Variability of Cadmium and Lead Concentration in the Waters of a Large Plain River During a Thirty-Year Observation Period

Abstract

The article presents new analytical data on the content of cadmium and lead in river water obtained by the authors using highly sensitive specialized methods of analytical spectrometry. For the first time, a more than thirty-year (1983-2018) study has been carried out, tracing the concentration of elements in the mid-stream water of the Oka River in the area of Prioksko-Terrasny Biosphere Reserve (PTBZ) - a location remote from the zone of formation of technogenic dispersion flow. The general trend was found to be characterized by a gradual decrease in metal content, correlating with the implementation of various environmental measures in the river basin. The trend of decreasing concentration is well expressed for cadmium from 1983 to 1991 and is weaker from 1992 to 2018. Estimates are made of the average regional anthropogenic-dependent concentrations of elements in the Oka River waters, exceeding the Clark (background) values for the world’s rivers significantly. It can be predicted that, if this trend persists, cadmium concentrations in the water of a large plain river will approach the background values for surface waters of the Russian plain.