基于生物有效性水体中锑的毒性预测模型研究

Antimony (Sb) is one of the emerging contaminants at home and abroad, and its hazard has recently received great attention. Sb exits in different speciation with low concentration in aquatic environment. However, little information is available about the bioavailability and toxic prediction of Sb with the effects of various water quality parameters. In the present project, field study and lab control experiment will be conducted, K[Sb(OH)6] and NaSbO3 will be selected to investigate the toxicity effects of pentavalent Sb on Daphnia magna. The dose-response relationship between the different speciation of Sb(V) and toxic effects under different environmental conditions (such as pH, organic matter, water hardness and cation) will be established to elucidate the main influencing factor of bioavailability, to reveal the interactive mechanisms of Sb with various combinations of water quality parameters, and to build biotic ligand model for Sb. The applicability of model would be validated with the actual water quality parameters in typical lake water bodies in our country. The results in this study will provide reliable basis for ecological risk assessment and control of Sb in China.

锑作为国内外新兴污染物之一，其危害已引起人们高度关注。但锑在水环境中含量较低、形态复杂，在水质参数影响下锑的生物有效性和毒性的预测尚不清楚，还需要系统研究。项目以五价锑酸盐(K[Sb(OH)6]和NaSbO3)为研究对象，以大型溞为受试生物，通过室内模拟和野外研究相结合，系统研究多个水质参数（pH、有机质、硬度和阳离子等）综合作用下不同形态锑含量与毒性的剂量效应量化关系，阐明影响锑生物有效性的主要因素和机理，建立基于生物配位体的毒性预测模型。结合我国典型湖泊水体中的实际暴露水质参数验证毒性预测模型的适用性。成果为我国典型地区锑污染生态风险评估和控制提供科学依据。

锑作为目前国内外新兴且较为关注的有毒金属元素之一，其在水体中不断积累给水环境和水生生物带来威胁，其水生态危害已引起人们的高度关注。目前，我国的环境水质标准和环境风险评价是基于水体中重金属总的浓度，忽视了水化学性质的影响。本项目选择较敏感的大型溞为受试生物，采用代表性五价锑化合物焦锑酸钾为研究目标，以锑对大型溞的48 h急性致死毒性为毒性终点，系统地研究多种水质参数不同水平作用下五价锑化合物对大型溞的毒性效应，以室内毒性试验结果和搜集的锑相关毒性数据为基础，获得锑急性和慢性水生态风险基准值。结合我国典型污染水体中的锑浓度，采用物种毒性敏感度模型对典型水体锑进行急/慢性生态风险评估。结果表明在不同水质参数下焦锑酸钾对大型溞的毒性大小不同，适当提高Ca2+、Mg2+、Na+等浓度能够减轻其对大型溞的毒性，而改变pH值则对大型溞的毒性影响不大。结合室内毒性数据，获得锑急性和慢性水质基准值分别为377.1μg/L和41.0μg/L；采用物种毒性敏感度模型分析发现典型污染水体中的水生生物物种存在不同程度的急性和慢性生态风险。