State health officials are urging fish eaters to limit the number of Mackinaw, or lake trout, they consume from Central Washington's Lake...
YAKIMA — State health officials are urging fish eaters to limit the number of Mackinaw, or lake trout, they consume from Central Washington’s Lake Chelan after a new study found high levels of DDT in the fish.
The state Department of Ecology assessed the levels of DDT, PCBs and dioxins in fish from Lake Chelan and Roses Lake as part of an ongoing effort to meet federal clean-water standards.
Nearly 200 fish were collected and analyzed for the study, which was completed in late 2003. Officials said it contains the latest data available.
Mackinaw, burbot, kokanee and rainbow trout were collected from the Wapato basin of Lake Chelan, the south end of the lake that is more widely developed.
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Burbot also were collected from the upper, undeveloped parts of the Lucerne basin, near the community of Stehekin, for comparison.
Rainbow trout and black crappie samples were collected from Roses Lake, just north of Lake Chelan and the community of Manson.
Only the samples taken from the roughly 80 lake trout in Lake Chelan raised health concerns, Dave McBride, toxicologist for the state Department of Health, said yesterday. DDT levels in those fish were about 1,000 parts per billion.
Environmental Protection Agency guidelines allow for about 250 parts per billion.
The results weren’t necessarily a surprise, McBride said. An EPA study in 1999 found levels of about 1,400 parts per billion, though that study included only five lake trout.
In addition, Mackinaw are a fatty fish that live a long time and are a top predator.
“All three of those elements would lead us to predict higher levels in those fish,” he said.
Following the EPA study, state health officials issued an advisory in 2003 recommending that women of childbearing age and young children not consume more than one meal a week of lake trout. That advisory will continue in the interim until the agency releases final recommendations this fall, McBride said.
DDT was used as a pesticide in orchards between 1940 and 1970. The chemical is now banned.
The presence of the chemical also prompted a fish advisory for bottom-level fish on the Yakima River, such as suckers and white fish.
The state Department of Ecology has been studying water quality in the Okanogan and Walla Walla rivers. Any advisory for those rivers will be released in October as well, McBride said.
In the meantime, the state has approved a grant for the communities near Lake Chelan to further study water quality, the source of contamination and how the fish absorb DDT, said Joye Redfield-Wilder, an Ecology spokeswoman.