Cd Pb污染土壤中蛋白酶酸性磷酸酶脱氢酶活性的变化

通过现场采样及室内分析方法,研究了Cd、Pb严重污染的土壤中蛋白酶、酸性磷酸酶和脱氢酶活性的变化及其与土壤Cd、Cu、Pb、Zn含量和土壤基本性质之间的关系。通径分析表明,影响蛋白酶活性主要直接因素为土壤有效Cd、土壤有效Zn、砂粒和黏粒,其中土壤有效Zn刺激了酶活性而土壤有效Cd抑制了酶活性;影响酸性磷酸酶活性主要直接因素为碱解氮、速效磷、pH值,土壤有效Cu、土壤有效Cd、土壤有效Pb、土壤有效Zn对酸性磷酸酶的直接影响较小;影响脱氢酶活性主要直接因素为土壤有效Cd、土壤有效Zn、土壤速效钾,其中土壤有效Cd抑制了酶活性而土壤有效Zn刺激了酶活性。总体而言,4种重金属有效态对酶活性毒性大小依次为：Cd〉Cu〉Pb〉Zn。综合简单相关分析结果可知,总体上Cu、Cd、Pb、Zn复合污染刺激了蛋白酶活性,抑制了脱氢酶活性,对酸性磷酸酶活性影响不大,脱氢酶可作为上述土壤重金属复合污染的指标。3种土壤酶活性变化是重金属与土壤理化性质综合作用的结果。

Changes of Protease, Acid phosphomonoesterase and Dehydrogenase Activities in Cd-Pb Polluted Agricultural Soils

The activities of protease, acid phosphomonoesterase and dehydrogenase in Cd-Pb polluted agricultural soils were investigated and the relationships between the enzymatic activities and the contents of Cd, Cu, Pb and Zn as well as the basic soil properties were discussed. Path analysis showed that the contents of available Cd, available Zn, sand and clay were the principal direct factors affecting protease activity. The protease activity increased with the increase in available Zn but with the decrease in available Cd. The principal direct factors influencing acid phosphomonoesterase activity were available N, available P and pH. Available Cu, available Cd, available Pb and available Zn had only small direct effects on acid phosphomonoesterase activity. The principal direct factors affecting dehydrogenase activity were available Cd, available Zn and available K. Available Cd inhibited while available Zn promoted dehydrogenase activity. The toxicity of the available metals to the soil enzymes was in the order of CdCuPbZn. As a whole, the combined pollution of Cu, Cd, Pb and Zn increased protease activity and inhibitied dehydrogenase activity but it had only small effects on acid phosphomonoesterase. Dehydrogenase could be used as a indictor for the combined polluted soil. Soil enzymatic activities were effected by heavy metals and soil physicochemical property.