土壤中三价锑的老化对秀丽隐杆线虫毒性的影响

为明确老化过程对土壤外源三价锑〔Sb(Ⅲ)〕毒性的影响，结合土壤中Sb的化学分析和生物毒性测试，以模式生物秀丽隐杆线虫(Caenorhabditis elegans)为测试生物，研究经Sb(Ⅲ)处理后老化7和56 d的2种土壤(安徽黄棕壤和新疆灰漠土)中不同价态Sb浓度、可提取态Sb浓度以及对线虫生长、生育、繁殖毒性的变化. 结果表明:①经Sb(Ⅲ)处理后老化56 d的安徽黄棕壤和新疆灰漠土中Sb(Ⅴ)的占比均显著高于老化7 d的土壤，与安徽黄棕壤相比，新疆灰漠土中Sb(Ⅲ)能更快地转化为毒性较低的Sb(Ⅴ). ②相较经Sb(Ⅲ)处理后老化7 d的土壤，经56 d老化的安徽黄棕壤和新疆灰漠土中可提取态Sb浓度分别下降了9.3%~36.8%和3.3%~47.0%. ③经Sb(Ⅲ)处理后老化56 d的安徽黄棕壤和新疆灰漠土对线虫生长毒性的EC₅₀(50%效应浓度)值较老化7 d的土壤分别提升1.7和2.3倍，对线虫生育毒性的EC₅₀值分别提升1.1和2.4倍，对线虫繁殖毒性的EC₅₀值分别提升1.2和1.9倍. 研究显示，老化过程可降低土壤中可提取态Sb浓度和毒性较高的Sb(Ⅲ)占比，导致外源Sb(Ⅲ)对线虫毒性的减弱，pH、有机质含量以及铁锰铝氧化物含量对土壤中Sb(Ⅲ)氧化和Sb吸附过程的影响导致外源Sb(Ⅲ)老化效应以及对线虫毒性的差异. 

Effects of Trivalent Antimony Aging on Toxicity of Soil-Dwelling Caenorhabditis elegans

In order to determine the effect of aging process on the toxicity of exogenous Sb(Ⅲ) in soil, different valence Sb concentrations, extracted concentration of exogenous Sb(Ⅲ) and their effects on growth, fertility, and reproduction of model organism Caenorhabditis elegans after 7 and 56 d aging in Anhui yellow-brown soil and Xinjiang grey dessert soil were tested by chemical analysis and toxicity test of Sb. The proportion of Sb(Ⅴ) in Anhui yellow-brown soil and Xinjiang grey desert soil aged for 56 d were significantly higher than that aged for 7 d. The results show that: (1) Sb(Ⅲ) in Xinjiang grey desert soil was oxidized to Sb(Ⅴ) faster than that in Anhui yellow-brown soil. (2) Compared with 7 d of aging, the concentration of extracted Sb in Anhui yellow-brown soil and Xinjiang grey desert soil after 56 d of aging decreased by 9.3%-36.8% and 3.3%-47.0%, respectively. (3) The EC₅₀ (50% effect concentration) of exogenous Sb(Ⅲ) on the growth toxicity of C. elegans increased by 1.7 and 2.3 times, respectively; the EC₅₀ of exogenous Sb(Ⅲ) on the fertility toxicity of C. elegans increased by 1.1 and 2.4 times, respectively; and the EC₅₀ of exogenous Sb(Ⅲ) on the reproduction toxicity of C. elegans increased by 1.2 and 1.9 times, respectively. The aging process reduced the concentration of extracted Sb and the proportion of Sb(Ⅲ) with higher toxicity, resulting in the weakening of the toxicity of exogenous Sb(Ⅲ) to nematode. The effect of pH, organic matter content, and iron, manganese, and aluminum content on the oxidation of Sb(Ⅲ) and the adsorption of Sb led to the difference of aging effect and toxicity to nematode.