Long-term exposure to 4-nonylphenol affects sexual differentiation and growth of the amphipod Corophium volutator (Pallas, 1766)

Concern has been growing recently over the aquatic toxicity and reproductiv e effects of the non-ionic surfactant LC-nonylphenol (NP). NP appears to in teract with development in some crustaceans. Using exposure response experi ments based on nominal NP concentrations, the 96-h LC50 for adult Coraphium volutator, was 1670 mu g l(-1) (95% Cl 1370-2170 mu g l(-1)). Juveniles we re subsequently exposed to sublethal concentrations of NP for 120 days and effects on growth, sexual differentiation and reproduction were assessed. A t the lowest NP exposure of 10 mu g l(-1) the density of surviving amphipod s was reduced and growth was retarded. Fertility of female C. volutator inc reased in NP exposed populations. Sex ratio was not affected by NP exposure , however, the second antennae of exposed male animals were significantly l onger than those of control animals (P < 0.001). It is hypothesised that NP may act via the androgenic gland which controls the development of male se condary sex characteristics in crustaceans. Males with large antennae are p otentially at a selective disadvantage in the wild being more vulnerable to predation. (C) 1999 Elsevier Science B.V. All rights reserved.