Toxicity, accumumlation and depuration of mercuric acetate in the fathead minnow, Pimephales promelas

Acute toxicity levels of mercuric acetate were investigated using static toxicity testing procedures and were found to be in the order of .1 ppm Hg (9-6HR LC5Q = .159 ppm HgCQAc). Possible losses of the toxicant during the static experiments were examined and are discussed in some detail. Accumulation of mercury in the fathead minnow was investigated by the use of 2Q3-HG(QAc)2, a gamma emitter. Accumulation was found to be rapid and usually lethal, depending upon the length of exposure to the toxicant. Minnows were able to biomagnify mercury in their tissues to a level of 5X the concentration in the water when exposed for 96 hours to a sublethal concentration (.5 ppm Hg). Depuration of the accumulated body burden of mercury proved to be a slow and incomplete process. Mortality was high in the depurating population even after 32 days in clean water. Some minnows were able to rid themselves of up to 3% of the accumulated mercury. However, these organisms continued to exhibit the erratic behavior which is symptomatic of mercury poisoning. There is a potential threat to public health from consumption of mercury-contaminated seafood. Monitoring programs should be continued for fish and shellfish for at least several years, particularly in regions where industrial discharging of mercury is known to have taken place in the past.