Measurement and modeling of bentazone in the river Main (Germany) originating from point and non-point sources

• Published in: Water research (Oxford) Vol. 44; no. 12; pp. 3725 - 3733
• Main Authors: Bach, M., Letzel, M., Kaul, U., Forstner, S., Metzner, G., Klasmeier, J., Reichenberger, S., Frede, H.G.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-06-2010; Elsevier
• Subjects: Applied sciences; bentazon; Bentazone; Benzothiadiazines - chemistry; Benzothiadiazines - isolation & purification; Computer Simulation; Continental surface waters; Exact sciences and technology; farms; General purification processes; Geography; Germany; Laboratories; Model DRIPS; Models, Chemical; monitoring; Natural water pollution; Non-point source; Other industrial wastes. Sewage sludge; Pesticide; Pesticides - isolation & purification; photolysis; Pilot Projects; Point source; Pollution; rain; River load; rivers; Rivers - chemistry; Sewage - chemistry; sewage treatment; Sewerage works: sewers, sewage treatment plants, outfalls; spring; surface water; Waste Disposal, Fluid; Wastes; Wastewaters; Water Pollutants, Chemical - isolation & purification; Water Purification; water quality; Water treatment and pollution; watersheds; Europe; Germany; Non-point source; Model DRIPS; Pesticide; Bentazone; Point source; River load; Pollutant behavior; Pollution control; Pesticides; Pollutant emission; Modeling; Sewage treatment plant; Rain; Diffuse source; Surveillance; Surface water; Water quality; Air pollution; Stream; Pollution abatement; Sampling; Material balance; Organic compounds; Photochemical degradation
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2010.04.010

A Water Framework Directive pilot project combines measured data and model approaches to calculate fluxes and mass balance of the pesticide bentazone in an 81 km section of the river Main (Germany). During the study period (six weeks in spring 2004) the observed bentazone inflow and outflow in the river section amounted to 52.8 and 53.1 kg, respectively; the maximum concentrations reached 220 and 290 ng l
−1. Based on sampling of seven sewage treatment plants a specific loss of 0.87 g bentazone per farm was calculated. Extrapolation to the entire sub-basin results in 2.6 kg bentazone in total as point source contribution from farms. Diffuse input into the surface water network occurred after an intensive rainfall event on May 7th. Total bentazone load was simulated with the pesticide emission model DRIPS to be 23.2 kg. One third of this load was estimated to be degraded by photolysis before reaching the main waterway, the river Main. The ATV water quality model was applied to predict the concentration profile of bentazone in river Main between Schweinfurt and Würzburg with reasonable results. The difference between total measured and modeled fluxes amounted to 1.5 kg corresponding to 2% of the overall input. The combined approach of monitoring and modeling appears to be a valuable strategy to quantify the relevance of point and non-point sources and to focus effective mitigation measures to the most relevant origins within a river basin.