不同性质土壤中锑对小麦根伸长的毒性阈值及预测模型

针对土壤中锑污染毒性阈值研究较少的现状,参考ISO11269-1根伸长毒性测试标准方法,采集7种不同性质的土壤,利用TableC urve2D软件拟合剂量-效应关系,得到锑对小麦根伸长的毒性阈值(EC10和EC20)及其预测模型。当外源锑质量比增加时,7种土壤中小麦的相对根长均减小。毒性阈值与土壤理化性质相关分析表明,毒性阈值EC10和EC20与土壤p H值呈显著负相关关系,与土壤总铁质量分数呈显著正相关。回归分析得出,土壤p H值和土壤总铁质量分数可以解释90%的毒性阈值的变异。EC10和EC20的预测值与实测值的比值在2倍范围内。研究表明,在不同性质土壤中锑对小麦的毒性阈值有显著差异,土壤p H值、总铁质量分数与小麦的毒性阈值间呈显著相关关系(p0.05),所得回归模型可较好地预测锑对小麦的毒性阈值。

Toxicity threshold of antimony to wheat root elongation in the different soils and its prediction model

The paper is devoted to an investigation of the toxicity threshold of antimony to wheat root elongation in the different soils and its prediction model.Taking into account the toxicity thresholds of antimony in the soils we have chosen to trace a great variety of their physicochemical properties.For the said research purpose,we have first of all derived the dose-response curves and the toxicity thresholds based on the so-called ISO 11269-1 rootelongation test by using the so-called TableCurve2D software.And,then,we have managed to identify and measure the physical and chemical properties of the soils chosen,such as their pH value,the organic carbon,the clay content and so on.And,in turn,we have made an analysis of the correlation indexes between the soils' properties and the toxicity thresholds.And,finally,we have gained the predictive models of the toxicity threshold by selecting the significant relevance indexes.The results we have gained through the above investigation and analysis show that the relative root elongation (％) tends to decrease with the increase of Sb concentration rate in the soils.The results of our correlation analysis indicate that there exists a significant negative correlation (p ＜ 0.05) between the soil's pH and the toxicity thresholds of Sb to the wheat in the soils,in which the toxicity thresholds have been found positively correlated with the iron content rate.More definitely speaking,the regression analysis proves that the soil pH value and the soil's total iron content rate should account for 90％ of the variance of the toxicity threshold.Thus,we have developed a predictive model for assessing the toxicity thresholds of Sb to wheat with the falling of the measured ECx to the range of twice as much as the predicted values.Thus,the investigation and the analysis results of ours can help to display the significant difference of the toxicity thresholds (ECx,x =10,20) of Sb to the wheat cropped via the root-elongation test.The significant correlation (p ＜ 0.05) we have identified and determined can be observed and determined among the soil's pH value,the iron content rate and the toxicity thresholds.The obtained regression model can be expected to predict the toxicity threshold of the soil antimony to wheat and provide a reference for the ecological toxicity of soil antimony pollution in China.