复合型螯合药肥对镉铅污染土壤的原位固定修复效应分析

以镉铅复合污染土壤为对象,采用田间试验,通过种植水稻、红薯和小白菜,施用钠基、钾基和钙基3种复合型螯合药肥,分析土壤中Cd和Pb的固定效率,探讨复合型螯合药肥对降低农产品Cd和Pb含量的效果。结果表明,复合型螯合药肥施用量在耕层土重的0.5%以上即可有效降低土壤中Cd和Pb的移动性,土壤中Cd和Pb的固定效率分别达到49.2%-66.2%和79.9%-93.6%,且可使稻米、红薯干和小白菜等农产品中Cd含量降低至国家标准(GB 2762—2012)限值以内,其降低幅度分别为69.5%-79.7%、42.9%-47.6%和80.5%-83.7%;但对稻米和小白菜中Pb含量无明显的降低作用。同时,该药肥对土壤pH值和稻谷、红薯及小白菜的产量无明显影响。研究表明,供试钠基、钾基和钙基3种复合型螯合药肥可推荐用作镉污染土壤的原位固定修复材料。

In-situ stabilization of Cd and Pb in Polluted soil using compound chelating fertilizers

To investigate the in-situ stabilization of Cd and Pb in polluted soil using sodium-, potassium- and calcium-compound chelating fertilizers, a field experiment was conducted in a Cd and Pb combined contaminated soil in Zhuzhou city, Hunan Province, P.R. China. Rice, sweat-potato and Chinese cabbage were planted, harvested and sampled. The results indicated that the 3 kinds of compound chelating fertilizers application significantly reduced the mobility of Cd and Pb in soil by 49.2%-66.2% and 79.9%-93.6%, respectively. Moreover, the contents of Cd in brown rice, dry sweat-potato and Chinese cabbage significantly decreased by 69.5-79.7%, 42.9%-47.6% and 80.5%-83.7%, respectively. However, no significant decrease of Pb contents in brown rice or Chinese cabbage was observed. This contradiction could be contributed to the deposition of Pb in the tested area. The field experiment was located in the downwind direction of a Smelter and there is heavily deposition of Pb in this area. Further, no significant effect of such fertilizers application on soil pH or yields of rice, sweat-potato or Chinese cabbage was observed. In conclusion, the 3 tested compound chelating fertilizers could be recommended for the remediation of Cd contaminated soil.