Hans Karow Co:ilition to Reduce Etectropollution (CORE) 1; 15 Poplar Grove Road PIENTICTON, BC E-mail, hkarow@shaw.@ Mr. Robert J. Pellatt Cornmission Secretary British Columbia Utilities Commission Sixth Floor, 900 Howe Street, Box 250 Var,couver, BC, V6Z 2N3 Tel : (604) 660 4700, Fax: (604) 660 1102 E-mail: Comtnission~~bcuc.com December 18. 2005 Dear Mr, Peiiatt, Re, FortlsBC Inc. Order No. G-114-06 I Project No. 3698407Certlflcate of Public Cot~venience and Necessity Application far NkWip East Osoyoos Transmission and Substation ht~-//www. bcuc.com/i4~~licatibnVi~ev~.as~~~Ag~licat1o 16=-;93 Please accept a follow up copy of Evidence # 11 b, Bonneville Power Adminstration Book 'rEjectrica/ and Biological Effects of TransrnTsslonLines: A Review'', published 1996, Chapter 2 L'E~posure Assessment and Non-Cancer Human Health Studies" pages 2-1 - 2-37. Attached to ihls chapter copy i also lnclude for the partrcipants' conventence my Evidence # I1 a a one-page summary/assessmcnt conclctding that 46.67% of the studies in chapters 2 - 3 show positive (adverse) results due to EMF exposure. The faxed copies of this submission w~ll be sent only to the Comrn~ssion and the Applrcant Anyone else from the participant's list may receive copies as well (via fax) upon special request Re:.pectfuily submitted, Hans Karow C1-26A
Transcript
Hans Karow Co:ilition to Reduce Etectropollution (CORE) 1; 15 Poplar Grove Road PIENTICTON, BC E-mail, hkarow@shaw.@
Mr. Robert J. Pellatt Cornmission Secretary British Columbia Utilities Commission Sixth Floor, 900 Howe Street, Box 250 Var,couver, BC, V6Z 2N3 Tel : (604) 660 4700, Fax: (604) 660 1102 E-mail: C o m t n i s s i o n ~ ~ b c u c . c o m
December 18. 2005
Dear Mr, Peiiatt,
Re, FortlsBC Inc. Order No. G-114-06 I Project No. 3698407Certlflcate of Public Cot~venience and Necessity Application far NkWip East Osoyoos Transmission and Substation h t ~ - / / w w w . bcuc.com/i4~~l icat ibnVi~ev~.as~~~Ag~l icat1o 16=-;93
Please accept a follow up copy of Evidence # 11 b,
Bonneville Power Adminstration Book 'rEjectrica/ and Biological Effects of TransrnTsslon Lines: A Review'', published 1996,
Chapter 2 L'E~posure Assessment and Non-Cancer Human Health Studies" pages 2-1 - 2-37.
Attached to ihls chapter copy i also lnclude for the partrcipants' conventence my Evidence # I1 a a one-page summary/assessmcnt conclctding that 46.67% of the studies in chapters 2 -3 show positive (adverse) results due to EMF exposure.
The faxed copies of this submission w~l l be sent only to the Comrn~ssion and the Applrcant Anyone else from the participant's list may receive copies as well (via fax) upon special request
Re:.pectfuily submitted,
Hans Karow
C1-26A
CNSMITH
Ni'Mip CPCN
PAGE { I -
Exposure Assessment and Non-Cancer Human Health Studies
+ Most of the early health studies of people occupationally sxpossd to EMF used job t~tles to estimate potential field exposures. Early residential studies estimated exposure by describing characteristics of nearby electrtc power llnes and substations. * Small insfrumenls were developed to measure personal sxposures to EMF. Electric-field exposures are very d~fficult to measure because they are greatly perturbed by conducting objects including the body. + Average occupational slectric- and magnetic- field axposures measured for electrrcal workers ranged from about 10-700 Vlm, and about 0.1 4-0.77 pT (1.4-7.7 mG), respectively. Average electric- and magnetic-field exposures measured in homes and offices ranged from about 1- 20 V/m, and 0.07-0.7 pT (0.7-7 mG), respedlvely. + There have been about 29 studies of the generat health of electrical workers, and about "I 1 general health stud~es of residents pear power lines. About six studies looked for damage to chromosomes in electrical workers, + Reproductive factors were included in about 13 cslectrical worker studies, and in about six residential studies. About 22 other studies looked at spontaneous abortion or other reproductive outcornes among women who used comp~~ters. Seven additional studies involved reproduction and use of various sources of eiectric heat. + About seven studies looked at mental health conditions among electrical workers; about nine montal health studies were done of residents near power lines. * About 34 studies looked for effects of short- term field exposures on human volunteers under controlled condtttons. + Many effects have been reported, but reviews generally find that there is no strong, replicated evidence far adverse health effects from EMF. w w
M ost of the interest that first developed i n r , 1970s about possible ilun-ian hcslth tiiecl< r , power-frequency 6elds cm be tanccd to vcpnl ts + I rn
the former Soviet TJnlon Begrnnlt-tg in the ear.1~ 1960. Sov~et researchers began to study the health of u or kel i i n new high-voltage substatloas (400 kV. 500 l,V aqti
750 kV). Researchers attributed a variety of phy s roiog~ cal and subjective ailtnents to the workers' exposilt e 1 ~ 7
50-Hz cIe~tric fields (Asatzova and Rakov 1966) Tbr Soviet reports were first widely reported to tesearchei -,
in other countrres at a sctentific meeting In 19 '2 (Korobkova et al. 1972).
Although medical. evalua.tions conducted on 1 O I r nc- me11 trr the U.S 121 the 1960s revealed Tin harrrrFltl ts feces of electric fields (Ko~zwenhoven el a1 1967 J ~ i - r
Soviet repons prompted further stud~e'; lri other cniiri tnes The health effects ~cported by rile Soviet.. \ s e t *
geuexally not found in these .studies of s u b ~ t ~ t i o t ~ 1,. or L
ers 111 other counates Research 1211 electric fields and human health ex
panded 111 the 1970s and 19SOs, 10 part becau2e oi rc ports of adverse effects of these fields ott laboxarorc anf m d s fe g., Marino et al. 1976). In the c~trlv 1 9 R O s , 111
. Xncz ,, terest also developed in powcr-fi-cqucncy 1 1 1 - i ~
fields, prompted by reports about a porsthle assoc~atloir between these fields and human cancel-. Wettheirne: and Leeper (1979) reported that cancer rnortallt? wni increased for children who had lived near high-cut lent distdbubox? lines.
EMF and occupational cancer became an issue fc11 lowing the publicatjoil of a paper by Milhain (1981) Milillam reporced that men irr electrical occupations Washington state dned mot-e frequently florn leukeirir J
compared to me11 m other occupations. Slnce these early reports. hundreds ot s iud~c i h d - i
beep conclucted throughout the world on the poi i th effects of power-frequency fields nti huttian Iie,tl t i ,
These studies have coveted gerteral. heattt-i rnerrt~l
health, reproduction, and cancec Most of these ~ t u d t t \
BPA E!ectr~cal and Biulogical Effects Review
I L , ( iizi L W U ~ I L : w c L ~ W L ~ Y J ~ ~ ~ W L PAGE # * L -
used epidetiliologic methods, and a brief tutorial 011 egi- clemiology i s presented in this chapter. Several othcr studies were done with hurrran volunteers in labot-atory facil ilies.
This chaptci. scitn~naxi;..crs the large body of research or1 the possible effects of EMF 01% hrrman health, other than cancer. Research on EMF and cancer in occupa- tional and residential environtnents is covered in Chap- rer 3. Tn this chapler we begin by describing research that has been done to character'ize huxnatl expasure to power-frequency EMF.
EMF Exposure Assessment
General Considerations
for a person sta~?dtnp in a. 1 -kV/jn vert~cal 60-HL cli- lrtc field, the enhanced frcld at the top of the hcild .is o u i ~ be about 18-kV/m {Kaune and Phillips 19SC)) 1: 1 r * person sat down ox bent ovcr. t l~c licld would be 1 % than 18 kV/m. At this time, there 1s n o ay-eirrnenr ~ 1 - n ~ b t l :
scientists ab to wllat, ~f any, rneasur'c of electr~c-itt r exposure 15 most approprratc
As described below, variou\ devtces ha\ c bee11 { I -
veloped to aqsess human exposures lo clectric t r ~ i - These devices measwe the elcclrrc Sreld b~ detcctri~, thc currcnt induced by the freld between two cond~irs ing surraccs. Dtffercnt approache5 havc been ithcd i i
a11 attempl to correcl thc leadlngs obtarr~ed ti I aci.03.i h r cffecrs of piacemetit of the devices on dlffe~eili 1)-1
of the bodv. I11 so~ne cases tneasutcs were alee 3 t ~ oped to account for human actr~tty In the iiclcl
-
The early epidsrniologic Iiealth sti~dies of EMF wet-e often criticized because of problems in measuring cx- posures (Coleman and Beral 1988). Occupatiollal stud- ies oftcn used job titles to estimate exposures; some in- c;luded spot measLlrementfi of EMF in work environ- ments. Residenliat studies often described cxposurcs by cstirnnting the distance o.F homes from electl-ic power facilities. Tn more recent studies, sopl~isticated instru- ments have bee11 used to quantify exposures to EMF (Eracken 1993, Bracken et a], . '1 993, Kavet '1 995). The pioneering efforts to develop instrumentation to mea- sure personal exposures to EMF are described in the scctiorw below,.
Electric Fields
4sscssing human exposure tn pnwer'frequency elec- tric fields I > very difficult because tlie prescnce of the body (which I \ a conductor) grcatly per~urbs the field,
Magnetic Fields
The body does not perturb power-rrequenc .c inn: netlc fields, so rneayuring hu~llan exporure to rheie l i t l i t
1s not as difficult as for electra~c fields Sevclai i r r 1 ~ ~ 1 magnetic-field exposure meters have- bezn develn:Ti-; that call be worn by people as they do thell 11o1 nial . l~ trvilies. These rnet-crs rnc7asui4e the ti~agnetic tleld ,.\ detecting the voltages induced on coils by rflc i-i-iagtieri z field
Three-axis per\onaI magnetic field e.ipc?>ui e rncrcs I-ecord at specifjc tinic 11iter~~a1s. the I-ei~rl tant i ICLI i tl-rc pottlt 01% the body whcrc t l ~ y ~11-c wo11-1 i i i j r ~ i i
cared above, the presence of he bod) dock lint -1tr--
this parameter. Howevci, the zrzc ,und po\ritc?ri ot r 3 body In relat~on to the magnet~c-ficld ioutcch iirb c t r
the cul-rents and electnc fields itlduced In thc tmr- 1 1
magnetxc fields. The electric f ield at thc surface of various body parts, and the amount and distribution of currents induced Oecupational Exposures
v
wtthin llle body, tiierefore, change wit11 the positlon of thc body, e,p., standing, iiitting, bendlng over
Foi- iristar?ce, assume that a person stood perfectly still for I hour in a I -kV/rn electric field (as measured without the person present). In this case, a basic mea- sure of cxpusure could bc designated as I -kV/rn-hour. However, if the goal. is to relate exposure to some po- tential biological effect, then it is necessary to specify what sspcct of exposure is of interest. At least three basic possibilities exist the electric field at the surface of a body part. the latal short-circuit body current, or thc induced cu.~-relit density across somc body part. All of these parameters are affected by body position and tlie pi-e-sence of nearby conducting objects. For example,
Electric Fields
Deno (1977. 1979) described one af the frrsr LI c of a device to neasute occupational exposuies to b0-F electric fields. In h is studies, small rnekrs were r ie l sl oped that could be atmched to a worker's hard hat el tl
an arm band Thc meters rccordcd the itme r t~tegrai T~
the unperturbed electric field In kVIji1-hnu1 c1 01 I T I * ~
grated the fielcl into three ranges: less than 5 k\'/n?. 1-t
tween 5 and 10 kV/rn, and greater than I O kV/irl
The work by Dcnu ( 1977) p~~o~nptcd i-ese,trcIi;r- Sweden to develop an Il-r.;t~-u~-l?ent tn measnte ~ c i - t \ i i
exposures to 50-Hz electric ftclds in t~-an~n~t.;ric?r statjons (Lovstrarld ct al. 1979) The mea\ut In?
2-2 BPA Electrical and Biologtcal Effects Review
L L I V S L U U J I L . " I L J U L t J J O J U L PAGE 1'5
Chapter 2.- Exposure Assessment K Not?-Cancer Health Studfes
O.i)O l kVll-rx-hours. In contrast, For all 500-kV work- ers combined,, the tnedian cxposure was about 0.5 kV/ m-hours per day. The highest (90th.-percentile) cxgo- sure W ~ S about 5 kV/rn-houl"s; it was recorded by clec- tt-lcians who worked around 500-kV Facilities.
A study in the U.K. also employed a small rnotcr to assess 50-Hz elcctric field exposures (Broadbent et al. 1985). The tnoter was worn on the wotker's upper arm and it had a measurement threshold of about '1 50 Vlm. During a 2-week period, only 28 of 287 electri- cal workex-s received exposures above 6.6 kV/m-hours. Es~irnates were made indcpcrxdently, fror a 6-month pe- riod, of percentages o.f working time spent in fields of I. .5-5.5 kV/m, 5.5-9.5 kV/m. and greater than 9.5 kV/ in. For the most highly exposed group, estimated per- centages of working time in the three ranges were 5.6 percent, 15 percent, and 2.2 percent, respectively.
In another study, a specially designed vest was used to Jncasure electric-field exposures I-~ceived by people in various fastming. rccreati~nal, and hnusehold situa- tions (Silva 1985) (Fig. 2.3). The large surface area o.f the vest permitted detection of 60-Hz electric fields as low as about 50 V/m. For the 18 farnls studied, the average time a farmer spent in fields above the thresh- old r?.f perception (3 kV/rn) was cstirnated as 1 I~our per veal- for farms with 500-kV lines, and a few hours per year for farins wit11 765-kV lines. The total curnu- larive exposure (in liV/m-hours) for farmers working near transmission lincs was comparable to the cumu- la,tive domestic exposures, ~ b o u l half of the latter ex- posure was related 10 the use of electric blankets. The I-ccrcation:il exposures studied (jogging, bicycling, horseback riding, skiing) wcre i n general lower than those estirt~ated foi- both agricultural and domestic ex- posures.
The performance of the electric-field monitoring vest was compared to the small BP-4 electric-field ex- posurc meter (EFEM) during 2 days of cont~~olled test- ing (Bracken 1985, 1987). Seven men wore the meters during a variety of activities to simulate work tasks of subsca,tion eleclr-icians and operat;ors. The vest and the EFEh? produced similar rcsults when the EFEM was worn on the arm or hard hat. When worn in a shirt pocket, the EFEM recorded field level?; 30-40 percent lower than lcvels I-@corded by the vest. Both rncters were judged to be adecluale for lneasurirrg occupational exposures In elcctric fields. Only the vest was judged to be suitable for trteasul:ing public cxposute to low- level electric fields.
Canadjan researcbcrs developed a small electronic instrurx~ent ellat could record EMF and transient fields for LIP to 2 weeks (H6roux 1991) (Fig. 2.4). In an ini- tial lest of the meter (later called the Pnsitmn), electtAi-
cal workers' expoqures to eleclr~c field5 on Il?c lob 2 11 at home were studied (Dcadtvan czt a1 li 988 t . Esposrr rL
meters were wort1 on a bclt or In a shirt pocket a t XT or
and at home during a l -week perrod Thc elactrrc fic i ~ l
th
r
eshold of dctect~on fnr thc metel* was about 200 X r the sarnp11ng rate wa5 I mtnute Resultr of the \ i l r L i
rhowcd that, I'or 20 electrical workers, the peobnetl rnean of the TW.4 ( t l~~~c-we~ghted ii\/er..ige) e lec l l~~-f i exposure at w o ~ k was 38.3 V/I?I, c o n ~ p n ~ e d tn { I , ,
4 9 V/m for 16 ofhce w o ~ ken For tlic electrrcal v , 7 1
ers the exl3osure.l ranged froni 4 7 Vitn foi 3ppx13t: mechanics to 4 1 8 9 V/rn fol trar-rsmission Ilnirmcn
EPRI sponsored development oS a dlg~t'+I e ~ p o s ~ l r - monitor called the EMDEX (Silva et al. 19881 ( F I ~ 2 - T h ~ s portable unit meawred both electric a ~ l c l rnagrict, fields, and could operate for up to several days on oi3
charging. A large mulli-ut~lrty occupational ~ I Q O ~ U - ?
study was conducted to obtain informatton on perf.)- mar~ce of the EMDEX under actual opeiating LQTI,;~
lions (Bracken 1990, Bracken et al. 1995b) Electric-field exposure data wsr-c collected ibitll ti I
EMDEX for 2082 workdays and 657 not-rwot k pel-rot1
(Bracken 1990) Becaiiqe of pt-nhlems 1r1 relating r EMREX data to the unpertiirbed elecrr~c field. I E . ; ~ ~ r
trode was attached to the wn~ker's hard hat, and the elec- tronics package was on!-ried 011 a belt, In initial tcsts, electric field exposures varicd. greatly, depending on the pal-ticrrlat. work activity. The highest cxposut-e rccorded wa'; for persynnel WOI-king for 3 hours on toy of a cir- cui t breaker where 3 1 perccnt of their time was sp r t~ t in fields above 10 kVln1.
BRA resea~.cbcrs also clevelnped a st??all I 1 8 g (4 ozj electric field espnsur-e monitor (EFENI) to mcasure the electric field crlvironrneni for- high-voltage workers (Chartier c t al. 19351 C11ar.liex and Brackcr~ 1987). The EFEM was worn on a hard hat, i n a shirt pocket, or un a lany aid (Fjg. 2.1 ). 'Tests were conducted to determitie electric-.field enhancement factors For each of these lo- cations. Resu1.t~ of the BPA study (Fig. 2.2) indicated hat, even for the ~nosl exposed personnel (230-kV and 500-kV workers), cxposurc to unperturbed f ie lds above 4 kV/m occurred for only minutes per day (Bracken and Chat~ier 1987)< However, acc~unulated expQsurc for high-voltage workct-s was nearly three 01'-
d e r ~ of mag~?i,tude gl'eatcr than exposures for office workers.
As shown in Figure 2.2, YC)S indoor workers (the T~OII-exposed group), t hc median daily cun~ulative: elec- tric fieid exposure above ~hceshnld was or.tly abuut
I
I Accumulated Dally Etectrie-Field Exposure (kVlm) hour
I 0.007 0.01 0. f 1 .0 10.0
All 500-kV workers (n=247)
I l i i l l i l l i
BPA Electrical and Biological Effects Review - ? - ,?
A i l I V . L U V 4 I L - U I L J V W J J U J U L t ' 4 ~ k
Chaoter 2: Exoosurt, Assessment 8( Non-Canc@r Health Studies
0 , O O l kV/m-hours. In contrast, for all 500-kV work- ers cotnbined, the median exposure was about 0.5 kV/ m-hours pel- day, The f~ighcst (90th-percentilc) axpo- sure was about 5 kV/r-n-hours; it was recorded by elec- tricians who worked around 500-kV facilities,
A 5tudy in thc U.K. also employed a small meter to assess SQ-Hz elecrl-ic f'ielcl exposures (Broadbent et a]. i 9;55). The meter was wort? on the worker's upper arm and i t had a fneilsurement threshold of about 150 V/m. During a 2,-wcek period, only 28 of 287 electri- cal workers received exposures above 6.6 kV/m-hours. Esti~nat.cc'j wer t tnadc independently, ~ Q J - a 6-month pe- riod, of percentages of working time spent in fjelds nf ! '5-5.5 kV/rn, 5.5-9.5 kV/m. ai?d greater- tfiarl9.5 kV/ rn. For. d?e most highly cxposcd group, estimated per- centages of working titne it5 the three ranges were 5.6 percent, 15 percent, and 2.2 pcrcen.t, respectively.
Tn another study, a specially designed vest was used to tneasurs elcctx-ic-field exposures received by people in variou~ i;;fn?~ii~g; recreational, and Itousehold situa.- rims (Silva 19851 (Fig. 2.3). The larse sufiface area of tile vest permitted detection of 60-Hz clcctric fields as low as atmut 50 V/m. For the 18 farms studied, the average time a f'at'rncr spent in ,fields above the thresh- old of pcrceptio~l i 3 1;Vlm) was cstiniated as 1 hour per year for fxmz; with 500-kV lines, arid a few hoitrs per year Sbr farms with 765-kV lines. The total curnu- lative exposure (in kV1m-hours) for fa]-mers working near transmission lines W8S colnparable to the culnu- lative domestic exposures. About fia1.f of the latter ex- posure was relaccd to the use ol'elcclric blat~kets. The rccrcational cxposurcs seudieci (jogging, bicycling, horseback riciing, skiing) were in general lower than [hose estimated fhr both agricultural and domestic ex- posures.
The performance of the electric-field monitori.ng vest was ca~npared .tu the firnall BPA electric-,field ex- jwsu~-e Ineter- (EFEM) du1~i12g 2 days of controlled test- ing (Bracken 1985, 1987). Seven men wore the tnerers during a variety of activities to sitnulate work tasks of substation electricians and operators. The vest and thc EFEM produced similar- results when thc EPEM was wo~t -~ on tlie arm or hard hat. When worn in a shirt pocket, the EFEM recorded field levels 30-40 percenr lower than fcvels recorded by the vest, Both meters were ,judged to be adequate for measuring occupatior~aJ exposures to electric fields. Only the vest was judged to be suitable for !measuring public exposure la low- lexrel electric ficlds.
Canadian I-eseai-chers developed a srnitll elecrro~lic instrument Lhat could rccor-d EMF and. tral-isient fields for up tu 2 weeks (Htroux I99 1 ) (Fig. 2.4). In an ini- tial rest of the meter (latcr called the Positron), electri-
cal worker.;' expo\ures to electrtc t~e ld i 012 tile ii'r) ii
a1 home were btudied (Dc,ld~nan er a1 198% 1 T;xpo..i-
meters were worn an a belt or in a shirt p v ~ E . e ~ a[ v, li
and at hottlc dul-tng a I -wcek parrod The electrrc tir
threshold of detectior? for the rneler was about 2011 \ :i
the samplti~g rate was 1 minute Results of t h e stn;i-
showed that, for 20 electrical worker?, thc georriert - mean of the TVVrA (rime-weiglttcd average) eiccLr1~- l I C ~ 8
exposure at work was 4 8 3 V/m compnrecl to 4.9 V / I ~ for 16 office wvrkcts. For the elecl~ical 1% i l i k
ers the expohures ranged fi-om 4.7 V/n? tor appaiatu tnechanrcs to 41 8.9 V/m for transnusston li~lcrnen
EPR1 sporr.;ored development of a digital exgosur - monitor called the EMDEX (Srlva et at 19881 rF1g 5
Tl?i~; portablc unit rneasur-ed both electtic and t ~ l a g n s t ~ fields, and could operate for up to cevcral d a ~ i ~ t l l r r -
chargrng A large rnultl-utjhty occupatlonLd e\l-?oci1i study was conducted to obrarll tl~formation uri r l t r T (
cn,. mance of the ER4DES under actual oyterattn, [tons (Brackcrt 1990, Br;tc\cer? ct 31 1905b).
Elactr~c-fteld exposure data were ioilectcrci n. tit) I 1
EMDEX f o ~ - 2082 workdays and 657 nonwork per I + 8-
(Bracken 1990) Because oi'prnhletni i n relating 1 1 1
EMDEX data to the unperturbed clcctric i~elii te~iii:
were presented as relative compariso~~s among job cat- Researchers in Deni-i~ark used ti Posit~on meter to egories. Thc highest elect!-ic-field exposures were re- measure occupational exposures to 50-Hz EMF iSkottc ccived by lirle workers, substation workers, and utility 19947. Tn thc study, subjects wore the meter dur i t~g a ciectricians. Office ~x/orltcr:, ~~eccivcd the 10west clcc- 24-i~our- period. The incdians o'f the miian electr-ic-liclii tr'ic-,field cxpoxurcs. exposures duritlg worlc for utility cmployccs in ~ c n c r i i -
tion. transmission, clistrihutii~n. and ~uhstaric?r~x wer,:-1 9.7, 53.9, 6.2, and 17.5 V/m, respeci.ivelv. Thc 95i11-
I I I i percentile exposures for these h u r occi~pational catego ries rangcd from 24.2 to 592 V11n
Magnetic Fields
Effol-t% to cievclop ~ n ~ t ~ x ~ n i c n t s t o rnea\ulc pel i . n ~ i
exposure to power- li zquetlcy tnagnetlc field5 t k ~ l lev, cci
Ihc work with electric fields. The fir'sr rt?struinen%i \r c1c7 developed, in the early 1980s (Fujlta andTenfi71 de 1 92.2 Lo ct 31. 1986, Male et al. 1987)
The BPA electi-tc-tield expnvul-c meter IEFEM I t ~ a i
lnod~fred to rneasurc 60-Hz magtletic-freld cxpo\u ie~ by adding a wtre cot1 rn the form of a bandolier uo~i ; across the chest, T h ~ c version was ba\ed on t112 cle\~gi i ol' Male et aI. 119871 The rnstl-umznr tncasil~~eii I tic
4-~acond avarage of he r n a p e t i c IrclJ on rhc st . l t \ ( f i :-. 51n'tll study \\!:IS conducted to tesr ~tre fc : \k .~l - \~ l~ , ; ( , * * I
ing the single-asis ~ r ~ s t r u t n e n t t o collect bra , , I . . I .:,
patiorial ~ X ~ O S L I I - 2 s ( R r ~ c k e r ) 1988 I . Fc)I. e~;hr -.:I!: .:+c
t ion operator days. t11c i n s t ! - r ~ n ~ e ~ i r t.c.;c~rd:-:~l : t , .!..<:I :::- ina;<rlzi~c-ficld esyosur'? o l 9.41 : ( ; . _ ' h ,I.!- . : '
2.8 mCI. In cornpartson, l o r tilne or'rlie u t ~ he1 iinl the average exposure was only 0.074 +. 0 036 1-17 ( 0 -4
i. 0.36 mG). Although occupatrnnal erprj\iire n ~ c a - ~ i ~ c rnents w ~ t h he rnetcr were fiastble. the re>c:rrchr~ r -ug- gested that a three-ax~s meter might produce ti lo^ e ~ u l i - able data.
The personal-exposul-e meter used ir? the .iiudl h\ Deadman ct al. (1988) (crrors corrected 111 Dectdi-i-idn
1996) was a three-axt:, Instrumelit that ~-nea\ured the 60-Hx rnagncclc field at 1 -minute ttltcrcali l ' l l ~ rnctct could also rccord h1gl.1-fnequency translent freldk in t l ~ r 5-20 MHz range In a 1-week tent of the mekr w ~ t h 1 k ut i l i ty electrical workers, the geornctnc mean magtici IC- field exposure dul-ing w o ~ k wd> 0 77 pT (7 7 1liG1 The highest work exposu~-e I-ecordcd bt nppat-ntu5 clct*i I i clans, had a geoinctric insan of 1 2 pT ( 1 2 1 ~ i C r i Tl l r comparison group of ~lonelectrtcal \;\.csrkers had -7 (-11 h cxposure geometrtc mean of 0 07 pT (0 7 1nG1
Thc EMDEX pel sc-rnall-e~posure mctcl- w35 ube2 to ahsess occupational arid home cxpo,urc,c, to pou ei-t7c quency rnagnetlc fields in a large study 1nvolv11-12 2 %
i~tiltty orgamzations (Bracken 1990) The EMDEX 1. .. three-axtq magnetjc fteld rnctel that can be p~ ogi winr r i t - i !
to take measurement3 at reoular intervals. ant1 to sior.z
BPA Electrical and Biological Effects Raview ?-i - -
Chapter 2: Exposure Assessrnenf & Non-Caocer Health Studies
data ur?til they are dowrlloaded to a persotla1 computer. wcttnen was 0.32 It 0.15 pT (3.2 2 1.5 inC]. TIIF 111<i1rj-
During thc multi-utility study, mugl-ieiic .I.iclds were mea- for each wornan ranged from 0.1 10 0.65 ,uT i I-.6.5 niG >urAed every 10-seconds by EMDEXs worn on the hip The high end of tile exposure runse wai; fcj~ttid t~ 5; by uborrl2000 workers j r ? the srudy (see Fig. 2.5). caused by electrical w i r i t ? ~ betiealh chc tlool- 01' i i j I:
Sotne of rhc genera\ i-esults of the EMDEX occupa- woman's workstatiun. Even with all oti-icc ci j i i ip~~ieri i riunnl cxl?osure stucfy are shown i l l Figure 2.6. Work in turned off in ttfc workstation, the backgsaur.iri m:Jgncti<- s ~ h ~ ( a t i o n ~ urns assc~cio(ed cvitli the highest incdian field cvav still 0.5 LT ( 5 mG). 1,rlagnetic-ticld exposure; 1.056 &-1" ( 10.56 mG). The Development c>f a very stnull r~iagnetic- 1-ielcl is n lowest occupational median tnagncric-field exposure. sure rneter that call be worn or? the wrist wai ipr1n.n::'
0,098 p,T (0.98 ~ I G ) , was I-ecosded by war-kern it? of- by EPRI (Fig. 2.71. The tirsl rnodcl uf (he Increi. ,:;i:ii- frces. ANIEX (averitgc 11tttgnetic-l'iei cxpo.:i~i e sy.;tetii I. \,.
I n the Dnnisl~ s t~ldy (Skocte 1(394), a Positron ~nctcr a single axis meter that au~ornatically r-ecol-ded ciii,ili:,,
wzis used 1.0 rxieasurc occupational exposul-es to 50-Hz tive inagne..tic:-field exposure ovcl- time. ,A later ! I I ~ - , ~ c ,
n~agrtttic fields, The medians of tl2e mean rnagnetic called the AMEX-3D was a three-asi.5 ineler- \i.'zigi,~:l,. I'irld exposures ciuritlg work for utiiily employees in 120 g (3.2 oz) that i s cvorti in a hip pr?cCo L I 01. III.IL:+:~
tt 'ar~st~~ission, distribution, and substations were 0.56 (Kaune ct al. 1992). (5.6) . 0.14 ( 1 .a). aijd 0.89 (8.9) pT (mCij, respectively. The two AMEX models wel-c co~-tiparru ill .I 1.e.. The 95lh-percct?tile cxposurcs .l'or ti.~e,.;e tlircc occupa- i l~vo lv ing 50 c~nployees, students, and .;pc?use,q ti-oil: :,
iionnl categories ranged from 1 .S to 2.5 pT ( 1 5-25 tnG). medical ur~iversity (Dlugosz el ni. 1994). Thc pci'r: i t
Pc,rs~nnt expclsuihe nlercrn were used la asscss 60-Hz wore botlt of the rnodels at the san-tc t i w e 1.01- 2 i i ~ ~ magnetic-field exposures of fc~nale einployees i n a11 The mean n~agnetic ticld recol-ded by rhe PIhqEX ii,ixk
olTicc environment (Bj*eysse er al. 1994). In thc study, 0.07 pT (0.7 rnGi with a range OF 0.02-0.27 VT (i? 2- IS wornel? who wor-kcd with computeel's in a payroll of- 2.7 ITIG). The corresponding mean and range ~-ccoi-dec! fice warc an EMDEX tnoniror in a hip pouch during by the AMEX-3D were 0.10 pT (1.0 1nGj. and (1 !!.:- ~?lost (31' one work clay. TIw 1xzcat.l exposure ,i'or all 15 0.31 pT (0.3--3.1 mG), respcctively. D i f f e ~ . e n ~ c ~ kt--
ribution (n=1771)
Travel (n=7618)
2-6 BPA Elecfrical and Biological Effects Rsvi@w
Chapter 2: Exposure Assessrrlenf & Non-Cancer Healti: Si~do, i
tween the readings i'ot* the two AMEX models were rnost Itkel? cltie to clectl-ical dtfferer~ccs between the meters, and to diffct.ences in wl7a-c they were worn on the body.
Residential Exposures
Electric Fields
Silva ( 1985) used a spccial vest to ~nake extensive t - r ~ ~ t t s ~ i - n e s o.F personal exposures to (70-HZ clectvic fields i t? residential cnvirontncnts (see Fig. 2.3). Expo- sures were reported i n tcrtms of' equivalent fields. The ccluivalcnt electric field i s the field that would induce thc .same body currcr?r as that ir~duced it1 a grounded person stilnding in a ut~i1i-tr.m ficId of thc satne strength.
To estit~latc annual exposure, the equivalel?t field data ware combined wit11 estir?latcs of: the arclount of time spent ~ I I VEISIOUS activities. For cxample, a pet-son reading by a Ian-p enpel-icnced at1 cyi~ivalsnt electric field 0.f about 9 V/m. If this; ctctivit,y occurred fur 7$0 hours pet' year. the a ~ ~ n u a l exposure fi-om that activity wc~irlcl be 6.75 k\rfin-houts. Based on this approach, (he estimated atmuall electric-field cxposul-e I-eceived by a perwnin a typical home was 69 kV/tv-hours, almost half of wllicb was fidorn a n elcct,ric blanket (SiIva 1985).
117 the ~ c c u p ~ t t i c ) n n l study by Dcadnlan ct al. (1988) workci-s were afsc, asked to wear the Positron meter when they were not at wurk during the I -week test. ,AT nrghr: they were to place the tucrer r?eard the bed but not near an electrical appliance. The geometric tneaa of che lime-
weightcd average electric-field exyosure d ~ ~ i - i n ~ ti;':
tlonwork periods was essentially the samc for boll1 c l c c ~ trical workers and office workcrs ( 10.8 and 10.5 \'!I I :
respectively). The EMF personal-cxposurc ~ t t ~ c i y in Dcnmai-h
(Skrrtte 1994) ii~clvded horne exposures nl' 3% peny~le living near vverhsad. powcr lincs, 6 li\/ing neal- an i l l ;-
dergrnuncl cable, and 5 living ncax a subsrnrinrl. Tlte power liljes ranged in voltage k'rotn 50 ta 400 k'V. I-101nr exposures were also measured Ihr 267 pec~ple ~ ' I l c i it!^^ not live ilear power. lines. The mediiln c?f tlic rnciln e x -
posure?; for people living near the electi-ic power f:iil i I -
ties was 21.9 V/m con?pated to 17.5 Vim tor pei>pl r L., cet-I- ~ i h o d.id not live neat- such facilitieg. The 95th-1'-r
tile exposure for the two groups was 91 \i/m. :ins: 47 V/m. respectively.
A Ciii~adiar~ sturl y iised ~usicron tile tci-s 10 C O I ~ I l331-:
60-Hz EMF exposures for 18 pcoplc who iivcci t i i r l : i ~ -
60-715 IT (190-241)ft) froin a 735-kV rrnnsinir;zinri l i r i ~ .
10 17 people who lived more than 366 111 11 200 11, (:I-~?IT
such lines (Levallois er al. 1995). Tola1 elecubic i i ~ l i i
0 noni- exposure at home (geometric mcan) for those i i vtnz the lilies was nearly twrce as llrgl? as for t t~nsc a u a l f'som the ltnes (26.3 Vlm, 14.0 V/m, rcsyectr\eI\ ) D.11- tng hleeping time, exposure for tho.;c near the 11ne n
2.8 times gxe-atel (27 3 Vim. 9.9 Vltn. tespecri.el\ i Fr boll? homf: total and sleep~ng expoiure5, the drffcir c n ~ r between thc two groups were stat1 \tical ly \ I g n i F i ~ , i i i t
Magnetic Fields
Pcrsunal rnagncttc-ileld exposLitei c\ et e t-ndiir. (i t$:
1"E nonwork time in the occupai~onai P Y ~ ( ) \ U I r: I J L ~
by l'3earltnari er a1. ( 1988) (erarnri rol recteci 113 D<<icin> I
1996). The iloliwol k gearnett I C rnem c ~ f the TU A r ? i -2
net~c-fteld exposul e Tor elec~rrcal wol.kel \ 0 ? i t i!-
(2 11iG). compared to 0.1 I pT ( 1 I inG) for office u. rlri. ers. Autl?orc of the ctudy wggestcd that tlic 111ghc1 c\ posure for the elcctl-leal wvrkcrs tmay ha\c bccn CL~L I -C~
by rnisclasstf~cation of sotne work rime ai tlon.v;oii,
Data on I-e.;~rfenttal 60-Hz magnetrc-ttcld expo.111 i i
wera obtanned in a study or over 300 homes t h ~ o u g h ~ i i t the U.S. (Erdcken 19943 A pr irnary t)hlec,t~>< i'i ihr
study was to collect rnensur'ed darn on rn,~grieLrc t ~ z l d assoc~atecl with thc power-line cnnfigu~ ation type, f i r \ r developed t n the ch~ldhood cancer i t ~ ~ d y bv M'cz~~rtieiiii~r and Leeper i 1979'1. For part of the study, pet sonal t-ri,ig- ntttc-field exposure data were collecred ki 1rh EklDl- '\ meters using a 10-secolid xirnpl itip intei x dl Sor-i~r I.?
t h c x data a l c . ihoun in F I ~ L I I C 2 8 Tl ic >tuiIv t r i ln
that people i t ) very-I?~gli-cut,~ent-confi~~~t ation lio~n -
BPA Osctrical and Giological Effects Review
L L 1 1 6 I L O W 3 A d : a i L 3 W q Y d i J 3 W L PAGE 1-
Chapter 2: Exposure Assessment & Non-Cancer Health Studies A-
tiad the highest magnetic f ield cxposures. Ovcrall, the power line classification types were poor predictors of residential rnagnctic fields becctusc o,F high variability.
Personal 60-Hz rnagt~ctic-field exposures i n homes were also obtained i n tht; EMDEX occupatii.tna1 srudy (Bracken 1990') (Fig. 2.5). The ineclian of the mcans for continuous exposures in the home was 0.073 ,LLT (0.73 i11G)~ and the 951h percentile was 0.401 pT 14-01 mG).
A study in ,h/lait?e used EMDEX meters to measure ~nagnetic field exposures of people living adjacent to and fat- away from trarlsmission lines IKavet et al. 1992). The mcan magnetic-field exposure at home for five pmple who lived within 9 ) tn (300 ft) of the center of a 345-kV transmission line rigtll-of-way was 0.3 13 pT (3.18 tnG). For 15 pectple who lived at least 213 rn (700 ft) from any transmission line, the mean exposure
at home was 0.159 p.T ( 1.59 rnG) The dllfcr e n c i twecn these mean exposures for the two groilps 1% n i --rcj
~lstically stgnificat~t In the Danish qtrtdy. the rnecl~an of the T'Ct -4 pcl
sonal magtiet~c-field exposure of people i ~ \ ing neclr trtc facrlities wa\ O 24 pT (2 4 rnG) iSkottr l'zjQ4-l F people who d ~ d not l i v e ncnr power l a c l i ~ t ~ s c . ~ h z r dlan exposute was 0 05 pT (0.7 rnG) Thc 9 5 t h ~ e i . - tile exposure Tor tlie twv gronys was 1 54 1-17 ( 12 - r 7 "
aad 0 17 11111 (1.7 1-G). respectl\~ely Tn R Canadian sltldy, 18 people Ilvlng near a ' 3 5 - b :
transmission ltr te had magnet~c-field expo~ul e\ 3 t l w r - that were s~g~lificanrly greater than those of 17 [ teo i l l who did not llve by such llnes (Levailorc et .ii iY'- ' Total exposures at borne (geotnctr-ri rnciirl) lor klic r 7 -
groups were 0.71 pT (7. Y mG) and 0.16 pT t l h mC respectively. During sleep the expowre rarro i n ] tpic
Magnetic
Field
0.0 1 I I I I i UG VLCC OLCC OHCC VHCC
Underground Service: N o overhead llneo within 40 m (130 ft) of home.
(77 homes) Ordinary Low- Current
/ Conllguration: Very tow-Current Primary or secon- Configuration: dary d~stribution Only overhead I!ne within 40 rn line withtn 40 rn (1 30 ft) 01 home (130 ft) I$ the ltna (79 homes) sowlng the home
f41 homes)
I Ordinary High- Current ConfigurSt8on; Tranernisslon lrne wlthin 40 rn (730 ft), 08 primary distri- bution lrnd withlr, 20-40 tll (84-1 30 ft), or secondary dlstn- butron line wwlthrn 15 m (50 It) of home.
(84 homes)
Very High- Current Configuration: Transmisstor l~no or large drstributron lrne with+!? 15 m (50 ft) or a sil-ail distribuhon ltnc wllhin 7 6 1- (T5 it) of home (50 homes)
2-8 BPA Elleclrical and Biological Effecfs Review
1.41 161 L W W ~ I L : W I L ~ W ~ Y J U ~ ~ ~ L PAGE & -
two groups was eve19 greater: 0.68 pT (6.8 rftG'), and 0. I I blT ( 1 . I mG), I-cspectiveiy, All ofthese differences between the two grr7ups were statistically significant.
24-Hour Magnetic Field Exposure
In tllc study by Deadmun et at. ( 1 988) (en-01-5 cor- rcctcd irt Deadrnan 1996) subjects wore r l~e Positidon mctcrs at work and at 11c1me for about 1 week. The geo- meti-ic mean of tlie weekly TWA tnapnetic field expo- sure for electrical workers was 0.34 btT (3.4 IIIG), corn- paredto 0.10 yT ( 1 ti7G) l'or Ihe office avorkel-s, T11c 3.4-fold diffcrctlcc i n mean exposure hetwccn thc two groups wits statistically significant.
FOI- the pec.q~le l i v i ~ ~ p t?cal- tl 345-kV transmission line in Maine, their 24-t~aur- magnetic-iield exposure was 1 .d-i'old greatet. than the mcan li)r.peoplo living far away L'rom tl~a~~stnissior~ lincs: 0.259 WT (2.59 mC), and0.157 krT ( 1.57 niG), respcctivcly, The. diFferen.ce was statis- tically significat~r. There was n(.; statistically signifi- cunt difcrcilce between the two groups for mean mag- netic-ficld exposttre wl~ i l c peuple wcrc away I?om hotne. ('These data excIude one person w110 had a very high cxposurc away from honw and was cot?sider,ed by tlze aitthnrs n i the study to bc i1.11 outlier.)
The 21-hour magt~ctic field exposure (work plus home) fur- pcnplc living tiear a 735-kV l i i ~ e ici the study by 1-evallois ct al. ( 1 995) was also significantly greater than for pcople living away frot?~ the line: 0.49 1,tT (4.8 rtlG), ~ ~ t t d 0.17 }AT (1.7 I-IJG), geometric means re- y3ecrivcIy.
~/lagnctic-i'ielc1eti-filc exposures over 24 hours we,re esti- rtlnted fiAotrr dosilnete~-s worn by electrical tvol-kers and by people living near trat?srrrissina? Iir~es in De~rt.mark (Skotte 1994). The averagc exposirre for the group of workers i n generation, rranstnission, and substation, was roughly the same as fh1- tllc peuptc living near transrnis- sion lines-about 5 pT-hours (50 me-hours).
AMEX-3D meters were used to assess magnetic field cxpasures of 29 children in tile Washington, DC area (Kaunc et al. 1994). Children wore tlie meters 'for 24-hours and exposure data were obtained for hornes, chc?o lx , and claycare centers. Results showed rhar the meal? of' the TU'A magnctic .field cxposurc.; irn I?otnes w2.s 0. i d l LIT ( I .41 mC;). FotA schoc~ls a n d claycare ccn- ter-s he rnean exposurc was 0.106 pT ( 1.06 mG). Ex- posures were hjghcst for cltildren living in high-cur-rent- configuration hol~ics compared to low-cu~.r.en~ t~ornes, bur the variability it-I the rneasu.remcnts was high.
A study 0164 chilcll-cn f 1 - o ~ ~ the mid-U.S. founcl. that inore than 80 percenr: of dleir time during a 24-hour week day was spent in their bcdl-ooms (Friedman et af. 1996). Eedrnnm 24-Iiour ti~agnetic lleld measurements coi-re-
latcd well w ~ t h perqonnl tixeawrer-tlents tnacic ar hon\i wrlh AMEX-3D meters. 'The 24-I1our rncdran f~eid 11 -
bedrooms was 0 086 pT (0 86 tnG) Ttte c;h~lcireil\' n i ~ dian total 24-haur cxposurtr: includrng time <it ficime 3112 away from homc W R Y 0 107 pT ( 1 07 mG)
figure 2 Y shows data collectecl by two BPA ~ 1 1 1 -
ployccs to illustrate exar-i?pIea of pattertl., of 21.-t>c,itr lnagnetlc ficld exposure One of the ernplo~eei u r 3 r (h
in an of'lice b u ~ l d i i ~ ~ wtth a computer MI\ liighcr\~ ,\ p s u r e On tile day of the measurcmcntc occui~ ed 14 lie1
at a 500-kV aubstat~on. HI> highest eupoiure O L L U I l r
whe1.1 he made an ullspcctlon tour 111 tile iubst,zt!iii-~ \ I (
Fox tlss partrcular 24-hour pet'locf the i u h \ t , i t i , ~ ~ opcrator's mean niapnetlc field expo5ute \i dhour t11 c fold greater than that of the offxce \;r,or-ker
Human Health Studies * .
Tile sec.tions to follow suinmari~e the re\car ch thcit Iias been conducted ro assess the possrhle eM'zct\ of EMF on lluman health. The informatron 1s piac~cntri i 117 ~t
rough chronology 1-eflect~ng the orcle~ In whtch the malor EMF health issues developed Studre5 fan each rn;iln1
type O F health isiue are described in t ab lo rI?:cr. 31 1 L ihi?
study design and primary rcsrtlts. in in^ matlr)n 113 tlic tables 1s purposely brrcf, because ovzz 200 I r ~ ~ i r \ iduil
section compares and contras1~ the stucfir% dnd pi o i iclc
more deraxls on key ctudrec An ~ntroduci~on to rptr't. rniology is presented on pages 2- i 1-2- I Z
General Health -- -- --
Occupational Studies
Occupatlonal rcscarch on non-cancer he,iith et te~ r. (\ur-i?~~~alizccl in Tablc 2 1) spa115 a Itri~od of nr,tl I \ 31
years. The 29 studtes from 12 couritr1e4 l~sted I n TciLtIc
2.1 mostly were concerned w ~ t h the health nf uorki.1 around hrgb-voltage facrllttes Siudres hepal? i n tl~c 2N 1\ 1960s. when the l i r ~ l 400-700-kV ttrins~?~is~lon liric
were ii~troduced
The frrkt st~iclres ~xlvolved a small group 01 C S lint- men (Kouwet,thoven et al. 1967,, and su rtch>i?~d \% o r K - el-? 117. Russra (Asanova and Rakov 11 966) Thew ;tud ies were filst co~npa~ed and drscu~sed by researclierh 115
1972 at the Internaltonal Contercnce on La~ge J31gil Loir age Elec~rtc Systetn\, ficld In Pdr~h tKniikcrbc?ike 1975) O\rexall, reuerirche1.s frotn the U.S. arlcl ? i h G
countries attendtng the meettng wcl-c sFicpt~c;~I n/ t i - r
Russran reports of health cffccts attrVlbt~ted io electr
BPA EIec2rical and B~oiogrcal Effects Review - 7
If1 1ai L W W 3 I L : W 1 L3W'+YJ i j3 t3L PAGE
Chapfer 2: Exposure Assesstnenf & Non-Cancer Health Studies
24-hour Magnelle: Field Exposure of an Office Workerwho Lives in 0 "Vary Low Current-Conflguratiori House
I I --i- 1-1 1- , Around I I I
house i
no electric blanket
0 1 - 1 1-4u
900 AM Noon 3:00 PM 6:00 PM 9:00 PM Midnight 3:QO AM B:O0 APJl 9:OO Aril
24-hour Magnetic Fleld Exposure of a Substation Operator Wha Lives in a House With Underground Serv~ce
Inspecnon In j subststion yard I Sleeplng
I (no electrlc blanket)
9:00 AM Noon 3:00 fJM 6:00 PM 9;00 PM Midnigtlt 390 AM 6;00 AM 9:00 AEA
2- 10 BPA Electrical and Biological Effecfs Review
I L ( . L ~ I L W W ~ IL: w I L ~ U W Y J B ~ ~ I L PAGE 12 - Chapter 2: Exposvre Assessment B Non-Cancer Heai2i-i St~icjit- s
Epide?miology. The study of the parterns of diseases or conditions in human populatrons, and of the iactors that influence thoee patterns. The purpose of epidemiology is to obtain information to hslp prevent or contfol dissasss atid health problems. Although epideminlogists want to find the causes ofdisease. determining cause and effect ofttit? reauires additional information from experimental studies.
the probability of dying during the specific time. Mortality rates are often adjusted to apply to specific age g r o u p s . Proportional Mortality Raiio (PMR). The proportion of deaths from a specific cause among a specific populat~on,
compared to a reference population. For example, the number of cieaths from brain cancer among electricians (s.g . within a company, industry: state) during a specific time period. divided by the expec'ed number of deaths from Oral? cancer for all other occupatiotls during the same time period, and multiplied by 100. The PMR is a rsiative conlparisill o: the importance of deaths from a specific cause: it is not a mortaiity rate. A PMR of 100 means that, in the exarnp;~. the electricians had .the same PrOpOrtiOn of deaths from brain cancer as in the reference population. A PMR of 200
tion (e.g., male welders in a large company), adjusted for age, divided by the number of deaths expected in an agw adjusted standard population (e.g., males in the state where the company is located), rnuliiplied by 100. An S M R of 100 means that the mortality rate for the walders was the same as sxpecTed in the standard population (an SMR of 155 means that the welders had a 50% higher death rate).
Types of Epidemiologic StudCes Cross-sectional (prevalence) study. Tne pressnce of specific diseases or health conditions in a group or groups
I at a specific time. For example, questionnaires may be used to obtain data o n tho number of electricians in a cormpony / who reported feeling depressed, as compared to the number of office workers in the c o m p a n y who reported daprsssioi- This type of study can be conducted relatively quickly, but it is usually difficult to determine the time sequence of hev! exposure may have preceded ths effect.
PMRlPiR study. Often used in occupational settings as a scresniog or hypothesis-generating study. A PMRlPlfi study yields only relative information on mortality or incidence among groups. An elevated PMRlPlR ma), suggest thal
specific disease or hoallh condition, and controls are people who are selected to be stmilar to the cases (based on zge .
were expossd compared to the controls. An OR of 1 .OO means that there was no difference between the cases and controls in the proportions that were exposed to the factor (i.e., them was no associetion between exposure and :be diseasej. An OR of 2.00 tneans that the cases were exposed to the factor twice as often as the conlrois, and this ~f?ob'#s a positive association between exposure to the factor and the disease. This suggests that t he factor may cause or influence development of the disease. An OR of 0.50 means that the cases were exposed ta the factor half as often as the controis, a n d this .is called a negative assoclatlon. This suggests ?hat exposure to the factor may help protec: people from the disease. The OR may estimate t he relative r isk w h g n relatively rare disaases are studied. e x p o s u r e to tne factor is common, and there are no important biases in the study.
BPA Electrical and Btological Effects Rsvjew r̂ - - I !
I Ii A Brief introduction to Epidemiologic Terms and Concepts Used in Chapters 2 and 3 (con*.)
Cohort study. in a prospective cohort study. a cohort can be a group of people exposed to some factcr of interest (e.g., tobacco smoke ) who initially do not have the disease of interest (e ,g . , lung cancer). The coho-t is studied over a number of years lo see how many individuals develop the disease. The incidence of d~seass in the exposed group can be compared with the incidence in another group that was not exposed (or exposed to varyii:g degrees) to the factor (e.g., nonsmokers). The relative risk is the ratio of the incidences for the two groups, and the attributable risk is the difference between them, For example a relative risk of 5 n-l~ans that the exposed group v:a live times mort.; likely to develop the disease compared to ths nonexposed group. SMRs can also be calciiiated :ran? data collect~d in cotiort studies. Prospective cohort studies can require very large t-iurnbers of people to be followeci for long periods of time if relatively rare diseases such as certain cancers are studied. An alternative is the retrospec- t ive cohort study (such as are used in some studies of EMF). In this type of study, both the exposures and the disease or condition have already occurred. The cohort may be a group of workers in a company or group of cornpa- nles beginning at some time in the past. Data on disease or deaths are obtained through company records or frow slate. regional, or national registries. As in case-control studies, a major problem is the estimation of exposures that may have occurred many years in the past, Risks can be calculated by cornparing ex~osed and nonexposed gro~ips internally wlthin the company, or by comparing exposed groups to external populations such as state or nationzl populations. Suppose, for example, that there were 50 deaths from a certain disease observed in a cohort of electr!cnl workers. If the workers it1 each age group had the same death rate from the disease as in the state population, assume that 30 deaths would be expected. In this example the SMR= 50/30 x100= 167. As compar~d :o the state population, the electrical workers In the company had a 67% increased risk of dying from the disease.
Confounders. A factor that is associated both with the exposure and disease of interest: and can be a cause of the association that may be attributed to the exposure of interest. As an example, suppose that electricians had iiig.i exposure to some chemical that causes cancer, and also happens to ba present when exposures occur to magnetic fields, If the researcher was not awarc of this, and only magnetic fields were rr?easur6d. the association bei\n/eer, magnetic fields and cancer could be due at least in pat< to the chemical. When informaiiol-i is available ot? poteniial confounders, they are often taken into account as epidemiologic studies are designed and analyzed.
Healthy worker effect. Generally, workers tend to be healthier and have lower death rates when ~x?et-~-iai colt-I- parisons are made with the general population. This is because chronically ill and disabled people are generally isss likely to be employed. This phenomenon can make it appear that employment or occirpational exposures h a w a protective effect, or it may mask risks associated with occupational exposures.
Statistics The various risk measures discussed above are usually point estimates from samples from larger populations. Tilerefore, they will have variability associated with them. The amount of variability depends on the size of the san:rile. and on the natural variability amang people in the sample for the various factors under sttrdy. Sfatistical tests are use6 to give some idea about this variability and whether the results could have been due to chance.
Confidence Intervals (GI). A range calculated around a point risk estimate, such as an oclcls ratio, that Inclccles the true risk with a certain level of probability (usually 95%). For example, an OR of 2.3 with a 95% GI of 1.5-4 8 means than there is a 95% chance that the true risk is somewhere between 1.5 and 4.8 (and a 5% chance that it is
pqti-natej oiitside of this range). In this book all confidence intervals Included (usually following a comma after the point -- are for 95% unleas noted ot l~er\~ise. If (a8 in the axample) the GI does not include unity (1 or 100 depending or1 tPe risk estimate), the risk is considered to be statistically significant, i.e.. it is very uniikely to be a chance fincling.
-rrient p (probabllity) value. The probability that a diffwence observed between groups is due to cbance. A stat- that p= 0.15 means that the difference would be expected lo occur by chance alone about 1 of t h e tii-ns. Usilallv. 1:) values of less than 0.05 are considered to be statistically significant (shown as p..: 0.05).
cause and Effect Although statistics can help epidemiologists decide whether their results may have been clue tu chance, a statls:~cziI.! significant association does not also mean that the finding proves that the association represents a cause-affect rdationship. Determining whether some factor is a cause of a disease requires further analyses and study. Ultimais~v the determination is a matter of judgement, Several criteria (e.g., Hill 1965) are often used to help in this judgetiisnt
i process. These attributes of the association to be considered include : 1) strength, 2) consistency, 3) specificity I 4) temporality, 5j biological gradient, 6) pl%\usibility, 7) coherence, 8) experiment. and 9) analogy. Assessing cause an0 1 effect is difficuli because diseases generally have multiple causes that may act through direct or indirect rnea.is. Y
Epidemiologic evidence alone is generally considered insufficient to scientifically establish causaliiy, However. there Is also considerable judgement involved in assessing whether evidence for causality from epidemiologic acd other studies is sufficient In practical terms to warrant preventative or public health action.
! 1 References Ahlbom and Noreli (1 9S4). HtII (1 9651, Last (1 99.51, L~llenfelci and Ltlienfeld (1981), Roihman (1968) a
I! StudylLocation Sub]ects/Exposure Selected Results I - I
I Asanova & Rakov Health exams of 41 men and 4 Variety of ailments attrrbufed to 50-Mz electrlc 'ields I (1 9661, women workln In 400-500-kV headache, fatigue, male sexual probierns, ctlest pans 1 Russia swilchyards. Eyecennc f~sldr ~rrltabllity. gastritis, and effects on blood cnmoosition iiio
I measured ~n switchyarct quant~tatrve data presented Mean f~eld = 14-18 iV,m i Sazono\la f 1967), Health exams of 29 swltch ard Exams before and after work showed seve~al stai~stic?lly Russra operators (-4 hr exposurehay), significant dstferences between groups. For na~ntei;?ce
I and 25 maintenance people 25 hr group pulse rate and blood pressclrs lowet ano sensitivli\:
I exposure/day Electric frelds to current hlgher, slowor reaction and higher test error rats measurad ~n swrtchyard Overall, stronger electrlc fields ~ncreeased fatrg~e
Kouwenhoven e? a! Health exams qiven to 11 tinemen No stgnrficant health changes noted Two men had low I :k7l, over 42-month%. Exposure by sperm counts No quantltallve ciata on results preserted hours of Iwe fine maintenance Range of body currants during ilne workm 85-840 I I A
I
I / Singewald et al 9-year foilow-up of !insmen In the Health of the linemen was not changed by exposurc to h ~ g P 1 (1973), U.S above stirdy voltage lines. Few quantltatlve data from 6xams pressr~teii I Krivova et al (1973), Health exams were given to 319 For 500-kV workers cot'npared to workeis at iowet or+- Russ~a me17 worklng around 220-500-kV ages, pulse rate and blood pressure dev~ated rnore i t mi
facilit~es, ENM normat Changes in blood cornposrtlon w e r ~ also r e p n - t ~ ~ r
3 rechn~c~ans and 3 rnedtcal Soma subjscta compla~nad of weakness and fat gue kes ' people wars exarnlnecf whlle II a tale was reduced ancf blood pressure rncreased No 400-kV stailon for 3-8 hr quantrtative deta wera provided Ffeld range 2-21 kV n
Roberye (1 976), 56 male 735-kV substation Canada workers given heaiih and lab
exams. Lab data were compared to a control group, ENM,
Malboysson (1976), Health of 84 men in 400-kV Spain substations cornpared to 94 lowar
voltage workers for 4 yr. ENM.
Knave st al, (1979), Health of 53 men in 400-kV Sweden substations was cornparad to 53
notlexposed workers. Electric field dosimeter used for base levels.
Subjective ailments reported hy Russian subs tat tor^ workers were nor found i t ? this study. Differences betweeis controls and substation workers in several lab iesls iwte sfaltsticfllly significant, especially for the 30-39 yr group.
Field exposure did not cause lasting pathological effecis since no biochemical changes were found. Exposure tu 400-kV facilities was of limited duration at time o%t:idy.
NO health effgcts were attributed to electric fields and tne 400-kV workers did better on psychologlcei psrformance tasts,
Stopps F; Health of 30 high-voltage workers No differences in healtn status were found between I-Ic$ / Janischeiw~kyj cornpared to 30 controls. Electf~c voltage workers and matched conlrois selected frony (1 979). fleld exposure estimated by rna~ntenance workers ~n the saine utility. / ~ a ~ a a a dosimeters an0 calculations
Puntoni et ai. (1979), Mortality (1 960-75) for 22000 RRs . Total deaths: electricians 1.35, eiectric ~vslders 0.99: j maie shipyard workers by job title, respiratory disease, electricians 2.45, als~trrc wefders 1 .C?3 i ENM. h ~ a r t disease electricians 0.41, electric welders 0.91 I I I $3;): Fanghua Health of 3 138 men and wometi No subjective cornpla~nts related to exposuts but :tire worklng around 44-220-kV lines effects reported on cholestetol blood pr6ss~lte EGG E I ? ~
I Chrna cornpafed lo 290 conttols EEG Few data~ls of statrst~cal tests reported I I Health of 79 men work~ng in 200- The 400-kV workers had h~gher frequency of leg palr kV switch rooms comparfsd to 37 oversenslf~vlty, fat~gue, and respiratory tnfections, aut Irwet 1 Ciechosiovak~a man ~n 400-ltV swrtchroonw frequency of disturbed concentratton, and disturbed sleep
McMillan Sr Causes of 52 deaths of welders at The only stat~stically s~gni:~cant cause of death 'or we de -5 Pethybndge a shipyard (I 955-75) compared to was for astrointest~nal diseases IPMR= 7 76 p<O 05' (1983),U K. 2 other groups of worker's. ~esearc%eis dld not attribute If 10 occupat~onal expoirter I Fpdp "n1 et ai Health questionnaires of 390 Some statisticaliy SI nrficant health differences betweeri 1 power-line workers. Ele~tiic-field group6 were found, gut ibaie were no significant corrali- 1 exposure meter worn lor 2 weeks, tions with measured electrlc field exposurQs
Compared to the general populat~on, morralrty was significantly lower for the engineers.
Risk of ALS was sign~ficantly elevated for eiectrlcally related occupations-OR= 3.3", 1.4-13.0 (19 cases)
Workers exposed to EMF of tnodera.te strength d ~ d riot snow the presenca of clear health effects basen un i-ealti~ exams and laboratory tests
No statistically slynlflcant clifterences between The 2 day5 wale found related to EMF exposures Patainsters stliclieo inclitded subjective cornplaillts reaction time menoi) EEG, ~ n d blood tests ~ncludirlg hormone levels
Rislts for MND were elcvatecl sIgt3l:lcantly for welders (OR=3 7*, I 1-1 3 0 ) r~sk foi electrlclty WGI k was on 'I'< bordetllne of stat~stlcal sign~ficance (OR=6 7 1 0-32 1 ,
The two grou s with tho h~ghest exposure drd not have elevared sM& for total deaths, heart disease or C616- brovascular disease
No stat~st~cally s~gnificant differences arnong enginee s eiectricrans, and serving staff were found ~n epinsphr,re norepinephrine, or serotonin 117 urlne
Levels of electrolytes (Na, K, Cl) in serutn and in erytliro cytes (Na, K) were significantly higher in the exposed group.
Mortality in utility workers was lower i h a ~ In the gene-al populatlon Total mortahty for exposed jobs compare0 I$? other utility jobs was elevated (RR=1.13*, 1.09-1 181
Lifet~me work exposute OR= 2 7, 0 9-0 3 At ieast 20 aoa R
years & 1 SD above average relatlve to rnlnimtini exgos i i l ~ OR;: 4,7*, 1 3-16 4
A statistically significant negative association nlas icuqi! between nighttime rnelatonln secretiori and magriet~c tieic exposures during the workday. Meail curn~liallve woiv magnetic field exposurea wcl?ro higher than for ti::~tiworL
For most causes of death, ut~lity rates were Iouls- Wan ti
the population For utility workers wltf-i electric fielcl expo sure above background compareci to bflow hackgiocn~~ deaths fvorn accidents and vtolence RRTI 82* 1 25 2 6;.
No srgntficant associations were foulid betweell siclc lea\ e over 5 yr for musculoskeletal dlsorde~s and W O I ~ i t ?
potrooms w~th exposure to DC and 4C magnetic 'ielrls
fields Th i s wa\ ri1 large p&rr because sl t~t i lar eSfcct5 10 Ilnc~ncn hail bcell compietcd /r\l\o ihc K ~ . i \ - i I - - \NEI.C nut bung rcpoi-teii by workers in thosc countrie\ per coritatnect rL\li, deinrl\ about thc -rut l \ i l - . < ~ _ r l
Ffoucvet- at the t i rnf nr~ ly fhc i-trelitnrtiarq study of rhe i-c\~tlrs s o the \tudy was clifttc-ult lo cvc~I~tsre i c
BPA Elecfncal and B~olog~cal Effects Review
- - - ------ PAGE A
-...-. Chapter
hcicntjsts called for additional research in response to thc Rus.;~ar? study. Several of the studies in Table 2.1 were spccificaIly conducted becausc ol: the Russian re- pol-t.
Exccpt for research in Spitin (Folc et al. 1974) and in C7.echoslnvakia (Peccny et al. 1983b), the subjective ailmellts reported by the Russian workers were gener- ally 11ot found in later studies from other coulitries. One difficulty ifl co~nparing results among these studies is that tlie electrical worak environments and work culture varied gl-early among cour?trics. Fur example, some wrork envirc~ntncnts rtiay cause workers to recciva frc- cIucnt shocks from objects due tt:} it-tduced voltages. Sl?ocks, ratlicr than field cxposure could result i n grob- lenis such as reported in some studics.
One of the largest srudies to examine mortality pal- r u n s among elec.tr-ical workers, and to include expo- sure asscssmct~t as we)\. w:ts coiKIucird by Savitz and Lnomis (1995). Althougi? the study Focused pr-ll~larily on catlcct: deaths froin other causcs were also rcpot-led, For all causes of death, wurkers as a group at five U S , electric urjliries had a lower rate than in the general popu- lation (S?/IR= 77. 76-78). Deaths f'rc7rn specific non- i a n c r r cauxs werc also all Icss khan i i~ the population. Authors of the study pointed out that these findings were consistent wit11 the healthy worker- effczt. When total r~to~*~illity for- magt~etic-field-exposed occupations was coinpared wit11 other utiIily occupariot?~, there was a .;~xall bur statisticalIy signil'icant elevation, especially for expobed workers with 20 or fnot'c. );cars OF ernploy- 117cfil (S?d.R= 113, 109-j 18). Tnforinatiot? was not yre- serlted for speoi I'ic nor%-cancer causcs of death for occu- pationi, exposed to ENIF.
Deaths I'rorn all causes were also reported for rhe Quebec utility (Baris ct 31, 1996b) (hat was part ofthe Canada-France strtdy by Thiriault et al. j 1994). Almost ;ill SMRs Tol- individual causcs of'death were less than unity, arid fvl- thc entire cohort the SMR for all causes conibincd was 75, 7 1-79, Fot- deatlls from accidents and violence (due in part to electrocutionsj, I-isks were elevated fcjr EMF, and for prtlscd t-nagnetic fieldti (e.g., for above hackgrout-~d cxposure to clectric fields, RR= 1.52. 1.25-2-65). A~lthors of the Quebec study said that tl?c ger~cr-ally lower- murtality lo^. t l ~ c utility workel-5 cn~r~pat-ed to t l~c popujation., was probably from tllc h e a l t h y worker effect, and possibility from ~inderassessmel~t of mortality.
Three sk~diea sr~gpested that occupational ENIF ex- pobure is assctciatcd wit13 ~ i ~ o f o r I I ~ L I P C ) ~ ~ disease, al- ~fir.tugh i n these studies expvsur-c wax ealirnatcd only by job title (Gunnar-ssnn et al. 1992, Deapen and H ~ J ~ ~ E ~ s o I ~ k956, Davanip~ur ct. al. 1995). The latter two st~idias
loui~d staustrcally s~gnlficant elevated r i i l c z to1 ct t~ f .
of motor neurone drseasc commonly called Lcru Gehl ip - drsease (amyotrophic lateral sclefoc~s)
Prel~m~nat-)I results of one study 111 Table 2 1 rou~io (ha( the pineal hormone nielarol?it? waq r6drrced i n i7ic i by occnpatic~nnl exposure to 60-Hz rnagnctrc l iclds (Rc i f
ct aI. 1995) In ai~other *tr~dy, mclafonln pittter n s 1 T l L i
sured at the beginning and end of shtfiq lor i ~ . i t c l ~ > :u d workers werc not ~~gr~ificantly different (RerBctlc\ ch r i and David 1906). When men were exposed to 60-H; EMF In alaboratory settmg, no ellecti on nlgl~tttine in-.- lator~tn levels were fvand (Graham et <tI. 1995. 199e $ee Tablc 2 10)
SIX addtt~onal studies are csvercd 11 j r h l . \ C C T I ~ , ! -
they addre,\ possrble eflects of ENIF on c h i o ~ . i ? i ~ w r i > ~ tu electrrciil workcrs (Table 2 2 ) These \luctizi I' ev protnpled In part becallre of I-cports of iepioCluLt~xt= CT
fecls In a s i u d v ol Swedibl~ \ub'.l,ttiol~ M c r k z ~ (Nor*dslrom el: a1 1083. see Tablc 2.41
The six crudtec ail lookecl at pcrtpheral I > ii1l7hoc1 tL-.k
(whrch are sornatlc cell\) ln blood iar~iple\ or I ailnil, kinds of elcctncal workers and controli If cttccr. ni
some agent are found ~sn somatic cells, th15 iuggcLti t l i t
possihrlity of other effects m the whole org~~n!>t-n itrc11 as catlcer or prernat~ixc aging t Eloon? 198 1 b. El icLi.,
fuund on gerln ceIls (spertnato7c)a and o ~ r ? ) ths\?i e t i -
cally suggests the pos.rib~lity of \tertIity ITI tlle ~trdit i d u ~ l or mutations that could be pahsed on to oil\p~tng it only somatrc cells are studied and chromosonial abet- r-at~ons are found, tht\ rrnplles rbe pohh~b~litv tl~'~i $e117
cclJs way alw be altected, alsuniing tlt1,~1 sxpokulc to
tho agent occut 5 ~ O I both type\ of cclls (B1noi-1-1 138 i i
All but ntie of 1k1e ~ * ~ I - V I T - ~ O \ ~ I ? ~ C ~ t i id~ec 111 T it>^^ 1 rcyorked onc 01 11101e statisticdll> .;tgri~Iit.aiii zftcct. $ 1 though there arc sornr incon\,stcnclec, Chion?ti\or- c 01 chromatid bleak4 were rcporled In t c ~ u of rhc XI. ILI !e% T l ~ e studtes by Eaucl~tnge~ et al j ('3s I ) , ~ r \ d t)\ Khahl et al. (1 993) did not spectfrcitlly mcnrto~i clircs-
mosolne breaks, Ncltlc of the 5tud1eb tot1~1~1 J ' - l ; i t ~ ti
cally s~gntficatlt effect on slsler il?ro~nartd r\ch;ir?sc: ('tr indicator ofpotenr~al gei?ccrc I~a~i\r.d) Therc IS slw c\ I dencepresented i1-i some of these itudscs rhnt a n c-iecrr I cal worker's current ol past 5rnokx1lg cxpe~renct: LAII 113
crcase i . 1 ~ IikeIlhood ol chromubotnc d<krxtape The pobsible rnrchanlsm, dssocintcd \nit11 i h t vmi.
solria1 effects t n e1ccttic;ll w o ~ kel i wa.; c x n t n l n r t l ! T I ? in ipifm rests iu I l ~ e study by Nordcn%ot? 23 id ( 1951 1
Tlie test5 showed thht a 50-Hz cullent dei-~,~t \ c l t 1 mA/crn2 applied lo blood satnplcs dtd 1 ~ 1 t tauw clxc- mt>iome bxcaks, wt~tle breaks wele fourid dtci 3 L I ~
long spark discharge pul?cs weie applted il-rcal\ i i e l ~
BPA E/ectricaf and Biolog~cal Effects Rev~eru - 7-15
Studyllocation S u b]ectslElrposure Selected Results
Ba~lchlnger et a1 CA in lymphocytes from 32 men No starlstlcally significant d~fferences between gloups in (1981), worklng rn 380-kV sw~lchyards chromosome gaps, breaks, acstltrics, atypical, or ScE Germany and from 22 controls T pica1 Swttchyard workers had occupat~onai exposure to EMF fn
maximum elenno-fleld revel given. over 20 yr. Maximum elsctr~c field in switchyards 12 [ r i l ' ~ ~ 1 ;=:;son et ai CA In lymphocytss from 20 men Statlstlcally stgntflcant dlfferencss were foilncl bstw.:er working In 400-kV swltchyards groups for chromatrd and chromosome breaks Tlis
weden and from 17 conlrols Typical percent aberrant cells in exposed non-snioks~s wa: E 1 maximum electric-fleld glvsn compared to 2 6 111 control non-smokers
I
1 Nordenson et al. CA in 19 men worklng rn 400-kV Compared to controls, substairon workers had slgniflcari! I '
(I 988), substat~ons and 19 controls. All more chromosome sberrattons, and cells wtth mrcro~i~icl.i
i Swedsn
subjects wore nonsmokers The hrghest rats of aberratlons was found in f i 1 ~ i k c ! s Electric frelds ware measured exposed to the highest electric fields No effects an SCE
I! Vaijus et a1 (19931, CA In 27 power-line workers and The rate of lymphocytes with chromattd-tvp creaks \.13s Firland 27 telephone llnemen controls All low 111 both groups but ~t was atsoill twrce a s ~ICJ- ir i c5
subjects were current nonsmok- power lrne workels mainly for ex-smokers No ~fft;cti 6 ers Exposure was estlmated, found on SCE, repl!cation, or tnrcroriucle~ ftec~usi-cg I ' Khalil st al (1993). CA in 15 men from 132--230-W The % aberranl ceils was signil~caniiy higher in subn~ainr 1 Jordan substations and in 8 controls workers (12.8%) than rn controls (7%) Prolrteiat~un, mli~i ', f
I Smoklng data separated. ENM, index were lowwr in substatroti workers No effect o n SCE
Skyberg Norway
et el. (1993), C A in 1 3 high voltage iahoratofy Mean chromosome breaks fof laboratoty wotiters w r ~ c workers and ln 20 controls were smokers (2 3) was signif~cantly highor ~ h a n 1r7 c c> i t i - Exposure was to AC and D C smokets (0 7) No $!gnlflcqnt effects were found cr SCE
1 1 f~elds. lrrulsed and continuous aberrant cetls. or on chromat~d breaks I L Abbreviattons: CA= chromosome analyses, SCE= sister chromattd exchange, ENM= EMF not measured
strength o f 3 5 kvlcm). These findtngs suggest that el-- culatoiy dtccases was ~ignlficai-~tly clevdred iun~~s i~c r -13- . feet4 on sotnatic cell3 in elecarical workers may be from people, hut auttlors of the study attrrbuizrl t h l i ir % (
dr scharge shocks recctved when wc)l-kers contact ohjeas class di\tlArbur~on. in stror~g elcctrlc Irelds, instead of from cxpo>ure to EMF Four other <tudrec, ol people It\~ng ne,ii I I J ~ $7
~ C Y S P (5ec 8150 "EMF and Genetics. Prolifei ation, and slall ltnzs fourtit no ~ t a t l \ ~ ~ c ' i I l ~ ilgiil~ l c ~ l n t eiltit
CancelA" rn Chapter 4). certain general hcatl.1 factors rel..zted ti. pri,t i i l l t t
Residential Studies
Table 2.3 surnfnat-izes siudies that looked at val-i- ous I~ealth factors for penple living near certain sources of EMF. The designs and methods varied greatly among the swdics: only three of the studies reported any mea- suretnents of EMF. Perry and Pearl ( 1988) reported that mean 50-Hz, tnagt~ctic fields in apartn>.snt groups t?cas nnd distant from elcctric supply cables differed by only 0.154 pT (1.54 mG). For thc 12 disease factors 1:elated to the cardiovascular system compared .For the two g~'oups. only one ciill:erence was close to statistical sis- nilicance. A later study by t h i s group .found no assc>cia- tion between myocal'dial infiircrion c?t.~d residel~tial mag- nctic fields (Perry ct nl. 198'3).
Magt~etic fields rnerts~~rcd in thc bornes of people in The Nethe\-landc who lived within 100 rn ( 328 .t'l) of a 150-kV line or a substation ranged froin 0.1-1.1 pT ( 1 - 1 I rtlG) (Schr-eihei. et 211. 1993j. Mortality fi-om cir-
lines. The i1ud.r by Srrutn/a ( l (770) htme\ :i 1
crude measure to identrfv \uch effect< 1 r .I.C or I-
cal servtces, That s ~ ~ l d y and the i>tt)t'i t ~ x o (Po, t i t
1993. NIcDowilll 19863 all urzd di\t'incc t~iiii) l i r ~
Inea>ulae for EMF cxpoburc Pnolc et a1 i 1903 O U L that rwiclential pi-oxtiinty drc\ noL nccii.ol relate M ' I ~ ~ I EMF ~ S ~ O \ L I T O , the) cctlled to1 ciLiiiitl health U Z L I ~ I C \ w 1t1i in~provcd ~ X ~ O S U I - e O\.\C\\IIISI
Three studies prov~dc somc e ~ ~ d e n c e th,it 1 1 around t r a ~ ~ s ~ n ~ s s i o n lir?es rncrenrcs thz I i>k oi iic aches. Pooleet a1 (19931 1ou11ti an etcvatcd I - i i h ol ,* tn~graine headaches, however, i[ w,u n c ~ t ' s ~ a t ~ ~ t r ~ ~ i l l ~ t-riftcant. Those authors poittted o~it th3.t lhc\ .ici.e~---
self-reported ~-~~igratt?c headache:, wirhout ~ ~ ~ i I i ~ . i i _ frrtnation. The study by Haysorn zt 31. i 1990 I dl(; rl clintccllly tested headache clueqtion~zarrc .iriii in1117
tlstlcally sign~licant elevatccl I - I \ ~ \ I-!CW+C\ C I i I L
h~gileqt 111 that study fc~l" p c ~ son\ Il\-ir~_c JI 3 rnii!-,lr
rrom tr,inamis~toil litic\, and not lot t1-1u.c i l r ~
11ne\ LZ siiiiilar 1.csu1t f~~urid 111 .in zs i 11;.
2-16 BPA Electr~cal and Biolo~ical Effects Revievv
A L ! LO,' L U U ~ IL . U: L ~ W ' + Y J ~ = ~ ~ O L P43E *
Strumza (1 970), Medlcal needs of 70 fam~lies No stat~stically significant dtffwences In medical needs France within 25 m of 220-400-kV lines between the two groups were found that were attrrbted +u
compared to 74 families 2 12Sm proxrmrty to the transmrssron lines. i from Itnos. ENM. I
Eckert (1 976), 494 Cases Of sudden infant dearh Locations of casas showed regional concentraitons c l c s ~ syndrome were studied on the to uncommon magnetic flelds or strav ground cdt rsnts basis of poss~bie EMF exposures. (power lines, railways, transmitters, airports, raoar) Rrsd ENM iNaS higher in ground or frrst floors
I NlcDown11 (1 986), 51 0 deaths (1 971-83) from Overall, mortalrty was tower than rn the general populatrort il
I circulatory and respiratory Death rate for respiratory drsease was elevated for disoases among cohor? l ~ v ~ n g restdents closest to electr~cal facilitfes but rt was not neat power facrltttes ENM statistfcally signit~cant (SMR= 127 77-1 95). i
i Porry & Pearl Survey of 576 hospital patients (1 988), who lived in muitistoy buildings U.K. Magnetic field exposure by
distancs to power supply cables.
Pet't'y et al. (1 989), Survey of 596 myocardial infarction U.K. cases and 596 controls by measur-
sd 50-Hz magnetic field outside the front door of residence.
Dowson st al. (1 988), Survey of headaches in 132 U.K. people close to 132-kV lines and
94 people awav from lines. ENM.
Slightly fnore people (62?/,) w~ ih cslrarn typss ~f h s e r ' dlsease lived nearer to electric supplv cables (or + ~ c bordsrl~qc of statist~cal signlticance) Near ?ield r1iear = 3 I 5 mG, distant mean freld = 1 61 mG
There was no statistically significant difference In the I
magnetlc flelds measured for rnyocard~al lnfarct~on case; and the freids for control addtesses I
I !
FIfteen (1 1.4%) people living wltfiin 100 m of transrrl3- ston I~nes reponed recurrent or rnigrarne headachss compared to 1 {l.lO'~) report from people away ttom I rss
/ Haysom et a1.(1990), Survey of headaches among 334 There was a weak trend for headaches, especially 1 U.K. people within 100 m of trans- migraine, to be mors common among people llvlng mfssron Irnes, and 358 people withrn 50 and 100 tn from 132- and ODD-kV transm~ssron
i more than 100 m from lines. ENM lines Some resctlls were statistrc~lly significant
Pooie et at (1 993, Survey of headaches among 382 Prevalence of nan-migraine tleadachss arnong peop e people including those lrv~ng near llving near lines was elevated but it was not stai~strcali\/ 230- and 345-kV lines ENM stgnrficant (OR= 1 5, 0 76-2 8 )
Schreiber et at. (7933),Deaths among 1552 people livrng For all causes of death, SMR= 11 1 , 96-128, for crrc~~latciy The Netherlarids within 100 m of lines or substations. dfsease, SMR= 126*, 101 -1 55
Coghill (1 994). Locations of 67 cases of sudden Cases lived closer to EMF sou~ces (mean= 126 rn) t t ~ n U K infatit death syndrome and 64 controls (mean= 206 m), the closer to tt.8 souics the
confrois were compared by younger the age at death EMF sources tnclucied pcvi i proxlmlty to EMF sour~es ENM ines, railways, terminals Statistrcal tests not desctbeil
McMahart & Meyer Survey of hsalth probierns for 152 Wor-nen near lines were not more likely to reporr health women living naar 66- and 220-kV problems (headaches, poor appetite, sleep disorders pool 1 Ilnes, or 1 block away concentration) than those away (OR= 0.85. 0 45-1 62 )
Aboreviat~ons. ENM= EMF not measured, OR= odcls ratlo, SMR= standard~zed mofcalrty ratlo.* statrstlcaily s gnrflcant
( 1995) lound no evidcf~cc that prevalence ai'hcadachss Reproduction ~ n ~ r e d i e c i 111 w01111ct-1 Ilvit~g I I C ~ I . transmission lincs
~n C,difo~-n~a Occupational 7~2'0 studies a~ten?pccd co relate the proximity of The carly study o f Russian yub.;~:itiar? ~~~or.ltcr..; i?:
Si [IS (.suc[dei-i i nhn t death syndrome? tv ~ r c e . ; of FMF As anova R A ~ ~ ( ,966) ttInr initikirzd ii,,cl.ci, i !Ecltert 1976, Cogl~ilI el al. 1994). Both o f these stud- sible health effects ol- EMF illclucia. a sta,emer,r rii:i : ies 3 1 ~ 0 used distance ft-otn snufces to esti~nate expo- one-third of the \vc)rkelLs cnti?plai~?ed c t f " h t j x i ~ a l \$:,,a:.- silre. Bccausc of t h e wide variety i n lhc su~tr-ccs iclei~ti- ness." This and 12 other >tudit-s of rcprixluct~., rz Itc~iii: Fred lo the studics. the weakness 01' illis exposure mea- of electrical workers are surmr-tlar~izcd in Tat3le 2 . ~ 1 Fc'L: vure i s even more apparct~t. The study h y Coghilt ( 1 994) or tl,ese cricr,ti cd LhaL rllc. lor,liiti ti)i :; .- was p~-eientcd on1 y in an ~tb'itl-act. with 1'ew details ~ L ~ O L I ~
effects repOr,ted in rile u5sia,l sttidy. bur ni,ilz ,l.lT;.
Chapter 2: Exposure Assessment (4; Non-Cancer Health Studies
Kouwenhoveti et al. Health exams given to I I linemen Two men had low sperm counts. over 42 months.
Sperm counts wsre judged to he highly variable. anci t i l e ; were no1 affected by the electric field.
Health exams cf56 male 765-kV Before 765-kV work, the meti had 27 bcys and 25 $isis, F substation workers. 9 months after start of work, 17 boys, 3 gtrls Fn~.r- c
h~gh-voltage workers reported sexual \rjea!tness
children was present before work began In substations
Nordstrljm et al. Questionnaires on reproductive Mates of switchyard wotkers had statistically significant health were sent to 542 male lower frequency of normal pregnancy outcomes, and power plant employees. higher freqtrenoy of bitths with congenital malformatiotia
The 400-kV workers had more girls con-tpared to controis.
Bcriatti et al. (1984), 112 malo infertility cases were Risk for infertility was elevated for radioolectric cvorksts 5:i: compared to 127 controls by it was not statistically significant (RR= 5.89, 0-86-40 I E ! occupation, ENM. No other electrical occupations were named.
study of 252,147 live births, ENM, lower risks for low b~rthweight (RR=0.8. 0.7-0 91
Juutifainen at 81. Early pregnancy loss studied in 89 No association found between early pregnancy loss ant? cases and 102 controls. Exposure mothers' occupational magnetic.?ielci exposure, baseu o8-: -. by job and some measurements. cases and 4 conlrols (OR=1,15, 0.3-4 7).
Cases were men seeking care at No statistically significant associations found bstwssti i i~yr an infertility clinic, Controls were occupational magnetic-field exposure and three nisasui-et men wlth normal semen. ENM. of semen quality. High exposure, >0.3pT 1i-G;.
F
finding the high percentage stated in that study. Of the Sour. the I~ighest ptr71-ccntage of repons of sexual prnb- lcms was giver) by Stopps and Janischewsky~i (1979). However, in that study the pel-cenlagc of complaints o f sexual pxohlcrns was lllc samc ( 1 3 %) I'or both the hiph- valrzigc woi-kel->. nr~d rhc CC)I?TI-OJ men.
Tl?rcc studies repol-tcd infor.iiiutior~ on the Sex ratio ofch i idrcn borr~ to suhst<'ttio~? workel-s. Robergc ( 1 976) fc)un<l 1l7ar t11c \vc)t-ker.i in his study had a larger pcrcent- age oi' boys. On the other hand. Knave et 31. ( 1979)
fvund that sub5tation workcr-s had lnclrc girl\ '111 the finding was largelq <Itsr?ll\red hrcauic the enceexistcd befure substation WOI k t'c.3;~) I I I the -!I 1
by Nardstl-0177 z t dl ( I 983) tile ~ n i i i ~ l t i i l l ~ i l t : it: i '
forcl?!ldtcn born t1.1 ~ i - x r r w ~ ~ * l i t r ~ g t t i 400-I,\ LIP.^ i t
was 0 92 coinpare to I 1 Cs L7i thc 16te1 e r~cc ~ t , )L :- Othrl 1esult.- of p~cgrutlrl) OUTCCIIIIC aL \~c~ ,~ t , i ?
~lcc.trica1 worket \ wwe repor-ted by thi-et: i~iidic U I I ,
percentage ol'cotlgen~tal malfnrmatio~ i i i i rn~i tg
-
SPA Elecfricaf and B~oloyical Effects Review
Chapter 2: Exposure Assessrnenr & Nor?-Cancer Health S fns i~ . - --. --
f-atthered by Swedish switchyard workers comparcd to the reference group, 10.1 itrld 4.0 percer~~., respectively (Nordstriiri? ct 31. l983). Autl?orc of st~tciy aaid that the f inding should bc iritcrpr-cted with caution becttuse the 101121 tlllinbcrs W C ~ C small 11 8 children with maiforma- tiorxi for both groups).
Thc ~ tuc ly fi-oin Scotlnnci f o u n d both inc,t.aaucd and ciecrca,sed risks associarcd with electrical ttccupationy 01' the mother and fathcr, rcspcctivcly isunjose et al. (99 l i . 1-lowever, i?cs irtl'ortnalio~? was available abo~tr poss~ble EMF exposures 171- these occu[,atinns. 11.1 Fin- land nr) assstcialion was found bcfwecl? 111othcr.s' gccu- pationix1 magnetic-field exposure and early pregnancy loss. Jthougl? the finding was based on very stnall num- bcrs (Juutitair-icn et al. 1993). Two studies looked at sei?lcn quality and they found no associations between poor quality and c!nploytncnt as all elec.trical worker iSir*!ge,wald et al. 19'73. Lundsburg ct A. 1995).
Residential: Power Lines
sl;udy. I~owcvcr, va,ried depending o n the rnaguctic . f~cic? cutol'f' level, Cutoff lcvcls of 0.63 pT (h..'i inG1. :,ri,.l
0.25 pT (2.5 112G) produced much difft71-ent ~.tsuit,s cic- per~ding on wlietlier- risk was calculated hayeti o1.1 iieiii levels at rht: f ront dool,, thc [ - O V I ~ I avcrilgc. (71. itlr r i i~ iu l - lnil~ii level. Autl?ors oi'thc stud!! <aid that ~.eq,i~lr.: (A 1h.r
stucly shoulci he viz\vrd with caution hccausc: of tile i1.1:1!
nnrnbei- c.)Fexpc~hed sul?iects i n f h c study. Savitz and An:tnth ( 1994) ibul~cl iio c\.ldencr i i ; , : ,
miscasr-iagc was associated with expn%ul'c. 01: Lt'(.i!?l?!' r ,
j ~ower line fields. I t1 r11at ,sc~idy. IILN ever* ~ I I Y C ~ ~ I . ~ : ? c; was asscsscd a t gcstatictnui agos iatcr llloti tlilv~c: 111 : 17
study by Juutilaincn et id. i 199.2). The lower risk for ~ r i a l f ~ r t ~ i a t i o ~ ~ s rzpol.trii b! Rni:s-
ert ( 1 993) is very difficult to interpret i n rel:lcii~t.~ [(.) l-ln.. sible exposures 10 EMF From power lines. Bec;iuiz t-,;
the way in which the study was dceignecl, i t i.; not, Aiioii,! whether any ol (kle u(c7rijen l ived clvsc tc, t~-:tn.;ii~i.>it~i: lines. There is, tl~erer'ore no r-cal basis ht. ccrnp:l1-lti: cxposuses between tlie cases and control.; in the sriiii!
At least six $ttldici; havc itivcsrigatecl possible ef- Resldentlai: Eiectrlic Heating Sources
iecls 011 I-cps~ductivc hcalth in wo!?len living near elec- tric power' lines (Table 2.5). Ovcra.11, the studies pro- Related to the studies descl-ibcd rn the ;:I?crvt i e c - vicie little eviclcnce for such cffccts. Thc strongest evi- ti013, i % agr-oug of stuclies that investigarccl ~-cpi-nduiii. r de'nce fol'a possible eflkct nI'r?-iapl?etic fields comcs frotn effects associated with magnetic fiieldh il-orrl ~ r l I C i l t i i k i l ! '
the ~ t u d y by Juutiiaincn rt a(. (1993). Resnlts of xlle healcd beds and cciling cnbtc h a t iTablc 2.6) . Elc;r;.i<
1685 cases of malformed infants A statistically significant lower risk of rnalforrnat~ans was were compared 10 controls by found between tnatcrnal residence in towns whrch had ai residents in areas with homes least one home within 500 m of a transmission line. within 500 m of transmissiotl lines. Distances af caselconlrol homes To lines no: cietzrn~rned
Measured magnetic fields and Pregnancies in homes above 2 rnG were not mora !lk81!/ 1,: power-line types were ?elated to end in miscarriage or preterrn delivery. Risk for iow b~rtn pregnancy outcome for c a s e s and weight w a s increased in the medium but not the high p ~ ? . ? ~ e ! controis. line category [OR= 2.6*. 1.2-6.5) ("/cases and 12
pregnancy were estimated by power line type near residence, and by dosimeters. sur-e (534 womenj or for 7-day exposure !858 wornen).
BPA Electrical and Binlogical Effects Review 2- 19
Cha~ter 2: Ex~osure Assessmenf & Nun-Cancer Health Studies
---- -- --- I r StudylLocation SubjectsIExposure Selected Rescflts ! d
I Wsrthe~mer& Telephone survey of 1256 new For heated bed users, conceptions dur~ny tho l-ieatln~ I Leeper (1 986), parents about t l le~r use of elecirrc season resulted ~n s~gn~f~cantly rnors below-niodial? biitt?
blankets and healed water becis, welghts wtth above ined~an gestations Frequency of fatal ' and checks of birth records E N M loss was h~gher among heated bed users than iloi'iiserc
I 'eta1 loss for families with and Fetal loss ratio was the same for familws wtth and v/ i - -u ii Lesper (7989) wlthovt csiirng cable heat Some ceiling heat, but fetal loss occuited mole o-tcl-I amr,iS l- U S OR magnetic field measurements cerling-heat group ditring months of rncreasing heari-11: i - Dlugosz et al (7992). 542 cases of babies with congoni- The use of alsctric blankets or heated watei beds liv 1 U S NI
9
tal defects and matched controls niothers was not associated with neural tube or ocal c i ~ i * Mothers' use of heated bed ENM defects In tbelr children
Yong et al. (1592), Wornens' use of electric blanket Risk for spontaneous abortion and total abnorn~al ~ i e g - i
Cnina for 986 cases of abnormal nancy wore 81~va16d for electric blankot use dutins car J
pregnancy and 975 controls. pregnancy (OR=1.95", 1.31-2 90; OR=? 61* 1 10-2 3:i 1 racken et a1 (t995a), Magnatic field exposure during No statistically significavt associations wsre found b s t m c n 1
U S , Canada pregnancy far about 2500 women, measurad axposurss to magnetic iields and btrth weight cr brrthweight and fetal growth. ~ntrautenne growth retardation i
4
I I Ls et al (1 995), 118 cases of babies with urinary For women with a history of subfert~irty association tounc f U S , W A tract defects and 369 controls. between heated bed use during fit-st trimester and iirinaiv
Mothers' use of hsatsd beds tract defects (OR=10.Oa. 1 2-63.5) (3 cases 3 cor-rols) I I
/ Lee et at. (1 996), Abort~ons among 5127 women Abortjon risk for electric blanket use RR= O,T3, 0 52-1 .O8 1 I U,S , CA and use of electrically heated beds, for water bed use RR= 0.84, 0.65-7.07. i I I Abbreviations ENM= EMF not measured. OR- odds ratio. RR= relative risk * slatlsncaly signifcart
b l a l ~ k s ~ s and electrically heated water beds can produce relatively high magnetic-field exposures to users (Flo- rig iu~d Hoburg 1'391 1. The first sludy fo investigate whether the use nS such devices durit~g pregl~ancy af- fccts 1'cta.I cicvclopment was co~?cttlctcd by \Vcrrhcin~cr and Leeper ( 1 986). In that study there wits 110 differ- ence between heated-bed users and non-users i tn the pro- pcltArion c ~ f ' low birthweight babies (4.5 vs. 4.1 pzrccnt, respectively. The users, however, had significantly more full-terit7 gcstatiow~s than non-uscrs (46 vs. 2 1 percent, i.esl?cctively). The PI-oportion af above- insd ia~~ gesta- tions was also higher far thc Scpcetnber-.Tune pelaiod for the U S G ~ S . Pxcsumably. dlis is tlie period when heated. becls were usecl most often. Tl?c scud!: (21~0 looked at it-cclucncy of :tbor-tions in thc ycar before tlis live birth. Abortions for. clcett.ic-blat~ker users (7.8 percent) and for water bcd. LISL-I-5 (~6.1 pel-cent) were significarltly high.ct- than thnsc for non-uscx-5 (4.2 pcrccnt).
Wrthei tncr. artd I,ccpcr ( 1989') concl~~ct.ed a second stuciy in an attempt to distinguish ei'l'ects due to heating frsorrr those due to magneiic fields. The study cornpal-ed fetal loss at homes with ceiling-cable heat, tu I?ornes with niostly electric-buhehoarci lzeat. The esti ma'tcd elcc- tric at314 magl*ictic f iclds in bc.)tl~ typcs u f 110111~5 were 111-50 V/tn. 0. I. pT i I0 177G) ; iki~d f O V/I?I! < 0. 1 pT j< I inGS), r'espectively. The study fvi)1117ci that the ovcrall
ratc of fetal losscs/livc births wak thc ian ic 11. ' ic
wrth and wrthout ccrl~t?g heat (0 1776 \ \ 0 0-5 I c-1 I trvely). However, there tva\ also n po~l t~vz . i l i \ c ~ ~ i t
for ceiling-hcar I - I O ~ C S compared to otllzl i.1orl1,
n-~onthly fctal loss and monthly i~catltig Cicgici. ii:t\ - Yonp et a1 (1992) repol-led J. stattxt~cnll! i i p r i
cant assocra~ion betweet? $lectnc-blankel 2nd i , > n tancous abortion. This rcrull was Loiind on14 rnl ti t i -
during early przgtlaney. and not ciunng n1tcIiilz c ? ~ I
pregnallcy In A btucty wrch extctlslve ~ncct\urcr~~elir-. jnagtletic-flsld cxpu%ureb, Biacltcn ct <\I ( l995..1) j i i l
f117d any statistically 5ignifrcrir1t asiociarioni bilt\i -- fetal deveinpnent at~cl cxpnsur c Somc odcli t < ~ T I rii -_
elevated, but they were l e ~ s than 1 5 , a n d I I I C I S i> ii I
itrung tndtcatton of a dosc-scsponsc crtcci Ri ,k rlf - 7 1
taneous abortlnn was red~icecl foi u mmen In Crti 1 4 i * who uscd cicctricnily t ? e ~ l e d tfeds d u ~ iris 1" ; ~ T ' ; I T : was 011 the bordcrlrnc of sta~ic t~cal srg~iitlcanc- 1,
at 1996) Two studte\ In Table 2 6 ttl,tt exair?ined hiir l l
fccts found overal'l no statlsi~cally iigt-iiiic~nt ,I-,( t
uons WICI? L I \ ~ 01 heated bed., (Dlugov et ,]I 1 992 _ al, 19Yii). The s~gntflci~it ds\octatton iepcjr red i?:: i d { al ( t 995) wa\ only Tor a subpopulauon i t [ ( 1 1 ~ li c31.1..
it? rliett*stucdy. Furtlter, btatistical irgniRcan;e t 1 ~t
in Lhis subgroup only fot- early ~1cgnat7cy
2-20 BPA Electr'ical and Biological Effects Review
Chapter
VDTs (Video Display Terminals)
Several studies investigated possibic reproductive cffccts ofocctipational cxposu~*e to EMF from the vicieo I T I O I ? I ~ ~ ~ ~ S that are used with computers (Table 2.7). Tl~ese 17101lit01.s rllAt: i.)f't.ci~ ~ ; ; i I I c t l VDTs (video displil)) termi- rials) or VDUs (video display units). VDT.; arc n snut-ce cf cornplex EMf; (Fig. 3.101 Lhat extericl frcltn DC up to I-adio ft-ecjuencies. Wivcfar'mi; include sinusoidal 1L.nt-n the power supply frequency, anc-l sawtooth I:lAotn pulsed I'ields from clcctlaical circuits that clisecl the electron beam acl-oss the screen (see Pig. 1.5). AS with TV sets, EMF from VDTs dscreasc in strcngth rapidly with dis- tance, howcver. while using a VDT a person i s much ulot;cr to the screen than when watching TV. .Bccausc of the cornplex EM.F cnvisortment around VDTs, Field irltcnsity aIotle ntsy nor be a sul'lieient nmisurc of hu- man exposure f rom t11csc devices (Nail- ai?d Zl~ctng 1995).
ELF Electric field ...., 1-10 V/m Magnetic field.. 0.07-0.7 yT
(0.7-7 rnG) VLF Electric fiatd ..... 1-1 5 Vlrn
.-. Magnetic field fl+?---Tk'i
0.05-0.6 [AT (0.5-6 rwG)
field.. 10-20 kV/m
Tnte~est in rhc possible health effects of VDTn arose bzcause of reports of clusters of effects on pregnant Lvornen ai; cotnputcrs bepitt~ to be iiltroduced into the work placc. Table 2.7 sur'utma.rizcs results of several studies that have been cot-ttluctcck since the early I98Os o f wot~~cn who wor1a.l wit11 VDTs . Only a few of tltc studics included Ineasurcnlcnts oiEMF cxpc~sui-cs; most r-esear'chcr*~ esttrnuted exposiu-c by asking women how
many hours per week %\?at they worked ~ f i t l i 1'DTi. C ) r i study CRolnail ct al, I '3923 also consider-ccl pas.civc (:\ posurc: to VDT-s.
Spontaneous aboition was che I'acrot tnol i t ~ ! c j ~ i ~ i ? i i:
invcstigatcd i n studies of VDTs, Of t l ~ c 12 >iiitilc., I !
TziL?lc 2.7 that Inr.,keci at this factor. f ive t-cpcl-trd :I{. Ie.',:
onc statistically srpnificant associ;i$inn \?viil.i L . 0 7 ; - posur-c. 01' tl~ese, t h e largest risli tor\= 3.41 \A ai ire-
pal-led fol- the l?igl?csr VDT cx1?o~ut~e p n u p r1.i t l l i : k1.11~3-
by Lindbcthln et al. ! 1993). In that strrdy, tnLipnetle t!ci;l. were measured for 17 VDT rnt7dels ur, uhrcl I? '~.~l:jzc! ir-1 the study. Oile of thc few other studie:; (hut 1 tlcliirici!
magnetic-field rncasul-emel-its fbund n o associacic?n u.-iti:
spontaneous aborciorl (Sch~~ost. et a!, 199 1 ). Hnu~c\,.:r. authors of t l~a t study (Schnurr et nl. 1993) cor?ltnenlt:i: tlut fields frotn theVDTs in their study wcrc n~ucli 11~u.zi- than tl-r.ose reported by LincZbol?tr~ ct 31. ( i '.l?:i Lindbol-trn ct al. ( 1993) i n rcsponsc pninrcil rs~ii . 111,ii
VDTs in their stcicly included many olcier n-iodcls l~ indr befo:orcmanuhctu~-ers began to cot?i;idet-magtlcric he i~ i i
Birth defects were included in 1 I of the >,tuciie. 113
Table 2.7. Three of these reported stnristicaii? #,i;liiO- cant associations, but there i s no consistclicy or y;itcz!.~; at~?oi?g results of the atur1ic-j that s u ~ g c s t s ;1 caiiirli ,I.-& 3 -
ciation with VDT use, Ofthe nine studies in Tablc 2.7 [ha1 incluileii hii-i:-!-
weight ctr low birthweight. on ly one (Ei-icson ai7d K1:Ilc:- ( 1 986a) reported n ststistically sig~~ificant ;ixsCici:iiir,;
L-<ll-lc\ *:-I? with VJ2T use. That srudy assessed t ~ w ciit,-:.. )ow bilThweiglt1 for thrcc VDT exposiii-e ie~el.\. tt:ic.l~ ~ j i
wl-iich included two time periods. Of thc 12 ri\it c;!icu- lations for tl~cse cninhinntions, only u i ~ w:1.: q t r i t i x i i -
cally significant; it occui-red i n the inediunj e>;pcihu!.t group. WO other studies in Table 2.7 asscsscd intrau- terine growth retardation. Neither rcportcd an) .\la[ i i i i - cally signillcant positive associations v;ilh 'JUT LI-c:
(Windl~arn et al. 'f 990. Brackcr~ et al. 199.5~ i.
Many of the studies it? Table 2.7 were tAeviewed 111 ;-
report o n health effects of VDTs by t h e Nation:~l R::d!::i- logical Protection Bctnrci from the U.K . I ,-2civi.\oi-! Gl.ilii-!!r
on Nan-ionizing Radiat io~~ 19041. The report cg,ncll~~!.lct: cillr ! . l i i '7; that the rvidetzcc does not indicate that \vom
VDTs affects ~ h c i c i u s . and that rl-irre I-: I I Q L ~ ~ . ~ C I I T ricci! for furthcr cl~idcmic?logical stcidics of \'LIT>.
A rcview hy 1-indhol~m ;lnJ Hiet i~nct i i IO9S I ni id-,
concluded chat: the mqjority of the stutlics s u g ~ ~ ~ i i k i j t ,
VDT use i s not related to adwrse prcgluncy i iu tc t~rnr However, those autl~ot-i; suggesrcd that solve VDT ~~irii- ies did indicate increased risks, ancl they recotrlmzndr; Furt-hcrL I * C \ I C L ~ I - C ~ ~ 1 1 fctal dcvclnp~-ulent in high-i-ieitJ .I-I-
dustrial enviroi?ments. Nair and Z11ar)g ( 1993) clues-
tioned whether the VDT 1-1caltI-i quc..;tion shvirld h r C i i i l -
BPA Elecfncal and Biolog~cal Effects Revtew 3 -7 L - 1
L L * U S i U U J A L . U I L 4 U - t 2 J V J U L PAGE _ r
Chapter 2: Ex~osure? Assessment & Non-Cancer Health Studies
SubjectslExposure Selected Results
1 I-ev\,ls et a1 11982). 30 cases of SAB and 60 controis Risk of SAE assoclated with VDT use was elevated but tt / Auscvai~a I i from 13 companres were coni- was riot seatistlcaily stgnif~cant (RR= 1 71 O 10-25 0.1, pared bv estimated VDT use ENM.
Kurppa et af, (1 985). B~rtl l defects for 235 case mothers Mothers' Llse of VDTs duilng trle Ilrst tnrnester at stsyi Finland and 255 referents were cotnparsd nancy was not associated wtth birth defects
1 by potential exposure to VDTs (OR= 0 9, 0 6-1 2 )
i ENM
Pregnanc outcome among three c~hor ts OYwOrnen with assumed different VDT exposufes (total of 10,025 births). ENM
Srgnlflcant elevated trsks for LEW only In the ~-I?BUILIP~ VET exposure group-obs~awediexpeetecf~ 2.2", 1 .":4 4 1 5" 1.2-1.8. No slgntfrcant effects for SAB, pet inatal deatt- ct blrih defects
Sweden
Ericson & KallBn (1986b), Sweden
428 cases, 926 controls from the three conorls In the above study. Jobs were categorized into three VDT exposure groups. ENM.
Significant elevated risks for birth defects, especiaiiy tor tkie highest exposure (for 720 hr VDT exposure!wesk. OR=2.3*, 7.4-3.9). No statistically significant risks for S A f 3 (for 3.20 hr VDT exposureiweek, OR-0.9, 1.3-1 - 4 ) .
Pregnancy outconies (47 17) for clerks. Estimated VDT job exposures c!assified into 5 levels. ENM.
R ~ s k of b~rth defects was elevated for the two high as^ exposure giaoups combined but not s~gnificantly (obsstvnd expected = 1 9, 0 9-3.8). No slgnificant rlsks for SAO b~rthweight, or petinaral tnortal~ty
Westerholm & Ericson (1 987), Sweden
SAB for 142 women at two airline booking offices. VDT users were compared to nonusers.
At one offlce SAB was slgntficanrly h~gher foi VUT ,Isen (40% vs. 22% for 2 1-30 age group) VDT usars ct _, I; officas suffered more ftom mensttual t roubles b i3 srs*~s:i-- tests were reported
Mikotajczyk st a1 (1987). Poland
Pregnancy outcome (1820 births) for women at a postal office before and during ititroductron of VDTs into the work place. ENM.
Introduction of VDTs into the work place d ~ d pa t lead t3 increases In adverse ptegnancy outcomes (sex ta:to stillbirths, blrthwelght, ~ l t i h defects, mot?al~ty) No siattsi~;; tests were reported
Nurrninen & liurpya (1 9881, finland
Pregnanc outcomes for 60 VDT users an11 79 nonusers who were referents in the birth defect study by Kurppa et al. (1 955).
Work with VDTs was not assoclated with adverse preg- nancy outcome including threatened aborlion, gestati-,~~ length, blrthwelght, placental weight, and tnotPeis b i o x i pressure
McDonald st al (1 988). Canada
Pre nancy outcomes (6876) for V ~ i i users compared to other working women. Exposure by astimated VDT ht - /wek , ENM.
For current pregnancies elevated risks for VDT users wEre found (observediexpected] for SAB 1.19", 1.09-1.30). acn urinary birth defects (1.84 , 1.07-3.1 & ). No effects wors found on birthweigtlt, stillbirth, o r preterrn birth.
452 cases of SAB or birth defects, and 723 controls among hospital workers. Exposure by estimated VDT hriweek. ENM.
Goidhaber et al. (1 388). U S
A s~gnlf~cani elevated risk for SAB was fourtd fot \runnier who worked w~th VDTs >2O hrikveek cotnpared to I-oti~sets (OR= 1 a*, 1 2-2,8) Risk of mrth defects was also e Gva'cc but not s~gnificantly ( O R = 1 4, 0 7-2 9)
Bryant & Love 11 989): C a ~ a d a
334 cases of SAB and two groups of controls. Home/work VDT exposure estimated. ENM.
There wsrs no statistically significant elevated I-isks ot SA? associated with VDT use (compared lo postnatai cotitrois OR= 1 .? 4. 0.83-1,56; compared to prenatal cotit!-01s. OR= 0.81, 0.59-7.1 11.
Nielseq & Brandt 11 990). Denmark
666 cases of SAB and 764 controls among office workers. Exposure by estimated VDT hrl week. ENIU.
There were no stat~sttcally signiflcarlt elevaied ti-.*r; r ' 1 -'- assoclated with VDT use (fut anv VDT use OR= G 3: 0 77-1 14 for >30 ht VDT uss/week OR= o 7t3 3 r3 1 -=
Tikkancn e i al Card~ovascular birth defects, fetal For mothers exposed to VDTs more than 4 tioui~!dav trio (1 990), growth, blrthwelght for 500 case risk of birth defects was not statlst~cally s~gr-ilkcant UP= Finland mothers and 7055 controls and 1.4, 0.5-3.8 Risk was not s~gntftcantly elevated for btrtr,-
estimated VDT exposure. ENM. we~ght, placental welght, or length of pregnancy j
I I Abbreviations: ENM= EMF not measured, SAB= spontaneous abortion, LBW= low birthweight,
.LA, ~ u , ~ U V J IL. u I L JOY 2.20 JUL F'AGE - t
Chanter 2: Exoosure Assessrnent cC Nan-Cancer t-leakh Studis:
StudyfLocation Su bjscts/Exposure Selected Results
Braticlt & Nrelsen 421 congenital nialforrnation only one of the 20 types of nlalfoi tnalrons studled cases and 1365 controls among hydrocephalus, had a stat~stically signtficnnt elevated risk
enmat k office workers Exposure by based on 7 cases ( OR= 12 Om, 1 38-104) For all malfo~ ms sst~mared VDT h~/week. ENM. tlot-ts and VDT exposure 1137 hr/week O R = 0 9 1 0 4 - 1 32
r Windhan-I et a1 439 cases of SAB and 909 For ail SAB cases and VDT exposure 220 hri~vzek 1 d i901
controls. Gases of CGW, IUGR OR= f .2, 0 88-1 6, for Ka~ser hospital membets from SAi3 controls. Exposure OR= 2 1 ", 1 1-3 8 For LBW, OR= 1 4 0 75-2 5 for IUGR
I esltmated by VDT hr/week, ENM. OR= 1 6, 0 92-2 51
Schr7orr et at. SAB amon cohort of 323 VDT a For SA6 and VDT use in first trimester of pregnancy, using telep one operators and OR= 0.93, 0.63-1.38; for >25 hr/week VDT expos~ire. 407 nonusers. VDT EMF were OR= 1.00, 0.61 -1.64. measured for 2 models.
Llndbohn st al. 191 cases of SAE and 394 There was no elevated rlsk for SAB for VOT kse [OR= I 1 (1 992), controls from three compantes, 0.7-1.6). Rlsk was increased stgnificantry In the hign "~eld Firland Magnetic fields wers nieasureci for exposure (> 9 mG peak) groups lor the two VDT mode s
17 VDT types used by sub~ects used by subjects (OR= 3 4', 1 4-8 6, OR= 2 8" 1 1-6 6,
Roman et a1 150 cases of SAB and 297 Risk of SAB was not elsvated by VDT lieo 11 992) controls. Occupational VDT use (OR- 0,9,O 6-1 4) ot by passtve exposure io VDTs a1 work U K and passive exposure to VDTs (OR- 0.9. 0 6 -1 6)
were estltnated ENM
LBW and lUGR for over 2500 For VDT use 2 20 hrltli~eek durng pregnancy for LBW (1 995a) pegnancles Magnetic f~cld OR= 0.58. 0 31-1 09, based on 424 cases, for IUGR,
exposures measured dui iiig OR= 1 17, O 70-1 81, based on 424 cases pregnancy,
1 L1 e l a1 (1995) Mothers of 37 cases of ut !nary There was no statrstrcally s~ynificant r s k of dr~nary tiac- b8trf1
I tract blrth defects and 116 controls defects associated wrth mothers' use of VDTs For > 225 l and VDT us6 ENM hours of VDT use during pregnancy, OR- 1 4 0 2-2 5
LBW arid pretertn brrths for a VDT use was not associated with LEW (OR= 0 9 O 5-1 7 cohort of VDT using teiephona or with preterm birth (OR= 0.7, 0.4-1.7). opefators and a cohort of norrus- srs. ENM.
& VDT use by mothers OF 3040 There were no stat~stically s~gnrficant associations bet.r?ieeii bab~es with birth defects, and VDT use and: trlsomy 13, 78, 21; Mendelian syndromes, ci 20.1 51 control mothars. multiple congenital anomaly patterns.
sidcrcd closed hecause nrcv tnonitors arc dcsigiled to tinve lower f'ield strength. "They belicvc that the cntn- plcs EMF environment iurrcjuncling VDTs rna,y riot be b s x ~ cha~-acte~*izeii by cunsiderit~p field. strengtli alone.
Mental Health
Residential
1;ivc o f six studies liaorn the 'E1.K. raportccl statisti- cally significant' associations between s~~icicle or- dcpres- sivn ar~d electric-power iacililirs {'l'ablc 2.8,). h stirdy by McDoLv~~II (1986) n l ~ o repol-tcd aiii clcvatcd SMR fnr v ~ i c i d e :Ilnong pecjple l iv ing closest to tt.ansmission
fa,cilicies it? the U.K.. but was 1101 stnii\tic;iiiy ~ : ~ I I I I I cant and il was based (711 only two C L Z S ~ S . Eo1ine11 t i L i i (1983) were critical of' the study Oy P~I.T.> CI n l . I i :!;-: 1 based on how cantrals we[-e seleclccl, l ~ o c $ ~ rnaci le i !~ f'iclds were n~easurecl, and o n the bixsrc clc.igii 01 117:
study. Authors of the c)r.iginnl sttidy (Mn~.rilc? l i :il. 1 0s 2 I-espondecl that they ilid not concl~~cle that ~ t - i ag~~r t i c - t~e i c : expcxure caused suicicle. and thr i t t-nore data were itceiiec to eval~iate the association that they fc>utid.
The study by Pen-y and p ~ a r l ( 1 988j foi~nd ;tatisti-
cafly sigtlificarlc associarions for ciepressiot? and for. ~ ~ i 1 - 1 -
ous cn~otior?aI disardcr-s tl?n~ clfcrc in opposite <lir.cctinn:-. Authors a f t he study did 11i7t add\-ess how l i \ ing c insc rr.
elect;ric s~tpply cnblec; might cause both advei-he ~1nc.1 b211- eliciaI ef2Sects on ~nental health.
Mortality for about 8000 people Eased on 8 suicide cases, S M R = 75; it was not statrstlcatlv living in the vicinity of electric significant. For people within 15 rn of transmisslor! 'aci!l!~.i,s transmission facilities. ENM. SMR= 743 based on2 suicide cases.
7 people living within 40 m of transmission lines repottat!
Perry and Pearl Survey of 576 hospital patients Significantly more cases (71%) of depression were fron-I vvho lived in multistory buildings. apartments near power cables compared to thoce avgciv Magnetic-field exposure by (29%) from cablas. Significantly fewer cases (24%) (2; distance to power supply cables. parsonallty defects. anxiety. and confused yo~ ing were
cables compared to those away (76C/,).
There was a small but statistically sigt-,ificant citfferencs ir the mean 50-Hz magnetic field tneasured ior cast?s (2.26 mG) and controls (2.07 mGj.
McMahan et al. Depression test was given to 152 There were no significant differences rn depressive women who livsd adjacent to or symptoms between the two groups when detnographic 1 block from 66-220-kV lines. variables were controlled for (OR= 0.94. 0.48-i,85j
Althoug1-i .the study by Precce ct al. ('1 996) found an cissocitltion between depression during pregnancy and ~'e~idct~tial proximity to transmi?;sion lines, authors 01- the paper said thar the finding was unlikely LC) be asso- ciated wit17 50-HZ imagnctic ficld exposure (EMFHcalth
S c r f r ~ Digerr .Julg-.A~~g~~st 1996: I ? ) , They suggested r17iit the pattern 01' stnoking among study sub.jecls could have confounded the results.
Of. thc twc~ U.S. studies Poole et al. (1991) h u n d statis(iccltly sig~~il'icant associatio~?s between depression iind ~tdults living near tr;tr-is~nissinu~ litws (fox adults com- bined, and for wc,xnet? separately). TI.le nthcr study in- vnlveii wntz~cn only and n o statistically significant as- stsci;trions wcl-c found (IvlcMahan ct al. 1994). In that slucl.y, magr~etic field:, were measui-ed at subjects' hornes, i\i~d a rccogl-rized test ft>izra nzcasuring depressiotl wa,s used. Authors of elw scudy srtiled, however. that the heta~oge- nctty of tl-ic pq~puiacion i n Lhc study may limit gertarali- 7.nt1on of the I-csults. Because the two studies differed
in the way that \ubjcct\ wetc ielected ancl t i )
rhar dep~essinn \x as defined, a d : ~ eci camp,tl-1s two studies 1.; dr i f~c~t l t .
gcqi tl?rtt there i-t-13) tf~: SOITIC t c l a t ~ ~ n h r tv CCI) I i l:lr I-
power fac111ttes at>d 1~1ent~1 1ierilrt~ e f f e c ~ ' ' 1 1 t c ,<+ - certain popufdtlons,
Occupational
Siudies that examrned pt,\\thlc etfectc ot F\ ;c mental hcalth of electrrcal woi-ker-s are wrrriilLirr/ct 'Table 2.9, The twv S ~ L I ~ I C S that looltcd ar d i p r i - 5 , provide little evtdct~ce for any c~verall . I . \ ~ C I : ~ ~ I ~ ~ I ~ I
elcctric li'elcl iBrnadbe~tt or a1 1935) or- ~ ~ r l h rii~igne ficld (Savitz et nl 1994 expo\ul-e Ti1 tlie Iattci- C I ~ J
however, thcre were sugpe%ltot?s that clciti I L I ~ I I - nl havc elevated r i ~ k . For electrlc~an%. O F t h e 20 R R culalions for dcpress~an repol-~eci 111 rhz -i~.rci\ I - \ -
2-24 BPA Electrical and Biological Ef tc ts Review
Chapter 2: Exposure Assessment B Non-Cancer i-ieaifi? 5fua.e:
Health questionnaires of 390 power-Ilne workers. PEN (eleclric field).
495 suicides were examined among occupations with assumed exposure to EMF, for 2 time periods. ENM.
Depressive factors were com- pared between i83 Viet Nam veteran slectl'ical workers and 3861 nonelectrical workers.
Mortality among 138,905 Inen from 5 electric utllirles from 1950- 66. PEM.
Cases of Alzhertner's disease arrd controls in 3 data sets wera compared by estimated magnetic field exposure. ENM.
Followcip to above study 3 7 6 new cases of Alzheimer's disease and 735 controls. Magnetic field exposure by job titla. ENM.
49 suicides in 21,744 electfic ullilty workers 1970-88). Risks compared insi d e utility and to the general populaaon. PEM.
Measures of depress~on anxiety, and obess~onal symp- toms amoflg male power-transrnissron and distr~butiot? workers were not associatod w~th electric-f~sld exposure.
For 10 electrical occupationai groups In one trme period two were slgn~flcantly elevated: radiokadar mecharlcs PMR= 153*, telegraph radlo operators PMR=25fii an3 m a was significantly decreas~d, telephone ~nstallers PF.4R=t.TA
For all electrical occupations combined, thore was littie svidence of increased risk of depression. For electricians there were sevetal irldicators with increased risk but only one indicator of depression was statistically significant
Compared To t he general population, risk of death hy suicide for utility workers was significantly less (SMR= 81 ' 74-88). Suicide risk and magnetic-field exoosure arnocg the utility workers was not reported.
The maln occcrpat~ons in the rned~urn- and h1g1-i-expos6 1s cat@gorres-seamstrass. dtesstnaker and tallor-bari a cotnbtned slyntficatit elevated rrvk for Alzhe~mer s disease (OR=3 O h 7 6-5.4: for wornen OR=3.8* 1 7-3 6)
Statisti~aliy significant associations were found in a foutth data set, For high to medium occ~~pational n-~agnetic Field exposure: for men and women, OR= 3.93". 1.3-1 0.6: foi men, OR= 4.90*, 1.3-7.9: for wornen: OR= 3.40. 0.8- 16.
Out of 3 0 EMF exposure indices studied, only the geomet- ric meat7 electric field cxposure showed a statistically significant: InCreased risk for suicide; RR= 2.76&. 1.1 5-6.162 (20 cases). Cohort compared to popcitation, SMR= SF*,
Abbrev~ations. ENM = EMF not measured, OR= odds ratlo. PEM= personal exposures measured, * statistlcally slgnifican-i
.. .-I
elevated (wnti'lge = 1.1-2.5) 'out only one was slati.stically .;i;~nif'icant. At1ti701-s of the study recornlncndcd that more compr-e.tler~sive studies should be done.
Three studies f o ~ ~ n d no elevaecd risk for suicide For clectl-1ca1 workers ovet-all. Of these, Earis rrvld ,Arm- strong ( 1 990) did f ind 3 few yignificant risks for cer-tajxr occupational $roups? but t h e risks wcrc in differSerlt di- rcctivns and wcre statislic:zlly significant in only one of the two t ime periods studied (1970-72). For that ti,me period, for all 10 efectrical occupations combined, the PMR u7as 89 with a 95 percent confidence i111efvaX of 75-104. T h c qtrrdy by Savitz and Loomis (1995) was directed pi-imarily at carxer inortality but they r-eposted deaths ftttn? olher causes, includi~ig s~ricide. Cornpared to the senera1 population tnost czuiscs of dcath, ir~,clud- ing sitiricie, for thc t~tility workers were reduced. Au- thoss of thc study said t h a the fillding was consistent t v ~ t h the healthy worker cffkct. Si~icidc m~>rtidity was not analyzed on the basts of estimated magnetic-field cxposure in thc report as were data 011 carlcer mortality.
Compared to the general pop~~lation, ihe siricidz riire for workers ar a large utility in Quihec was :71grni.lcant1> smaller iSMR= 56) (Ba1,i.s ct. al. 1996h) Thai ~II.IL!..
also assessed suicide r-isk xx'itl?ir~ the i l t i l i t ? ~ . i t l i a cili;-
cohort study using 10 different itldiieh of FWtF ?ip< - sure (Baris et al. 1996a). Or~ly thc elecrric-Ireid ~ C I I -
tlletric mean For the medium exposure gi-oup 4 1 u ~ ~ = c ? ,: statistically significant elevated risk (Tablc 2.1) 1 . Hi?\\ -
ever, there was n0 dwe-response rraend. and rhe ~ ~ 8 2 -
metsic mcam electric Fieid was not detc-r~nincd to bc the innst reJevai~f exposure at the: start of' bite stud)..
The studies by Sobcl et al. ( 1 995a. 1995b) :Irne. r c i
date, apparently the only ones that Iiavc ir\vestigatzd li
possible associaciort between mag~iet ic Fields ai.13 Alzheimer's disease. I h c evidence fur t l ~ c association is strengthenad be~airsc the finding is consisicnt. ;lrnong widely divergctlt data sets, Aiso, risks were cfeiateJ for people who work wieli sewing machines, and other
jini- ilia- studies have corifirnlcd that exposures from s c ~ i ' , chine% are among the highest recnrdcd fill- o c c ~ ~ p i i r i r ~ r ~ : ~ ~ magnetic ficld exposures (Hansen et a7. 1'393
-- - - - - -
BPA E/acfr/cal and B~ologtcal Effects Revrew
Chapter 2: Exposure AssessrnsnZ & lVon-Cancer Health Studies --
Human Experimental Studies
Since the early 1970s, sevcral studies havc bccn conducted o.f: h~~rnavl volur?teei-s exposcd tc~ puwer-fre- qucncy EMF under cxpcrimental condidons. Often these studies were cc;inductcd in specially constructed indoor facilities, hut in somc cases people were exposed out- doors to EMF It*an? power- lines. Tablc 2.10 surnma- rizc,.; these expcrimcnial srudias or vnluntccrs cxpvsed ~ t 3 EME
Exposures in 11ic hua-r~an experimental studies typi- cally lusted c:)niy a fcw hours or less, so such studies Focus o n pclssible acutc cffects. Otle result most ~ A e t ? rei>nrted In these studies is an effect on fhc cardiac rl~ytlirn. especially a slight siowir~g of the heart ratc. One of the i'irsr cil.t~es this effect was melieioned was it? the genel-al health study vl' inen who %vul-ked in Russian 100-SMI-kV subbcacions (Saxonov:i 1.967). Tn that s t ~ ~ d y , 17-1~11 w h o f?ad the highest exposure to SO-Hz EMF also had ii.twer heart rates after work compared to rnen with lower exgt.>sur"es.
Nine of the expcrirnental s t~~dies in Table 2, I0 re- ported ultcra~ions in heart rate in people exposed to EMF. This finding was coufin-fled in the excessive laboratory studies conducted at the Midwcst Research Institute and summarized by G ~ . a h ~ ~ n j et al. ( 1 933) (Fig. 2.1 I). Those studies Found that effects on the heart rate (both speed- ing i ~ l d slowing) were no1 a Iitlear frtnctinn of field in- tensrty or exposure duration. Effects were found with expoxu-c to cornbinecl60-Hz fields of9 kV/m and 20 pT (200 r-r~G), blrl n i > c wilt) 6 kV/m and 10 yT ( 100 IT~G), or- with 12 kV/m and 30 yl: (300 mG).
'The strrdies also found thai exposure to the 20-LLT (200-rnGj Geld without the electric field pr.oduced the effect on heart I-atc fmi.nd i i ~ studies wid1 combit-ied fields. In col1tr:ise to effects found when the fields were rapidly swrtct~cd on and ctfF during exposure. exposure to a con- h t a l l t 60-Hz. lnagnetic field did not affect heart I-ate (Sas~1-e et al. 1 995). Three ot,her studies also forrnd n o effecls of clcctt-ic and/or magnctic fields nn heat , rate {Beischcr ct al. 1973, Hauf 1976, Eggert and Rupge
1 996). 'The efi'ects of E M F ~"eported on tc~uman heart rate
are genel-ally s~uall, rransicnl, and to date have r.lot been assucittted wit11 any adverse health effects, As pointed o u t hy GI-aliatn ct at. (1993) the biological significance of the finding is that some rnechanisrn(s,l rnusr exist fox EMF at levels as fou.ni1 in the environrner~t to cause a nlcasul-able physiological effecl in exposed humans.
One known mechanism for a biological itltel-ac~ion of' electric fields is surfacc stimulaiiori of skin or hair. In thc studies at the Midcvest Research l[nstih-ite which sub.jects were silting with tl?eir ai*rz~s rwt ~.nised, tests
ihowcd that subjecis co~ \ ld not reltahi> clctcct \%her : 60-H;. f~elds wci-e on (GI-ahnm et al 19871 Thl. \ I
gcsts that e l i c t s found 111 he studte\ ~ o n d u c t c t l b\ laboraalory wcre due to othcr rnechc~ntsrn~. po.iihl> perception body cur-rent* it~duccd by the i ~ e l d i
Wachlel el a1 (1996) used a model or p.~cci??,ii. - cells to zcc whethcr the cells wot11c.l ~-c%pc~nd tc, tl?: t \
of intewmittenlmagne-tic fields that affected h ~ i ~ n : ~ t ~ 11 - ratc in the studrcs by Graham ct a1 (1993) Tl-ie i: I
did respo~~d at currclit denstt~es s~rmiltu- to tho<c zL l mated to be ~nclcrced In the human hadl hv ? k y c ~ i i i j - used by Graham et al, ( i C l Y 3 )
Thrcc of t h e 4tudics i1-r TLlhle 2.10 were clc51r: -IC I
tneasurc threshold\ Sor I~uni:\n pel-cej~iion ol p ~ ~ k t ti ;
quency clccrrtc fieldc, TWO (>I t hew t i ~ t o i \ e u p e ~ p i e standing rn electr3tc fields, they produ~eki
- - - -
BPA Electrical and Btolog/cal Effects Rev~ew
--~ ~. Chapter 2: Exposur@ Assessment & Non-Cancer Health S:LIC;~,F-
psrformanca tests, and memory.
10 men were exposed To a 45-Hz A significant increase in serum triglycerides 1-2 days after 0.1-mT (1-G) magnetic field in a exposure. No effects on blood, heart rate, blood pressure. laboratory for up to 22.5 hr. 3 tsrnpsrature, urine, respiratory gas, reaction titne, perioi-- nonexposed controls. mancs tests, memory. cholesterol, pupil diameter.
Krivova et al. (1973), 23 men were examined during Paper has few details but implies that biological affects wet-k activities in a 10-32 kV/tn wars found whicti, a l o n ~ with results of other studies, led iri 50-Hz electric field. establishment of occupational electric-field siandarcls :I?
Russia.
3 mT (30 G ) .
Detection of 50-Hz electric fields With both arms a1 sides, 4% of the people datscted 5-kVTm by 75 man and women standing field. With one arm raised above head 20% detected a inside a high-voltage laboratory. 5- kVlm field and 40% detected a 10-kVlm fieid. 3 people
detected a 0.35-kV/m field with any arm position.
Sander et ai. (1 982), 50 people exposed for 3 wk to Electric field; leukocytes increased 2.4% in 20 iiV1t-n. :3lood 50-Hz elsctric fislds of 10 or 20 sedimentation increased 12.5% in 10 kV/m, less reductioi? kV/m, and 17 poople exposed to a in average EEG value end of day. Magnetic field: slight 5-mT (50-G) magnetic field. difference in hznd tsmperaturo, small change in lact~c acrc!
at sides 1% of the people could detect a 1-kV/m field
Pscany st al. (1 983a) Study 1 : 7 0 p%opI@ exposed for Statistically significant effects were found o n h e a r t rate. Tuhackova & 6 hr to 50-Hz 15-18 kV1m electric thyroxine, Achilles tendon reflex, epinephrine, cortisoi, and Csn kova ( t 9E;2), frelds. Study 2: 13 people exposed testosterone. All results were not consistent for both Czectioslovakia over 3 days, studies.
>I00 people exposed <I hr (head Approximate thresholds for effects at 50 Hz: visual f l i c k ~ r 8: or chest) to 5-100-Hz horizontal 7 mT (70 G), changes ~ r i visual evoked potentrat at 70 ,-iT tnaynstic fields up to 100 mT (700 Gj, headaches at 600 G. No effects on ECG, EEG (I000 G) while laying down. blood prsssure, or body temperature.
76 men were exposed to electric Significant differences between exposecf and s h a m - Curtents (up to 0.5 mA) s~rch as exposed were found only on the second day with sham induced by a strong electric field group more alert at end of the day, and impro\/ed respnn$.o (36 kV/m) for 5.5 hr. t~mes to a complex syntax reasoning Cesf.
et al (1 988). 11 men exposed in a laboratory to Effects of exercise were not affected by EMF exposut e 60-Hz EMF of 9-kV/m & 20-p,T Hsart rats was significantly slower at 30 and 120 rnit-iu:ss (FOO-rnG) for 2-hr rn combination into EMF exposure periods. No effects of EMF on covtisoi,
i wcth 45 min of sxercise. growth hormone, testosxerone, temperature, or lactic acio
Teresrak & Szuba 64 people (22-63 yr old exposed Reacfion t~mes 2 0 both so~ind and ltght stirnul~ were I I 11 989), to 50-Hz electric field o 0, 4 4, increased stgnifrcantly only at the htghcsst electtic fmid I Poland 10 9, or 13 kV/rn, or to currents of (13 kVim), and the hlghest current level (160 LLA) C itret-'q
0,50, 135, or $60 p A were applted Thfough \he hand. i
I 1 Kato et al, ( 1 989). Detection thresholds for 7 men Detection thresholds in summer were 30-65 kV1m for ti le Japan and 4 women for 50-Hz electric hairy back of the hand, and >I15 )Vim tot the ~ a l r ~ U!JI IT- I
fields indoors from slecttodes fall, detection for hack of the hand was 1 15 ki/)rm around the hand I
/ Wilson et a1 (I 990), Melatonlll excretion was mea- No effects on urine melatonin melabolrte wrth cn~veritio?: a
U S sured in 32 women and 70 men electlit: blanket With cont~nuous polymer wile AC and i i i after slaeprng with AC and DC blankets, 7 of 28 people showed a dectease 111 n-iet;boIitt
I electr~c blankets for up to 10 wk during exposure and an Increase rn post-exposuie
I Cook el al (.1992), 30 men were exposed for F3 hr to Stat~stically significant effects were found on slowing oi 1 U.S. 60-Hz EMF of 9 kV/m & 20 p.T heart rate, changes in event-related brarn potent~als at-d I 1 (200 rnG) while sittirig in exposuze decreased errors in a reaction test No effects on subject i~~ 1 I room in a double-blind study. measures, sleep~ness time estimation, or field percel:)t!oi3 i
Bell et al. (1992), EEG fof 20 people exposed to Most subjects showed field-related rncreased EEG acti?iit:r 1 60 Hz 0.078 mT (0.78 G) and/or The response during combined AC/DC, exposure; did not
I DC magneclc fields in a laboratory differ from the sum of indrvrdual responses.
I Fields on 2 seconds, off 5.
Sadafi & Wood ECG for 9 2 men and 6 women A trartsient 5% slowin of the heart rate 10 s~cot~cls aftct . Wood et al, exposed in a laboratory for 60-150 switching fiom field of?to on snd persisting tor 60 second; seconds to t5.3-20 p,T (753-200 An opposite effect occurred when switchirig from on to of: mG) 50-Hz magnetic fields. Because of hlgh varlabrlrty. resuits were no? concl~~sive
/ Korpinen el a1 ECG for 27 male electrtc transrnis- Volunteers showed a sl~ght slowing of the heart late (1993: Korgrtien B slon workers ancf 26 volunteers followtng exposure Vol~znteers (mean age 25 7 yts) viere
I Partansn ( 3 994) were exposed outdoors to EMF tested after walking beneath :he line Workers jn?een age F~nland ft'om 50-Hz transmission lines 40 8 vr) were tested atter wotkrng In and ocir of EMF
I 1 Koipinen & Partanen EGG for 26 men exposed for I -hr The slight slowlng of hesn rate in a previoui srunv (aeiiJr I ( 1 993). perlods to a 50-Hz 400-kV 11ne ~n was not found rn thts second sttidy A passrble increase in 1 Finiand 3 5-4.3 kV/m, 1.4-6.6 btT (14-66 systolic blood press~rre was focind ~n the msn cxpo;eci ro
I niG), 15 men sham exposed the line Data presented wet e prellniinai y i
at al (1983], 11 women & 9 men In a laboratory Statlstlcaliy slgnlflcant ef2ects fotind increase ~ r , a:pha r rs i - i exposed to 45 Hz magnetic f~eld wave acttvity, decrease lo delta wave activity beti; \rrz\c; (32 5 G ) from coils around their and rneanlpeak EEG fteq~toncies incroasod in ftont~~l 1 head (continuous & ~ntermittent) d~rivattons Also a possrble decreased test lealnrng rate ;
1 Graham et al (1 9Y4), Three groups of 1% men each For 9 kVim & 200 n?G: statistically s~gnificent slowing ni I
exposed sitting down In a labora. heart, changes in event-related brain potentials Fot 6 kV/rn tory for two 6-hr periods to 60-Hz & 100 mG: significant decrease m reactton time and test i EMF (6-12 kV/tn & 100-300 mG). performance accuracy No effects for 12 kV/m & 300 niG f
Litovitz et al (f994), Diabetic subjects were exposed to Blood glucose levels rncreased In magnetw frelcis $3 6 LIT a 60-Hz magnetic field (2.90 mG) (6 mG) (no sTatistlcal tests were reported) and to noise while sleeping. i
Sastre el al. (1994) Heart rhythrn in 2 studies of men There were stat~stically significant modificatfons to Ihe exposed while sleeping to 60-Hz heart rhythm in the 0.0-0.1, and 0.1 5-0.40 Hz spectral I interm~ttenf rnagnet~c ftelds of 1 bands In man exposed to intermtttent ma nettc f~elds
I and 20 pT (1 0 and 200 mG). (on I hr, off i hr, onioff every 1.5 seconds 3urnii on pet fad)
i i , IU. L U U J LL. u t L J U V J J O J U L PAGE
Chapfer 2: Exposure Assessrnent & Nor?-Cancer Health Srudie:
Three experiments of melatotlin in In the first experiment, rnen with r-tormaily low nigtii bloocl- nlen (1 13 total) exposed during melatonln levels had statistically significant rfiduccct level,, slgep to 60-Hz magnetic firzids, after field exposure, but not it? the second expenment bolh intermiitetlt and continuous. Authors concluded magnetlc fields did not affect msrlatonir
Graham et a/. SO men in groups of 20 were No significant effects of exposure were found on blood exposed or sham-exposed melatonin concentrations. Significant alterations assoc~aie:; overnight to intermittent 20-p,T with exposura were seen for testosterone. T-helper ceiis (ZOO-mG) 60-Hz magetlc fields. (CD4). and natural killer cell (CD56) acrivity.
57 men and 44 women were Compared to nonexposure trials, during oxposure sulijects exposed around the head to a were 14 msec faster on the most difficuft task In revponoin.; 50-Hz 100-pT(1 -G) field for 9 to cornpar@ t h s duration of 2 light flashes. No effects an 2 minutes during performance tests. easier levels of difficulty, or on blood pressure or heart rate.
10 men and 10 women were No effects of exposure were seen on body temperature or exposed for 10 min to 50-Hz on heart rate. There was a tandency for a reduction 111 magnetic fields of 0.5, 1, and 2 mental performance on psycholog~cal tests. rnT (5,f0, 20 G).
Kurokawa et al. Melatonln secretion was studied in Preliminary results indicated no significant effects of 8 mqn who slept for 6 wk with exposure on melatonin concsntrations measured it7 u r ine speclal slectric blankets that The median magnetic field measured at the surface o; the produced EMF but RO heat. electric blsnkets was 3.4 yT (34 mG).
Sslrnaoui et al
1-esults (Cabaney and Gary 198 1 , Deno and ZnfinnsXla lYX2j. Most people in the studies could not detect elec- tric fields of the strength found beneath Cransrnissio~l lines tilt less they stlatche.d o ~ ? c or bolh arrns above their head. I n the tcsts by Cabanes and Gary ( 198 1): it was f'ound thar a sn~all percentage of people are sensitive t;c!
xelativcly weak electric fields o' less than 500 V/m. Not all of the studies in Tab1.e 2.10 that found biolo~ical ef- I'ects of field exposures reported whether subjects ir? the studies couId detect whcvl the I'ieids war6 011.
Six studies in Tablc 2,10 repcwted rhat tield expo- sure resulted in a decreasc it? peoplesi performance on various j~~errtal tests iilvc!lving reaction time 01" accu- racy (Kalyada 21; 31. 1985. Qskov ct a]. 1993, GI-aham et al, 1094, Eggerr and Ruppe 1996, Lyskov et al, 1.8963. Three other studies reported improved psrfoi-rnance on tests associated will? exposure {Stollery 1986. Cook et al. 1992, LVhittingLan tt al. 1996). Corl-tparisons atnong the studies arc: dif'iicull to make because of the wide
differences in cxpo~;uz-e ~c-rndrtlom5 t ~ ~ d 111 tflz t? pc v L performance tecv iced ir t t he studiei 111 3 r e \ i i . \ r
t h i s research, Whtttington and Podd ( 1 996) supge\tei that the inconsistent results may have been cau\eii tl low statistical power of the studres They tound tliar i -13
average, the 12 studies that they re\ 1ewte~1 had oni\ dil
8 percent chance of dctccting smell effects-the i ( 7 i i?r effects on human performance nrphy\lolog mobt irI,cl~
to be produced by EMF;. Four research groups exatnrned tlte hurr~~oiic I I I C J ~
tonin in human volunteers exposed to 60-Hz T T I ~ ~ T I ~ I I L
f~elds. In one serres ot studtes, tr~elatonin u:~s I I I C ~ Y L I I C , ~
R~oir~ blood samples rakct~ from men \\htlt: the\ \ l , j i i I r
c~tculai-ly polarrzed iieldq of 1 or 20 yT (10 or _ 3 ( r ( l PIC,
(Graham et al. 1995. 1996h) Tn o n e oFtflc s i t i r t i ec 1% 1 1
1nterrnit.tant field evposcrre of 20 pT (300 tnG) I r I
nal fnelatontr~ was ctgnificantfy dcp~es~cci o n l \ 1 1 , i trr
who had nol-mally low ~ n e l a t o t ~ ~ r ~ l e ~ e l i tjut the tii1J11 -
Chapter 2: Exposure Assessment & Won-Cancer Health Studies
did not occur in a replicate study. A third study in the series foutld no effects on ~iocturnal nqelatonin from ex- posure tc! a 20-pT (200-mCi) cot?tinuc>us magnetic field.
Other reseaiachcrs tnzasiircd a metabolite of mcla- tonin in ut-ine (6-hydwoxymelatollin sulfate) of 35 wornen nncl 10 tnen who slel>t under electric blankets for sev- eral wccks (Wilson ct al. 1990). Mihell subjects used c:ot?ver?tional electric blankets, thcxe were no diffel-ences in nocturn;ti levels of the metabolite compared to pre- :und p o ~ t - ~ ~ s c rir~?es. For 7 of 28 sut?jecr,s who used con- t i n u c ~ u s poly~mel- wi re blankcty iCPW)? the lnetabojite decreased with exposure, but it increased h l l ~ w i n g ex- posure iihc researct~ers called the lattcr a rebound ef- fect). The CPW blai~kets switched on arid wff twice as often, and ptAnducecI rliagnetic fields that were 50 per- cetlt stronger than co~iver~tionnl blankets.
Prelir71ir1nry results ol'anothe~- sludy of elec,tric hlati- Itcts found rpjo evidence that rnclatot~in concentrations in vrjne were affecteci hy r.l?c use of such blankets by eight Inen (Kurokawa et al. 1996). The blankets used irr the study were 1-tlod.ifiiad so Lhar they produced EMF but no licat. This was done so that heat would not be a confounder to possible effects of EMF.
The fourth exyerirncntal s l ~ l d y of melatonin in hu- m mi ins Ihund no intlicatiotl that exposure to a lit?earlp polarized 50-Hz 10-pT (100-mGi magnetic field af- lectcd levels of either serum rnelatonir-1, or the urine n~ctabolite ti-sutfa~oxyi~~elatonin in tnen (Selxnaoui et 0 1 . 1996). The trier1 were exposed to the field while ihcy were lyin~clowti for 9 hours at night. for twu ~zighrs.
Some vf the lot?ge&r human cxperirnental EMF ex- p o s ~ ~ ~ were incl~~dctl in the studies of 50-Hz fields by Sander ct ai, ( 1 982). Up to three people at a time spent I week it? a special room ( i n ~ l ~ l d i t ~ g sleeping) exposed to electric fields fitr 6-22 Iiours pcr day, while three other people were it1 a r-tcarby cont-rol rootn. Extensive data were collccred o n blood components. hor~nonc lev- C ~ S , EEG; ECG, temperature. and blood pressure. Two psychulopical rcsts were administered, and eye flicker ft3equency was measured. For tnagnetic-field studies, one expclsed at?d one control person were tested at a ritnc during a scvcrcll I I C ~ L ~ I - period. 'I'l?e same physioiogi- cai tiara -arere c(?IJcc~cJ as 1'ix. C ~ C C C ~ ~ C fields. Most pa- inrnctcrs i t? boih the electric- and tnagnetic-field stud- ies sl~owed 110 c i i l'ikrcitces between exposed and contraol sub.jccts, with a lew cxccptions (Table 2.10).
Electrical Hypersensitivity
It1 additin13 lo chc possible rcpruductl\ie effects sf EMF I-uon~ VDTs discus:ied in the section above, there are also rcpor-ts of' skin discjrclers and other syt~113tonis ar*notjg some users of these devicea. "rl?ese efrccls are
often rcported by per-sons who belteve tlletn\ei. ci t
hypersensitive to clcctriclty (Knave 1991). Otlier LO^^ also beiievc that fl~ey are seizsi~tvc to the r,lcsti ~c o i I ?
iictrc fields produced by electrical applrance~ ,ind cq r l
ment i n general (Grant 1995, K t ~ a v c 19943. Such periv report a varicty of health effects inci uct~t?g he,iiia; 1 ,
fatigue, nausea, ~n.iornnia, slio~.tne\i of kreatl?. he ' I i 8 1
pitatton. dizz~ne,\, m d t-tlemt-tt-y d~tticullic., GI-ant ( 1 995 J consldc~ed e le~ t r i~d l \e11\ii1\ 1
s. forin of envrtonmcntal iline\i .uch '3, , i iei~iic,~~ -:-
t~vtty, ,41ck t.itilCi~np iyricltntnc, anci j-tic-.li-~,~hi\ Ci) I i
syndrome The autl?c~t a c k n o ~ lzdped hour\ ei. was an clectr-lcally ietl\rltve patrenl and n o t ,I r i i - 8
doctor or a scientr.;t Compared lo t-natly o i ~ h c othel he;llil~
cluded in research on EMF isucl? ,ii iaplotlu cancer), there have been raiativcly few it~idie., (37 man electrical sensitivity, One xrudy In thc C' F tjgatcd se~lsitivley of gritlents to sc1uul.e t \n \e I-rlayr r fields with frequencies of 0 1 Hz to 5 h1Hz (Kz,i r i
1991) Of' 100 patlenls who complained ol hc~ng \ell
tivc to EMF, 73 sespondcd to f'ield c?pt~\uic ( i 9 0 1 - i ~ -
tl~c cvnrrols responded). Howevcr, 50 oi thc pG~tl;$ also responded duriilg field offeoiidittoti\ 3116 rile\ it c removed irorn tile study. Of the reti~~lillng 2 p2 \ T
16 were found to lespond co the i'leldi 111 ~ L I ~ I L C , + I ,
phases of the \ludy Most reaction\ uzrc ncur oioz - Snrnilar studre5 tn Swcden co~ild not conttrm r t i t s i r 1
uf elect1 tcaily srnsitivc patlent\ to dzrcct 11 r
( s tud~eq crted In Ktiave 1994 r A revrcw b! the Nattonal Ratlti,>lc?g~ccll PI or,
Board cotlclilded that the ik11-1 dirc:i\ci tey~orrcci I > \ 1 - user5 of VDTs du not appe:itd to bc c , i u ~ e d b~ e i to AC r-t-tagnctic fields iAd\ I $01 y Gl pup o n ' I c
<,"E\[ Ing Radraliotl 1994). The Boatd d1t1
isring s k ~ u i i~~ordcrs, ehpectally In cnnd~r io r~~ ot I ( m~dity. They added that strain ahroctated M ~ i i h \.
t%ay also give rise to skin probletns. A i t ~ ~ d > t)b 41 PC=--
et al. 11 993) found that people with VDT-n\iocrai~cl - I- cornplannts suffered more from occupaiion:tl \ t i +\ , pared to hcaltiiy controls who also u\cd 'b DT.
Many of the report5 of elcctrtcal hyper-eii-ira have cotne frorti Swzdcn. A repol t on EhlF 17.1, .L 1 - Swedish Govsi-nn~ent agencies pnitlted o u t that .\ - tom3 reported by eiactl-ically hypcr>eni~ii\c yci r.1. common tn the Swed~sll popuiatlon, and rhc\ ,,1i7
Illany causes (Scvedrsh rZgciicie\ I O Y i ) Tli said that such cymptornr h a d iiot -, et bceii nii experlrnents cvhetc the sen\ttr'te 11icli\,1(iiiai . aware that EMF had bee17 aclixateJ The ;t;cn that rno1-c ieseatch 1s needed fo leal-n thc criu.:-s syn?ptot-tis reporled by electl-ically 11) per icnittl\ e
2-30 6PA Ellsctrical and Biological Effects Review
.Advisory Group on Nnn-ionizing Kndisf io~t . 1')'ld. Nrciirli /$rrr'ir Xr/t'c/e:'tf t t //ic Osi. i?/'I/irtrtii Di,?//icc.t. [it:;!s. N;u~tin,~l R;idicil~\:.ic,tl Pn~leciiiui R.I.I:-LI L ' I ~ I L ~ I ~ c 5 Kt>. 2. Cli~ltoii . I>IC,?I. (,>x<:II. !,).I<.
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i\srnctvn TT', Rrtkos A.1. i W h . "Tllc >c.!ir r i f hc;ii~h r.al'pcr\(rni \v<,rkilig in clcclric i idd oI'i.>citdiirtr 400 > I I : ~ 500-i.V ~wit~liv:isil~.." (T11;1~,11 .,-,~.i, . : I
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51.95 31.
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I3nt1chingcc- M., Iiiir~FR.. Sr i%~-t~id I?.; nw-sp 3. lL7K I . "Aii;ilysis nf sli.uct(tla1 ~ l ? rnn~osn tne c.harigcs and SCF afti'c'i.ccl~piitin~~:iI icng-trc-;i? ~x.[?rr,bt::% 1 . 8
c ~ . a ~ c . t r ~ c $it1<1 I Y ~ ~ ! I ~ c ~ ( i c fieiih ~ ~ O I I I 380 kV-S>fstet~~s." Kt~[ili<~icti~ t i~#<l E ~ t ~ t i i ~ ~ r f r r ~ ~ r ~ ~ ~ t I 8ir)p/z j ,s ic;3 l9:235-238.
i s 1 i t I . i h e l I . I ! k G ! 1 c f : ci/ic.i~$tcii,t~ (11 t;vir-c~ncly /rru:~fici/rrcrji~y. R e p ~ r ( NP,hIRL- I l >:I i'. \ .
licll (;.I$.. hilaritio i\.r\.. Chesst~n ,4.l,. I9V2. "A1te:'arioflc iii hr,!iri clcctrrcal activity cauhcd hy tnagnaic licitib: dctcciirig thc cIcr:.cirrst' p ~ r : ~ : . ~ E / c . ~ I I ~ o ~ ~ ~ ~ ~ ~ ~ ' / ~ / ~ ~ I / , ~ ~ ( I % I : ~ / I \ . iiiltf C/ii~ic-(i/ i\!riiiiipIr! ?ii:Ic.r~y 83:38(1-307.
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ticlii:i cIuring pregnatlcy rvith stnphasii on aicctrlcaily t)cr:.lcd hcds: aqcociatinti u/itli hirlhwaighr and r~itratltcrine g1'(lwtl1 r~l;~.cd~~.tliv~ ' k:.i:l:.~? ..'.,, h:?h3-270.
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Urackctl T.R. (principal ilivwtig+tor). I99d Tiic EMDEX Pr,oj?iccf: Rcsidct?lial Stad:/ (T1.ircc Vului?tch?, EPR 1 T4- 1 Od35-VZ R ~ ~ ~ a c i l i Pll,jcL* I+"-1 1
Find R~1gitt.i. Dcc-cmboc. I'f'lJ. r i~p t t r cd by T D n i ~ Dsnckcii. Irlc ; fvs, Elcctric Pnwo. Rc*cnl-ck Tnnticutc. [.>;.,lo Alto, Caiif<,r.niil.
Rl"ackrn 7'.13. 1057 "Ev;tlrt;ttioi~ i ~ f 5ti-Hz clcrtric-+isid expowre trrnr\it<-,rsring inst~urrrcntatinn:' Y a e e ~ 13.5-154. trt. Andei.\clir I.,E., rt ;rl ietlt!~~.. ; '1; . ,.! 791;171 Hiiiititi.d /,!f& Sr*rc~rc.i,.\ Sn;li.c.r,viitn~ Jii~e,zic.iititr crfUii~Io,qic.rtl .~ys~or~:.s u:itk S~rrric nnd kLP t.1rc.11.i~ rritci illn,qiteiir i.i'c/;ls. 0cic:ber 1-4. IL1r-
RicI11:inci. \<i;~>f>~tlgti>ii. k';\citk N O I ~ Z ~ W ~ Y I ~. : \ I?I>I '~~JII~. fficl~l<\s?<l~ Wq$t%I~q&\t>r'~.
Brnclccn T.W. 1988. I!-?< ct,srtrz.l>nt.fri (11 Or'< ci/!cftict/it!l A\:pn%r~r-d: t!f Si,l~rtntio#i W<)i-ket..r. In cj(i./-i: nt*igi,cstic Fielrlr, Q(JEf:,/BP-634!)3- I Pl.cpes-cd h:; 7. i?,i.~ Rritckcn. inc.. i t ~ r Bonnrvillc Pnwcr k d ~ n ~ n i ~ t i n t t t l n . V~~IIC~ILIVGI.. Whsh~ngtnn.
Bracken T.D. I YQO, Tlir, K M r ) K X Pir){c.i.i: E~c.17tirtIn~) Twi.rfe~. n~rn' O~~c.tt/mrioiicii Meosumrrcrrrs (Three \4-!unies!. EPRI EN-7048. Rc \~ , r c l t F'r :~;c<i 2 .I(-,'-
1 J'lepsi'ed h? ' f ' 13<if1 tti',ickct>. Irtc. k>r. f<iccrttc Ptlwci, R ~ Y C ~ I I - c k Inslilt~ic. R r l ~ Alii~. Ci~lil'c~l-tiia.
Hri~cko~> T.D. 1')07,. "Enpo\i~t'e a+.;surlnctil 1'oi. p-rim~cl. f'~'cqllcnr;? cicctvic onci i%\agincL:c licldr," Aw?eirt~?i? f;?c:ti:<t,-ini i+.ie~cvlt, cs.,, i,.l?ion: 3 $1. I < i s . 1 --
1ivrr.hr.n T.0.. (:ltwrtirr- V.1. 1987. "(-I~ctlpi~li:wiiil cxpr.+rli~.c ,;I' tiigl~-iinila& wnrkcrs In 6li-f.ti. o lcc(r~c livicl\. I,:lrf 2: *ui;11!!<1i ;iiic.t rc:.c~l'. P,,gc,. ; i ,F--A li c c
I I . . . , I I t . I - I t f i L 5 I . i t i i i i i i ~ . r f I i l . 1 I I . I ; I ! 1 5 ) L ; 1 9 -
f21.urkrn T.D.. Khcifcts l,.l., tiussntarl S.S. IVV"."Rapnru~.c :~s\c.;.h~snr Ibr power I-cqiicncy clcctl-IC nrJ ~.)aprl!:rii I i ~ i J ~ cRi\,lr) ;.i,~l i t % a?i;iir..iri~-ir I cl:iicic~iiioi<~gic S I~ IL~ICY. ' . J ~ I ~ I I . I ~ ( I ~ ~/L.Y/JO,Y~II.? d f i d E!~t.i~.o!?~i~fi~ir/<?\ fi1.~!(/+fii7ic)/(!p -3: 1-21.
I.tl.ackcn 'Rlf,. Rankin R.E, Srnior R.S.. A l l d ~ - ~ d ~ c .J.R., Susslnan S. 199%. "R4ajinctic field c x ~ ~ r r s u ~ ~ c r iuiiiwg utility wcit-kei~, i i i s , i . . c ' 1 1 : 3 1 ; . ~ , . i';',r 10 .2 1<,-2Zf,.
Tlrsndt 1,.IS.4., Nielsen C'.C: 1')Uo. "Crinycnit:~l m:~li;trn?::ti~,ni: . i m o ~ i ~ slii l~lret~ i:f wonie:i u'c)rkin; with vidzc~ i?iipl:t) tzrmin:tla.'. %.,1!1<!1~i~ I i , i , ~ ;,.',, p s
I3rcysw. P,. Lccs P.S..J., McDiar-mid MA., Curhrm fi. I vVa . ''E1.F: ~~iagi lc l ic cnpo5itrc:i in an nllicc rnvironrricni." Ariw ri<.:t~t .Ii~tii.:iii/ r',f 111 25,177- i b5,
DfA Elecfrical and Biological Effects Review 7-2 8 - .
Krnndltent D.E., Rrnrtdhent M.H., Male J.C., ,Jones M.R.L. 1985. "I loi~ltli o f worker. cxposcd tr? ~1rcr1-iu iii.ld<." &I ifirli , f r i r r r . r r ( r r ,,I ir,c/,, , i # . i r d , .;;L i;,
42175-84,
Bryilfil H.I., J,ove F,..I. 1 ' I K V . "Vicicc, ilisploy terminal vsc i i n c i spouriiilcc,irs ;ibortinn risk." Iriror~~rcirii~ricrl .fr~~cri!cri r:l'Ef?i,itle~!r~iol~:,y:. 18: I .::-I IF
Buiatti E., Barchielli A., C;eddes M., Nastsi I,., Kr i~hc i I f . , Prailchini M., Scarselli C:. 1984. . 'R ihk I;ictc.'rs in i~iiilc 1Crt:iity: : i c i ~ s ~ - c : ~ ~ i i ~ . ~ : i i t !~j ix
A1.i irivc,? of ~ J ~ I ~ / I ~ ~ ~ I ! ~ I ~ ~ I ~ ~ I / Hcaltl:, 3Y:260-270.
C:ahancs J.. C;ary C . I ' i X I . "I3il.ci.l pcr-ccptiuri ol' !i!c ciertrir; fiqld." P;rl?il.r. 233 OR. I;flt?.~~ofi#,!?nl f'iiirfi<~.crtr:.c. nrT I.ii~:?c, H i ~ l t t/r~li.,igr. 7i.,inrilir\ \ii*~ i ',.i
Sbartietb V.l,., Bracken T.L3, 1 W7. "C)cct~j?ntion;~l cspuriti'c nf hrgh-vi>ltagc workcis tct 60-Hr c.lcc'(ric Blcltii, p;irl I: e s p o ~ u m t i i ~ ! ~ , : ~ i ~ ? c - > t ; ~ t t r ~ ~ i " ?, ,g:- ' - f34. j ~ ) , A~iclcr<or~ I..E.. c?L i l l . (c~lrt~)rhl. T~t~~,tr~\~-T/r~~x/Hctt~/ i !r<l l i f i .~t~;c,tic~c~ sT:t~!r~/;<~,rir(~~f trt(t*r<r<.,i<)t~ ->f'l?~<d<>,v?< : t i . T ~ ~ ~ t ~ ~ t r ! s \ L . ~ I / ; c,l<:l:,. ,'>!<.; .FI.17 L , . iiiid h+',ieni-rii. Fic*kii. O c l o b ~ r 2-4 . 1984, Richliind. 'vVn41ii~gto!i. Pitcific Ni?rthwcsc Lahoi-alory. Rlc-~larrd. \V,~.'ci\liirigirii
C11;irticr \'.I,., Erackeit T.D., Cslyon A S . IYR5. "BP,i\ slurly of occul,?ttic>n:il srpas?:rc ?P 60-Hz clsc\ric lizltis." IECE T,r:ir,-t,; !!i,i!: t * ; .
:i.!ri Sssirrtt\ PAS- 1 iiU:733-744.
Ciip~~ll l R . IQfr4. " S u C ~ I c t i rn!;tt!t ~lr:rtli cyilrlrr,!iic iStr)S) & EM fields.'' Ab.~ri+ncr L-I-? / ' , . ~ ; r ~ ~ r i c ~ i ; a : l l ic. iijild .iiri:ui,i Mr clio,c 01 S r x i c ~ ~ . I i - ; 7 11,1116. C~l)~:tlhi)gctt, f3clir11~r.k. piigc 46.
Colcmatl M., Her31 V. IOj jZ; . ."A rcvicw of ~prclc1i~1t~i0gicii1 slildies of t l~e lhsull!? cllhctr of irvirip near cl. .wtn.kii~p wit11 clcelricic~ ;c!?ri-,:\ttT13 :.ri,l . i . i b ' \ '
\ion cqi~rpmcii(." Itrtr.iiirrlimiizil ./r~ur!~oi of Cf?l,ir/c.~~:ir>ir~~). 17: 1 - 13.
Curtk M.R., Grnfiarlb C., Colten F1.D.. f k r k o v i k h il.1.M. 1992. "A icvlicoijn:i study of Iiiitnan c h p ~ ~ u r c t o (,O-I-J<. lLiil.id~~ effects on %~c~r:.ni.cl?:i\ :. i , i o
n?eaz;u~cu." f 3 i r r r ~ I r ~ i ~ r r r 1 1 t t c i ~ / ? i ~ 1 i c ~ ~ 13% 1-233.
r~Ie(v>sj<." l J i ' ( ! j ~ ~ t Ahrrrr.ic$li '171e A~rri~irtl Rc~oew of R@rrcrir'lr 011 @fnl{)gictil Elpcr,c r..J'Plac.?iir iirrti MCIKII( ,~~U Flc'Iti.\ P'r.oili iiic Ci( i f t ' f - ~ ~ i ! ( v i C ) i , ' , ' . , - I/se rif E'/'ic.c.rr.;~ri,v. N o t . 12- 16. Pk~iin Yortngs, Califc~r,ini;\. Abstract Ad.6.
Dcadrrtan J.I.:., Carnus pi., Armstrnng W.G., H6mux P., Cyv I)., Piante M.: TBCriault G. 1988. "Occupalinnal aod reuidcnlial OO-k[-[r clcctrt~r?~,~::.':::, frcld; ;ind I~igI?-l'fccl~:ciic electric trailhicnlb: C X P O R U S ~ assesamen/ using u new doxitnetrc" An~c!r.it.c:u /rrdt~.;!i.rctl IJvgirit~~ A.rsr1r i~iri,}~: J r a , * * . ~ ~ i , ; -1 ' ' ' ' ,
419.
D e a p c ~ DM., Henderson J3.E. iOX6. "'A case-cnntrol brttdy ol'nt??yoirophic lateral sclcrasir." Arlzt,ricoii .lorcirrtrl r?r&j,idcr~riti!o,qv 123:790-"!'1.
Dcno I).V\. 1977. "Cur r~n i :~ iniii~cccl in the !~un-rnn horiy hp iqigl? volrage traosmiusiun Iinc electric iicld - Measuremeni an:i czlcuirl:tion i l l cl~~i:'~h!t:~*); .A ' -
cinse.'2E&'E Tr~nrii!<.i!e!ii.~ <i l l lJf?i.1.c7r A/?[zcrr~rrt!, crrrd ,~y+ieri?J PAS-96: I f , 17-1 527.
1)crrn V.W. L 979. ''M<vti(~.,<ir~$ of ~?ersonnri exposed lo ri 60-WT clcstric ficid." Pages 91-108. In. Ph~lirpc R.D., C;illis M.F. (cli:iii.~~it.n? Rrr4,:i:rf "7.. ,
L . v I I ~ I ~ : E / ~ l , r ~ i v F1:18e/~cr,ir..v ~~e( . l !~o l l l~ r~ i l~ l i ( . Ijj~tiis, P I . C I C B C ~ ~ I ~ ~ S t?f(i/le Eigiilecrtrii Aifnual ifo~$orc.i Lift Sric,rtf:c.? Syrirl)i,~:!i~rii, 17;: hl'i~~r,: ! i ) i *J* '-..:' Ocrn/?c~. 16-lh. 1978. CONT-78 I 0 1 6. Nat~r,nal Techriical I~il'ortnatinn Servicc, Sl7ringtield. Virginia.
Dcno I).%V., %affa~~ella L.E. 1082. "Field errecLa or uvcr:icad ~i-n!~-.n~,j+-,ivr? lifter, nljd starions." Piigcs 3?9-d19. i;; CirTul csi i I (
Diugasz L.. Rclitnger K.. .inbnscm P.. Bracken M.R. 1991. ',Human cxpoittir ro mtignalic iicids: z c~~illc;:rali\c arwiqment 0 1 n : ~ - # ~ ; ~ r / t < v 15:5<>3-.5T7.
Dlrrgu..;:, I,.; Vzna 3.. Dyurs I , Sever I,., Brackc-n IW., Mnr-ihirtt E. 1992. ~'Cc.m$ctlital clcfccrr: iind clcctr~c iccl hc ;~ : i r?~ in Ncrv Y.?rlc St.11~: .; id5 irc.-c.~.c case-ccrntr~ii \ludy." Atvriirw14 .ionr.i?tr/ i,J'Epicic~ir~io/~~,r:~v 135: 1 OUO-10 I I .
Eckort 1;.1?. 1976. "St~drlcii iirirl ~~r~cx(~lnrticcl tlcnth ol'iitlkntr and cIcctromi:g~~c1ic I'icid~. Med Klri? 71: 1500-1505. {Engliqh trnttcl~titw Iro.irn i:c!-in.i.i
I3agert S., Ruppo 1- 1096. "l.nt?nratc~ry rnveitiyiiliun ot117c inflnencc r ~ i ' . i O 117 magneric firltl., on hutnnn i>eii:gs." Ah%:ract P-1 JfrB. Pt.-icntct ::: :lit I.., . Airriicoi Mt.i.firtj. r l i IIIY h';flc:/cc*(i~r)n(6iiqrietic i. 3oc.iei.v. 9-1 4 It!nc.Victoria, B.C., Ck~nk~d8. pilacs 2.57--258.
k:ricsnn :%., KSliBn R. i 9Xha. "Ati epidemiolugicnl study of work witl? viden screens iind grcgnency outcome: J. a rdgistty ';t~i!)t. Airic'~.i(.riii .i.:t,riiL:i ..:: i~itli,ialr.i,t/ Metiii;it,c. %:.157-957.
Ericson 4., KiillGn a. li7Xhh. "At? cprrlet?~inle\pic:~I stiitty ni'wnrlr w:th vidct? Y C I , C C ~ < and pregnancy nulcorriz: 11. a casc-c;l?~ifftll study." 4inci-I: i r i ?
li~c/irir!.ini lif~tii.i!rc, Y:9.50-475.
Fli~rig W.K., Wol?urg .I.F. 199 1 . Ueclii<, irrrd IW~IXIIPIIL. Fic'ld E r p n s r ~ ~ ~ A , Y * Y N ~ ' ~ o ? B ~ LVitli Electrid Lslankers. TR-I001 PO. Research Prnjcct 2966.-3 T,.i.il i.cyol.t, r7cccrl11?ci. 193 1 . P~"c~,it*ild hy Ciircicgic I\4cllort Uitivcrsity fcir Bleelric Power Rsr;e:trch Inst~tute. Pwln Alto, Cnlibrtli:~.
liotnpoultw S.S., Cook M.R., Gerkosich M.Wt., Itonntz E.. Gtaham C.? Cnhcn H.D. 198:. "60-Hz field ct?ccl& PI I 11~1n;lti I~cI I I . I ;~c~ :J~ ;LL~?~? . i:iilii . t - ' . I
i1crnii:ningic nod t i i i ~ ~ l oi.$ii!? dcti~ity.'' P L I ~ I . 471-985, i n . Ai~ricrnrin CF, Kclnian B.I. W'eiprl RJ (ccl~tor.=l 7i1:,+8rty.rlrt~~~l H.!ni>pr.i ! ile '. :t :i
.~-~I?Z!:O.S;L~II~ I i ~ ~ ~ ~ i ~ ~ r ~ r ~ ~ ~ ~ ~ l f:/'h'~r~!it:qic,~~/ .?I vrcrri.s :!*ir/t .Yi<iri~. ~.111d LLF /?I~~:tr?c, t~itci Pd<i,q!?eri~~ Fi~!/d:~. Octche~ 2-4 i ~ J W I < I C : ~ I : I I I ~ I , WLi%-.:~r:~,:: P B
N ~ ~ r ! . h v ; t i i ~ t i.iit.rni.aror\. Ricl?li~rid. Minsh~n$tttn.
Friecltila~~ D,R., Hatch E.E., Taronc K., Kxur~e W.T..T., Kleincr~nat> R.A., Wachrtldcr S.! I3nice ,J.D. Jr.. Linst M.S. 199C. '.Chtlii!iond .c-::i - . I . i. rnaTncirc fielcls: r.c.iidcnlia! : r ru ii?eaxuretneiitc; i:oi?il7arcd to pcrson;:l Josi~nclry'. E[iii/#~tiin:ogy 7 ' IS i-155
I[jt!iita T.Y.. Tenforde T.S. iciii2. "Portal?le tnugnetic iicltl clos~rrietcr with d;zia acquisition c;lg;~biliriil.$.' Rc.!.ir$i,.% Scir,r!:ific. I r ~ ~ i i ~ i ~ r ~ ! r . i ~ f ~ i i r ~ ~ ~ ~ ?:: 326- ' <;amberale F.. Qlst~n I3.h,, Ftleroth P-. T,indh T,, Wennberg A. I9K9. "Acntc cfrecis n iEW eIcc:ctrorna~net~c fields: a Geld qrud:i 1.f ;~nc.-:cii ,:.(..: h:.i 1
Grahani C., Cohen H.D.: Cnnk M.R.. Gerlcovich M.M., Riffle D.W. 1'393. '.Human czrrdiac rcspsiise el? 6(:! ML f i i l d ~ crpnsurc p;vamctc:s utid ~ n d ; i I:,,.
differcnccs:' Pnpcr 767-70'3. in, Blank M. (cditr?r). t l<!~i t?~t ly cind Mc~~nerrsni iit 5i0fn~q.v tznd Mcdii.ittf. Sail r rmci~co Yl'e*~, itic. Sati F~.,:rii'<c:!. c ~ l ~ l ~ l ) r l l i ~ i .
(;rahstn C., Cohcn I.X.D., Cook M.R., Pllelps J.W., Gerkovich M.M., l~otopoulos S.S. IY87. "i\ douhlc-blind cvaluntioi~ ef GO-Hz fielcl ciieci,, i in :I;.-, :. pcri'orn~ancc. physiology ~lrid .;uhjcct~ve stair.'" Pages 47 1-485. in, i?\nclcrson L.E., Kcltnan B.J., Wcigcl R.J. (editorb!. R4,~1?t,y-r/iiri! Hrr,!ii.>rr: , . I .
S'ci~~ri 'e.~ .S'~YI/)O.S~I~!II I i r rei t~i~l l~~it t?IBiolof:iz.ni S''~s:crii? ~ttirlt ,Sf(itii ntrci ELF Elsr.n.ic 0rtt.i Mrrl(trc>iii. F;r.i,iv. Oc~ohci. 2.4. I 984. Ricl3liind TS:iul~t.,;i ;B.
G r a l ~ s m C.. Co<*lc M.R.. Coilen H.D.. Gerlcovich M.M. !994. "Dose rcspmlsc study ofliuinan cxpus~rc IU o(;-Mz c i c c ~ v c ilr~cl r~iiqnctic i t id , " i i , < s . z 8
~rtrr,i-~tc,i;r. . i 15:417463,
G~'ah:im r., Cnnk h1.R.. Giherrirti M.. Riffle D.W., Gerkovieli 2~r.M. 19Ufiii. "EMF eft'ecrs c l r ! iiiclnf(~ni~i. hi.rii~niicr iliicl Irninunit! 11, ;i- .ri
A Presented o( the' lt+ifi Artfrttffi !Mc~iiit,q c?f'/hc Bic~elcrrt;71ttncifefir Sncipr).. 9-14 J~~nc.Victorta. R.C. Canada. page ? -. 61-sham C., Cook Nl,K., Rifllc I3.W. IBVS. "Hi~mitn mclal~nin i i i 60 I+ nliipnclic fislds: onnrinuou= versils ~ntci.rriit:ent cxpc~surc." P:.,):P,-I i i . ; ' t ; ! . 's
A,rri!tr<i RP. \ .~E.I~ . C I / ' R I . . Y C ~ ~ ' h ('11 X ~ T I [ O , Y I ( (11 K[TEr.i, r
