CHEMICAL INDICES IN THE ASSESSMENT OF TOXIC POLLUTION OF THE LOWER DON

A. M. Nikanorov, T. A. Khoruzhaya, A. G. Stradomskaya, and T. V. Mironova

On the basis of analysis of the various systems for assessment of the surface water pollution level from chemical indicators, criteria are proposed for estimating the toxic pollution level of the lower Don taking into account classes of hazardous chemical substances. Assessment according to concentrations of petroleum products, phenols, and organochlorinated pesticides provided the basis for conclusions about high and even extremely high levels of toxic water pollution, which is confirmed by biotesting data obtained previously by the authors. Long-term trends in water pollution are indicative of its decrease; however, concentrations of toxic pollutants essentially exceed the standards (sometimes by tens of times). Reasonable assessments are hard to make due to regional hydrochemical properties.