Ecological Risk Assessment for Occurrence of Toxic Elements in Various Land Use Types in Vietnamese Mekong Delta Province

A total of 316 soil samples in the An Giang province were collected from the industrial zone (48 samples), mining (40 samples), farming (112 samples), landfills (88 samples) and cemeteries (28 a samples) to analyze toxic elements, including Cu, Zn, Pb, Cd and As. The geoaccumulation index (Igeo), pollutant load index (PLI) and potential ecological risk index (RI) were used to assess pollution levels and ecological risks. The results showed that the concentrations of heavy metals were almost still within the allowable limits of national standards. Cd was not detected. Heavy metals were detected in the soil in the following order: As < Pb < Cu < Zn, mining < industrial < landfill < cultivation < cemetery areas. The heavy metals contributing to soil environmental variability were similarly identified in the cemetery with industry and landfill with farming. The value of Igeo shows that As has a high potential to accumulate in soil in all land uses. The ranges of PLI values presented that the soil in industrial, farming, mining and landfills areas were classified moderate, while the cemetery areas has been rated at a high level. The RI values identified very high, high, and moderate ecological risks for cemetery, industrial and farming land and landfill, mining, respectively. The combination of PLI and RI indices showed that the cemetery areas were at the highest levels of pollution and risk. The results of this study provide scientific information on pollution level and ecological risks in various land use types supporting environmental zoning and managing strategies in the An Giang province.