The acute and behavioral effects of a copper-nickel mixture on roach Rutilus rutilus.

Semi-static acute toxicity tests were conducted on adult roach, Rutilus rutilus, to estimate its sensitivity toward an equitoxic binary mixture (EBM) of copper and nickel. The sum of their individual LC50 values was considered to equal 100 %. The main endpoints of the study were mortality and behavioral responses: detection, locomotor activity, coughing rate and pectoral-fin activity. The 96-h LC50 of EBM was 14.4 (10.1 %-20.5 %), indicating a synergism of individual metals. The most meaningful behavioral results were obtained after 10-min, 1-h and 24-h exposures, and the most sensitive and informative behavioral response was found to be coughing rate. This bioassay response may be used successfully to evaluate wastewaters containing heavy metals for their toxicity toward fish.