Geochemical Distribution and Ecological Risk Assessment of Soil Heavy Metals in a Typical Selenium–rich Area of Guizhou Province

<p indent="0mm">In order to identify the geochemical distribution characteristics of heavy metals and assess the ecological and environmental risks in soils in selenium-rich areas of Guizhou Province, this paper took an abnormal selenium enriched area of Jiuan in Guiyang City as the research object, we collected soil and crop samples and and determined the contents of heavy metals and Se by inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometry (AFS). The ecological risk of heavy metal pollution was evaluated by pollution index method and potential ecological hazard index method. The results showed that the soil pH in the study area was between 4.07 and 5.69, belonging to acidic soil, and the average selenium content was <sc>2.18 mg/kg,</sc> which far exceeded the standard value of Se-rich soil at all sampling sites. In addition to Pb and Zn, the average content of 6 heavy metals in soil, such As, Cd, Cu, Cr, Hg and Ni, exceeded the background value of the soil in Guizhou Province, and the spatial distribution of elements varied greatly, with local high value points. The heavy metal pollution of soil is mainly in medium and light grade, and some points reach serious pollution. The potential ecological risk of soil heavy metal pollution was moderate for Hg, and the risk of other heavy metals was low, and the overall potential ecological risk in the study area was low. Heavy metals in crops exceed the standard in some locations, and it should pay attention to special high-risk points. Therefore, the overall ecological risk of soil heavy metal pollution in the study area is at a low level, but special attention and control should be paid to individual high–risk points to ensure the efficiency and safety of selenium-rich land resources development and utilization, and promote the sustainable development of local selenium-rich agriculture and industry.