fisher16
11-01-2006, 12:29 AM
LONGMEADOW - Although mercury levels are high enough in Connecticut River fish to justify restrictions on eating them, recent studies have found that, contrary to popular belief, mercury contamination declines quickly when sources of it in the atmosphere are reduced, according to federal researchers.
The U.S. Environmental Protection Agency released a report here yesterday that for the first time details levels of mercury contamination in fish on the entire length of the Connecticut River.
"For the past 10 years, it's been very apparent that mercury deposition in the environment is a very big problem and this study confirms that," said Michael Kenyon, director of the agency's New England Regional Laboratory. He presented the results at the Pioneer Valley Yacht Club on the banks of the river in Longmeadow.
The study found that for people who fish for food and eat meals of it daily, so-called subsistence fishers, 100 percent of the fish fillets tested had mercury levels that would have put that group above the federal health standard for mercury.
Even for people who eat only an occasional meal of fish caught on the river, just about half an ounce a day on average, 26 percent of smallmouth bass fillets tested would have put that group above the health standard.
The federal agency warned that because of mercury contamination, eating Connecticut River fish poses a health risk to those who fish for food; pregnant women; women of child-bearing age who might become pregnant; nursing mothers and children. Based on the threat of mercury, Massachusetts health officials issued a similar warning in 2001 for eating fish caught on all the state's freshwater ponds, lakes and rivers.
The federal study also tested fish for contamination by PCBs, an industrial chemical and a suspected carcinogen, and the pesticide DDT. The researchers found PCBs posed a threat to subsistence fishers and those who ate a meal of Connecticut River fish occasionally, and that remnants of DDT, which was banned in 1972, posed a risk to subsistence fishers but not to those who ate the river's fish occasionally.
Mercury was the toxin that concerned the researchers most, though. It accumulates in animal tissue, and if ingested in a high enough quantity, it can affect the central nervous system of humans, potentially causing learning disabilities as well as impaired hearing, coordination and speech.
"The conventional wisdom was that mercury persisted in the environment for a long time," said Gregory M. Hellyer, the lead EPA researcher on the study.
However, when municipal trash incinerators in northeast Massachusetts, which were a principal source of mercury pollution in that area, were cleaned up, "there was an extremely fast response in the environment" as measured by a markedly lower levels of mercury in the tissues of local fish, he said.
Coal-fired power plants are also a major source of mercury in the atmosphere. The federal study, which tested only samples of smallmouth bass, yellow perch and white suckers, found a significant increase in mercury levels in smallmouth bass in the section of the Connecticut River from Holyoke to Turners Falls. A coal-fired power plant is located in Holyoke, the closest such plant to the river along its entire 410-mile length. Although it operates within state and federal pollution guidelines, it does have emissions of mercury.
"That plant certainly could be a factor" in the elevated mercury levels in that portion of the river, Hellyer said. "However, it's hard to draw a cause-and-effect relationship."
The study did not find significantly higher levels of mercury in that stretch of the river in either yellow perch or white suckers
The U.S. Environmental Protection Agency released a report here yesterday that for the first time details levels of mercury contamination in fish on the entire length of the Connecticut River.
"For the past 10 years, it's been very apparent that mercury deposition in the environment is a very big problem and this study confirms that," said Michael Kenyon, director of the agency's New England Regional Laboratory. He presented the results at the Pioneer Valley Yacht Club on the banks of the river in Longmeadow.
The study found that for people who fish for food and eat meals of it daily, so-called subsistence fishers, 100 percent of the fish fillets tested had mercury levels that would have put that group above the federal health standard for mercury.
Even for people who eat only an occasional meal of fish caught on the river, just about half an ounce a day on average, 26 percent of smallmouth bass fillets tested would have put that group above the health standard.
The federal agency warned that because of mercury contamination, eating Connecticut River fish poses a health risk to those who fish for food; pregnant women; women of child-bearing age who might become pregnant; nursing mothers and children. Based on the threat of mercury, Massachusetts health officials issued a similar warning in 2001 for eating fish caught on all the state's freshwater ponds, lakes and rivers.
The federal study also tested fish for contamination by PCBs, an industrial chemical and a suspected carcinogen, and the pesticide DDT. The researchers found PCBs posed a threat to subsistence fishers and those who ate a meal of Connecticut River fish occasionally, and that remnants of DDT, which was banned in 1972, posed a risk to subsistence fishers but not to those who ate the river's fish occasionally.
Mercury was the toxin that concerned the researchers most, though. It accumulates in animal tissue, and if ingested in a high enough quantity, it can affect the central nervous system of humans, potentially causing learning disabilities as well as impaired hearing, coordination and speech.
"The conventional wisdom was that mercury persisted in the environment for a long time," said Gregory M. Hellyer, the lead EPA researcher on the study.
However, when municipal trash incinerators in northeast Massachusetts, which were a principal source of mercury pollution in that area, were cleaned up, "there was an extremely fast response in the environment" as measured by a markedly lower levels of mercury in the tissues of local fish, he said.
Coal-fired power plants are also a major source of mercury in the atmosphere. The federal study, which tested only samples of smallmouth bass, yellow perch and white suckers, found a significant increase in mercury levels in smallmouth bass in the section of the Connecticut River from Holyoke to Turners Falls. A coal-fired power plant is located in Holyoke, the closest such plant to the river along its entire 410-mile length. Although it operates within state and federal pollution guidelines, it does have emissions of mercury.
"That plant certainly could be a factor" in the elevated mercury levels in that portion of the river, Hellyer said. "However, it's hard to draw a cause-and-effect relationship."
The study did not find significantly higher levels of mercury in that stretch of the river in either yellow perch or white suckers