Chemometric analysis of rainwater and throughfall at several sites in Poland

Precipitation and throughfall samples were collected over a period of 4 years (1 January 1996-31 December 1999) at three different sites in Poland: one on moraine hills, one in the lowlands and one in a mountainous region. The aim of this project was to study the chemical composition of the samples, ionic correlations and fluctuations of selected variables with time in relation to geographical location, type of tree cover and climatic conditions. The samples were characterized by determining the values of pH, electrolytic conductivity and concentrations levels of SO42−, NO3−, Cl−, Ca2+, K+, Na+ and Mg2+. Statistical analysis revealed significant differences between the results obtained for different sampling site locations and characteristics (region of Poland, open area vs. throughfall) in four cases. The results obtained for precipitation samples were similar to those for throughfall samples only for acidic anions (SO42− and Cl−). For open areas, pH fluctuations were observed in 12-month cycles. Differences between the concentration levels of ions in the samples from the three sites could be explained by different amounts of precipitation at these sites. Concentrations of ions in precipitation and throughfall samples followed similar trends, the concentration levels being dependent on the kind of trees in the area, their age, and acidity of the precipitation. Significant differences were found for the concentration factors of the individual ions in throughfall between the sampling sites. Ionic correlations were examined to determine which salts contributed to the observed ion levels.