In 1998 observations as to the chemical composition and activity of atmospheric precipitations were carried out at 49 stations. Each of the 49 stations carried out an analysis of pH of each rain, and 33 stations took monthly samples for chemical analysis of total pH.
Atmospheric precipitations and snow cover included sulphates, nitrates, ammonium, nitrogen, chlorides, hydrocarbonates and the trace elements sodium, potassium, calcium and magnesium, and were characterized by acidity.
Sulphate and hydrocarbonate anions were basic components in precipitations. These components made up about 60% of total mineralization.
Annual average content of sulphates varied from 2.7 to 19.05 mg/l, that of ammonium nitrogen from 0.13 to 1,33, nitrates – 0.24 to 1.47, chlorides – 0.29 to 1.43, hydrocarbonates – 0.0 to 9.97, sodium 0.42 to 6.1, potassium – 0.32 to 3.62, calcium – 0.52 to 3.68 and magnesium – 0.17 to 1.13 mg/l. Precipitations of total sulphur made up 0.11 – 2.02 g/m2, total nitrogen – 0.07-1.04 g/m2.
Total mineralization of precipitations in the territory of Ukraine varied within 7.16-49.76 mg/l.
The value of precipitation pH was mainly neutral, but in some sites subacid rains (pH 4.5-5.5) were observed.
In 1998 the content of most mass ions and total mineralization of precipitations were at a minimum for the whole period of observations, which began in 1989. The most considerable decrease for 10 years and up to 1997 was that of the sulphite ion, which is mostly of anthropogenic origin. There is a tendency of precipitations towards the hydrocarbonate type, which is more characteristic of natural ecosystems. The acidity of atmospheric precipitations in 1998 has not undergone essential changes.
In the winter 1997-1998 observations as to the chemical composition of the snow cover were carried out at 49 stations.
According to observation data the content of sulphates varied from 1.5 to 35.0 mg/l, nitrogen – 0.1 to 5.4 mg/l, nitrates – 0.35 to 8.16 mg/l, chlorides – 0.1 to 7.17 mg/l. pH was mostly neutral. A subacid reaction was observed in the Transcarpathian (Beregove, Nyzhni Vorota), Zaporizhia (Gulyai-Pole) and Vinnytsia (Bilopillya) regions.
As compared to the previous winter period of 1996-1997 a decrease in the content of nitrates, chlorides and hydrocarbonates was observed in the snow cover.