Mass balance of selected pharmaceuticals in an Austrian river catchment area: estimation of the different source contributions

The study refers to the assessment of the annual loadings of two pharmaceuticals (sulphamethoxazole and carbamazepine) released in the river of an Austrian catchment area (108,000 inhabitants, 404 km2) by different pathways: wastewater treatment plant (WWTP) effluent, combined sewage overflows (CSOs), surface runoff, tile drainage and deep water (referring to the sludge- or manure-amended soil). WWTP loading was based on national human consumption of the two compounds, common water demand, literature excretion rates, modelled WWTP removals (Activity SimpleTreat by Franco et al., 2011); CSO loading was modelled by MoRE (Fuchs et al., 2017); surface runoff, tile drainage and deep water loadings were estimated based on pharmaceutical concentrations in sludge (Activity SimpleTreat model) or in manure (literature data), average annual municipal sludge/manure rate applied on soil (real amount for sludge and estimated manure quantity on the basis of animal number), pharmaceutical and soil properties, flow rates of surface runoff, tile drainage and deep water and mass flow of sediment transport from arable soil modelled by MoRE. The study carries out a mass balance of the different pharmaceutical loading contributions to the receiving water body by means of STAN model (Cencic and Rechberger, 2008) and highlights the uncertainties associated to the selected values in the estimation. It emerges that manure amount applied on the soil is fundamental in defining the priority contributions among the different sources. In case of limited amount, the principal contributions are due to WWTP effluent and CSOs, if manure amount increases, surface runoff, tile drainage and deep water increase their contributions and can become the main sources. Cencic, O., & Rechberger, H. (2008). Material flow analysis with software STAN. Journal of Environmental Engineering and Management, 18(1), 3-7. Franco, A., Song, L., Trapp, S., 2011. Activity SimpleTreate User Instructions. Available at: http://homepage.env.dtu.dk/stt/Homepage%20anf/Website.htm. Fuchs, S., Kaiser, M., Kiemle, L., Kittlaus, S., Rothvoß, S., Toshovski, S., . . . Ziegler, S. (2017). Modeling of regionalized emissions (MoRE) into water bodies: An open-source river basin management system. Water (Switzerland), 9(4) doi:10.3390/w9040239