TOXICITY IDENTIFICATION EVALUATION OF LAKE ORTA (NORTHERN ITALY) SEDIMENTS USING THE MICROTOX SYSTEM

Pore waters extracted by centrifugation from Lake Orta (Northern Italy ) sediments were studied with a modified Toxicity Identification Evalu ation (TIE) procedure using the Microtox bacterial luminescence toxici ty test system, The most toxic pore ,vater samples were from stations near a rayon factory, known as a source of copper and ammonium dischar ges, The TIE manipulations used were filtration, EDTA chelation, and C 18 solid-phase resin adsorption. The most effective treatments to remo ve toxicity were the EDTA and C18, indicating that both metals and non polar organic compounds contribute to the observed toxicity. (C) 1996 Academic Press.