Acute and embryo-larval toxicity of phenolic compounds to aquatic biota

Because of the prevalence of phenolic compounds in various types of effluents, both acute and embryo-larval bioassays were performed on eight phenolic compounds with rainbow trout, fathead minnows andDaphnia pulicaria. In flow-through bioassays, the 96-hr LC₅₀ values for rainbow trout and fathead minnows ranged from <0.1 mg/L for hydroquinone to >100 mg/L for resorcinol.Daphnia pulicaria was consistently the least sensitive species tested as measured in 48-hr bioassays, while fathead minnows and rainbow trout varied in their relative sensitivity to phenolics as measured in 96-hr tests. Fathead minnows were more sensitive to phenol at 25°C than at 14°C.In embryo-larval bioassays with phenol, fathead minnow growth was significantly reduced by 2.5 mg/L phenol, while rainbow trout growth was significantly reduced by 0.20 mg/L phenol. For both species the embryolarval effects concentration was 1.1% of the 96-hr LC₅₀. Another embryolarval bioassay was attempted withp-benzoquinone, a highly toxic phenolic compound found in fossil fuel processing wastewaters, which was discontinued because the compound was rapidly degraded chemically or biologically in the headtank and aquaria.Work funded under an Interagency Agreement between the U.S. Department of Energy and the U.S. Environmental Protection Agency under Contract No. DE-AS20-79 LC 01761 to the Rocky Mountain Institute of Energy and Environment, University of Wyoming.