Article:
Lake Superior fish meet contamination risk
MATT CIMITILE
South Bend Tribune
June 14, 2009
LANSING — The largest, deepest and coldest Great Lake holds another distinction — the highest levels of the contaminant toxaphene in the region and possibly anywhere in the world.
Since federal bans on persistent pollutants took effect in the 1970s and 1980s, most chemical concentrations have declined in the Great Lakes.
Some toxicologists say the same is true of the insecticide toxaphene.
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But toxaphene levels in Lake Superior have increased by 25 percent since its ban in 1990, according to Mel Visser, of Kalamazoo, a former environmental health safety officer and author of "Cold, Clear and Deadly," a book about Great Lakes contaminants.
Toxaphene has been shown to damage the immune system, nervous system and lungs and to cause cancer. The principal human exposure comes from eating fish.
It contains more than 670 chemicals and was one of the most heavily used insecticides in the United States. Nearly 40 million pounds were produced in 1977, according to the U.S. Environmental Protection Agency.
Lake Superior has double the concentration found in Lake Michigan and five times that found in Lake Ontario, according to a University of Minnesota study.
Superior is "so big and cold that it acts like a sponge for these contaminants in the atmosphere," said Matt Simcik, a University of Minnesota environmental health professor and an author of the study.
Most toxaphene arrives in the Great Lakes from the southern United States, where it once was used to kill insects in cotton fields and unwanted fish in lakes, according to the federal Agency for Toxic Substances and Disease Registry. It continues to migrate into the Great Lakes from other parts of the world where it's still produced.
Despite its federal ban in 1990, toxaphene continues to enter the water by air, breaking down slowly in the environment and accumulating in sediment and fish.
It poses a risk for Lake Superior because of the lake's size and how cold it is, Simcik warned. "Coming from outside the region, toxaphene is going to be the same source for all five lakes, and because Superior is the biggest and coldest, it is going to contaminate it the most."
As concentrations have increased, the advice on what levels of toxaphene in fish are safe to eat has weakened, said James Clift, policy director for the Michigan Environmental Council, a coalition of environmental groups.
"I think people thought that once we started to see the concentration of toxaphene drop, then we would have a handle on this — but that assumption was not correct," Clift said.
Michigan's state funding for studies to determine fish consumption advisories was scrapped about a decade ago, said Kory Groetsch, a toxicologist with the Department of Community Health. Its Environmental Health Division now pays for testing of fish for advisories, but on a much smaller budget.
When dealing with a pollutant with more than 600 chemicals, budget cuts create limitations, Groetsch said.
"The fish advisory is outdated and the problem is that the funding for it went away," Groetsch said.
Changes in regulations for toxaphene are happening elsewhere in the region.
According to an Environmental Defense report, a Canadian environmental group, Health Canada, raised the concentration that triggered fish consumption warnings from 1.6 to 1.9 parts per million in 2005. However, levels deemed safe for dioxins, furans and polychlorinated biphenyls (PCBs) decreased at the same time.
PCBs and dioxins have more restrictive consumption advisories because they have been causing more fish advisories recently, said Kate Jordan, of the Ontario Ministry of the Environment.
As a result, the number of Canadian fish consumption advisories caused by toxaphene in Lake Superior dropped from 71 percent in 2003 to zero in 2007.
Mel Visser, former environmental health safety officer, said, "It gives the appearance that toxaphene has been cleaned up from Lake Superior."
But that couldn't be farther from the truth, he said.
The Environmental Defense report "Up to the Gills" gives two explanations for the dramatic drop in toxaphene fish advisories. Either toxaphene was eliminated or the decrease in allowable concentrations of other chemicals caused the dramatic drop in toxaphene-driven advisories.
Clift said states around Lake Superior are reevaluating toxaphene regulations and fish advisories for the lake.
Meanwhile, Groetsch and other scientists are working out new methods to look at specific chemicals in toxaphene, the ones that predominantly accumulate in fish and people, to provide a more precise fish consumption advisory.
But to ensure environmental and human health from persistent pollutants like toxaphene, only an international ban will do, Clift said.
"Regional bans and regulations are not protective enough; the major step that needs to be taken is for international treaties to outlaw toxaphene and others like it globally," Clift said.
