Estrogenic activity in sediments from European mountain lakes

Superficial and bottom sediment samples from 83 European mountain lakes, ranging from Norway to the Pyrenees and East Europe, were tested for estrogenic compounds by the recombinant yeast assay. The results showed widespread potential estrogenic activity arriving at remote lakes. Tatra Mountains (Slovakia) and Scotland Highlands were the regions with the highest prevalence of lakes with high estrogenic values. Comparison of the estrogenic activity in the superficial layer of sediments with pre-industrial age sections showed that estrogenic compounds were predominantly deposited in recent times. Chemical analysis showed that highly estrogenic sediments were significantly enriched in both polycyclic aromatic hydrocarbons (PAH) and organochlorine compounds. For PAH, enrichment ratios in highly estrogenic samples versus nonestrogenic ones were inversely correlated with the vapor pressure value for each compound, indicating a significant relationship between estrogenicity and accumulation of less volatile PAH. Two PAH of predominantly diagenetic origin, retene and perylene, did not show specific enrichment in estrogenic samples. Principal component analysis revealed a strong correlation between estrogenic activity and the presence of contaminants of anthropogenic origin. These data reveal significant amounts of estrogenic compounds in remote lakes, relate them to the overall human activity, and suggest that they may affect organisms inhabiting these ecosystems.