This study provides the first EU-wide reconnaissance of the occurrence of polar organic persistent pollutants in European river waters. 122 individual water samples from over 100 European rivers, streams or similar water bodies from 27 European Countries were analysed for 35 selected compounds, comprising pharmaceuticals (e.g. carbamazepine, diclofenac), antibiotics (sulfamethoxazole), pesticides (e.g. 2,4-D, mecoprop, bentazone, terbutylazine), perfluorinated compounds PFCs (PFOS, PFOA), benzotriazoles (corrosion inhibitors), hormones (estrone, estradiol), and alkylphenolics (bisphenol A, nonylphenol). Only the dissolved (liquid) water phase, and not the suspend material was investigated. Around 40 laboratories actively participated in this sampling and monitoring exercise organised by the Joint Research Centre's Institute for Environment and Sustainability (JRC-IES) of the European Commission (EC) in autumn 2007. The selection of sampling sites was done by the participating EU Member States. The most frequently and at the highest concentration levels detected compounds were benzotriazole, caffeine, carbamazepine, tolyltriazole, and nonylphenoxy acetic acid (NPE1C). Other important substances identified were naproxen, bezafibrate, ibuprofen, gemfibrozil, PFOS, PFOA, sulfamethoxazole, isoproturon, diuron, and nonylphenol. The highest median concentrations of all samples were measured for benzotriazole (226 ng/L), caffeine (72 ng/L), carbamazepine (75 ng/L), tolyltriazole (140 ng/L), and NPE1C (233 ng/L). Relatively high perfluorooctanoate (PFOA) levels were detected in the Rivers Danube, Scheldt, Rhone, and Wyre, and "elevated" perfluorooctansulfonate (PFOS) concentrations in the Rivers Scheldt, Seine, Krka, Severn, Rhine, and Llobregat. A higher median concentration for all river samples was found for PFOS (6 ng/L), compared to PFOA (3 ng/L). Only about 10 % of the river water samples analysed could be classified as "very clean" in terms of chemical pollution, since they contained only a few compounds in very low concentrations. The most pristine water samples came from Estonia, Lithuania, and Sweden. For the target compounds chosen, we are proposing limit values in surface waters which are not based on eco-toxicological considerations; these warning levels are (for most compounds) close to the 90th percentile of all water samples analysed. A first EU-wide data set has been created on the occurrence of polar persistent pollutants in river surface waters to be used for continental scale risk assessment and related decision support.
