镉、汞复合污染对土壤脲酶和酸性磷酸酶活性的影响

通过土壤培养试验, 研究了重金属镉（Cd）、汞（Hg）复合污染对小粉土和黄红壤脲酶和酸性磷酸酶活性的影响.结果表明：整个培养过程中，Cd、Hg单一及复合污染都对两种土壤中脲酶和酸性磷酸酶的活性具有明显抑制作用，且随重金属浓度增强而增强（浓度≤1 mg·kg^-1Cd除外）.与单一Cd或Hg污染相比，同剂量Cd和Hg复合污染时两种酶活性的净变化量均大于0，表明Cd和Hg复合污染在两种土壤中对土壤脲酶和酸性磷酸酶活性的抑制作用均表现为一定的协同作用.所有处理黄红壤脲酶和酸性磷酸酶活性均高于小粉土，这可能与黄红壤有机质和粘粒含量相对较高有关.

Effects of cadmium and mercury combined pollution on soil urease and acid phosphatase activities.

With incubation test, the effects of cadmium (Cd) and mercury (Hg) combined pollution on the urease and acid phosphatase activities in marine sediment silty loam soil (S₁) and yellowish red soil (S₂) were studied. The results indicated that during the whole incubation period, Cd and Hg, whether singly or combined together, had significant inhibitory effects on the urease and phosphatase activities in the two test soils, and the effects increased with their increasing concentration (except for Cd ≤1 mg·kg^-1). Compared with that under Cd or Hg pollution, the net change rates of soil urease and acid phosphatase activities under the same level Cd and Hg combined pollution were higher than 0, suggesting the synergistic effects of these two heavy metals on the inhibition of soil urease and acid phosphatase activities. In all treatments, the activities of urease and acid phosphatase were higher in S₂ than in S₁, possibly due to the higher contents of organic matter and clay particle in S₂.