东莞某工业镇农用地土壤镉污染及生态风险评价

【Objective】The objective was to find a way to effectively prevent and control cadmium (Cd) pollution by investigating the characteristics of Cd pollution in agricultural soils and agro-products in an industrial town of Dongguan.【Method】A total of 123 surface soil samples and 27 agro-products(leaf vegetables, solanaceous fruits, and fruits) from different land uses(vegetable field, orchard, woodland and waste land) were collected and the Cd content of soils and and the edible part of agro-products were determined by using graphite furnace atomic absorption spectroscopy, and were analyzed and evaluated by using using single factor index, geo-accumulation index and potential ecological risk index .【Results】Results showed that the average concent of Cd in tested soils was 0.36 mg/kg (0.02-1.52 mg/ kg), and the Cd content of 91.06% sample soil was higher than the natural background value of Guangdong Province (0.056 mg/kg). The Cd content of 48.78% of the sample soil was higher than the screening value of the soil pollution risk management standard for agricultural land (0.3 mg/kg, 0.6 mg/kg at pH>7.5). The average concent of Cd in agro-products (0.013 mg/kg) was lower than the maximum allowable concent in vegetables (0.05 mg/kg) specified in the national food safety standards, but some vegetables exceeded the standard by 11.11%. The average concent of Cd, pollution index, geo-accumulation index and potential ecological risk index of vegetable plot were higher those of woodland, those of woodland were higher those of orchard, those of orchard were higher those of wasteland, and the vegetable land differed markedly with other three lands. 【Conclusions】The Cd concent in soil of the study area showed obvious accumulation, and 48.78% of the soil had pollution risk. The Cd content in agricultural products poses a health risk to human. The concent of Cd in soils varied in different land use types, while the highest Cd concent was observed in vegetable field.