Occurrence of estrogen-like substances in the marine environment of the Northern Mediterranean Sea

Evidence has been presented that a number of environmental agents perturbs the function of the sex hormone signalling pathways in marine animals. In this work the estrogenic/antiestrogenic activity of coastal marine water samples from five sites of the Northern Mediterranean Sea was assayed using a recombinant Saccharomyces cerevisiae yeast strain (RMY326 ER-ERE) transfected with the human estrogen receptor α. Extraction of potential EDCs from seawater was performed in columns packed with XAD-2 resins. The estrogenic activity was calculated as percentage of the activity of 17β-estradiol (10 nM) and it ranged from 4.8% and 59.03%, significantly depending on sampling site (p = 0.0013) and season (p < 0.05). Antagonistic activity of extracts was also detected and the percentage of inhibition of estradiol-dependent β-galactosidase induction ranged to 52.8%. These results point the reliability of the yeast assay as a first level screening test to assess the quality of aquatic environments.