EFFECTS OF NARCOTIC INDUSTRIAL POLLUTANTS ON BEHAVIOR OF MIDGE LARVAE (CHIRONOMUS-RIPARIUS (MEIGEN), DIPTERA) - A QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP

Fourth-instar larvae of the midge Chironomus riparius were exposed for 96-98 h in a semi-static substrate-water system to nine industrial pollutants with a narcotic mode of action. Effects on the behaviour of the larvae were registered by means of the impedance conversion technique. Despite the common mode of action of the tested chemicals, different behavioural responses were observed. No-observed-effect concentrations (NOECs), based on aqueous concentrations, were derived. Correlation of these NOECs with octanol-water partition coefficients (K(ow)), ranging from -0.77 to 4.64, demonstrated a very accurate quantitative structure-activity relationship (QSAR). The results indicate that behaviour of chironomids is one of the most sensitive parameters in aquatic toxicity tests with narcotic chemicals.