Spring water chemistry in a formerly glaciated area of western Poland: the contribution of natural and anthropogenic factors

Abstract

To assess natural and anthropogenic impacts on spring water chemistry, seasonal and spatial hydrochemical changes in 20 springs were studied in the western part of Poland. Spring water was sampled every 3 months from November 2011 to October 2013. The analyses investigated major cation, anion, and trace element concentrations. Moreover, water temperature, electrical conductivity, and pH were measured in the field. For five springs, isotopic analyses of nitrates were conducted. The results revealed that the water composition was similar for most of the elements studied. However, in the case of Fe, Mn2+, Pb2+, and nitrates, spatial and seasonal variations were relatively significant. The concentrations of total iron and manganese were found to exceed the Polish legal limits for drinking water in 70 and 85 % of the springs, respectively. In addition, Pb2+ levels were found to be highly variable; in some periods, the concentration was 10 times higher than the limit for drinking water. In some springs, elevated nitrate concentrations were found with a maximum of 74-mg NO3−/L, which is also in excess of the legal limit. The seasonally high levels of total Fe and Mn2+ are considered to be related to natural geo- and hydrochemical changes, but the high concentrations of Pb2+ and nitrates suggest anthropogenic pollution. The nitrates originate from agricultural practices, whereas Pb2+ may come from several sources. Hydrochemical monitoring must, therefore, consider seasonal variations, because the water properties may not permit its use during some periods, i.e., for drinking purposes.