我国酸性土壤地区土壤环境质量标准实践中的修改建议——以铅、镍和镉的标准研究为例

Advice on Revision of Environmental Quality Standard for Acid Soils——A Case of Pb,Ni and Cd

通过Pb、Ni和Cd的盆栽试验,并结合广东省9市的土壤污染现状分析表明,目前我国以上3个元素在pH<6.5的情况下的土壤环境质量二级标准(分别为250、40和0.3 mg/kg)并不适应实际情况。在试验结果的基础上,认为可以将目前我国酸性土壤地区的土壤环境质量标准(GB15618-1995)二级标准中的Pb、Ni分别调整为100 mg/kg和60 mg/kg,Cd的标准保持0.3 mg/kg不变:依照建议标准,对广东省土壤的以上3个元素污染状况重新评价,结果表明,土壤中Pb的超标率从0.13%上升为5.25%,Ni超标率从23.23%下降为7.21%,与作物中Pb和Ni的超标率分别为3.90%和0.00%情况相对一致。

Our pot experiment of heavy metals of Pb, Ni and Cd and soil investigation of nine cities in Guangdong Province indicated the thresholds of total Pb and Ni of the Environmental Quality Standard （GB 15618-1995） unreasonable for the acid soils （grade I[, pH〈6.5）, they should be decreased to 100 mg/kg from original 250 mg/kg for Pb and increased from 40 mg/kg to original 60 mg/kg for Ni. If according to the new thresholds, 5.25% and 7.21% of soils in Guangdong could be judged to be contaminated by Pb and Ni respectively which are consistent to the percentages of Pb and N i in crops exceeding the Maximum Levels of Contaminants in Foods, which are 3.90% for Pb and no for Ni respectively.