COMPARING ECOLOGICAL EFFECTS OF 2 DIFFERENT TYPES OF POLLUTION USING MULTIVARIATE TECHNIQUES

The effects of pollution by organic wastes were compared with those ca used by dumping of coarse metalliferous residues on the benthic faunas in two areas in Greece. The efficiency of several univariate and mult ivariate methods in describing these effects was evaluated. Both types of pollution caused a decline in the number of species and diversity, except when dumping of solid wastes took place on finer sediments. Th ere, the above parameters increased due to the increased heterogeneity of the sediment. Pollution by organic matter resulted in increased de nsities of opportunistic species. Conversely, lack of organic matter i n the solid wastes did not enhance settlement of opportunists, with th e exception of two species which were thought to benefit indirectly fr om the slag. The effects of organic pollution were described successfu lly by all mathematical methods used, while diversity and species abun dance curves were not very adequate in describing solid waste pollutio n. Classification was not very helpful in distinguishing between pollu ted and clean sites, while ordination proved useful in separating poll uted and unpolluted stations as well as the two different types of pol lution.