4/24/2007
People should not harvest or eat Columbia River clams
Vancouver, WA—Following reports of high levels of PCBs in freshwater clams in the Columbia River, southwest Washington residents and visitors are urged not to harvest or consume these shellfish. Harvesting freshwater shellfish is illegal in Washington State. Clark County Public Health has posted multi-lingual warning signs in areas where PCB levels are highest, including areas near and downstream of the former Vanalco plant (5701 NW Lower River Road in Vancouver), as well as areas with river access where harvesting has been observed.
Harvesting freshwater clams has also been observed in Kalama, Washington near Exit 32 off Interstate 5, and in Skamokawa, Washington in Wahkiakum County.
“We are conducting outreach to let people know that eating these clams can have serious health consequences. PCBs are potential carcinogens and may cause developmental deficits to newborns exposed during pregnancy,” said Dr. Alan Melnick, Health Officer for Clark and Skamania counties.
“We are especially concerned about the harvest of these shellfish by people who may speak limited English. We are working to get the message out to them,” said Dr. Mimi Fields, Health Officer for Cowlitz and Wahkiakum counties. The clams were introduced into local waters from Southeast Asia in the 1970s and are a common food source in that region.
A recent study by the U.S. Army Corps of Engineers involved sampling Asian freshwater clams in the Columbia River for a variety of toxins. The study found especially high levels of PCBs ranging from 382 to 3500 parts per billion downstream of the former Vanalco plant. The Washington Department of Ecology will oversee cleanup of the contaminated sediments during the next 18 months.
Although “safe” levels for PCB consumption have not been formally established, any seafood with PCB levels of 50 ppb should generally be eaten no more than two or three times per month. Freshwater clams from the Columbia River have many times that PCB level.
Freshwater shellfish are found in most of Washington’s streams, rivers, and lakes. Because they are filter feeders, often living near sources of contamination, freshwater shellfish can concentrate toxins, chemicals, bacteria, and viruses in their bodies that make people sick. Washington State Department of Fish and Wildlife regulations prohibit the recreational and commercial harvest of freshwater shellfish. Harvesting these shellfish can result in a fine.
To ensure that shellfish purchased at food markets comes from an approved source, consumers should check for shellfish tags. Commercial shellfish containers are required to be tagged or labeled by the harvester. Tags include a health certification number, area name, and date. For recreational shellfish information, visit the Department of Health Web site at www.doh.wa.gov/biotoxinmaps.htm. In addition, biotoxin information can be accessed by calling the biotoxin hotline at 1-800-562-5632.
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