BIOMONITORING AQUATIC POLLUTION WITH FERAL EEL (ANGUILLA-ANGUILLA) .3. STATISTICAL-ANALYSES OF RELATIONSHIPS BETWEEN CONTAMINANT EXPOSURE AND BIOMARKERS

In a large-scale field study, sediments and eel (Anguilla anguilla) sa mples were collected from six Amsterdam freshwater sites with varying degrees of pollution. All sediment and eel samples were analyzed for o rganic trace pollutants, such as polychlorinated biphenyls (PCBs), org anochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PA Hs). In addition, the pollution-induced responses of a suite of 21 bio chemical parameters in eel (notably phase I and phase II biotransforma tion enzymes, antioxidant enzymes, PAH metabolites, DNA adducts and se rum transaminases) were measured. The resulting comprehensive database was subjected to statistical analyses in order to determine the bioma rkers which were most suitable to assess inland water pollution and to classify the environmental quality of the sites. Bivariate correlatio n analysis, principal component analysis (PCA) and residual maximum li kelihood analysis (REML) all revealed that the eel tissue levels of mo st PCB and OCP analyte groups were suitable to assess exposure to thes e contaminants, whereas PAH tissue levels were not. The phase I biotra nsformation enzymes in eel were found to be the most responsive to org anic pollutants in the environment. Phase II enzymes and cofactors, as well as DNA adducts, were found to be less sensitive biomarkers, wher eas the antioxidant enzymes and the serum transaminases did not show s tatistically significant correlations with pollutant levels. Similar r esults were obtained by means of the postulated bivariate correlation- significance index (CSI) and the multivariate PCA analysis. Discrimina nt analysis (DA) was used to classify the pollution status of the vari ous sites. It appeared that the best discrimination between reference sites, moderately polluted sites and heavily polluted sites was obtain ed using DA on data of the nine most responsive biochemical markers. T he importance of monitoring biota for the classification of the pollut ion status or environmental quality of freshwater sites was demonstrat ed in the present study, since no dear discrimination between moderate ly and heavily polluted sites could be made using sediment pollutant l evels only. The results indicate that biological effect monitoring is the only appropriate method providing a reliable environmental risk as sessment. (C) 1997 Elsevier Science B.V.