Storm Event-Driven Occurrence and Transport of Dissolved and Sorbed Organic Micropollutants and associated effects in the Ammer River, Southwestern Germany

Environ Toxicol Chem. 2020 Oct 20. doi: 10.1002/etc.4910. Online ahead of print.


Storm events lead to agricultural and urban runoff, to mobilization of contaminated particulate matter and input from combined sewer overflows into rivers. We conducted time-resolved sampling during a storm event at the Ammer River, Southwest Germany, which is representative for small river systems in densely populated areas of temperate climate. From two sampling sites suspended particulate matter (SPM) and water were separately analyzed by a multi-analyte LC-MS-MS method for 97 environmentally relevant organic micropollutants and with two in-vitro bioassays. Oxidative stress response (AREc32) may become activated by various stressors covering a broad range of physico-chemical properties and aryl hydrocarbon receptor induction (AhR-CALUX) by hydrophobic compounds such as dioxins and dioxin-like molecules. Compound numbers, concentrations, their mass fluxes and associated effect fluxes increased substantially during the storm event. Micropollutants detected in water and on SPM pointed towards inputs from combined sewer overflow (e.g., caffeine, paracetamol), urban runoff (e.g., mecoprop, terbutryn) and agricultural areas (e.g., azoxystrobin, bentazone). Particle-facilitated transport of triphenylphosphate and tris(1-chloro-2-propyl) phosphate accounted for up to 34 and 33% of the total mass flux despite SPM concentrations below 1 g L-1 . Effect fluxes attributed to SPM were similar or higher than in the water phase. The important role of SPM-bound transport emphasizes the need to consider not only concentrations but also mass and effect fluxes for surface water quality assessment and wastewater/stormwater treatment options. This article is protected by copyright. All rights reserved.

Keywords: Chemical analysis; Organic micropollutants; Storm event; Water quality; in-vitro Bioassays.