土壤中铜生态阈值的影响因素及其预测模型

Major soil factors affecting ecological threshold for copper and the predictable models

利用中国土壤的铜毒理学数据通过物种敏感性分布法推导了土壤中铜的不同风险水平（P％）的毒害浓度值（P％Hazardous concentration，Hcp），并利用淋洗一老化因子校正Hcp获得不同土地类型土壤中铜的生态阈值，探讨了土壤性质对铜生态阈值的影响并建立了两者之间的量化关系．结果表明，土壤性质对铜的生态阈值有显著影响，土壤pH值和阳离子交换量（CEC）是影响土壤铜生态阈值的最主要因子，可达铜生态阈值变异的80％以上．基于土壤pH值和CEC的两因子回归模型能较好地预测铜生态闽值，其决定系数群为O．820~0．913；增加土壤有机碳含量（OC）的三因子模型具有更高的准确性，其决定系数癣为O．852～0．988．研究结果可为科学合理地进行土壤中铜的生态风险评价和建立土壤环境质量标准提供依据．

The hazardous concentrations （HCp） are the concentrations of a substance in soils which can be toxic to p% of bio-species in ecosystems and, in other words, protect （1-p）% of bio-species in ecosystem. The values of HCp are the scientific basis for setting up soil ecological quality standards. In the present study, the values of HCp for copper in soil were derived using a method of species sensitivity distribution based on copper toxicity data from Chinese soils. Correcting the derived HCp with aging factor （AF） to obtain soil ecological thresholds of copper, i e., aged HCp. Predictable models for copper ecological thresholds based on soil properties were also developed. The results showed that soil pH and cation exchange capacity were the main soil factors affecting soil ecological thresholds of copper. Soil cation exchange capacity and pH could explain the 〉80% variation of it. The two-factor predictable models based on soil pH and cation exchange capacity could predict copper ecological thresholds with determination coefficients （RE） from 0.820 to 0.913. While the three-factor predictable models with taking into account the effect of organic carbon on copper ecological threshold were more accurate than the two-factor models with RE from 0.852 to 0.988. The predictable models developed in the present study proved the quantitative relationship between soil properties with copper ecological thresholds and the necessity of developing and implementing soil specific or regional soil environmental quality standards.