Geochemical Characteristics of Selenium-rich Soils and Evaluation of Eco-environmental Effects in Xiayi County of Henan Province

In order to carry out the investigation and evaluation of selenium-rich soil in Xiayi County of Henan Province, 980 surface and 85 deep soil samples were collected to test and analyze the geochemical characteristics and genesis of selenium-rich soil in the study area, and to evaluate the eco-environmental effects. Studies show that there are uneven distribution of soil selenium on the surface layer of the area, and there is a local enrichment phenomenon.The average content of selenium in soil is 0.20 μg/g, and the area of selenium-rich soil with selenium content greater than 0.300 μg/g is about 32.24 km², accounting for 2.96%.The selenium content in deep soil is below 0.2 μg/g, which is negatively correlated with the sampling depth.The parent material of soil is one of the factors affecting the content of selenium in soil. The nutrient elements (N, P, Corg, CaO), trace elements (Mn, Mo, I, Sr, F) and heavy metal elements (Pb, Zn, Ni, Hg, Cr, As) in soil are positively correlated with selenium, and the influence factors on selenium content were large. The soil of pH has little effect on selenium content. The surface soil with good quality is 1071.03 km² in the study area, accounting for 98.45%. The overall soil quality is good, which provides a good foundation for the development of selenium-rich agricultural products industry.