Anthropogenic impact of urban settlements on inorganic anions content in selected watercourses in the Subcarpathian Region of Poland.

BACKGROUND Legislation for environmentally protecting surface waters in Poland and the EU is considered a priority because of the large human impact on this environmental feature in both highly industrialised countries as well as those that are agriculturally well developed. The biggest threats are regarded as being sewage arising from economic, industrial and agricultural pollution along with rain water run-off from fields treated with fertilizers. One of the most characteristic indicators of pollution exposure in surface waters are inorganic anions which form the principal components of town sew- age and fertilizers. OBJECTIVES The estimate the effect that six selected sites of human settlement have on variously sized watercourses running through. The human environmental impact was based on determination of chlorides, nitrates and sulphates concentrations in such waters. MATERIALS AND METHODS Water samples were obtained from the following rivers and towns, respectively; the Nil in Kolbuszowa, the Mleczka in Przeworsk, the San in Jaroslaw, the Wislok in Rzeszow, the Bystrzyca in Olimpow and an unnamed watercourse in Niwiska. Sampling sites were chosen at 4-6 points along each watercourse for a given locality. Analyte levels were measured by ion chromatography using the Dionex ICS 1000 instrument. RESULTS Mean chlorides concentrations were found to vary from 8.52 (±0.17, n=3) mg/L to 78.41 (±0.19, n=3) mg/L, mean nitrates were 6.76 (±0.00, n=3) mg/L to 23.97 (±1.50, n=3) mg/L and mean sulphates from 29.89 (±1.57, n=3) mg/L to 62.48 (±2.99, n=3) mg/L. The clearest environmental effect of settlements on watercourses were observed for the small to medium sized towns of Kolbuszowa, Przeworsk and Jaroslaw in the form of frequently elevated chlorides levels from sewage. CONCLUSIONS By designating various sampling locations, along the watercourses for measuring the human environmental impact of nearby settlements, it is possible to identify sources of river pollution and thus take appropriate remedial action, as and when required.