Toxicity of 4-tert-octylphenol to early life stages of Japanese medaka (Oryzias latipes)

Japanese medaka (Oryzias latipes) were exposed to octylphenol (OP) during embryolarval life stages, from fertilization to swim-up, to determine lethal and sublethal toxicity. Replicate embryotoxicity tests produced LC50's of 450, 830, and 940 mu g l(-1) OF. Developmental abnormalities observed in embryos and larvae ranged from circulatory problems to failure to inflate swim bladders. The mean duration to hatch was not affected by exposure to octylphenol. Hatching success was reduced by OP exposure in a concentration-dependent manner. Although environmental levels of OP are usually below lethal concentrations, octylphenol is present in the environment with other similar alkylphenolic compounds. Additive responses to alkylphenols may induce lethal or sublethal effects in early life stages of fish chronically exposed to this class of chemicals. (C) 1999 Elsevier Science B.V. All rights reserved.