EDTA及低分子量有机酸对土壤Cd活性的影响研究

Effects of EDTA and Low Molecular Weight Organic Acids(LMWOA) on Availability of Cadmium in Soil

利用模拟Cd浓度为10mg·kg-1的污染土壤研究了EDTA及柠檬酸、酒石酸、草酸3种低分子量有机酸对于棕壤、潮土、褐土中Cd的活性影响。结果显示,EDTA及3种低分子量有机酸对棕壤中Cd的活化能力依次为EDTA>柠檬酸>草酸>酒石酸,活化效率最大可达91%、71%、48%和45%;对潮土和褐土中Cd的活化能力依次为EDTA>柠檬酸>酒石酸>草酸,活化效率最大可达87%、55%、2.5%、1.3%和90%、35%、3.9%、2.9%。EDTA及3种低分子量有机酸对Cd的总体活化趋势随浓度的增大而增大,最佳活化浓度出现在10～30mmol·L-1之间,3种土壤中对棕壤Cd的活化效果明显好于潮土和褐土。

This paper studied the effects of EDTA and three low molecular weight organic acids （LMWOA）, citric acid, tartaric acid and oxalic acid, on Cd availability in brunisolic soil, fiuvo-aquic soil and cinnamon soil with simulated Cd concentration of 10 mg· kg^-l. The results indicated that the activating ability of EDTA and three organic acids to Cd in brunisolic soil was in the order of EDTA〉citric acid〉oxalic acid〉 tartaric acid, and their activation efficiency reached 91%, 71%, 48% and 45%, respectively, while, in fiuvo-aquic soll and cinnamon soil, the activating ability was in the order of EDTA〉citric acid〉tartaric acid〉oxalic acid, and the max activating efficiency was up to 87%, 55%, 2.5%, 1.3% and 90%, 35%, 3.9%, 2.9%. In addition, the available concentration of Cd increased with the increase of EDTA or organic acid concentration. The optimal concentration of organic acid was 10-30 mmol·L^-1. The activating effect on Cd in brunisolic soil was better than that in fluvo-aquic soil and cinnamon soil.