Canada

The State of Canada's Environment — 1996

Chapter 9 Arctic Ecozones

Pollutants from distant sources

Uptake by terrestrial ecosystems

The air/plant/animal pathway is the major route followed by many contaminants. Airborne contaminants, particularly organochlorines, are deposited on vegetation, eaten by and concentrated in herbivores (Caribou, Muskoxen), and further bioaccumulated by carnivores (Polar Bears, Wolves) and eventually humans. The most prominent contaminants in terrestrial biota are lindane and hexachlorobenzene (HCB). Southern Baffin Island Caribou herds have the highest PCB levels (Elkin and Bethke 1995), although levels are much lower than in southern domestic animals (Ryan and Norstrom 1991). In general, organochlorine levels are lower in terrestrial mammals than in marine mammals owing to shorter land food chains. Spatial trends show an increase in PCBs, chlordane (an insecticide), and DDT from west to east in Caribou (Elkin and Bethke 1995). Caribou, however, are long-lived herbivores and can bioaccumulate significant levels of heavy metals, such as cadmium. Elevated cadmium levels in Caribou kidneys are due to natural sources and accumulated airborne contaminants in lichen, their dietary mainstay. Current radiocesium levels in Caribou are low (Elkin and Bethke 1995), although levels of polonium^-210 (natural source) in Lake Harbour Caribou appear to be slightly higher compared with levels in other herds (Macdonald et al. 1996).

Migratory birds are generally exposed to higher contaminant levels in southern latitudes, but determining exact sources is extremely difficult. Normally, birds like geese, grouse, and ptarmigan do not accumulate high levels of contaminants. Fish-eating birds like mergansers and loons have the highest organochlorine levels (DIAND 1996a).

Organochlorines

Produced for agricultural and industrial uses around the world, many organochlorines are stable and volatile enough to be transported over long distances. Although concentrations are generally lower in the Arctic than in highly polluted areas in southern latitudes, some of the more volatile compounds, such as toxaphene and lindane, can occur in concentrations similar to, and in some cases higher than, those in the regions where they originate. Trends in levels of organochlorines in the Arctic environment vary according to production and use of the various compounds on a global basis. Chlordane and toxaphene use continued well past the DDT ban in 1975.

Chlordane was used as a replacement for DDT throughout the 1970s and was deregistered only in 1988. Recent analyses of PCBs in the Agassiz Ice Cap on Ellesmere Island suggest that the rate of deposition was high in the early 1960s, decreased until the early 1980s, then returned to higher levels in 1990 (Gregor et al. 1995). The major local source of PCBs seems to be associated with Distant Early Warning (DEW) Line sites, where disturbance caused by cleanup activities results in re-emission of on-site contaminants into the atmosphere. These local sources contribute negligible amounts to Arctic ecosystems on the whole. Within marine ecosystems, organochlorines generally declined in marine mammals and seabirds during the 1970s (D. Muir, Freshwater Institute, Department of Fisheries and Oceans, personal communication). Other evidence indicates that levels of organochlorines decreased in seabirds but appeared to increase in Polar Bears. Toxaphene and other organochlorines appear to have increased relative to PCBs and DDT in Beluga blubber in the 1980s (Muir et al. 1992). Levels of chlordane have increased in Arctic seabird eggs (Noble 1990).

On a seasonal basis, concentrations of DDT and lindane in Arctic air peak in spring, and levels of toxaphene and PCBs are highest in summer (Han 1994). Migratory patterns of raptors offer evidence of contaminant sources and pathways. Generally, there has been a decline in levels of organochlorines over the last 30 years in Peregrine Falcons (Peakall et al. 1990; Court 1993). Peregrine Falcon eggs have significantly higher (30–70 times) levels of DDT and PCBs than Gyrfalcon eggs; this reflects the fact that Peregrine Falcons winter in Central and South America (where these contaminants occur at relatively high levels) and prey heavily on shorebirds, which are also migratory (Thomas et al. 1992), whereas nonmigratory Gyrfalcons prey on Arctic upland game, such as ptarmigan, lemmings, and hares.

For organochlorines, there seems to be a link between the amount of marine mammal tissue eaten and the amount of contaminants that accumulates in the body tissue of the person who eats the meat. Studies of mothers' milk from Inuit women in northern Quebec show elevated levels of organochlorines, in some cases four to eight times higher than those of women in southern Quebec (DIAND 1996a). In a number of mammal species, including humans, females of reproductive age tend to have lower levels of organochlorine contaminants than males of similar age, because they excrete the organochlorines to their young through their milk (Dewailly et al. 1989). The Quebec study caused concern and led to additional studies, which resulted in no conclusive evidence of health risk associated with consumption of country food (Usher et al. 1995).

Lurking legacies: paying off past environmental debts

Often the magnitude of the environmental debt overwhelms the potential value of the site. The cost of cleaning up leaking underground storage tanks has averaged about $150 000 in Canada, with some sites costing millions of dollars, particularly where contamination affects aquifers. Although hundreds of sites across Canada have been remediated, most older gas stations (of which there are thousands) likely lie atop tonnes of contaminated soil. Normally, this soil must be cleaned or removed if the site is to be sold or used for other purposes. Nearly all former heavy industrial sites have areas contaminated by hydrocarbons, heavy metals, or waste materials produced through decades of "normal" industrial activity. Former military bases and Distant Early Warning (DEW) Line sites are known to be contaminated with a variety of wastes, including waste oils, aviation and diesel fuels, PCB-containing transformers and capacitors, solvents, CFCs, and lindane.

Decommissioning military radar sites

Of the first three radar systems, the DEW Line was the largest construction project, with 42 stations in Canada. In 1957, the significance of these radar sites as a point source of contamination was not known. At that time, wastes, including military wastes, were either allowed to sink through melting ice into lakes or the sea or buried in pits on land. In 1963, every second radar station on the DEW Line site was abandoned. A survey in 1985 identified a variety of wastes at these decommissioned sites, including waste oils, aviation and diesel fuel, PCB-containing transformers and capacitors, solvents, chlorofluorocarbons (CFCs), and lindane. PCBs were identified as the most environmentally significant waste, with an estimated 5 000 L of PCB-containing liquids removed from the sites (Thomas et al. 1992).

water and aquatic environment

Insecticides account for only 10% of the pesticides sold in the ecozone (Agriculture Canada and Environment Canada 1993). A survey of over 118 000 records from a federal water quality database during the period 1971–1988 showed that the nine most frequently detected pesticide residues were alpha-hexachlorocyclohexane (HCH), 2,4-D, lindane (gamma-HCH), MCPA, atrazine, diclorprop, picloram, disulfoton, and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). Production of 2,4,5-T was discontinued in 1985, and its use became illegal in 1990. The remaining 52 pesticides were detected in less than 2% of the samples taken. Although the Canadian Water Quality Guidelines for protection of aquatic life were exceeded on numerous occasions, the Guidelines for Canadian Drinking Water Quality were not exceeded (Integrated Environments 1991; CCME 1994). Aquatic life guidelines are exceeded more commonly because they are several orders of magnitude lower (in the nanogram per litre range) than those for drinking water (in the microgram per litre range) (Wood 1995). For unknown reasons, detections of alpha-HCH and lindane declined to zero by the mid-1990s, even though sales of lindane doubled (Wood 1995).

Agricultural practices that affect water quality in the ecozone include contamination of surface water and groundwater by pesticides, nutrient loading from fertilizers and livestock manure, and increased water turbidity from soil erosion. Pesticides have been detected in fish and other aquatic organisms years after their use was discontinued or banned in Canada. Sales of the insecticide toxaphene were discontinued in 1983; however, levels of the chemical found in Burbot livers caught in the Slave River in 1992 led Health and Welfare Canada to recommend that the public limit consumption of this species (Peddle 1995). In samples of Alberta surface waters taken between 1971 and 1993, four herbicides were detected in more than 1% of samples: 2,4-D in 19%, the discontinued pesticide 2,4,5-T in 5%, atrazine in 3%, and bromacil in 3%. The three insecticides detected in more than 1% of samples were alpha-HCH in 69%, lindane in 19%, and dursban in 2%. Guidelines for protection of aquatic life exist for all of these substances except bromacil and dursban (Dunsmore 1995). Many newer pesticides are now being used in such minute quantities that they are not detectable by current monitoring technology.

Thursday 8 March 2001

Canadians at toxic risk, report warns

Liberal cuts have prevented agencies from providing adequate protection; Millions more needed, government-appointed advisory group says

One of the studies examined how regulators keep tabs on lindane, a pesticide registered in Canada 60 years ago which is generally used by farmers to treat canola seed but is also found in lotions sold by pharmacies to rid humans of scabies and lice.

In the past decade, there has been growing evidence that potentially links lindane to cancer and adverse effects in reproduction, the liver and the immune system. It is banned from use in 28 countries, but Canada is the sixth largest global user of lindane.

 LAKE DIEFENBAKER

WHAT'S ON THE HILL MENU? TOXICS IN FOOD
NOT LEGISLATIVE CONTROLS ON TOXICS

Ottawa: Environmental and conservation organizations "brought home the bacon" today on Parliament Hill to highlight that proposed legislation must be improved in order to respond to the toxic pollution problem in Canada. The Canadian Environmental Law Association and World Wildlife Fund Canada fear that Bill C-32 – the new Canadian Environmental Protection Act (CEPA) - will do little to protect Canadian citizens and wildlife from toxic chemicals.

The groups purchased five foods – bacon, broccoli, bananas, oranges and french fries - from the West Block cafeteria on Parliament Hill. An assessment by an independent, Montreal-based lab revealed that contaminants were present in the food, including PCBs, DDT, lindane and chlordane. While contaminant levels in the food sampled were below consumption limits set by the federal government, effects such as endocrine disruption can occur at levels many times lower than what is currently considered safe. The food items may also contain other toxic substances, but this analysis was limited to key persistent contaminants.

LEGISLATIVE ASSEMBLY OF MANITOBA

Thursday, May 11, 2000

 Lindane Levels–East St. Paul

Mr. Larry Maguire (Arthur-Virden): Mr. Speaker, after seven months of concerns having been raised with the Government in this House about the presence of toxic lindane-treated seed in East St. Paul and little or no follow-up for these citizens, we have now found that tests show lindane to be present in the local water wells.

Mr. Speaker, will the Minister of Conservation tell this House how many homes in East St. Paul and Winnipeg now have contaminated drinking water and how this was allowed to happen after repeated warnings about the need to clean up this toxic site?

* (14:20)

Hon. Oscar Lathlin (Minister of Conservation): Mr. Speaker, I would like to say to the Member that ground water samples were taken on May 5 from three monitoring wells that were dug around that area. Monitoring wells are installed in six metres of clay.

Those results have revealed low levels of lindane in two of the three monitoring wells that are there, the highest level being one tenth of the safe level of lindane in the drinking water, as determined by the World Health Organization. The monitoring well results are indicative of ground water quality directly below the site.

They do not represent the quality of the water that is in the aquifer used for the drinking water supply in the area, so we are doing further tests to the soil and water in that area. As I am speaking, tests are being done.

As soon as I get those results from that review I will be happy to share the results of that investigation with the Member.

Mr. Maguire: Well, Mr. Speaker, I do not know if there is a void in the Department, but the tests that I am talking about were tests that we received word on this morning.

Will the Minister explain what steps his government will now take to deal with the well contamination to properly remediate the compost site and to ensure that the health and safety of Manitobans will not be further compromised?

Mr. Lathlin: I met with staff this morning, and I have made it known to our staff that we are prepared to take additional well water samples upon request from residents in that area. Those that are concerned with their drinking water, we are prepared to go and test them as well upon request.

Mr. Maguire: Mr. Speaker, given that these tests are just new this morning, what kinds of communications have been taken to alert these impacted residents in their area? They know that there is contamination in those wells.

Mr. Lathlin: I want to advise the Member that we are just as concerned about the quality of the drinking water there.

In fact, I have asked my staff to arrange for a visit for myself. I want to go and see personally myself the site that we are talking about and maybe even meet the individual that has phoned. I say "maybe" because I am in the process of trying to locate her. If I can catch up with her maybe this afternoon I will go there and see for myself.

http://www.gov.mb.ca/leg-asmb/hansard/1st-37th/vol_025/h025.html

Municipal Wastewater Pollution in British Columbia

Health Hazards

Conventional wisdom has it that treated domestic wastewater is "clean." Nothing could be further from the truth: Just as raw sewage poses an obvious risk to public health, so does poorly or partially treated sewage. The health hazards associated with STP effluent originate from both the toxic substances and the organic matter present in that effluent.

The ability of persistent toxic chemicals to cross the placenta, to bioaccumulate, and to persist in the environment for long periods of time poses a health threat to individuals as well as to a wide range of species including fish, birds, reptiles, and mammals.⁽⁶³⁾ Subtle effects have been observed at extremely low concentrations. Interference with the endocrine system--which regulates hormonal activity in people and wildlife--is the effect most frequently associated with synthetic organic contaminants found in many industrial and agricultural chemicals. By interfering with cell-to-cell communication, mimicking natural hormones, and triggering wrong biological responses, synthetic compounds disrupt normal hormonal functions and cause potentially life-threatening and irreversible neurobehavioural or developmental damage.⁽⁶⁴⁾ Documented effects on wildlife include immune and thyroid system disorders, disrupted sexual development (feminization of males and masculinization of females), decreased fertility and birth defects.⁽⁶⁵⁾ Table 2 lists the toxins most frequently found in the effluents of STPs, as well as some of their potential health and environmental hazards.

In addition to the toxic materials frequently found in treated effluents, organic substances and their related pathogenic micro-organisms also flourish. Bacteria, parasites, and viruses found in human and animal stools, i.e., in wastewater, cause many serious diseases such as hepatitis,

http://www.nextcity.com/EnvironmentProbe/pubs/ev535.htm