Cadmium content in mekong delta flooded rice soils and warning of soil cadmium contam tion
2004
Nguyen Huu On | Ngo Ngoc Hung
The long-term application of phosphorous fertilizers in the intensive production of rice in the Mekong delta may have resulted in cadmium contamination of the soils. To access the contamination, a survey of the phosphorous fertilizer application and the extent of the resulting soils were conducted. Using GF-AAS, the cadmium concentration in the analyzed soils was found to range from 0.01 to 0.56 mg kg-1. The alluvial soils were found to contain significantly more cadmium than saline soils, which consistently showed the lowest level of contamination of this heavy metal. The concentrations were lower than the critical values considered by Vietnamese (TCVN - 2000) and the international levels (EC Directive, Canada), but the results of the present study strongly indicate an anthropogenic impact on soil cadmium levels. Concerns of food-chain contamination should be evaluated more closely, especially the areas with dykes. Because these areas appear a potential Cd contamination of the ecosystems.
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