南方典型稻田土壤-水稻系统环境质量评价

为研究南方典型区域稻田土壤—水稻系统中重金属含量,系统采集了江西省进贤县、金溪县、渝水区、高安市、安福县和兴国县等6个水稻主产区典型田块土壤、水稻和灌溉水,重点分析了土壤和水稻铅、镉、砷和汞含量及其土壤养分,并采用单因子污染指数和内梅罗综合指数对土壤—水稻系统中重金属含量进行评价。结果表明,研究区稻田土壤pH、有机质、总氮、总磷、总钾、碱解氮、有效磷和速效钾总均值分别为5.48、32.99 g/kg、2.06 g/kg、0.54 g/kg、16.04 g/kg、156.71 mg/kg、14.00 mg/kg和94.98 mg/kg。研究区土壤铅、镉、砷和汞含量总均值分别为35.46、0.18、7.21和0.17 mg/kg,单因子污染指数均小于1,内梅罗综合污染指数为0.56,土壤环境质量等级为清洁;但渝水土壤镉含量为0.37 mg/kg,超过限量标准(0.30 mg/kg),土壤环境质量属于警戒状态。研究区糙米铅、镉、砷和汞的含量总均值分别为0.06、0.17、0.24和0.0086 mg/kg,单因子污染指数均小于1,内梅罗综合污染指数均值为0.77,糙米环境质量等级为警戒限;但兴国和渝水糙米镉含量分别为0.22和0.35mg/kg,均超过限量标准(0.20 mg/kg),环境质量等级分别为警戒限和轻度污染。相关性表明,糙米镉与土壤镉和铅呈显著正相关,而与土壤砷呈显著负相关;糙米砷与土壤砷和有效磷呈显著正相关。总之,重金属镉是调查区域水稻安全性最主要的潜在污染元素,需重点关注兴国和渝水两地水稻食品安全。

Environmental Quality Assessment of Soil-Rice System in Typical Paddy Fields in Southern China

In order to study the content of heavy metals in paddy soil-rice system in typical areas of southern China. Soil, rice and irrigation water samples were collected from six typical paddy fields in Jinxian, Jinxi, Yushui, Gaoan, Anfu and Xingguo County of Jiangxi Province. The contents of lead, cadmium, arsenic and mercury in soil and rice and soil nutrients were analyzed. The content of heavy metals in soil-rice system was evaluated by single factor pollution index and Nemero comprehensive index. Results showed that the mean values of soil pH, organic matter, total nitrogen, total phosphorus, total potassium, available nitrogen, available phosphorus and available potassium were 5.48,32.99 g/kg, 2.06 g/kg, 0.54 g/kg, 16.04 g/kg, 156.71 mg/kg, 14.00 mg/kg and 94.98 mg/kg, respectively. The total average contents of lead, cadmium, arsenic and mercury were 35.46, 0.18, 7.21 and 0.17 mg/kg in the soil of the study area. The single factor pollution index was less than 1, the Nemero comprehensive pollution index was 0.56, and the soil environmental quality grade was clean. While the soil cadmium content was 0.37 mg/kg in Yushui, exceeding the limit standard (0.30 mg/kg), and the soil environmental quality was alert. The total average contents of lead, cadmium, arsenic and mercury were 0.06, 0.17, 0.24 and 0.0086 mg/kg in brown rice of the study area. The single factor pollution index was less than 1, and the average Nemero comprehensive pollution index was 0.77. The environmental quality grade of brown rice was alert. The cadmium contents in brown rice of Xingguo and Yushui were 0.22 and 0.35 mg/kg, which exceeded the limit standard (0.20 mg/kg). The environmental quality grades were warning limit and mild pollution, respectively. Correlation analysis showed that cadmium in brown rice was significantly positively correlated with cadmium and lead in soil, while negatively correlated with arsenic in soil. The arsenic in brown rice was significantly positively correlated with arsenic and available phosphorus in soil. In short, heavy metal cadmium is the most important potential pollution element for rice safety in the survey area, and it is necessary to focus on rice food safety in Xingguo and Yushui.