Analysis of heavy metal pollution and potential ecological risk at the relocation site of a chemical plant

Abstract

In recent years, the relocation sites of heavy industrial enterprises have caused great harm to human health, environmental and ecological safety, society and economy. Taking a relocation site of the chemical plant as research object, 18 soil samples of 0~20 cm were collected, and the contents of seven heavy metal elements, including Ni, Cu, Cd, Pb, Hg, As and Zn, were tested. The quality ratio statistical analysis, pollution characteristics analysis and potential ecological risk were used to determine the heavy metal pollution. Results show that mean concentration of Ni, Cu, Cd, Pb, Hg, As and Zn were 30.16 mg/kg, 35.10 mg/kg, 0.28 mg/kg, 31.74 mg/kg, 0.92 mg/kg, 18.99 mg/kg and 72.63 mg/kg, respectively. Compared with the background value of Guanzhong area, Shaanxi, China, the heavy metal exceeding rate of sample points was 83.3%. Hg and As were the main pollution source, and they had exceeded the risk screening values in (Soil environmental quality Risk control standard for soil contamination of development land) (GB36600-2018). Geo-accumulation index and potential ecological risks showed that the mercury of Hg was polluted heavily. All these showed that the potential ecological risk in the chemical plant was extremely strong which was mainly determined by industrial production and human activity at the same time.