锑对土壤中秀丽隐杆线虫的毒性效应

为明确锑（Sb）对土壤无脊椎动物线虫的毒性效应及不同类型土壤中Sb的毒性差异，以生长量、生育率和繁殖力为评价终点，研究了3种土壤（西安垆土、鹰潭红壤、江门红壤）中外源Sb对模式生物——秀丽隐杆线虫（Caenorhabditis elegans）的毒性效应。结果表明：基于西安垆土、鹰潭红壤、江门红壤的土壤总Sb含量推导得出的Sb对线虫生长毒性的EC₅₀ （半数效应浓度）分别为1 138、2 163、4 074 mg·kg^-1，对线虫生育毒性的EC₅₀分别为849、1 472、3 244 mg·kg^-1，对线虫繁殖毒性的EC₅₀分别为574、836、1 470 mg·kg^-1。通过毒性阈值可知，线虫的评价终点对Sb毒性的敏感性由高到低依次为繁殖、生育、生长。相关性分析表明，阳离子交换量、有机质含量和非晶质铁氧化物含量是影响土壤中Sb毒性的主要因素。基于有效态Sb含量推导得出的3种土壤中Sb的毒性阈值差异缩小，说明有效态Sb含量能够更好地解释不同土壤中Sb毒性的差异。

Toxic effects of antimony on Caenorhabditis elegans in soils

To determine the toxic effects of antimony(Sb)on soil invertebrate nematodes and the toxicity differences of Sb in different soils, the toxicity effects of Sb in the model organism Caenorhabditis elegans were assessed in three soils(Xi''an loessal soil, Yingtan red soil, and Jiangmen red soil)using growth, fertility, and reproduction as evaluation endpoints. The EC₅₀(median effect concentration)values expressed in measured concentrations of total antimony for the growth of C. elegans were 1 138, 2 163 mg · kg^-1, and 4 074 mg · kg^-1, respectively. The EC₅₀ values for C. elegans fertility were 849, 1 472 mg·kg^-1, and 3 244 mg·kg^-1, respectively. The EC₅₀ values for C. elegans reproduction were 574, 836 mg·kg^-1, and 1 470 mg·kg^-1, respectively. The results showed that reproduction was a more sensitive evaluation endpoint than growth or fertility. The results of the correlation analysis showed that cation exchange capacity, organic matter, and amorphous iron oxide were the main factors affecting Sb toxicity in soil. The differences in EC₅₀ values expressed as the concentrations of Na₂HPO₄-extracted Sb among the three soils decreased, indicating that the concentrations of Na₂HPO₄-extracted Sb could better explain the toxicity variations among different soils.