南方典型镉污染稻田土壤有效态镉预测模型研究

Prediction model for soil available cadmium in typical cadmium contaminated paddy fields of South China

为了更好地指导重金属镉污染稻田实施土壤修复、管控土壤镉毒害风险,以我国南方典型镉污染稻田为研究对象,基于316个监测点位的土壤镉及理化性质指标测定,分析土壤有效态镉含量与土壤理化因子间的相互关系,并通过逐步多元回归方程,建立稻田土壤有效态镉的预测模型。结果表明,土壤总镉、有效锌、有效硫、有效磷及有效铜是影响南方稻田土壤有效态镉含量的主要因素。通过区域调研,借助逐步回归分析得到南方稻田土壤有效态镉含量的预测模型方程:Cd_(ext)=-0.006+0.371(Cd_(tot))+0.014(A-Zn)+0.001(A-S)-0.001(A-P)+0.006(A-Cu),模型预测达极显著水平(P<0.001),决定系数(R2)为0.745。故以上述5个土壤因子建立的回归模型可实现较好的预测水平,为镉污染稻田的土壤修复提供参考。

In order to better guide the heavy metal cadmium polluted paddy soils to implement soil remediation and control the soil cadmium poisoning risk,typical cadmium polluted paddy fields in southern China were taken as the research object,the relationship between soil available cadmium content and physiochemical factors was analyzed based on the soil cadmium and the physiochemical properties index determination for 316 monitoring sites,and the forecast model of paddy soils available cadmium was established through stepwise multivariate regression equation.The results showed that the soil available cadmium content of paddy fields in southern China mainly depended on the soil total cadmium(Cdtot),available zinc(A-Zn),available sulfur(A-S),available phosphorus(A-P)and available copper(A-Cu).Through regional investigation and stepwise regression analysis,the prediction model equation of available Cd content(Cd_(ext))in the southern paddy soils was obtained:Cd_(ext)=-0.006+0.371(Cdtot)+0.014(A-Zn)+0.001(A-S)-0.001(A-P)+0.006(A-Cu).The model prediction reached a very significant level(P<0.001),and the determination coefficient(R2)was 0.745.Therefore,the regression model based on the above five soil factors can achieve perfect prediction,and it can provide reference for soil remediation of cadmium polluted paddy field.