抄録
Mining activities in the Co Dinh chromite mine, Vietnam, have exerted adverse environmental impacts due to the dispersal of heavy metals from the mine to downstream agricultural soils. In the present study, the extent and degree of heavy metal accumulation in rice plants were investigated and the potential health hazard caused by polluted agricultural products in this area was evaluated. Rice plants (Oryza sativa L. var. Lua Nep) were sampled from four paddy fields at different distances (2.5-6.0 km) from the mining site. The rice plants grown in fields near the mine contained significantly higher amounts of Ni, Cr and Co than those grown far from the mine, due to severe contamination of the soils with these elements as a result of mining activities. Among the examined elements, Ni appeared particularly problematic owing to its considerably high concentration in brown rice (2.66-4.29 mg kg-1). The estimated daily intake (EDI) of Ni through the consumption of brown rice (0.019-0.030 mg kg-1 day-1) exceeded the tolerable daily intake (TDI) recommended by WHO (0.011 mg kg-1 day-1), indicating a potentially serious health risk to the local inhabitants. Moreover, high concentrations of Ni were also detected in leaf blades and sheaths (3.66-28.2 and 9.79-93.1 mg kg-1, respectively) which are fed to livestock. These findings raise the possibility of an increased health hazard as Ni could further accumulate in the food chain from crops to humans.
