International Joint Commission Zanada and United States

[he Portier, in cooperation with Stote and Provincial Gov- ernments, shall conduct research, surveillance and monitoring and implement pollution control measures for the purpose of reducing ai- mospheric deposition of toxic substances, po~iculerly persistent toxic substances, to the Greot Lakes Basin Ecosystem."

Annex 15 C o d a - United States

Greot lakes Water Quality Agreement, 1987

I i rborne pollutants hove become irreosingly recognized as important contributors to contamination of the Great Lakes. The Inter-

national Air Quality Advisory Board, an odvisory body to the Interna-

tional Joint Commission, is attempting to gain a better understanding of long range transport of pollutants and how this contributes to the totol burden of pollutants entering the Greot Lakes-St. Lawrence River

basin.

I Ihe International Joint Commission has a long history in as-

sisting the Governments of the United States and Canada with air qual- i ty matters beginning with the Trail Smelter Reference in 1928.

References, or assignments from the Governments, on air pollution in the Detroit-Windsor area followed in 1949, 1966 and 1975. Under the 1966 Reference, the Commission was a k e d to bring to the atten- tion of Governments air pollution problems in areas along the bound- ary. The International Air Quality Advisory Board was created to assist

the Commission with this responsibility. 'Ihe Commission also received a Reference under the Canada-U.S. Air Quality Agreement of 1991 to

assist the Governments by inviting comment and preparing a synthesis of views on the biennial reports of the governments' Air Quality Com-

mittee.

Ib r a r e n e s s of the relationships k e n air and , water pollufian ha 'msasingly drawn the Commission into the field of

atmospherk ds. L i s role of assessing and evaluating Govern- ments' prcqess under the Great Lakes Water Quality Agreement, the Commission hacks progress in controlling atmospheric emissions of taxic substances that cantribute to pollution of the Great Lakes. The

In~noliend Air Quolity Advisory Board and the advisory bodies estab- P i d m the Great Lakes Water Quality Agreement - the Water gwlity Baord and Science Advisory Board - omist tlre Cinnmission in

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f o r many yeors scientists studying pollution in the Great Lokes have been perplexed by a number of questions: 1 . . -* -, * Some Great Lakes fish contain toxaphene, a pesticide ,used almost

exchsively an cotton crops in the southern Unired States. How did it get to the Great Lokes, hundreds of miles away? DDT, the dangerous pesticide that has been virtually banned in the. United States and ~anada'sincd 1972, is still turning up in samples af Great Lakes water. Is i t possible the pedidde comes from hun- dreds and perhaps even thousands of miles away, from countries south of the Rio Grande -where DDT is still legally used? In tiny Siskiwit Loke, located on Isle Royale in the northwest part of Lake Superior, a variety of toxic chemicals have been found in the water, sediment and fish. How could the chemicals have gotten to- this isolated spot?

Sbr~, as research has continued, answers have emerged. Scientists hove found tlwl bx ic substances are being carried hundreds of miles by winds and deposited in places far from thek source. For the Great Lokes, thk meens ihat some of the toxics in the water, fish and soils are not nsmswr* from nearby sources.

I t hor bsmm nvident that even t b q b plm centrol programs around the lokes may be effective, coAlrdhg pollullen from faraway sources is a different sort of challenge. BDI mi@ be out- lowed in one counky, for example, but its use in e d ~ arrhies moy rouse p e k ~ n meny miles away and still pose a serious threat tti citi- zm d o thought t b i r gwernments had "solved" the problem.

!eter&iq 1* exact source of airborne pollution is very d i f ~ u l i . Unlike o M s course, which is clearly established, air move- ments are less prdictoble. ~ e u t h e r conditions, wind speed and wind directectka vary, changing where airborne pollutants end up.

Sc iemia on both sides of the Great bkes - in the Wed W s and Canada - are working t o g e h ta get a better un- h t d i n g of how long-range transport of oir pdlution works. Some d this remarch is carried out by the Internotiorrot Air Qlrafity Advisory Baard, an cldvisory body to the International Jpint Commission.

, 1 major activity of the International Air Quality Advisory Board is c M n g air movement patterns and determining how airborne

, toxic substances end up where they do. '[he scientists working with the Board have developed the concept of an "atmospheric region of influ- ence (AROII" - or "airshed," to use a f i r term - to help them understand what happens.

The concept of an h airs he^ is similar to that of a 'water- shed": both spply to the movements of fluids (air or water) over great distances. However, there are importapt dilfwences.

With an airshed, there are no fixed geographical boundaries. In- stead, its area is defined in terms of a given travel time of the air and of the probability that the air clrriving at a certain place has come from a specified area.

Varieus sites within a r e b e l y small area might have different airsheds.

The aspect of time is particularly important. That's because different pollutants stay in the air longer than others. Those that stay longer may eventually be dispersed over o much wider urea than Ikw that fall to the earth more quickly. For exrqle, Imp parfide pltut- ants such as dust, fly-ash and soot that have long been assaciated wiih urban and industrial areas, tend t t j settle quickly. They have atmo- spheric lifespans of only a few hours at most, and typically their im- pact is confined to areas near the source of the emissions. Other pollutants, however, have lifespans of many years. Some of the more familiar are dbrofluorocarbons, which remain in the atmosphere and stratosphere for long periods, damaging the earth's protective ozone shield. These pollutants are slowly dispersed over vast distantes, mak- ing the atmosphere of the entire planet their "airshed."

I I e atmospheril lifespans of toxic chemicak a f f e c t i l tha Great Lakes are usually in the median range, from severel days to a few weeks. But even with what might seem a short lifespan, the p e l b ants can be transported hundreds of miles in the atmosphere to the ' Great Lakes as well as other areas. 'Their emission sourte might be far from the lakes. Tracking the pollutants and controlling their emissions is difficult.

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L i s t s typimlly use what is callad a "moss-bolance model" to track the .movement of pollutants through the enviranmeni. The model calculates the amount of o pollutant entering a designated ,area, the amount d r kar formed and the omount that leoves the area.

fm &FH pdkoa the model is c@cated. Follutants are emitted in p a r t i i a b m . Carried by Ql wind, they reach a surface or ore w o d r l mid otmosphere by d n or snow. Whot happens to Ls pMmts &.CY reach a sucCnp is influenced by the individual characteristics of each chemical or w o u n d in the pol- lutants, as wd as by the characteristics of the surface ond thtprev& ing weather conditions. T h t e ~ ~ u r o oi a surfoca, for example, mi& couse one mudion to occur; or, in other coses, th'e pollutants may be changed i n b qrite different substances.

fm he perspective of the Great Lakes, it is seldom pas- sible or & b apasure directly the amount of a pollutant depos- id brh (Ib -1 w rhr surface of a body of -Ukc, lb d ld ,avk b md~ hdirectly, combining &Id dm &mdb~~ wlDJ filrrslid mdeling, and "load- ' b # b r d d m d d w ~ l m g a k a b a l P t e d E e C r o J v .

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[he a& t thai of dota is required # .Jw am mk&mii& rkrl the "loading" af just n f ~ a p a o s l b b o .

fa k p( h e ' m s at Environment -4iWth~ &I&&c Wb h been developing a

km h m b l q b sbmwr J &ma pdlutants deposited at qdCl$llbd p& B) IJd imk vdq map overlays thot ~ - ~ a U l r k a p o l s u r b R ~ ~ ~ ~ &

~ ~ 0 a x a t f h a t o 6 s wea8w d .directions a i the pint llbrs tbii idmmh k mmbid

lverage otmosphwk $ a pirtidw bmbl er .'", it is possible to as@mb ike &b d mkim fla # b s u r c e area on a selected "receiving" point. ,

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Fairly comphte information an atmospheric behaviour and longevity is available for some chemicals - sulfur dioxide, for ex- , ample - but for mony other toxic chemicals there is little informa- tion. Among the mony toxic chemicals or compounds causing concern in the Great Lakes region, sufficient dota exist for only four to esti- mate their effect an the lakes. These are: benzo(a)pyrene, DDT, lead and PCBs.

) rp i te this lack of information, the existing dota show the nagnitude of the airborne pollution problem. In the upper Great ,ekes, where fewer taxics came fram direct discharges or from rivers flowing into the lakes, atmaspheric transport of toxic pollutants has a very big effect.

In Lake Superior up to 90 percent of the new PCBs added ta the lake come from the air.

3 Most DDT enters Lake Superior the same way, and' far benza(a1pyrenq and lead, atmospheric transport has an important effect even in the lower lakes.

h e threat to an individual's health from pollutallts trove1 ing hundreds of miles may seem remote. How can o pariicle small !nough to be airborne for so long pose any danger?

[he answer lies in the "behaviour" of the particles as they ravel through the air. Particles "look" for compony, often picking up ~ther particles and effectively accumulating more and more pollutants he longer they stay oirborne. (As on example of this phenomenon, onsider whal happens when baking soda is placed in a refrigerator to lick up odors: the particles of boking soda in the box do a gaod iob of

dbsorbing odors ond other particles released by stored food, effectively taking smells "away" - although they still remain in some form.) mall particles hove o particularly high surface-area-to-weight rotio, meaning they have greater potentiol to pick up other particles.

I h i , oirborne pariicler, when finolly depasited, bring a omplex combination of pollutants to the surface they land on. They m y be a maior source of many contaminants.

. In 1990, in its Fifth Biennial Report on Great Lakes Water Quality, the lnternational Joint Commission said "there is o threot to the heolth of our t w i n d i n g from our exposure to persistent ioxic substances, even ot very low ambient [general] levels.". A February 1992 report of the lnternational Joint Commission on air quality in the Detroit-Windsor/Port Huron-Sarnia Region concluded that "Sufficient information exists on airborne toxic chemicals in the

region to conclude that there is a significant public heahh issue . - '

h i c h requires the immediote implemeniotion of odditionol oir emis- sion obotement ond preventive measures".

I he Gnat Lakes can be though! of as giant pollution ellec- tors. Pollutants from city sewer systems, indistries and farms are tar- ried into the lakes by groundwater, rivers, direct dischrges and the' air. Much of that pollution - such as phosphorus, which con harm fish by causing olgoe to bloom and lake oxygen to be depleted - con be controlled, largely becouse the sources are identifiable. But toxic pol- lutant are more formidable.

Many toxics don't breok down easily. They are only slightly soluble in water, ond they con occumulote in sediments and toke many

years to dissolve. If the toxits are taken in by onimals, however, they are soluble In lipid (fat) cells, ond they tend to accumulate as they move up the . food chain. Often, concentrations in the body tissue of fish and wild- life can be 10,000 to 100,000 times greater than concentrations in the surrounding water. Since 1950, ot leost'lb species of wildlife in the Greot Lakes region have been offected, at one time or another, by reproductive pmb- lems or declining populations. In every case, high concentrations of

toxics were found in tbe animals' tissue.

I r e message is that we should be very corerned about

-toxics ond should continue yorking towards a more complete under-

stonding of how they enter ond move around in our environment. Fur-

ther research into the concept of airsheds will broaden our knowledge

of how toxics put into the air hundreds of miles away have an impor- tant effect on the Greot Lakes region:

11 keeping with their commitment in Annex I5 of h e Great lakes Water Quality Agreement, the Governments of Canada and the United States are establishing an "Integrated Atmospheric Deposition Network" to develop information on how certain toxics get into the Great Lakes and where they come from.

The network will be in full operation by 1995: One "master" research and monitoring site bn each loke has been set up jointly by Canado and the United States. Data gathered from experiments will be used in planning and build- ing an expanded network of up to 20 "satellite" monitoring sites. A d d i l i l stdions might be necessary for special praiects, such as proposed mass balance studies for. Lake Michigan and a demonstra- , tion program for Lake Superior. Together, the "master" and "~teUi te" siies will creote an irdegroted monitoring system that will provide estirnetes, updpted every two years, of airborne pollutants entering the lakes.

Scientists designing the network face many rhollenges. They must identify the toxic substances to be monitored and design an appropiate monitoring network to allow calculations to be made of where the pollutants come from. In addition, they must keep a watch for new environmental problems by'monitoring other toxic compounds.

I h e devabpsn, of a amprehensive and consistent moni- toring network is critical to achieving the goals of the Greot Lokes Wo- ter Quality Agreement of 1978. The Agreement's overall objedive is p rd ik i i ng the discharge into the lakes of toxic amounts of ony sub- stance and "virtually eliminating" the discharge of all persistent toxic substances. Meeting this objective requires effective surveillance of the transport of pollutants by air as well as by water.

e often hear that many Lake Superior {ViY pollutants, and about 90 percent of some pollutants,

enter via air transport . . . We would like to know

about air deposition to,lake Superior so any future

recommendation will be based on good science."

G& >dl /99/

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tmospheric emissions of varied toxic

substances have been shown to have a definite . - 1 I n human health. We, as citizens, must deal

this crucial problem."

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