title: Organic micropollutants in rivers downstream of the megacity Beijing: sources and mass fluxes in a large-scale wastewater irrigation system.
abstract: The Haihe River System (HRS) drains the Chinese megacities Beijing and Tianjin, forming a large-scale irrigation system severely impacted by wastewater-borne pollution. The origin, temporal magnitudes, and annual mass fluxes of a wide range of pharmaceuticals, household chemicals, and pesticides were investigated in the HRS, which drains 70% of the wastewater discharged by 20 million people living in Beijing. Based on Chinese consumption statistics and our initial screening for 268 micropollutants using high-resolution mass spectrometry, 62 compounds were examined in space and time (2009-2010). The median concentrations ranged from 3 ng/L for metolachlor to 1100 ng/L for benzotriazole and sucralose. Concentrations of carbendazim, clarithromycin, diclofenac, and diuron exceed levels of ecotoxicological concern. Mass-flux analyses revealed that pharmaceuticals (5930 kg/year) and most household chemicals (5660 kg/year) originated from urban wastewaters, while the corrosion inhibitor benzotriazole entered the rivers through other pathways. Total pesticide residues amounted to 1550 kg/year. Per capita loads of pharmaceuticals in wastewater were lower than those in Europe, but are expected to increase in the near future. As 95% of the river water is diverted to irrigate agricultural soil, the loads of polar organic micropollutants transported with the water might pose a serious threat to food safety and groundwater quality.
authors: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland.
authors: Florian
authors: F
authors: Heeb
authors: Heinz
authors: H
authors: Singer
authors: Benoît
authors: B
authors: Pernet-Coudrier
authors: Weixiao
authors: W
authors: Qi
authors: Huijuan
authors: H
authors: Liu
authors: Philipp
authors: P
authors: Longrée
authors: Beat
authors: B
authors: Müller
authors: Michael
authors: M
authors: Berg
mesh_terms: D057914:Agricultural Irrigation; D002681:China; D009930:Organic Chemicals / Q000032:analysis*; D045483:Rivers; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009930:Organic Chemicals; D062065:Wastewater; D014874:Water Pollutants, Chemical