Role of rivers in restricting pollution movement, as evidenced by chemical and isotopic research on the Widawa River in Wrocław (SW Poland)

This article presents results of chemical and isotopic studies of shallow groundwater and surface waters in order to determine the degree of their contamination near to artificial irrigation fields. The study applied the methodology of detailed sampling around the river in order to capture the direction of pollutant flow and to determine the state of the environment. Samples were taken on both sides of the river, from its bottom and directly from the river. Thanks to bottom pressure measurements, it was possible to determine in what section the river drains or infiltrates groundwater, which, combined with chemical and isotope analyses, made it possible to determine the aims of this study. As it turns out, the nature of the river in the study area is mainly neutral and in lesser extent draining, which does not translate into the degree of groundwater pollution at every point. Due to the sampling methodology used, it was also possible to determine the depth of redox processes and the origin of sulfur in water, which comes mainly from precipitation and other anthropogenic sources. Chemical tests indicate an average quality of shallow groundwater, anthropogenically transformed to varying degrees depending on the location of measurement point. These preliminary results support the applicability of this sampling methodology to other studies and indicate the need to perform more detailed chemical analysis.