Cu and Zn pollution and soil enzyme activities in sewage irrigation area near smeltery
冶炼厂污灌区土壤铜和锌污染与土壤酶活性

This paper studied the Cu and Zn status in soil and rice plant as well as the soil enzyme activities in the sewage irrigation area near a smeltery. The results showed that the soils near the smeltery were polluted. The soil total and extractable Cu contents at the distance of 100 m were 182.45 and 81.91 mg x kg(-1), respectively, 9.3 and 34 times higher than the control. The Cu concentration in different parts of rice was in order of root > leaf and stem > grain, while the Zn concentration was in order of leaf and stem > root > grain. Zn was more mobile than Cu which was likely to accumulate in rice root. It was considered that root could act as a barrier which retarded the upwards transport of Cu and protected the above ground parts of rice from toxication. The Cu contents of rice stem and leaf had a significant correlation with soil Cu contents in the sewage irrigation area. Among the three test enzymes, urease was the most sensitive one to Cu, and its activity had a significant correlation with soil Cu content. Therefore, it is feasible to use soil urease activity as an indicator of soil Cu pollution in sewage irrigation area near the smeltery.