Contents and Profile Distribution of Heavy Metals and Arsenic in Soils of Northern Tajikistan
Year: 2024
Type: paratext
Abstract: On the basis of the results obtained using the methods of X-ray fluorescence analysis, the pollution levels of heavy metals and arsenic in the territory of Northern Tajikistan in the period from 2020 to 2022 were estimated. Pollution coefficients and complex pollution for the studied heavy metals and arsenic, as well as overall pollution indices in administrative centres or other settlements in the territories were calculated, taking into account elements belonging to 1, 2 and 4 hazard classes. The results of the calculations revealed slight contamination of the territory with the elements of the hazard classes 1and 4. Under the influence of technogenic load, elements of the hazard class 1 (zinc, arsenic and lead) accumulate to the greatest extent in the upper soil horizons of the studied areas. The content of the hazard class 2 elements (chromium, nickel and cobalt) is comparable to a relative abundance of the elements or lower it, except for copper, the average content of which is 2.6 times higher than the Clarke numbers. The obtained data were compared with the established standard for MPCs for heavy metals and arsenic, as well as with the results of the assessment of technogenic pollution calculated by the traditional method. The excess of the MPC for lead according to average values was recorded near the Digmai tailings dump (2.93 times) and Asht district (1.2 times); the highest average concentration of zinc in Konibodom district exceeds its MPC in soil by 11.4 times. It was revealed that the excess of the MPC for elements of the hazard class 1 (Zn, Pb and As) was mainly registered in the surface horizon, i.e., contamination was observed only in the upper layer of soil. The comparison of the concentrations of the studied elements with their proved that the average content of Zn in the upper soil horizons was 2.82 times higher than the Clarke number, As – 10 times, Pb – 1.8 times, Cu – 2.5 times. The contents of the remaining heavy metals under study in soil samples are within the relative abundance of the elements or below.
Source: Экосистемы
Language: English
Topic: Heavy metals in environment
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
SDG: Life on land
Open Access status: bronze
OpenAlex ID: W4405734625