随着人类对钴(Co)元素开发利用活动的增强,土壤Co污染问题日益受到重视。然而,目前对土壤Co的生态风险和阈值研究还很有限。本研究通过文献检索收集筛选Co生态毒性数据,并结合毒理学实验和物种敏感性分布法推导我国土壤Co的生态风险阈值。研究结果显示,文献检索和生态毒性实验获得了不同土壤性质下Co对10种生物的10%效应浓度(EC₁₀),变化范围为7~4 696 mg/kg。利用逐步线性回归建立了8个物种EC₁₀和土壤性质(pH、CEC、OC含量和Clay含量)以及这些物种自身敏感性k值的关系,得到8个物种的k值在-0.21~1.458,并通过种间外推模型获得无归一化模型的黑麦草及玉米渣矿化k值(-1.207和2.201)。最终获得包含土壤性质和k值的10个物种的回归模型,据此模型将预测的EC₁₀值归一化到4种土壤条件下。利用物种敏感性分布法推导得到4种土壤条件下Co的生态安全阈值(HC₅),经过老化淋洗因子的校正,在酸性、中性、碱性和石灰性土壤条件下分别为7.3、44、72.08和38.88 mg/kg,该结果可为土壤Co污染风险评价及相关标准的制定提供依据。

With increasing cobalt (Co) uses cobalt contamination in soil has attracted increasing attention. However, the potential ecological risks of Co contamination in soil and related risk thresholds have not been well researched. This study aims to derive ecological risk thresholds of Co in soil in China, using Co ecotoxicity data collected and screened through literature research, combined with ecotoxicological experiments and species sensitivity distribution (SSD) method. According to results, the EC₁₀ values of Co in soils with different properties ranged between 7 to 4696 mg/kg. The relationships between EC₁₀ and soil properties (pH, CEC, OC, Clay) and sensitivity k value of species were established by stepped-linear regression for eight species. The k value of the eight species ranged between -0.21 to 1.458. The k value (-1.207 and 2.201) of the non-normalized ryegrass and maize residue mineralization(MR) were obtained by extrapolation of the interspecies correlation estimation (ICE) model.Finally, regression models, with soil properties and k value as independent variables, were obtained for 10 species, and the predicted EC₁₀ values were normalized to four soil conditions. Using SSD method and adjusting for aging leaching factor,the ecological risk threshold (HC₅) values for Co in soil were derived for acidic (7.3 mg/kg), neutral (44 mg/kg), alkaline (72.08 mg/kg) and calcareous (38.88 mg/kg) soil conditions. The results provide a scientific basis for the formulation of soil standards for Co and for risk management.