冶炼厂污灌区土壤铜和锌污染与土壤酶活性

通过对冶炼厂污灌区土壤和水稻中Cu、Zn含量分析以及土壤酶活性的测定,研究了距冶炼厂不同距离土壤Cu、Zn含量状况、水稻对它们的吸收和分配以及土壤酶活性的变化.结果表明,冶炼厂造成了周围农田土壤的Cu、Zn污染,其中Cu污染较严重,距离冶炼厂100 m处的全量和提取态Cu分别为182.4和81.91 mg·kg^-1,是对照的10.3和3倍.污灌区水稻各器官Cu、Zn的分布规律是,Cu:根＞茎叶＞米;Zn:茎叶＞根＞米.Zn在水稻体内的移动能力大于Cu,Cu主要累积在水稻根部,根可作为一种屏障阻碍Cu向地上部分迁移,使地上部分免受其害.水稻茎叶Cu含量和土壤中Cu的浓度密切相关.对蔗糖酶、过氧化氢酶和脲酶活性测定表明,脲酶活性变化最显著,其活性与土壤中Cu的浓度显著相关,建议用脲酶活性作为污灌区Cu污染指标.

Cu and Zn pollution and soil enzyme activities in sewage irrigation area near smeltery

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.