PLATTSBURGH — Fish that live in Lake Champlain appear to be recovering from contaminants that have plagued the lake and its inhabitants for decades.
A recently released report that studied mercury and polychlorinated biphynls (PCBs) in several species from the lake identified lower levels of contaminants in some samples and stable levels in others.
“It definitely does look good,” said Eric Howe, staff scientist for the Lake Champlain Basin Program on what he labeled as promising results from the independent study.
The U.S. Environmental Protection Agency has established acceptable levels of mercury in fish for consumption at 0.3 parts per million.
Both white perch and yellow perch have hovered around that mark since the late 1990s but are now well below the EPA recommendations.
Lake trout and walleye are moving closer to acceptable levels. Mercury in walleye is just below 0.5 parts per million while, in lake trout, it is below 0.4 parts per million.
“We’re optimistic that these species will all be below that line (of 0.3 parts per million) in the next five to 10 years,” Howe said.
LOWER PCB LEVELS
The degree of PCB pollution is best exemplified by the positive results in Cumberland Bay, where industrial sludge beds had created heavy contamination in the bay’s yellow perch and other species.
The State Department of Environmental Conservation had issued advisories against eating fish from the bay, but those warnings were adjusted following a successful cleanup of the sludge beds in the early 2000s.
The recently completed study, conducted by Biodiversity Research Institute in Maine, utilized fish that were caught during the 2011 Lake Champlain International Fishing Derby.
“The lake trout we looked at had lower PCB levels (than reported in previous study),”
said Ian Johnson, an institute research specialist. “We targeted the main lake for sample collection.”
Research staff members were posted at five of the eight weighing stations during the popular Father’s Day weekend tournament, Johnson said. For mercury sampling, researchers removed some tissue from lake trout but treated the fish with antibiotics and sutured the incision before releasing them back into the lake.
Testing for PCB levels required a much larger tissue sample, and lake trout had to be sacrificed for the study, Johnson noted. Fish were shipped to a laboratory in Texas, where levels of PCBs in the fatty tissue were recorded.
About 450 fish were sampled over a 10-day period for both studies.
“We had tremendous support from anglers,” Johnson said. “Collecting samples from the tournament proved to be a very valuable and efficient way to conduct our research.”
Mercury is the most widespread toxin in the lake. It is a naturally occurring element, but human activities have increased the amount of mercury by five to six times in the northeastern United States.
The main sources are coal-fired power plants, diesel combustion and medical- and municipal-waste incinerators outside the Lake Champlain Basin.
Efforts to reduce mercury sources continue both nationally, with more stringent guidelines for mercury-producing industries, and locally, by enhancing recycling programs for mercury-bearing products.
Meanwhile, information from the recent study on mercury and PCB concentrations in Lake Champlain fish will be forwarded to both New York and Vermont in helping to determine whether existing fish advisories in each state should be revised, Howe noted.
Email Jeff Meyers: firstname.lastname@example.org
FISH CONTAMINATION STUDY
To access the formal report, visit the Lake Champlain Basin Program's website at www.lcbp.org. Basin Program staff are also working on a summary fact sheet of the study's findings.