Monitoring of fluorine content in soils of the Minusinsk forest steppe of the Krasnoyarsk region

In the Minusinsk forest-steppe of the Krasnoyarsk Region, the content and spatial distribution of water-soluble fluorine in agrocenoses is influenced by the chemical composition of soil-forming rocks, soil formation conditions, soil properties, agricultural land use and technogenic factors. On the arable soils surveyed in 1999, the fluorine content varied from 0.2 to 8.9 mg/kg with an average value of 0.9 mg/kg. In 2016, the fluorine content in the 0-20 cm soil layer increased by 1.1-1.7 times. Man-made emissions from the Sayanogorsk and Khakass aluminum plants of JSC “Rusal Sayanogorsk” contribute to an increase in the content of fluorine in soils. The level of fluoride accumulation in soils is influenced by the load of man-made emissions on agricultural land, distance from enterprises and weather conditions. On perennial forage grasses and uncultivated agricultural lands, the degree of soil contamination with fluorine is more pronounced. Under the influence of aluminum smelters in the Shushensky District, a fluoride geochemical anomaly was formed with fluorine content on an area of 1.35 thousand hectares at the level of 0.5-1.0 MAC. On the reference sites of local monitoring in 2016, the content of water-soluble fluorine in the 0-20 cm soil layer increased 1.3-3.3 times. The highest fluorine concentrations are observed in the Shushensky and Minusinsky Districts areas, located at a short distance from the sources of soil pollution. A general regularity for chernozems, gray forest soils and midsoddy soils is a lowered content of fluorine in the upper horizon and its increase in the parent rock. In 2016, in comparison with 1999, the average content of fluorine in the profile of chernozems increased by 1.6-5.5 times, in gray forest and midsoddy soil by 1.3 times. The maximum amount of water-soluble fluorine accumulates in the lower part of the soil profile, which indicates a high degree of migration of the trace element in different landscapes of agrocenoses.