Geochemical characteristics and evaluation of ecological environment and human health of selenium in soil-crop-human system in Shuangyang River Basin, Heilongjiang

This paper is the result of ecological geological survey engineering.

Objective The natural endowment, genetic source, ecological environment effect and human health evaluation of soil selenium in typical black soil distribution areas are the research focus of healthy geology, a quantitative study on the migration and accumulation of selenium in the soil-crop-human system in the Shuangyang River Basin was carried out.The development of selenium-rich agricultural products in black soil and the prevention and control of endemic diseases are of great significance.

Methods The selenium content of parent material, soil, atmospheric dust, irrigation water, crop seeds and human hair was determined, and the results were statistically analyzed and evaluated by GIS and SPSS software.

Results The selenium-enriched land is 46.4 km², mainly distributed along the Shuangyang River and its tributaries; the selenium is largely caused by human beings, mainly from atmospheric dust supplementation with an input flux of 0.21-1.47kg/km²·a.The mean selenium contents of soil, soybean, rice, corn and human hair are 0.305 mg/kg, 0.0352 mg/kg, 0.0287 mg/kg, 0.0198 mg/kg and 0.145 mg/kg.The enrichment coefficient of selenium from crops to soil (0.120) is much less than 1, and the enrichment coefficient of selenium from human hair to crops (4.834) is greater than 1, indicating that human hair has a strong concentration and amplification effect on selenium.The migration and accumulation of selenium in the soil-crop-human system shows a "V" -shaped pattern.

Conclusions In general, the selenium content in the soil is sufficient or rich with no potential environmental risk.Soybean and rice are rich in selenium, accounting for 28.4% and 9.4%, with no selenium exceeding the standard and poisoning in organisms.The content of selenium in human hair is significantly lower than the reference value of 0.20-0.60 mg/kg, indicating that the human body is in a state of selenium deficiency, and the selenium content tends to decrease with age.There may be certain health risks, which should arouse the attention of local relevant departments.