Multi-Level Approach for the Integrated Assessment of Polar Organic Micropollutants in an International Lake Catchment: The Example of Lake Constance

Polar organic micropollutants (MPs) can have ecotoxicological effects on aquatic ecosystems and their occurrence in drinking water is a threat to public health. An extensive exposure assessment of MPs in large river and lake catchments is a necessary but challenging proposition for researchers and regulators. To get a complete picture of MP exposure in a large catchment, we employed a novel integrated strategy including MP measurement in the international catchment of Lake Constance and mass-flux modeling. A comprehensive screening of 252 MPs in the lake water by high-resolution mass spectrometry was used to identify the most commonly present MPs for the study site. It was found that the wastewater borne MPs diclofenac, carbamazepine, sulfamethoxazole, acesulfame, sucralose, benzotriazole, and methylbenzotriazole accounted for the most frequent and prominent findings. The concentration pattern of these compounds in the catchment was calculated based on regionalized inputs from wastewater treatment plants (WWTPs) and substance specific elimination rates. In 52, 8, and 3 of the 112 investigated river locations the concentration exceeded the predicted no-effect levels for diclofenac, sulfamethoxazole and carbamazepine, respectively. By coupling the catchment and lake model the effect of future trends in usage as well as possible mitigation options were evaluated for the tributaries and the lake. The upgrade of the major WWTPs in the catchment with a postozonation step would lead to a load reduction between 32% and 52% for all substances except for sucralose (10%)

Organic Micropollutants in Rivers Downstream of the Megacity Beijing: Sources and Mass Fluxes in a Large-Scale Wastewater Irrigation System

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

Strategies to Characterize Polar Organic Contamination in Wastewater: Exploring the Capability of High Resolution Mass Spectrometry

Wastewater effluents contain a multitude of organic contaminants and transformation products, which cannot be captured by target analysis alone. High accuracy, high resolution mass spectrometric data were explored with novel untargeted data processing approaches (enviMass, nontarget, and RMassBank) to complement an extensive target analysis in initial “all in one” measurements. On average 1.2% of the detected peaks from 10 Swiss wastewater treatment plant samples were assigned to target compounds, with 376 reference standards available. Corrosion inhibitors, artificial sweeteners, and pharmaceuticals exhibited the highest concentrations. After blank and noise subtraction, 70% of the peaks remained and were grouped into components; 20% of these components had adduct and/or isotope information available. An intensity-based prioritization revealed that only 4 targets were among the top 30 most intense peaks (negative mode), while 15 of these peaks contained sulfur. Of the 26 nontarget peaks, 7 were tentatively identified via suspect screening for sulfur-containing surfactants and one peak was identified and confirmed as 1,3-benzothiazole-2-sulfonate, an oxidation product of a vulcanization accelerator. High accuracy, high resolution data combined with tailor-made nontarget processing methods (all available online) provided vital information for the identification of a wider range of heteroatom-containing compounds in the environment