Cadmium and lead in sludge deposits Ural rivers: gross content, distribution and enrichment

Solovykh Galina Nikolaevna, Shostak Elena Ivanovna, Osinkina Tatyana Vladimirovna

Purpose: analysis of silt deposits in the middle reaches of the Ural River for the presence of cadmium and lead, the distribution of these metals and the level of pollution of the river (by enrichment factors). Methods: determination of the gross content of cadmium and lead in bottom sludge was carried out by atomic absorption spectrophotometry. The level of contamination of bottom sediments was identified by the enrichment factor, which is a value equal to the ratio of the content of heavy metal in bottom sediments (mg / kg) to the value of the metal clarke in the lithosphere (mg / kg). Results: the total content and level of contamination of silts of some sections of the middle reaches of the Ural River with cadmium and lead were studied. An uneven distribution of pollutants in bottom sediments has been established, despite the lenticular (fluid) nature of the reservoir. According to the enrichment factor (KO), the sites with the highest (for cadmium the Ural river - above the city of Orsk (KO = 1.64), for lead the Ural river - Treatment facilities (KO = 103.1)) and the smallest (for cadmium the Ural river - Water intake (KO = 0.42), for lead from the Ural River - Camp "Dubki" (KO = 31.9)) levels of metal pollution. Conclusions: cadmium and lead are present in the silts of all study areas of the Ural River, which indicates the presence of natural or anthropogenic sources of these metals with different mobility. The accumulation of toxicants in the ecotopes of the river is uneven, which may be due to differences in the structure and properties of silt deposits, the nature of the river flow, and the unevenness of its average annual and interannual runoff.

Keywords:heavy metals, pollutants, environmental standard, enrichment factor, gross content, level of pollution, accumulation, toxicity, complexing ability.