保定市污灌区土壤的Pb、Cd污染与土壤酶活性关系研究

RELATIONSHIP BETWEEN SOIL Pb AND Cd POLLUTION AND ENZYME ACTIVITIES IN WASTEW ATER IRRIGATED AREA OF BAODING CITY

本文应用一元线性与非线性回归拟合寻优模型，着重研究了保定市污灌区土壤重金属Ｐｈ、Ｃｄ污染与土壤酶活性之间的关系。结果表明，污灌区土壤Ｐｂ、Ｃｄ含量比清灌区有明显的增加，且均高于国内外重点城市的土壤背景值，已接近或达到轻度污染程度。土壤脲酶和过氧化氢酶活性随着土壤Ｐｂ、Ｃｄ含量的增加而有明显的降低。经回归拟合寻优结果表明，脲酶和过氧化氢酶活性与土壤Ｐｂ、Ｃｄ含量之间呈极显著的指数负相关，其最大γ２模型方程均为ｙ＝ａｘｅ－ｂｘ，其γ值分别为－０．８０４，－０．７９５和－０．８９９，－０．８５２。故用脲酶及过氧化氢酶活性作为判明污灌区土壤重金属Ｐｂ．Ｃｄ污染程度的主要生化指标是可行的。

This paper deals mainly with the relationship between Pb and Cd pollution and enayme activities of soil in wastewater irrigated area of Baoding city. The results show that the contents of Pb and Cd in soils of wastewater irrigated area were higher than those in soils irrigated with fresh water and exceeded the standards of soil background values for some cities at home and abroad, and the contents of Pb and Cd in soils of wastewater irrigated area approched or reached the lightly polluted levels. There appeared a close relationship between heavy metal pollution and enzyme activity. The soil urease and catalase activities decreased evidently with increasing contents of Pb and Cd.According to the regressive fitting results there existed a very significant exponential negative correlation between soil urease and catalase activities and Pb and Cd contents with the maximum γ2 model equation of y=axe-bx and the correlation coefficients (γ)of-0.804, 0.795 and -0.899, 0.852, respectively. It is feasible to use soil urease and catalase activities as primary biochemical indexes to evaluate Pb nd Cd pollution in soils of the wastewater irrigated area.