GEOECOLOGICAL REGULARITIES OF THE MOLYBDENUM AND TUNGSTEN DISTRIBUTION DURING ANTHROPOGENIC TRANSFORMATION OF THE GEOSYSTEMS OF PRIONEZHYE

Abstract

Molybdenum and tungsten in polluted geosystems have been insufficiently studied. The goal of this work is to compare the distribution of Mo, W and Mo/W ratio in the components of geosystems near the western shores of Lake Onega. To achieve this goal, the content of the metals in soils, bottom sediments, river water and, additionally, street dust and road asphalt was determined, dependence graphs were constructed, linear correlation coefficients were calculated. The most polluted soils are those in the central part of Petrozavodsk, while the least polluted are those in the rest of the city. The geometric mean content of Mo and W is maximum in the fraction < 0,1 mm of the soils at the former Onega Tractor Plant site (20,9 and 70,9 mg/kg, respectively); the content is lower in large fractions 1,0–0,1 mm (4,84–8,26 and 15,6–26,3 mg/kg). Mo/W ratio in the soils of the industrial site is on average lower than in the soils of the rest of the city. The soils of the South-Western Onega region are not polluted with the studied metals. There is no statistically significant correlation between Mo and W in most soils, with the exception of the most contaminated ones. Bottom sediments of the urban Lososinka River contain an average of 2,70 mg/kg Mo and 3,73 mg/kg W, while the suburban section of the Shuya River contains 0,573 and 0,572 mg/kg, respectively. In the urban river water, the geometric mean of Mo/W ratio varies from 0,090 (dry weather) to 0,385 (rain). Both values differ considerably from the literature data due to significant tungsten contamination. When conducting geoecological monitoring in the future, more attention should be paid to various sources of harmful metal pollution. These studies are important for reducing health risks associated with pollution.