Distribution profiles of endocrine disrupting PAHs/APEOs in river sediments: is there a potential ecotoxicological problem?

Abstract

The endocrinic/mutagenic potencies of the endocrine disrupting chemicals (EDCs) polycyclic aromatic hydrocarbons (PAHs), alkylphyenol ethoxylates (APEOs) and their metabolites are well documented. Less so is the endocrinic ecotoxicological/health risk potential of these persistent organic pollutants (POPs) in river sediments. From approximately 5 x 10(8) m3/y of sewage produced in Israel, approximately 70% are reused, mainly in agriculture, following a conventional activated sludge treatment (AST). A major related question is: does this practice conform to sustainability? We have found the APEOs concentration profiles of Israel's rivers/streams, Mediterranean Sea coastal water and groundwater, to be 12.5-74.6, 4.5-25.0 and trace-20.2 microg/L, respectively. In two "representative" rivers, in the central coastal region of the country, the total concentrations of the PAHs and APEOs were found to be (in the upper layers of their sediments) 1.02-1.59, 1.78-2.30, 1.48-3.12 and 31.27-376.23, 2.40-91.70, 62.99-63.63 microg/g, respectively. The distribution of the PAHs in the co-presence of APEOs in rivers and their sediments, can be rationalized in terms of the hydrophobicity/nonbiodegradability of the former and the hydrophilicity-CMC/nonbiodegradability of the latter. Based on (a) the zebrafish egg production test (ZFEPT) - a long-term exposure of zebrafish to actually found environmental concentrations of EDCs; and (b) the low effectiveness of POPs removal in AST, our preliminary conclusions are that (1) there is a potential ecotoxicological/health risk problem; and (2) the practice of conventional wastewater treatment plants (WWTPs)-treated water reuse is incompatible with sustainability.