Evaluating Ecological Risk Associated with Heavy Metals in Agricultural Soil in Dong Thap Province, Vietnam

Abstract

Heavy metal pollution in soil has received more attention in recent years because of an increase in human activities and its potential effects on ecology and human health. This study assessed the occurrence of heavy metals (As, Pb, Cu, Zn, and Cd) in different cultivated land and their ecological risk in Dong Thap Province, Vietnam. Seventeen samples collected in paddy, vegetable, perennials, and ornamental soils were measured for heavy metal concentrations and soil structure. The data were analyzed using Pearson correlation, principal component analysis (PCA), cluster analysis (CA), Nemerow pollution index (PIN), geoaccumulation index (Igeo), pollution load index (PLI), and potential ecological risk index (RI). The results revealed that the soil structure was clay loam and silt clay loam. Heavy metal concentrations were within the national limits with the order of Zn>Cu>Pb>As>Cd. Pearson correlation and PCA indicated that heavy metals were strongly correlated, and agriculture and soil formation were responsible for their presence in soil. The sampling sites were divided into four groups using CA, in which paddy and crop soils had the highest content of heavy metals. Based on PIN values (0.82-2.92), the heavy metal pollution ranged from warning to moderate level. As had the highest accumulation potential in the soil, with the Igeo values ranging from 0.12-2.05. The risk of heavy metal pollution in agricultural soil to ecology was low to moderate. Despite that, it is recommended to annually monitor the occurrence of heavy metals in agricultural soils to have proper solutions to protect public health.