Agencies plan study of mercury levels in fish

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Agencies plan study of mercury levels in fish

Health department flags high-level contamination

Concerns about mercury contamination in fish have prompted various agencies to take action toward better understanding the problem.

The Southwestern Water Conservation District and the U.S. Geological Survey have scheduled a meeting next month to lay the foundation for a study.

A conversation several months ago between Bruce Whitehead, executive director of the water district, and David Brown, a supervisory hydrologist with the federal agency, led to the meeting, set for March 8 in Durango.

Agenda topics include what role partners in the project could play and how large a geographical area it would cover, Whitehead said. Questions by Southwestern Water Conservation District board members about the extent of contaminated fish was the impetus for the conversation with Brown.

Limited resources make a joint project logical, Whitehead said.

Colorado Parks and Wildlife always is willing to help where it can, Joe Lewandowski, an agency spokesman in Durango, said this week.

Scant data exists after the initial listing of potential sources of mercury in fish, Whitehead said.

The state health department has suggested limits on consumption of fish from certain reservoirs since the mid-1980s because of contamination, principally from mercury but also arsenic and selenium.

Six reservoirs in Southwest Colorado – Vallecito, McPhee, Totten, Navajo, Narriguinnep and Jackson – have a posted consumption advisory because of elevated mercury readings in fish.

Mercury levels build in the food chain as small fish ingest mercury from micro-organisms and then are eaten by larger predator fish.

Health officials flag reservoirs when they find mercury levels of 0.5 parts per million or above, Amy Konowal, manager of the health department’s environmental data unit, said Monday.

The Environmental Protection Agency limit for mercury in fish is 0.3 ppm.

Eighty-three percent of mercury deposited by wind and precipitation in the Four Corners originates outside the United States, Southwestern board members were told at recent meeting.

Mercury found in Southwest Colorado also comes from coal-fired power plants in northwest New Mexico and from runoff that occurs as the result of forest fires.

Lake Nighthorse, the reservoir built by the Bureau of Reclamation as part of the Animas-La Plata Project, would be a good place to test fish for mercury in order to establish a data base, board members said.

Rainbow trout and kokanee salmon have been stocked in the newly filled reservoir.

A mercury sampling project would require 20 years of data to be meaningful, board members were told. Fish in reservoirs probably wouldn’t be tested every year.

daler@durangoherald.com

Agencies plan study of mercury levels in fish

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