ASSESSMENT OF DEVELOPMENTAL EFFECTS, CYTOTOXICITY AND GENOTOXICITY INTHE MARINE POLYCHAETE (PLATYNEREIS-DUMERILII) EXPOSED TO DISINFECTED MUNICIPAL SEWAGE EFFLUENT

While sodium hypochlorite is widely used as a disinfectant for municip al sewage effluents and power station cooling waters discharged into c oastal environments, there is limited information on the potential in vivo genotoxicity of such disinfection procedures to marine organisms. Using a recently developed test system based on the marine polychaete Platynereis dumerilii, we have evaluated impacts based on embryo-larv al development, cytotoxicity and genotoxicity following exposure to di sinfected settled (primary) effluent from a municipal sewage treatment works (STW). Sewage samples were collected from Newton Abbot STW; Dev on, UK and then disinfected with sodium hypochlorite based on standard operational procedures. Exposure of polychaetes to dilutions of disin fected sewage in seawater (20 +/- 1 degrees C) led to a marked reducti on in normal embryo-larval development (7 h EC50 from 0.57-1.88% (v/v) , n = 4), with a simultaneous increase in cytotoxicity. Following the calculation of the Maximum Tolerated Dose (MTD), based on developmenta l and cytotoxic effects, the organisms were also analysed for the indu ction of chromosomal aberrations. This investigation demonstrated the absence of genotoxicity in polychaetes exposed in vivo to sewage disin fected with sodium hypochlorite. These observations extend our previou sly published studies in which polychaetes exposed to non-disinfected sewage, while showing developmental toxicity and cytotoxicity, did not exhibit any evidence of cytogenetic damage. (C) 1998 Elsevier Science B.V.