specific site isnot possible. We have tested some new methods

(chemically blocking either thymine or cytosine andthen digestion with a non-specific enzyme) but thisapproach has not been successful thus far. However,some progress has been made using an indirectapproach. Polypyrimidines from mouse DNA were foundto act as template for E. coli RNA polymerase; P H ]complementary RNA containing only A and G residueswas synthesized. This RNA was digested with ribonuc-lease T\ to yield oligonucleotides of the form (Ap)nGpand witn ribonuclease T2 (after blocking with glyoxal)to yield (Gp)nAp. The oligonucleotide patterns arefairly complex, supporting our previous conclusion,based upon reassociation kinetics, that polypyrimidinesare not part of a very simple sequence (satellite-type)DNA. More detailed analysis of this complementaryRNA is in progress.

5.3 STUDY OF LONG PYRIMIDINE TRACTS IN PROSOPHILA DNA -H.C. Birnboim, J.M. Ostrom and R.R. Sederoff*{•Columbia University, New York)

Analysis of DNA from Drosophila melanogastercells revealed the presence of long pyrimidine tracts(polypyrimidines) which differed significantly fromthose found in other organisms, as described above.These tracts were much longer (averaging 750 nucleotidesin length) and their reassociation kinetics and thermalstability suggested they were part of a simplesequence, satellite-type DNA. This was verified byidentifying a "cryptic" satellite (buoyant density1.707) containing the majority of polypyrimidinesequences and by oligonucleotide analysis of comple-mentary RNA. From the latter, the predominantsequence was determined to be -T-C-T-T-C-, withsmall amounts of other sequences -C-C- and -T-T-T-T-C-.Like other satellite-type DNAs, polypyrimidines havebeen shown to be localized to heterochromatin,predominately in the centromere region of chromosome 2.Its precise function there is not yet known.

5.4 PYRIMIDINE DIMERS IN POLYPYRIMIDINES FROM MOUSE DNA -H.C. Birnboim and C.E. Grant

For pyrimidine dimers to be formed with highefficiency by UV irradiation, pyrimidine bases mustbe adjacent to one another on the same DNA strand.Polypyrimidines (described above) are regions of theDNA where pyrimidines bases are clustered together

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in groups of 25-150. It was of interest; to see ifthese sites were particularly sensitive to dimerinduction by UV» Mouse L-cells in culture werelabelled with L3H) thymidine, then exposed to UVlight (100 J/ra^). Polypyrimidines were isolated andtheir content of dimers was compared with thepyrimidine dimer content of total DNA. It was foundthat there was only a slight enrichment (less thantwo-fold) of dimers in polypyrimidines. We concludethat polypyrimidines are not especially sensitivesites for the production of pyrimicline dimers by UVlight.

5.5 EXCISION OF PYRIMIDINE DIMERS PY SEVERAL UV-SENSITIVEMUTANTS OF A FISSION YEAST, S^ P0KBE -H.C. Bimboim, A. Nasim* and C.E. Grant(•National Research Council, Ottawa)

Using previously developed methods for assayingpyrimidine dimers produced in yeast DNA by UVirradiation, several radiation-sensitive mutants ofSchizosaccharomyces pombe were studied. Althoughindirect parameters used previously suggested thatsome of the mutants might have been defective in theirability to excise pyrimidine dimers, this was foundnot to be the case. All of the nine mutants (exhibitinga variety of phenotypes) appeared able to excise dinersas well as wild type cells, or nearly so. Thus,there appears to be a contradiction between the abilityof these cells to excise pyrimidine dimers effectively,and their highly UV-sensitive phenotype. This dilemmahas not been resolved but it is suggested that repairpathways in S_ pombe (an inherently radiation-resistantorganism) may differ from other organisms which havebeen studied. Details of this study have been acceptedfor publication.

5.6 RADIATION-INDUCED TUMORS IN RATS -D.K. Myers

It is currently estimated that 60 to 90 percentof all tumors in humans are due to chemical carcinogensin the environment- Under these circumstances, itbecomes increasingly important to know whether thecarcinogenic effect of ionizing radiation and ofchemicals will simply be additive or will be synergistic.

For our initial experiment, we chose to study the

interaction of whole-body X-irradiation and of urethane(ethyl carbamate) in rats. Urethane was selected as asimple water-soluble chemical that is uniformly andrapidly distributed to all tissues of the body; it isonly weakly carcinogenic in adult rats but has beenused to induce a virus-associated leukemia in mice.

An initial experiment with a C R N L colony ofblack-hooded Collip rats showed that the combinationof X-radiation and arethane in high, near-lethal dosesdid induce an appreciable number of leukemias in theseanimals. Considerable numbers of mammary tumors andof skin tumors were also noted in the female and inthe male animals, respectively. This experiment wasrepeated with Collip rats to obtain more reliablestatistics. In addition, the same experiment wascarried out on Sprague-Dawley rats and on Long-Evansrats that were obtained from a commercial breedinghouse, since it is known that various strains of animalsmay react differently to carcinogenic stimuli. Thecombined experiments, which have been in progress forthe past 2 years, have now been completed and thedata are being analysed.

The results obtained with the Collip rats were ingeneral agreement with those of the initial test. Thenumber of leukemias produced by X-radiation and urethanecombined was greater than the arithmetic sum of thenumbers produced by X-radiation alone and by urethanealone. However, the incidence of mammary tumors andof skin tumors induced by X-radiation was decreasedwhen X-radiation and urethane were combined. Tumorsof various other organs were also induced in smallnumbers; these showed no indication of a synergisticaction of X-radiation and urethane. The overalleffect of combining these two agents, as judged fromthe mortality curves, was close to that expected forsimple additivity.

Different results were obtained with the otherstrains of rats. The Sprague-Dawley animals developedvery few leukemias and few skin tumors but a largenumber of mammary tumors after treatment either withurethane or with X-radiation. The pattern of tumordevelopment in the Long-Evans rats was intermediatebetween that of the other two strains. No evidenceof synergism betweeh X-radiation and urethane wasobtained with any of the categories of tumors ineither the Sprague-Dawley or Long-Evans rats. Thefinal conclusion would therefore seem to be that the

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total carcinogenic stimulus of urethane is additiveand not synergistic with that of X-radiation in rats.

Two other experiments with Collip rats have alsobeen completed during the past year. It had beenreported in 1971 that all Sprague-Dawley ratsexposed to X-radiation doses between 25 and 350Rdeveloped leukemia when the animals were bled one tothree months after irradiation. When this experimentwas repeated with Collip rats exposed to 330RX-radiation, we found that post-irradiation bleedingdid not accelerate the development of leukemia or ofother tumors. A similar negative finding was reportedby another group of investigators while our experimentwas in progress.

The combined effect of iododeoxyuridine andX-radiation was also tested. This chemical isincorporated specifically into the DNA cf growingcells and increases the sensitivity of these cells tothe lethal effects of X-irradiation; although notcarcinogenic by itself, it was reported to increasethe number of skin tumors produced in mice by asubsequent application of chemical carcinogen.Injections of iododeoxyuridine in Collip rats wasfound to increase the lethality of subsequentX-radiation; however, the number of tumors thatdeveloped in the surviving animals was not increased.

5.7 RADIOSENSITIVITY OF MICRQCOCCUS RADIODURANS TOIODINE-125 -D.K. Myers and L.D. Johnson

Work at other laboratories has shown an unusuallyhigh radiotoxicity from the disintegrations of 1-12 5that is incorporated into the DNA of mammalian tissueculture cells in the form of iododeoxyuridine. Thisradiotoxicity has been attributed to massive localdamage and double-strand breaks in the DNA, caused bythe low energy Auger electrons released with each 1-125disintegration; it is thought that this damage is notreadily reparable by the cell. This hypothesis canbe tested using M _ radiodurans which is highly capableof repairing the different types of damage (double strandbreaks, single strand breaks, base changes) producedin DNA by X-irradiation.

Preliminary experiments on the optimal conditionsfor incorporation of isotope into the DNA of

M. radiodurans have been completed. We are currentlypreparing samples labelled with 1-125 and with H-3iododeoxyuridine to be stored in the frozen stateuntil appreciable numbers of radioactive disintegrationshave accumulated; survival curves will be measured onthese samples.

5.8 IONIZING RADIATION DAMAGE TO M^ RADIODURANS CELL WALLS -R.E.J. Mitchel and K.M. Baird

The radiation induced damage and repair of geneticmaterial has been extensively studied, but verylittle is known about damage to other cellular com-ponents. We are studying the effect of ionizingradiation on cell walls and membranes. The bacteriumMicrococcus radiodurans is useful for this study sinceit can tolerate high doses. Such high but sublethaldoses of gamma radiation cause a variety of changes tooccur in the cell walls of this organism. Approximately6% of the cellular dry weight and up to 30% of the wetweight is lost. Several proteins and carbohydratecontaining polymers are released from the wall. Theproteins range in weight from approximately 2 0,000to 12 5,000 daltons. One of the proteins is anexonuclease and is released as an active enzyme. Therelease of this enzyme is induced by OH radicalsproduced from the radiolysis of water. This enzymeis normally located in the middle, lipid-rich layerof the cell wall. Some evidence suggests that OHradicals may act by causing a change in a hydrophobicbinding site holding the enzyme to that position.The enzyme exists in two functionally distinct states,one with the catalytic site available to the cellexterior and the other with this site masked. Ionizing -radiation-produced OH radicals are effective inreleasing both. The masked activity is active afterrelease. Mechanical fracture of the cells does notunmask exonucleas2 activity. Attempts to allowreassociation of the released enzyme with the depletedcells have been unsuccessful. The removal appears tobe irreversible.

Attempts are being made to determine the naturecf the sites attacked by OH radicals. Treatment ofwhole cells with a chemical cross-linking agent causesno apparent change in the activity of the exonucleaseavailable at the cell surface. After this treatment,however, ionizing radiation no longer activates the

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masked activity. This cross-linked protein mayprovide information about the structure to which theexonuclease is normally bound.

..9 ENZYMOLOGY OF DNA REPAIR IN MICROCOCCUS RADIODURANS -N.E. Gentner and M.M. Werner

Although the ability of the extremely radiation-resistant bacterium Micrococcus radiodurans to repairradiation-induced damage has been well documented,little is known of the enzymatic sequence of eventsby which this very proficient repair process isaccomplished. In order to understand the basis forsuch high repair efficiency, this study seeks toidentify the enzymes involved in the repair pathwaysin this organism and to elucidate their role.

1) DNA Polymerase

The radiation-sensitive mutant UV-17, which wehave shown to be deficient in DNA polymerase, isbeing used in investigations of the role of this enzymein DNA repair and related processes. This mutantshows an enhanced rate of DNA degradation afterradiation exposure, and Bonura and Bruce have shownthat it is defective (compared to wild-type) inrejoining of X-ray-induced strand breaks; theseresults corroborate the polymerase deficiencydemonstrated in_ vitro, since an E^ coli polymerase-deficient strain shows similar properties.

The relation between repair and mutagenesis hasalso been studied. The radiation-sensitive, polymerase-deficient mutant UV-17 seems to make more errors ofincorporation: UV- and X-irradiation induce mutationsin this mutation but not in wild-type.

2) Repair Exonuclease

In an effort to identify the exonuclease responsiblefor the DNA degradation that accompanies repair, wehave been studying a semi-in vitro system in order todefine certain properties of what may be the "repairexonuclease". For this system, Mn 2 + appears to be moreeffective as divalent cation than Mg . The DNAbreakdown which Driedger showed was activated byexcessive n-butanol treatment may be related to thissystem.

3) Polynucleotide Ligase

When niacin is not included in a defined growthmedium, or when it is incubated with NMN, strandbreaks accumulated in the DNA of M^ radiodurans,indicating that NAD + is the cofactor for the ligationactivity in this organism. In spite of the accumu-lation of strand breaks, however, such cells wererelatively resistant to inactivation by X-rays, Theproperties of DNA degradation post-irradiation andrepair incorporation are being studied under theseconditions of presumed restricted joining activity.

4) Repair Inhibition by Caffeine and Acriflavine

The recovery of X-irradiated cells from repairinhibition (manifested by lethal enhancement) bythese compounds has been used to determine parametersof the repair process. These two repair inhibitorsappear to affect the same pathway, and the inhibitionby acriflavine seems to occur at an earlier stagethan that by caffeine.

Both caffeine and acriflavine inhibited post-irradiation incorporation of H-TdR into DNA.Acriflavine appears to "uncouple" degradation fromrepair, and very little rejoining of X-ray-inducedstrand breaks was seen for cells incubated in thepresence of acriflavine. Caffeine had no effect onDNA degradation, in either irradiated or unirradiatedcells, and inhibited the rate of rejoining of strandbreaks but did not prevent it; since most of the cellsfail to survive undar such conditions, the restorationof single-strand molecular weight is not necessarilyindicative of full repair.

5) Repair in vitro of radiation-inactivated transform-ing DNA~

UV- or X--irradiation inactivates the biologicalactivity of transforming DNA (tDNA). Using aM* radiodurans transformation system, we investigatedwEether repair of the irradiated tDNA could beachieved in vitro using a M _ radiodurans extract. Thestudies were complicated by nucleolytic "activities inthe extract, which caused loss of transforming activityon incubation, even with unirradiated tDNA; heatinactivation of such degradative activities, afterthe initial incubation, minimized this. Some limitedrepair of X-irradiated tDNA seemed to occur, relative

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to controls with unirradiated DNA. With UV-irradiatedtDNA, however, the remaining biological activity wasrapidly lost on incubation, indicating the presenceof a nucleolytic activity specific for UV-irradiatedDNA.

A more fiondamental problem related to the highefficiency of repair of radiation-damaged tDNA thatcould occur in the very repair-proficient M.radiodurans recipient cells. Attempts to increasethe "sensitivity of the in vitro repair as'jay bydecreasing the amount of"~repair that could occurinside recipient cells (with inhibitors of repair,for exanple) were unsuccessful. Future efforts willuse the M^ radiodurans extract in attempts to repairirradiated tDNA in some other transformation system,where the recipients are much less repair proficient.

5.10 SYNERG1SM BETWEEN HEAT AND RADIATION IN MICROCOCCUSRADIODURANS -N.E. Gentne'r and M.M. Werner

Sublethal heat treatment (HT) sensitizes M^radiodurans to inactivation by UV- and X-irradiation.The effect of HT seems to be rapidly repaired: onsubsequent incubation, HT-cells rapidly (within 90 min)regain resistance tc radiation. The sensitivity ofHT-cells to radiation may be due, in part at least,to inactivation by heat of component (s) of theenzymatic DNA repair machinery. In the HT-cells,the level cf a DNA polymerase shown previously tobe involved in repair was about 20% normal. Onincubation of HT-cells in growth medium the normallevel of this activity was restored; this regainoccurred concomitantly with regain of resistance, andboth events were prevented by inhibitors of proteinsynthesis.

The HT appears to introduce some strand breaksinto the DNA. The HT alone does not stimulate DNAdegradation nor does it affect post-HT incorporationof 3H-TdR. After HT plus either UV- or X-irradiation,however, there is a pronounced lag period beforeincorporation of 3H-TdR into DNA resumes.

5.11 ACTIVITY ASSAY FOR DNA POLYMERASE IN DISC GELS -N.E. Gentner and M.A. Marko

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Disc gel electrophoresis is capable of rapid andhigh resolution of prottin species. An activity assayhas been developed for DNA polymerase in disc gels,providing a rapid and sensitive assay for this enzymein essentially a purified system not subject tointerference from competing nuclease activities.Nicked DNA primer-template is cast into the gel, andDNA polymerase assayed by incorporation of label from3 H_ T T P into a form which cannot be electrophoreticallyremoved. Incorporation of "ClCT1^ mole of nucleotidecan be deteated. The DNA polymerise of M;_ radioduianshas be^n visualized and studied, and the absence ofthe Mg"+ - dependent activity in the radiation-sensitive mutant UV-17 confirmed. Activity requirements(the four dXTP's, metal ion, DNA) are strictlyobserved. This assay method should also be applicableto other nucleotide-incorporating systems such asRNA polymerase. reverse transcriptase, or terminaldeoxynucleotidyl transferase.

Elutior. assays from gels with and without DNAincorporated revealed an affinity effect of DNApciymerase for DNA which caused a lower relativemobility in gels containing DNA. Since the variationin relative mobility with gel concentration wassimilar in all systems, however, the apparent molecularweight determined by the activity assay is valid.

5.12 DNA REPAIR IN CULTIVATED ANIMAL CELLS -M.C. Paterson and B.P. Smith

The ability of living organisms to overcomedetrimental effects caused by such environmental agentsas ultraviolet (UV) and ionizing radiations can belargely attributed to the presence of intricateenzyme-mediated processes capable of repaifiny damageto the deoxyribonucleic acid (DNA). Thus, despiteexposure to these harmful agents, each individual cellis still able to maintain the integrity of its DNAand thereby preserve the genetic information vitalto survival and reproduction. One of our long-termgoals is the elucidation of repair mechanisms operativein artificially cultured animal cells, in particular,those of human origin. As a necessary prelude to thecontinuation of studies, initiated in Holland, inwhich purified lesion-recognizing enzymes are used ashighly sensitive probes for monitoring repair of radi-ation-damaged cellular DNA, we have undertaken the

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following projects: (1) Establishment of stockcultures of 10 human diploid fibroblastic strainsobtained in Holland from skin biopsies of patientssuffering from the hereditary skin disease Xerodermapigmentosum. The salient characteristic at the molecularlevel of each cell strain is a deficiency in the abilityto overcome radiation-induced damage in DNA due todefective repair processes. (2) Cultivation of fibro-blasts derived from a 'carcass' biopsy of 12-daychick (White Leghorn) embryos. An important propertyof these avian cells is the presence of one type ofrepair process, termed photoreactivation, which isabsent from human cells. (3) In conjunction withP.H.M. Lohman (Medical Biological Lab. TNO, Rijswijk,Holland) and E.G. Long (Math and Computation Div.),modification of a computer program designed for therapid calculation of the weight average molecularweight (M ) of DNA samples sedimented in alkalinesucrose gradients. M , a measure of the average sizeof a population of molecules, must be computed foreach DNA sample when employing our repair assay.(4) Determination of both substrate specificity andsensitivity of highly purified enzymes, isolated frombacteria, which are capable of detecting specificlesions found in DNA extracted from irradiated animalceils.


5.13 RADIATION SENSITIVITY OF BACTERIOPHAGE T4 -J.D. Childs, L.A. Chant, A.D. Steljes and B.S. Tromp

(a) Effect of ionizing radiation on giant particles

Bacterial cells singly infected with phage T4particles which have been inactivated with ultra-violet light, fail to yield viable progeny. However,if the cells are each infected with several inactivatedparticles then viable particles are produced. Thisprocess, termed multiplicity reactivation, does notoccur if particles are inactivated with ionizingradiation. We are using giant T4 particles whichcontain several copies of the normal T4 genome withina single particle, to determine the reason for thislack of multiplicity reactivation.

Giant particles are much more resistant to UV

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light than normal size particles due to multiplicityreactivation. In contrast, we have previously shownthat giant particles have a similar sensitivity toionizing radiation compared to normal size particlesif irradiated before infection and are only slightlymore resistant to ionizing radiation after infection.This suggested that irradiation has little effect onthe injection of DNA by phage particles. To confirmthis we have examined the UV resistance of Y irradiatedgiant particles. We have found that the giant particlesare still very UV resistant after \ irradiation indicatingthat"/ irradiated pr.rticles can inject multiple genomes.Thus, unlike bacte j.ophage T4, the lack nf resistanceof qiants to V i-iodiation must be the results ofevents occurring after infection.

(b) Mutants affecting radiation sensitivity

In bacteriophage T4, there are only four genes'y.' *' Y. a n ° lpn6) , whose function can be dispensedwith~for grow'th under normal conditions, that we knowto be involved in the repair of radiation damage. Thev gene product is an exonuclease involved in theexcision of thymine dimers formed after UV irradiation,but the function of x_, _y_ and 1206 are unknown. Wehave previously isolated 16 mutations, which aresensitive to UV irradiation, and these are beingexamined by complementation and by mapping. Of the 11mutants tested so far, four are v mutants, five arex mutants and two cannot be clas¥ified with certainty.One of the two gave ambiguous results when tested forcomplementation with v. It maps in the same regionas v, but possibly counter-clockwise from v on thecircular map of T4. The second may carry two mutations,neither of which map near knov;n UV sensitive mutations.We intend to separate these two mutations and charac-terize them.

(c) Mapping the site of the x gene of T4

Of the four radiation sensitive genes v, x, y_and 1206, only the map position of x is in doubt.On an early map of T4, x was placed between genes42 and 43, but we have now shown that it maps betweengenes 41 and 42. Another gene (flgt) is also locatedbetween genes 41 and 42 and we intend to determine thelocation of x with respect to flgt.

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5.14 POLYACRYLAMIDE GEL ELECTROPHORESIS OF BACTERIOPHAGET4 -J.D. Childs and H.C. Birnboim

Polyacrylamide gel electrophoresis has been usedto separate a variety of macromolecules, cell com-ponents, small spherical viruses (maximum diameter30 nm), and a long filamentous virus (800 nm x 6 nm).We have previously shown that this method can alsobe used for T4 (approximate dimensions 75 nm x 2,000 nm)A number of mutants of T4 have been screened todetermine whether any of them affect the mobility ofT4 particles in gels. One mutant was found with areduced mobility compared to wild type. This mutantcarried a defect in a gene which specifies a minortail protein, but this would not be expected to affectthe mobility of the particle to any extent. Asexpected, revertants of this tail protein mutation towild type also had a reduced mobility compared towild type. This shows that the mutation affectingthe electrophoretic mobility was distinct from thetail protein mutation. The electrophoretic mutationis probably in a gene which specifies one of thehead proteins.

5.15 RADIATION GENETICS IN INSECTS - DAHLBOMINUS -W.F. Baldwin, G.D. Chant, A.G. Knight and P.A. Knight

In the interpretation of the genetic hazards ofradiation, the possible effects of environmentalfactors as moderators of response in irradiatedorganisms and their cells are of prime importance.In the chalcid wasp Dahlbominus, early experimentshad shown that heat before radxation had little orno effect in killing the insect. Heat followingradiation, however, had a drastic effect, and only afew survived more than 2 4 hours. Current experimentswith Dahlbominus are concerned with genetic effects,and tests of combinations of radiation and heat onthe production of eye colour mutants and major bodymalformations are in progress. Both eye mutants andmalformations have been scored after different com-binations of 250 R (at 100 R per min.) and heattreatments of 40°C for 45 min. Heat alone did notaffect the production of either eye colour mutantsor malformations; heat in combination with radiation,however, produced a high frequency of eye mutants. The

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same combination (heat during radiation) did not affectthe frequency of malformations, the rate of occurrenceremaining identical to that with radiation alone. Thusit seems that eye colour mutants and malformationsprobably arise through different mechanisms, the eyemutants presumably as point mutations, whereas themalformations may be due to chromosomal anomalies.

The synergistic effect of heat and radiation ininducing eye colour mutations indicated that hightemperatures may interfere with some importantradiation repair mechanism, and tests to explore thishypothesis have been partially completed. The datashow that when heat is applied to females at differentintervals up to 24 hours, the mutation rate undergoesa sharp decline, returning to levels given by radiationalone. Thus, in terms of human hazards, these resultswith D;hlbominus indicate that the frequency ofmutations which occur at definite loci may be enhancedby an environmental factor such as heat; this enhance-ment does not seem to occur in anomalies arising fromradiation-induced chromosomal events. Farther, themechanism of radiation-heat induced locus mutations isevidently amenable to repair, with numbers returningto control levels within 24 hours. A paper on thisresearch has been accepted for publication by MutationResearch.

5.16 RADIATION STUDIES ON BITING FLIES -W.F- Baldwin and G.D. Chant

In the development of research on the ecologyand possible control of mosquitoes, a thoroughknowledge of the species present and the seasonalsuccession of species in any particular area is aprime necessity. Studies to obtain this informationwere initiated here in 1972, and the results of thecollection of larvae and adults since that time haverecently been submitted for publication.

Larvae of the mosquitoes occurring in the poolsand swamps of the CRNL area have been collected byhand with small dippers. For adult collections, anew type of trap, consisting of a large tin with acone entrance, equipped with a light source and baitedwith dry ice, has been developed here. Our finalresults show that at least 26 different species ofmosquitoes breed in the Chalk River area. The pre-dominant mosquitoes were Aedes communis,A. excrucians,

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A. punctor, A. vexans and Mansonia perturbans, allbeing serious pests of humans. The species Culisetamelanura, a vector of eastern equine encephalitis,occurred in high numbers both as larvae and adults.

In the early spring the two species A. communisand A. punctor dominate as the principal BTtingmosquTtoes in this area. Later, in late June andearly July, this role is taken over by A^ excrucians,which in turn is displaced by NL_ perturbans and to someextent by A_ vexans.

The trapping of black flies in Deep River wascontinued in 1974, and it appears that control measuresfollowed during the past three years have substantiallyreduced the spring populations throughout the town.Data on numbers for the past four years are nowavailable, and are being prepared for publication.

5.17 PUBLICATIONS

W.F. BaldwinReport on Black Fly Control Programme.Atomic Energy of Canada Limited.Unpublished Internal Report CRNL-1236.

H.C. Birnboim and A. NasimDetection of pyrimidine dimers in hydrolysates ofyeast DNA by high voltage paper electrophoresis.Molec. gen. Genet. 130., 291-296 (1974).

N.A. Straus and H.C. BirnboimLong pyrimidine tracts of L-cell DNA: Localizationto repeated DNA.Proc. Nat. Acad. Sci. USA, 11, 2992-2995 (1974).

J.D. ChildsInactivation of giant bacteriophage particles bygamma rays.Radiat. Res. .59, 285 (1974)(Abstract).

N.E. Gentner and R.E.J. MitchelIonizing radiation-induced release of a cellsurface nuclease from Micrococcus radiodurans.Radiat. Res. in press (Jan. 1975 issue).

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N.E. GentnerRecovery from enhancement by caffeine ofradiation-induced inactivation.Radiat. Res. _59. 16-17 '1974).(Abstract).

N.E. GentnerEvidence for two DNA polymerases in Micrococcusradiodurans and for involvement of one Inrepair .Federation Proceedings 33.- 1600 (1974).(Abstract).

R.E.J. MitchelIonizing radiation damage in bacterial cellwalls.Federa t ion Proceedings 33 , 1242 (1974).( A b s t r a c t ) .

D.K. Myers and L.D. JohnsonEffect of X-radiation on the DNA-membrane complexfrom Escherichia coli.Radiat. Res. £0, 314-320 (1974).

A. NasimUV-induced replicating instability inSchizosaccharomyces pombe.Mutation Research 2_2, 25-31 (1974).

A. Nasim and B.P. SmithDark Repair Inhibitors and Pathways for Repairof Radiation Damage in Schizosaccharomyces pombe.Molec. gen. Genet. 132, ?.3-22 (1974).

M.C. Paterson, P.H.M. Lohman, A. Westervtld andM.L. Sluyer

DNA repair monitored by an enzymatic assay inmultinucleate Xeroderna pigmentosum cells afterfusion.Nature 2_4£, 50-52 (1974),

M.C. Paterson, P.H.M. Lohman, E.A. de Weerd-Kasteleinand A. Westerveld

Photoreactivation and excision repair of UV-injuredDNA in primary embryonic chick cells.Biophys. J. 14, 454-466 (1974).

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M.C. Paterson, P.H.M. Lohman, A. Westerveld andM.L. Sluyter

DNA Repair in human/embryonic chick heterokaryons.Ability of each species to aid the other in theremoval of ultraviolet-induced damage.Biophys. J. 1±, 835-845 (1974).

C.A. van Sluis, I.E. Mattern and M.C. PatersonProperties of uvrE mutants of Escherichia coliK12. I. Effects of UV irradiation on DNAmetabolism.Mutation Res. 2J5, 273-279 (1974).

M.C. Paterson, P.H.M. Lohman, A. Westerveld andM.L. Sluyter

Repair of UV-damaged DNA in human-embryonic chickheterokaryons.ICN-UCLA Winter Conferences on Molecular Biology -Molecular Mechanisms for the Repair of DNA, SquawValley, Calif., Feb. 24 - Mar. 1, 1974.(Abstract)•

P.H.M. Lohman and M.C. PatersonAnalysis of DNA repair processes in variouseukaryotic cells.ICN-UCLA Winter Conferences on Molecular Biology -Molecular Mechanisms for the Repair of DNA,Squaw Valley, Calif., Feb. 24 - Mar. 1, 1974.(Abstract).

M.C. PatersonUse of a purified lesion-recognizing enzyme toassay DNA repair in cultured animal cells.Radiat. Res. 5JJ, 7 (1974).(Abstract).


5.18.1 Presented papers

H.C. BirnboimLong pyrimidine tracts in animal cells DNA.Paper presented at the Canadian Federation ofBiological Societies, Hamilton, Ontario,25-28 June 1974.

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J.O. ChildsInactivation of gianc bacteriophage particlesby gamma rays.Paper presented at the 5th International Congressof Radiation Research, Seattle, Washington,14-20 July 1974.

>i.E. CentnerRecovery from enhancement by caffeine of radiation-induced inactivation.Paper presented at 5th International Congress ofRadiation Research, Seattle, Washington, 14-20July 1974.

N.E. GentnerEvidence for two DNA polymerases in Micrococcusradiodurans and for involvement of one in repair.Presented at 1974 Biochemistry/Biophysicsrr,eeting, Minneapolis, Minnesota, 2-7 June 1974.

R.E.J. MitchelIonizing radiation damage in bacterial cell walls.Invited paper presented at the 1974 Biochemistry/Biophysics Meeting, Minneapolis, Minnesota,6 June 1974.

M.C. PatersonRepair of UV-damaged DNA in human embryonic chickheterokaryons .Invited paper presented at the ICN-ICLA WinterConferences on Molecular Biology - MolecularMechanisms for the Repair of DNA, Squaw Valley,C a l i f . , F e b . 2 4 - M a r . 1 , 1 9 7 4 .

M.C. PatersonUse of a purified lesion-recognizing enzyme toassay DNA repair in cultured animal cells.Invited paper presented as part of a symposium on"Repair Processes in Eukaryotes" held during the5th International Congress of Radiation Research,Seattle, Washington, 14-20 July 1974.

W.F. BaldwinDispersal and biting response of black f l i es .Paper presented at the combined meeting of theEntomological Society of Canada and the AcadianEntomological Society, Halifax, Nova Scotia,24-29 August 1974.

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5.18.2 Lectures or seminars

W.F. BaldwinWork in the Biology Branch.Talk to visiting students and professors fromUniversity of Guelph, at CRNL, 11 Jcnuary 1974.

N.E. GentnerDNA repair.Lecture to visiting students and professorsfrom University of Guelph, at CRNL, 11 January 1974,

N.E. GentnerEnzymes involved in DNA repair in Micrococcusradiodurans.Lecture at the Ontario Radiobiology Group meeting,Victoria Hospital, London, Ontario, 15 May 1974

N.E. Gentner12 hours of formal lectures in Graduate Course65-603 (Bacterial Physiology) at University ofGuelph, Dept. of Microbiology. Lecture topics:DNA Replication, DNA Repair. Presented 2 8 Octoberto 29 November 1974 while a Visiting Professor.

N.E. GentnerDNA polymerase of Micrococcus radiodurans and itsrelation to repair.Seminar presented to Department of Microbiology,University of Guelph, 15 November 1974.

N.E. GentnerAspects of DNA repair in the extremely radiation-resistant bacterium Micrococcus radiodurans.Seminar presented 27 November 1974, to BiophysicsGroup, University of Guelph.

M.C. PatersonRepair of UV-damaged DNA in human-embryonic chickheterokaryons.Lecture at the Ontario Radiobiology Group Meeting,London, Ontario, 15 May 1974.

M.C. PatersonUse of purified lesion-recognizing enzymes tomonitor DNA repair in vivo.A seminar presented to the Biology Division,Oak Ridge National Laboratory, Oak Ridge, Tenn.,U.S.A., 24 June 1974.

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M.C. PatersonAn enzymatic assay to monitor DNA repair incultured animal cells.A seminar presented to the Department of Genetics,University of Alberta, Edmonton, Alberta,23 July 1974.

M.C. PatersonAn enzymatic assay to monitor DNA repair incultivated human cells.A seminar presented to the Biological SciencesDivision, National Research Council, Ottawa,18 October 1974.

5.18.3 Local Talks

W.F. BaldwinRadiation-induced eye colour mutations.Talk to students from Madawaska Valley DistrictHigh School, Barry's Bay, at CRNL, 17 January 1974.

W.F. BaldwinRadiation repair in insects.Talk to visiting Chemistry and Biochemistrystudents from Algonquin College, Ottawa, atCRNL, 1 February 1974.

N.E. GentnerRepair of radiation damage.Talk to students from Madawaska Valley DistrictHigh School, Barry's Bay, at CRNL, 17 January 1974.

N.E. GentnerEnzymology of repair in Micrococcus radiodurans.Talk to visiting Chemistry and Biochemistrystudents from Algonquin College, Ottawa, atCRNL, 1 February 1974.

N.E. GentnerEnzymology of repair of radiation-induced DNAdamage.Talk to visiting students from Sir George WilliamsUniversity, Montreal, at CRNL, 15 March 1974.

N.E. GentnerDNA repair.Talk to summer student guides on training courseat CRNL, 17 May 1974,

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5.19 INVITED SPEAKERS

1. Dr. W. ThiemannInst i tute of Physical ChemistryKernforschungsanlageJulich, W. Germany"Origins of Assymetry in Biological Molecules"22 October 1974

2. Mr. D.R. ChampDepartment of Medical GeneticsUniversity of TorontoToronto, Ontario"Endonuclease Activity of E^ coli"25 October 1974

3. Dr. I. BrownDepartment of ZoologyScarborough CollegeUniversity of TorontoToronto, Ontario"Gene Activity in the Mammalian Brain"7 November 1974

The International Standard Serial Number

CN ISSN 0067-0367

has been assigned to this series of reports.

To identify individual documents in the serieswe have assigned an AECt- number.

Please refer to the AECL- number whenrequesting additional copies of this document

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