COMPARISON OF ECOTOXICOLOGICAL AND PHYSICOCHEMICAL DATA BY USE OF MULTIVARIATE ANALYSES AND GRAPHICAL DISPLAYS

Bioassays allow the appreciation of the toxicity of complex effluents, which is difficult to characterize by the sole measurement of some ph ysico-chemical parameters. We have developed a macroinvertebrate multi -test (M.M.T.) with species characteristic of different trophic levels in order to appreciate the ecotoxicological impact of various effluen ts (especially landfill leachates) and chemicals on aquatic environmen ts. Our aim was: (i) to compare the sensitivity of the macroinvertebra tes among themselves and with regard to those of three standard bioass ays; (ii) to characterize the effluents according to their toxicity on one hand and according to their physico-chemical composition on the o ther hand; (iii) to search for possible correlations between the physi co-chemical composition of an effluent and its toxicity. In order to a chieve these objectives we used first a combination of graphical displ ays of the raw data, and secondly multivariate analyses: clustering te chniques and scaling (ordination) techniques (Principal Components Ana lysis).