人工湿地去污对灌溉农田土壤重金属污染的修复

Remedial effect of constructed wetland on heavy metals polluted farmland soil

大量工业废水的排放使得黄河白银段重金属质量分数较高,由于当地干旱缺水,农田多是直接引用受污黄河水进行灌溉,这给当地农业生产带来风险.本实验构建人工湿地对灌溉水进行前处理,用处理水灌溉农田,在不同月份对灌溉水和农田土壤中四种重金属(Cu,Zn,Pb,Cd)的质量分数进行测定,评价人工湿地对灌溉水和农田土壤重金属污染的修复作用.结果显示:经过4个月处理后,灌溉水和农田土壤中的重金属质量分数均有显著的降低(P<0.05),土壤综合重金属潜在生态危害指数逐月下降.由此可见,人工湿地对受污土壤具有良好的修复作用,这将有利于实现农业的安全和清洁生产.

Owing to industrial and agricultural development, heavy metals （HMs） pollution in the Yellow River （YR） becomes increasingly serious, especially in the Baiyin region. Irrigation with polluted YR water has been common in Baiyin where the water supply is extremely limited. This has significantly contributed to the agricultural risks in this area. In this study, a surface flow wetland （CW） was constructed and used to treat the polluted water from YR, and then the farmland soil was irrigated with the treated YR water. Samples including water from YR and CW, and farmland soil were collected and determined monthly during the spring wheat growing season from April to July. The remedial effect of the constructed wetland on the polluted irrigation water and farmland soil was assessed and the results showed that CW could significantly reduce the concentrations of HMs in irrigation water and farmland soil （P 〈0.05）. The comprehensive potential ecological risk of the HMs in farmland soil decreased gradually in the 4 irrigating months. In conclusion, CW has good remedial effects on the HMs polluted farmland soil in the BYR and it is advantageous to realize the safety and cleaner production of agricultural products.