[Determination of certain pesticides, nitrates, nitrites, ammonium ions, sulphates, urea and chlorides in surface and underground water and in certain agricultural products. VI].

The subject of this study was determination of the residue of pesticides (lindane, methoxychlor, and chlorfenvinphos) nitrates, ammonium ions, sulphates and urea in surface waters and underground waters and in potatoes in 11 localities in the eastern part of the Province of Szczecin in 1987. The pesticides were determined by gas chromatography, while nitrates, nitrites, ammonium ions, sulphates and urea by spectrophotometry, chloride--by precipitation. The obtained results showed that contamination of surface and underground waters with these pesticides was below the permitted value. The concentration of nitrate nitrogen exceeded the permitted in Poland level in 15% of underground water samples. These samples were taken from wells in private farms. Nitrites were demonstrated in all of the samples of surface waters and 78% of underground water samples. The highest concentration of nitrite nitrogen was in the well of a private farm. The concentration of ammonium nitrogen exceeded in 22% of underground water samples the permitted value. Sulphates were detected in all water samples, but their concentrations were not exceeding the permitted level. In none of the analysed potato samples these pesticides were demonstrated. On the other hand high levels of nitrates and nitrites were found.