Acute and Chronic Toxicity of Hydrogen Sulfide to the Fathead Minnow, Pimephales promelas Lloyd L. Smith, Jr.*, Donavon M. Oseid, and Larry E. Olson Department of Entomology, Fisheries, and Wildlife, University of Minnesota, St. Paul, Minn. 55108 ~
w Toxic effects of molecular hydrogen sulfide to eggs, fry, and juveniles of the fathead minnow, Pimephales promelas Rafinesque, were determined in flow-through bioassays. The 96-h LC50 of laboratory-cultured juveniles a t 20 "C was 0.0243 mg/l. H2S. Fry were approximately twice as senskive. Response with temperature in wild stock juveniles varied from a 96-h LC50 of 0.7754 mg/l. a t 6.5 "C to 0.0423 mg/l. H2S a t 25 "C. In chronic exposure to H2S from egg through two generations of laboratory-cultured stock in flow-through bioassays, adverse effects on growth, survival, and fecundity occurred above 0.004 mg/l. H2S. Chronic exposure of wild stock up to 346 days caused adverse effects on growth and survival above 0.008 mg/l. H2S. At comparable temperatures apparent safe levels with long exposure were five- to sevenfold lower than the 96-h LC50 for both stocks.
Hydrogen sulfide is highly toxic to fish and invertebrates and occurs naturally a t levels that can be inimical to survival of eggs and fry ( I , 2) and thereby reduce fish production. Smith and Oseid ( 3 ) reported that concentrations within a range commonly occurring in nature could be lethal to eggs and fry of several freshwater fish species. Adelman and Smith ( 4 ) , working with northern pike (Esox lucius Linnaeus), showed that egg survival and fry development were limited by concentrations of H2S as low as 0.0060 mg/l. and Adelman and Smith ( 5 ) found that its toxicity to goldfish (Carassius a u r a t u s Linnaeus) was affected by temperature and oxygen concentrations. Smith et al. (6) showed that reproduction of bluegills ( L e p o m i s macrochirus) was adversely affected by H2S concentrations of 0.001 mg/l. Field observations indicate that the fathead minnow ( P i m e p h a l e s promelas Rafinesque) survived over winter under very adverse conditions where H2S was known to be present. The study reported here on
Table I . Analysis of Laboratory Well Water0 Item Concentration, mg/l. Total hardness as CaCO, Calcium as CaCO, Iron Chloride Sulfate Sul f ide FI u ori de Total phosphates Sodium Potassium Copper Manganese Zinc
Cobalt, nickel
a
220 140 0.02
