Assessment of Occurrence, Ecological and Health Risk of Heavy Metals in Agricultural Soil in the Hau Giang Province, Vietnam

The study aimed to evaluate the occurrence of some heavy metals in agricultural soil in the Hau Giang province, Vietnam. The geographical accumulation index (Igeo), pollutant load index (PLI) and ecological risk index (RI) are used to assess the pollution levels and potential ecological risks due to the presence of heavy metals in agricultural soil. The results showed that the mean concentrations of Cu, Pb and Zn in the soil ranged from 16.25–40.32, 18.05–29.92 and 52.78–147.22 mg/kg, respectively, within the limits of QCVN 03-MT:2015/BTNMT. Cluster analysis showed that Pb originated from the process of using fertilizers, especially phosphate fertilizers in farming. Cu and Zn possibly share a common origin from the use of pesticides and fungicides in agricultural production. The Igeo value of Cu, Pb and Zn gradually increases in the order of Cu < Zn < Pb. The PLI (1.03–1.97) reflected that the soil in the study area is moderately polluted. The RI (14.80–25.33) represented a low potential ecological risk. In particular, position D3 had the highest level of pollution and risk among the study sites. Pb had the highest level of accumulation in soil with the highest single ecological risk factor; thus, measures should be taken to limit the source of Pb generation. The results of the study also indicated that ingestion route is the main exposure pathway by which heavy metals can be harmful to humans.