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 Evaluation (TIE) procedure using the Microtox bacterial luminescence toxicity test system, The most toxic pore ,vater samples were from stations near a rayon factory, known as a source of copper and ammonium discharges, The TIE manipulations used were filtration, EDTA chelation, and C18 solid-phase resin adsorption. The most effective treatments to remove toxicity were the EDTA and C18, indicating that both metals and nonpolar organic compounds contribute to the observed toxicity. (C) 1996 Academic Press.