State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
J Hazard Mater. 2009 Dec 30;172(2-3):1602-7. doi: 10.1016/j.jhazmat.2009.08.033. Epub 2009 Aug 18.
There is a growing concern on the potential application of a direct current (DC) electric field to soil for removing contaminants, but little is known about its impact on soil enzyme activities. This study investigated the change of enzyme activities of a heavy metal contaminated soil before and after electrokinetic (EK) treatments at lab-scale and the mechanisms of EK treatment to affect soil enzyme activities were explored. After treatments with 1-3 V cm(-1) of voltage gradient for 420 h, soil pH, electrical conductivity (EC), soil organic carbon, dissolved organic carbon (DOC), soil heavy metal concentration and enzyme activities were analyzed. The results showed that the average removal efficiencies of soil copper were about 65% and 83% without and with pH control of catholyte, respectively, and all the removal efficiencies of cadmium were above 90%. The soil invertase and catalase activities increased and the highest invertase activity was as 170 times as the initial one. The activities of soil urease and acidic phosphatase were lower than the initial ones. Bivariate correlation analyses indicated that the soil invertase and acidic phosphatase activities were significantly correlated with soil pH, EC, and DOC at P<0.05, but the soil urease activities had no correlation with the soil properties. On the other hand, the effects of DC electric current on solution invertase and catalase enzyme protein activities indicated that it had negative effect on solution catalase activity and little effect on solution invertase activity. From the change of invertase and catalase activities in soil and solution, the conclusion can be drawn that the dominant effect mechanism is the change of soil properties by EK treatments.
人们越来越关注直流（DC）电场在去除污染物方面在土壤中的潜在应用，但对其对土壤酶活性的影响知之甚少。本研究在实验室规模上研究了电动（EK）处理前后重金属污染土壤的酶活性变化，并探讨了 EK 处理影响土壤酶活性的机制。在施加 1-3 V cm(-1)的电压梯度 420 h 后，分析了土壤 pH 值、电导率（EC）、土壤有机碳、溶解有机碳（DOC）、土壤重金属浓度和酶活性。结果表明，在没有和控制阴极电解液 pH 值的情况下，土壤铜的平均去除率分别约为 65%和 83%，所有镉的去除率均高于 90%。土壤转化酶和过氧化氢酶活性增加，最高转化酶活性是初始值的 170 倍。土壤脲酶和酸性磷酸酶的活性低于初始值。双变量相关分析表明，土壤转化酶和酸性磷酸酶活性与土壤 pH 值、EC 和 DOC 显著相关（P<0.05），而土壤脲酶活性与土壤性质没有相关性。另一方面，直流电流对溶液转化酶和过氧化氢酶酶蛋白活性的影响表明，它对溶液过氧化氢酶活性有负面影响，对溶液转化酶活性影响很小。从土壤和溶液中转化酶和过氧化氢酶活性的变化可以得出结论，主导作用机制是 EK 处理引起的土壤性质变化。
