[Analysis of Heavy Metal Pollution Evaluation and Correlation of Farmland Soil and Vegetables in Zhaotong City].

ABSTRACT

A farmland area in Zhaotong City was taken as the research object， and the method of point-to-point collaborative sampling was used to collect farmland soil and vegetables in Zhaotong and test the content of six heavy metals， namely As， Pb， Cu， Zn， Cd， and Cr. The geo-accumulation index and potential ecological risk index were used to evaluate the heavy metal pollution of soil. The health risk model was used to evaluate the risk to the human body imposed by vegetables. The results showed that Cu， Zn， Pb， Cd， and Cr pollution existed in the research area. Compared with the risk screening value of farmland， the over-standard rates were 34.35%， 6.87%， 2.29%， 80.15%， and 6.11%， respectively； Pb， Cd， and Cr were found in vegetables. Compared with the pollutant limit in food， the over-standard rates were 6.87%， 15.27%， and 36.64%， respectively. According to the soil pollution evaluation， Cd in the soil showed a strong ecological risk， and other heavy metals in the soil showed a mild ecological risk. The human health risk evaluation model showed that both non-carcinogenic risk and carcinogenic risk were out of the acceptable range and had a greater influence on children. Correlation analysis showed that As in the soil had an antagonistic effect on Cu and Zn absorption by vegetables， whereas Cr in the soil could promote Cu and Zn absorption by vegetables.