Factors leading to high concentrations of pollutants in surface waters

Abstract

The dependence of the frequency of excess of hygienic standards in surface waters on individual substances and complex indexes is investigated. It was found that in some cases, there are significant dependencies on production-induced factors (water withdrawal, wastewater discharge, percentage of plowed lands), while in other cases natural factors (climatic humidity, geological structure of catchment areas) are the predominant ones. Technogenic factors are predominate in case of high values of biochemical oxygen consumption, concentrations of petroleum products and nitrogen compounds. Natural factors of high concentrations are more significant for metal ions, chlorides, sulphates and total salt concentrations. With regard to metals, especially copper and zinc, very strict standards have been adopted in Russia, which also contributes to a very high repeatability and multiplicity of their excess. As for phenols and chemical oxygen consumption, the role of natural or man-made factors is less unequivocal.