Nitrate contamination in South Russia.
Nazarenko O.V.

Rostov State University
Rostov-on-Don, Russia, e-mail: olesyanv@mail.ru

      Many studies of ground water pollution in general and nitrate contamination in particular have often relied on a one-time investigation. Studies of changes in spatial distribution of contaminants over time are lacking.
      Agriculture has become the leading non-point source of water pollution and estimates suggest it is the single largest source of pollutants, including sediments, nutrients, and pesticides, to water resources. Among other water pollution problems related to agriculture, nitrate pollution has been of growing concern.
      One of the main contaminants in groundwater of South Russia is nitrate and being one of the essential problems of water providing system needs a solution. It was in 1981 when World Organization of Health pointed on necessity nitrate studying soil and water.
      Estimation of nitrate contamination in groundwater, used in housekeeping, of Rostov region was held. Results give an opportunity to find out and estimate tendency of changing quantity of contaminant in groundwater and can be regarded as foundation for further exploration.
      The level of pollution is differing from the size of its average concentration, which can be found as comparison between average concentration and maximum contaminant level of the same element. According to raising concentration of nitrate that has poor results for nature we should appreciate min and max level of environment pollution. In dependence of intensity of the nitrate pollution groundwater forms of different types: with min phone concentration of nitrate as result of natural process and contaminated groundwater - result of technologic pollution.
      Average quantity of nitrate in groundwater of hyper genesis zone is 45 gram per liter. Main sources of contamination are fertilizers, livestock wastes, and contaminants in rain, snow and dry atmospheric fallout, leaky sewer lines. But geochemical peculiarity is not the contaminant is it, but what kind of geochemical environment will surround it afterwards.
      Problem of the nitrate contamination is urgent not only for our region, but it's essential for all agricultural and other districts. More over situation can become sever if groundwater has no or low natural protection. This can be explained by high porosity of aquifer and level below earth (1,5-5,0 m). That is why agricultural fields have disturbed hydrogeochemical level of groundwater. Pollutants can be find 14-16 m below earth surface and as far as 1,5 km from sources of contamination. Over 90% of springs in Rostov region is contaminated by nitrates and shouldn't be used for drinking. Due to experimental observation four zone of water contamination were found, it depends on the level of overcoming the average level. It was noticed that level of concentration becomes lower.
      High nitrate loads have continued, or increased in many streams in the region, despite the reduction in point source contributions. This can be explained by climatic variation. The variations in precipitation likely are the major cause of the significant differences in nitrate concentration from year to year. The study shows that for given hydro geological settings, nitrogen management practices and climate are the two most important factors that affect nitrate dynamics. The improvements in water quality (reduced nitrate concentration and loads) in relation to improved nitrogen management are often overshadowed by the impact of climate, especially in extremely dry of wet years.
      The present groundwater-monitoring network in Rostov region consists of wells and a number of natural groundwater springs. But studies on the spatial distribution of nitrate in groundwater have often relied on one-time investigations. In order to give further development to a long-term groundwater management plan, for all groundwater resources of Rostov region, was established a separate spring monitoring network throughout the groundwater provinces of the region.
      Newspaper reports alerted area residents and helped focus attention on the groundwater pollution. Even where we might not use it directly as a drinking water supply we must still protect groundwater, since it will carry contaminants and pollutants from the land into the lakes and rivers from which other people get a large percentage of their freshwater supply. Although progress is being made in this direction, efforts are hampered by an ignorance of people and general lack of knowledge about how groundwater behaves.
      The results of this study have significant implications in the management of nitrogen from developed watersheds.