State issues consumption advisory for walleye from Twin Lakes, Pudwell Dam
FOR IMMEDIATE RELEASE: August 7, 2008
Pat Snyder, South Dakota Department of Environment & Natural Resources, 773-4729
Todd St. Sauver, South Dakota Department of Game, Fish & Parks, 362-2700
Clark Hepper, South Dakota Department of Health, 773-4945
State issues consumption advisory for walleye
from Twin Lakes, Pudwell Dam
PIERRE - The state Department of Health has issued two consumption advisories for walleye – one for Twin Lakes, five miles north and one mile west of Humboldt in Minnehaha County, and one for Pudwell Dam, three miles east of McIntosh in Corson County. Recent testing found mercury levels exceeding 1 part per million (ppm) in the walleye population on both bodies of water.
Mercury passes up the aquatic food chain from invertebrates to bait fish and ultimately to predators like walleye and northern pike. Fish exposed to mercury contamination accumulate mercury in their flesh. Because larger and older predator fish are often those with the highest mercury concentrations, anglers can reduce their exposure to mercury by eating only smaller predators or panfish.
Fish is low in fat and a good source of high quality protein and other nutrients. It can be an important part of a balanced diet as long as consumers follow some simple consumption guidelines when eating fish caught from waters with advisories in effect. The Department of Health recommends that healthy adults eat no more than 7 ounces per week and children younger than 7 should eat no more than one 4-ounce meal of the specified fish per month. Women who plan to become pregnant, are pregnant or are breast-feeding should have no more than one 7-ounce meal per month. Seven ounces of fish is roughly the size of two decks of playing cards.
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.
Fish in South Dakota lakes and rivers are routinely screened for metals, pesticides, and PCBs through a collaborative effort of the Department of Game, Fish and Parks, the Department of Environment and Natural Resources and the Department of Health. Since 2000, that testing has resulted in consumption advisories for just eight lakes, including the latest two.Of all the contaminants analyzed, mercury is currently the only concern; all other contaminants have been either non-detectable or found only in low concentrations.
For a list of other consumption advisories in effect and for more information about mercury and fish consumption, see the Department of Health website at http://doh.sd.gov/Fish.