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Consumption advisory issued for Lake Isabel pike

FOR RELEASE: July 16, 2002
Contact: Dave Micklos, Department of Health, 773-3361
Dennis Unkenholz, Game, Fish & Parks, 773-4508
Pat Snyder, Environment & Natural Resources, 773-4729
Carlyle Ducheneaux, Cheyenne River Sioux Tribe,
Environmental Protection Department, 964-6568 

Consumption advisory issued for Lake Isabel pike

     PIERRE – The state and the Cheyenne River Sioux Tribe are recommending anglers limit their consumption of large northern pike from Lake Isabel due to mercury levels exceeding 1 parts per million (ppm). Recent testing of game fish in the lake found mercury levels of 1.19 ppm in a composite sample of northern pike 25 inches and longer. Larger, older fish have more exposure to mercury contamination and thus accumulate more mercury in their flesh.

     The 1.19 ppm level exceeds both the state's and the Cheyenne River Sioux Tribe's guidelines for mercury in fish. Lake Isabel is located in Dewey County on the Cheyenne River Sioux Reservation north of the town of Isabel. 

     The Department of Health recommends that healthy adults eat no more than 7 ounces per week of Lake Isabel northern pike 25 inches and longer. Children younger than 7 and women who plan to become pregnant, are pregnant or are breast-feeding should have no more than one 7-ounce meal of the fish per month. Seven ounces of fish is roughly the size of two decks of playing cards. The Cheyenne River Sioux Tribe consumption advisory is more restrictive for children younger than 7 and women who plan to become pregnant, are pregant or are breast-feeding. CRST recommends that these groups do not consume fish from Lake Isabel or other water bodies on the reservation.

     When mercury levels in fish reach 1 ppm, meals should be spaced to prevent potentially dangerous mercury accumulation. The Food and Drug Administration (FDA) has set 1 ppm as the action level for commercial fish. This action level is 10 times lower than the lowest levels associated with negative neurological effects observed in mercury poisoning incidents.

     The Department of Health uses the FDA action level to issue consumption information to the public. The Cheyenne River Sioux Tribe uses EPA guidance levels to issue consumption advisories. There have been no incidents of mercury poisoning related to fish consumption reported to the department in South Dakota or to the Cheyenne River Sioux Tribe.

     Fish in South Dakota lakes and rivers are tested for metals, pesticides, and PCB's as a collaborative effort of the South Dakota Departments of Health, Game, Fish & Parks, and Environment & Natural Resources. The Cheyenne River Sioux Tribe also conducts an extensive testing program for metals and pesticides in fish in the Cheyenne and Moreau Rivers, Lake Oahe and also smaller reservoirs and ponds. 

     A state consumption advisory is also in effect for fish from Bitter Lake near Waubay in Day County. For more information about mercury and fish consumption, see the department's web site at www.state.sd.us/doh/Fish