Organotins in a medium-size Mediterranean basin (the Herault River).

This study reports the first assessment of organotin pollution in the Hérault watershed, a medium size Mediterranean basin. Organotin compounds were analyzed in surface waters, wells supplying drinking water and sewage treatment plants (STPs). In surface and ground waters, a background contamination by total organotin compounds has been identified in the range of 0.51 +/- 0.02-71 +/- 2 ng(Sn) L(-1), which is of the same order of magnitude as those observed in other European areas. Organotins were systematically present in STP influents and sludge. Total or partial elimination of organotin compounds from treated wastewater was observed. STP effluents appeared nevertheless to be a non-negligible source of contamination not only of rivers but also of aquifers tapped for drinking water supply. Tributyltin concentration was higher than the maximum allowable concentration proposed by the European Commission in some surface waters and wells supplying drinking water. This could compromise the water resource and have serious and irreversible consequences for the aquatic eco-system. As it was the case for the ban of antifouling paints, a regulatory regime in decreasing point-source emissions of these harmful compounds used in household products might be applied.

Consequences of treated water recycling as regards pharmaceuticals and drugs in surface and ground waters of a medium-sized Mediterranean catchment.

In Mediterranean regions where the population is rapidly growing, the risk of water resource contamination by wastewater is likely to increase. This is the case of the Hérault watershed (south of France), where the presence of treated wastewater in surface and ground waters has been shown in a previous study. To assess the consequence of these wastewater contaminations as regards pharmaceuticals and other organic compounds, 16 common pharmaceuticals (amitryptilin, acetylsalicylic acid, carbamazepine, clenbuterol, diazepam, diclofenac, doxepin, gemfibrozil, ibuprofen, imipramine, ketoprofen, naproxen, nordiazepam, paracetamol, salbutamol, and terbutalin) as well as wastewater related pollutants (caffeine, gadolinium anomaly, and boron) were analyzed in wells pumped for potable water supply and in two wastewater treatment plant (WWTP) effluents. In addition, a monitoring along the Lergue River (the main tributary of the Hérault River) was achieved to assess pharmaceutical behavior in surface waters. Pharmaceuticals and other wastewater-related contaminants are present in several reservoirs tapped for drinking water, confirming wastewater contamination; paracetamol, caffeine, and diclofenac are the most frequently detected. Paracetamol is present at rather high concentrations (up to 11 microg/L and 211 ng/L, respectively, in a wastewater effluent and in a drinking water sample). Though degradable in WWTP, caffeine is commonly encountered in surface waters and detected in highly polluted groundwater. On the contrary, acetylsalicylic acid concentrations are generally low despite a large consumption in France; this is related to its metabolism in humans and rapid degradation in the aquatic environment. The monitoring of pharmaceuticals along the Lergue River shows that dilution is sufficient to decrease pharmaceutical values.