Scholarly record

INFLUENCE OF FLUORINE SURPLUS ON THE ENVIRONMENT OF THE JAMBYL BIOGEOCHEMICAL PROVINCE (KAZAKHSTAN)

Vladimir L. Safonov, В. В. Ермаков, Margarita Samburova

Abstract

The emission of fluorine compounds by industrial plants that process phosphorites and apatites and the spread of their wastes become one of the main sources of formation of a persistent technogenic anomaly nearby Taraz (Zhambyl) town in Kazakhstan. Ecological-geochemical monitoring of the content of this element in the environmental objects is an essential measure because of the severity of consequences caused by hyperfluorosis. The study aimed to evaluate the levels of fluorine in the water, soil, and plants. Local small and large bovine cattle were examined. The content of the element was measured by the method of alkaline hydrolysis of the samples with further potentiometry with fluoride-selective electrodes. It was revealed that the concentration of fluorine in the air was 0.23-0.4 mg/m3 and exceeded the maximal allowed level set by the local regulations. The levels of fluorine varied within 0.2-0.6 mg/L in the majority of water reservoirs and did not depend on the distance to Zhambyl chemical plants. The samples of grey soil did not show a significant dependence on the distance to the source of pollution either. The maximum concentration of fluorine on the plots 1.5-5 km from the source of pollution reached 500 mg/kg, which exceeded the mean content of fluorine in the soils worldwide by 2 times. Primarily, pollution with fluorine affected its content in plants: in the north-north-west and east direction from the plants, it reached 200-500 mg/kg. Dry grass stand contained the highest levels of fluorine (5000 mg/kg), which exceeded the maximal allowable level by 250 times. The study of the feeding sources (hay, straw, cereals, grasses, Artemisia, and dry grass stand) samples at a different distance from the industrial plants revealed 6 to 5000 mg/kg of fluorine in the dry matter. The feeding sources were also characterized by an increased content of lead (9.6-36 mg/kg). During the study of the animals from the Zhambyl Region farms, the cases of fluorosis were revealed based on typical signs of the disease and samples of biological material. The records on the number of sheep stock in single farms showed that 30-60% of the livestock die from fluorosis annually. The prevalence of this pathology in milking cattle is high (65.4%). Based on the obtained data, the studied region can be defined as a technogenic biogeochemical province with excessive content of fluorine in the environment, which leads to the development of endemic fluorosis and chronic intoxication with fluorine.

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