Toxics Persist in Washington Rivers, Lakes and Fish
OLYMPIA, Washington, June 25, 2007 (ENS) - Toxic chemicals banned decades ago continue to linger in the environment and concentrate in the food chain, threatening people and the environment, according to three recent studies by the Washington state Department of Ecology.
The new data on toxic contaminants in freshwater fish and sediments add evidence to the state's push to reduce and eliminate the use of toxic substances.
"These studies provide initial screening and long-term monitoring that help show us where we need to focus our work to reduce toxic pollution in our lakes, rivers and streams," said Dave Peeler, manager of the department's water quality program.
In one of the studies, state government scientists found unacceptable levels of toxic substances in 93 samples of freshwater fish collected from 45 sites.
The toxic substances included polychlorinated biphenyls, PCBs; dioxins; two chlorinated pesticides, DDE and dieldrin; and brominated flame retardants known as poly-brominated diphenyl ethers, PBDEs.
As a result of the study, the department will investigate the sources of PCBs in the Wenatchee River, where unhealthy levels of PCBs were found in mountain whitefish.
Washington's Wenatchee River. Authorities are warning people not to eat the mountain whitefish caught in sections of the river. (Photo courtesy Washington Department of Ecology)
Based on the new information and a previous 2004 Ecology study, the Washington Department of Health is advising the public not to eat mountain whitefish from the Wenatchee River from Leavenworth downstream to where the river joins the Columbia, due to unhealthy levels of PCBs.
Study results also indicated high levels of contaminants in fish tissue that scientists collected from Lake Washington and the Spokane River, where fish consumption advisories are already in effect.
In Seattle's Lake Washington, department scientists sampled cutthroat trout, common carp and northern pike minnow. In the Spokane River, rainbow trout and mountain whitefish were sampled.
The study also indicates elevated concentrations of toxic contaminants in fish from the Snake, Columbia and Palouse rivers. The Health Department is evaluating the need to provide consumption advice for fish from these rivers.
PCBs are a family of manufactured, chlorinated chemical compounds that were once used in products such as coolants and lubricants in transformers, capacitors, electrical equipment, old fluorescent lighting fixtures, and hydraulic oils. Commercial production of PCBs was stopped in 1977 because of concerns about toxicity and persistence in the environment.
"Fish is good for you, so it's important to include fish in your diet, and it's just as important that you have information to help make good fish choices," said Dave McBride, toxicologist for the Washington Department of Health. "We've been working with Ecology and Chelan-Douglas Health District, and we're advising people not to eat whitefish from the Wenatchee River."
Two other studies of mercury from 2005-2006 represent the Department of Ecology's first year efforts of an ongoing initiative to monitor mercury levels in freshwater fish and lakes in Washington.
"It's important that we continue to track mercury in the environment," said Rob Duff, manager of Ecology's environmental assessment program, which conducted all three studies. "Mercury releases to our air and water eventually end up in fish, threatening our health, particularly that of our children."
The purpose of the mercury monitoring studies is to track mercury levels in fish from Washington over time and look at patterns of mercury deposition in lake sediments.
Mountain whitefish are too toxic for human consumption. (Photo courtesy U.S. Fish & Wildlife Service)
"We are making progress." Duff said. "We have increased proper disposal and recycling of mercury-containing products and eliminated its use in other products, thus reducing mercury releases to our environment."
In the past four years, Washington state has reduced mercury use and releases to the environment by more than 10,000 pounds. People are using more mercury-free thermostats and local governments have new programs to increase proper recycling of mercury-containing thermostats and fluorescent lamps.
The department also has found a 50 percent drop in mercury levels in biosolids from several of the state's wastewater treatment plants from 2003 to 2006.
The drop coincides with Washington's mercury reduction efforts as well as the state's work with dentists to collect and properly dispose of dental waste containing mercury rather than washing it down the drain into wastewater treatment plants.
More success in reducing toxics in the state came this year when Washington became the first state in the nation to target all forms of PBDE flame retardants for elimination from the many common household products in which they are used.
Flame retardants such as PBDEs are compounds added to plastic and foam products such as electronic enclosures, wire insulation, adhesives, textile coatings, foam cushions, and carpet padding.
In 2004, a study of 40 mothers from Oregon, Washington, British Columbia, and Montana found PBDEs in the breast milk of every woman tested.
"The women in the study have some of the highest PBDE levels on record," said Clark Williams-Derry, research director for Northwest Environment Watch, the Seattle research and communication center that conducted the study. "It's more evidence that we need to phase these chemicals out."
Studies in animals show that PBDEs can affect the developing brain, altering behavior and learning after birth and into adulthood. Levels of PBDEs are rising in people worldwide, but are highest in North America. Children are at the most risk from these chemicals.
Increasing concentrations of PBDEs in humans and wildlife worldwide continue to raise concerns about their health effects. The highest levels of PBDE in human tissue have been found in the U.S. and Canada
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