Published December 29, 2013
Mercury wafting out of oilsands operations is impacting an area – or “bull’s-eye” — that extends for about 19,000 square kilometres in northeast Alberta, according to federal scientists.
Levels of the potent neurotoxin found near the massive industrial operation have been found to be up to 16 times higher than “background” levels for the region, says Environment Canada researcher Jane Kirk, who recently reported the findings at an international toxicology conference.
Mercury can bioaccumulate in living creatures and chronic exposure can cause brain damage. It is such a concern that Environment Minister Leona Aglukkaq signed an international treaty in October pledging Canada to further reduce releases to the environment.
The federal scientists stress the mercury loadings around the oilsands are low compared to the contamination seen in many parts of North America including southern Ontario and southern Quebec.
But they say the mercury is “the number one concern” when it comes to the metal toxins generated by oilsands operations. It is also a major worry for aboriginal and environmental groups concerned about the oilsands’ impact on fishing, hunting and important wildlife staging areas downstream of the oilsands.
Environment Canada scientists are sampling everything from snow to lichens to bird eggs as part of the federal-provincial joint oilsands monitoring program.
Kirk, who will publish the findings in a scientific study in 2014, told the Society of Environmental Toxicology and Chemistry conference in Nashville in November that about 19,000 square kilometres are “currently impacted by airborne Hg (mercury) emissions originating from oilsands developments.”
The levels decrease with distance from the oilsands. “It’s a gradual thing like a bulls’-eye,” says co-investigator Derek Muir, head of Environment Canada’s ecosystem contaminants dynamics section.
The highest mercury loadings were found in the “middle of the bull’s-eye,” he says, and cover “probably 10 per cent” of the 19,000 square kilometres found to be impacted.
Both Muir and Kirk stressed in an interview with Postmedia News that much higher levels of mercury pollution are seen in southern Ontario and southern Quebec, which are on the receiving end of toxins created by incinerators, combustion and coal-burning power plants.
The scientists say much research remains to be done on the mercury around the oilsands, but there are indications the toxin is building up in some of the region’s wildlife.
Environment Canada wildlife scientist Craig Hebert has been comparing eggs from waterbirds from northern and southern Alberta. He told the toxicology conference that mercury levels have been increasing in eggs of several bird species downstream of the oilsands. And in 2012 the mercury levels in the majority of Caspian Tern eggs “exceeded the lower toxicity threshold,” he reported, noting more work is needed to evaluate the sources and impact of mercury in the fish-eating birds.
Kirk’s team studies snow. The researchers visit close to 100 sites every March collecting cores of the snowpack near the oilsands and in forests and on frozen lakes in northeast Alberta. Back in the lab they measure the contaminants that have collected in the snow over the winter months and calculate how much contamination enters the ecosystem at spring melt.
The oilsands’ upgraders, open pit mines, exposed coke piles, and tailings ponds have been associated in previous work with polycyclic aromatic compounds, which have been linked to cancer, and a long list of other chemicals including 13 priority pollutant elements such as lead, cadmium and selenium.
Kirk’s team reports “springtime snowpack measurements demonstrate that aerial loadings of many of the inorganic contaminants examined increased with proximity to the major development area.”
The highest loadings of mercury were 1,000 nanograms per square metre, much higher than the background level for the region. But she says the “pulse” of mercury in meltwater entering the ecosystem in the spring is below the limits in water quality guidelines for the protection of aquatic life established by the Canadian Council of Ministers of the Environment.
The scientists also found up to 19 nanograms of methyl mercury per square metre near the oilsands, 16 times the region’s background level. It is the first report of this more “toxic” form of mercury in snow. Microbes typically convert mercury into methyl mercury when the metal enters aquatic ecosystems and begins to work its way up through the food web.
“Here we have a direct source of methyl mercury being emitted in this region and deposited to the landscapes and water bodies,” Kirk said. “So come snowmelt that methyl mercury is now going to enter lakes and rivers where potentially it could be taken up directly by organisms and then bioaccumulated and biomagnified though food webs.”
Muir says there may be microbes in the snow converting mercury into the methyl mercury. Another possibility is that it’s coming from “dust and land disturbances.” Giant excavators dig bitumen from enormous open pit mines in the oilsands, but the scientists don’t have details on those emissions. “To our knowledge, emissions data from blowing dusts due to various landscape disturbances (open pit mines, exposed coke piles, new roads, etc.) and volatilization from tailing ponds are not publicly available,” they say.
Kirk’s team has also found mercury and a long list of other priority pollutants on the bottom of five remote, seemingly undisturbed lakes located 10 to 50 kilometres from the oilsands, confirming findings of a related study last year.
The latest work shows that level of zinc, nickel and vanadium increased after oilsands development started in the 1960s but peaked in the lake sediments in the 1990s and has decreased since. “We think this may be due to improvements in the air pollution catcher technology at the upgraders,” says Kirk.
But mercury and other so-called “crustal elements” in the lake sediments have been “going up more or less continually” in parallel with oilsands development, Muir says. These toxins may be related to emissions from the open pit mines and exposed coke piles.
The researchers say it will take more research and refined surveys to find out why levels of toxins like mercury have continued to rise.
And Kirk wants to get a better read on the fate of mercury. “Is it affecting fish levels and is it going to result in increasing fish consumption advisories?” she says. “We don’t know.”
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