土壤中镍生态阈值的影响因素及预测模型

利用实验室获得的毒理学数据建立土壤生态阈值需通过老化-淋洗因子校正以消除外源添加的人工污染与野外实际污染的差异。该文利用基于中国土壤的17个物种的镍毒理学数据建立镍土壤生态阈值并利用老化-淋洗因子对数据进行校正。结果表明淋洗效应在pH值大于8.5的土壤中尤为显著,除个别土壤外,淋洗因子(LF)值均大于2;老化效应在碱性土壤(pH值>7.0)中更为显著,且老化因子(AF)值随着土壤pH值的升高而增大。pH值、有机碳含量(OC)、阳离子交换量(CEC)可分别控制镍生态阈值变异的86.2%、9.0%和4.1%。土壤pH值是影响土壤镍生态阈值的最重要因子,基于土壤pH值和OC的2因子预测模型能较好地预测土壤镍生态阈值,其相关性达到95.2%,利用该研究获得的两因子模型并依据土壤性质参数可预测不同类型土壤中的镍生态阈值。

Influence factors and prediction model for soil nickel ecological threshold

Correction with leaching-aging factor should be applied in deriving soil ecological threshold with toxicity data from laboratory toxicity test in order to eliminate the difference of toxicity in field-contaminated soils and that in laboratory amended soils. In the paper the soil ecological threshold for soil nickel was derived with 17 species toxicity data and corrected with leaching-aging factor. The results showed that leaching effect was more significant in the soils with pH>8.5, and the values of leaching factors were all more than 2 except for exceptional soil. Aging effect was more significant in the soil with pH>7.0 and the value of aging factor increased with pH value. Main soil factors controlling soil ecological threshold for nickel were found as soil pH value and soil organic carbon content (OC). The pH value, OC and CEC could explain the nickel ecological threshold variation by 86.2%, 9.0% and 4.1% proportion respectively. The two-factor predictive model based on soil pH and OC were developed and validated for predicting ecological threshold of soil nickel. The results showed that the model could predict ecological threshold for nickel based on soil pH and OC well and the determination coefficient (R2) reached up to 0.972. The model can be applied in predicting nickel ecological threshold for different kinds of soils according to the soil properties.