物种敏感性分布法在土壤中铜生态阈值建立中的应用研究

利用不同累计概率分布函数拟合了基于中国土壤的21个物种的铜毒理学数据,建立了不同土壤条件下的铜物种敏感性分布曲线.结果表明物种敏感性分布方程Burr Ⅲ在X轴(浓度)方向及y轴的较小累计概率范围内拟合优度较佳.在构建土壤中铜物种敏感性分布曲线时,利用铜生物毒害模型归一化处理能体现土壤性质对铜毒害的影响,相比于未归一化(不考虑土壤性质差异的影响)的结果更具科学性.结合铜的生物毒害模型利用Burr Ⅲ构建了中国土壤4种典型情景中的物种敏感性分布曲线,并基于此推导出了不同土壤情景下的铜5％毒害浓度(HC5),其在酸性土壤、中性土壤(包括水稻土)、碱性非石灰性土壤和石灰性土壤中的值分别为13.1、29.9、51.9和26.3 mg·kg-1(以土壤中外源铜为单位).此结果不仅表明了不同土壤条件下的不同物种对铜毒害的敏感性分布规律,还为建立对应土壤性质的铜生态阈值提供了可靠的科学基础.

Application of species sensitivity distribution in deriving of ecological thresholds for copper in soils

In this paper, copper toxicity thresholds of 21 species based on Chinese soils were fitted with different cumulative probability distribution functions to obtain species sensitivity distribution curves for copper in soils. The result showed that the species sensitivity distribution equation Burr III fitted better than other functions in the X axis direction and Y axis with lower cumulative frequency. Utilization of copper ecotoxicity regression models in the establishment of species sensitivity distribution curves could represent the effect of soil properties on copper ecotoxicity. It is more scientifically robust to normalize toxicity threshold with ecotoxicity regression models compared with that without normalization. On the basis of copper ecotoxicity regression models the species sensitivity distribution curves in four representative scenarios of Chinese soils were fitted with Burr III. The 5% hazardous concentrations for copper were derived from the species sensitivity distribution curves, determined as 13.1, 29.9, 51.9 and 26.3 mg·kg^-1 (dw) based on added Cu for acidic, neutral, alkaline non-calcareous and calcareous soils, respectively. The results not only identified the species sensitivity distribution of copper in different soils but also provided the scientific basis for deriving of ecological thresholds for copper in soils.