锑对土壤跳虫(Folsomia candida)的毒性效应

Toxicity Effect of Antimony to Soil-Dwelling Springtail (Folsomia candida)

为了解Sb(锑)对土壤无脊椎动物的毒性效应及对比不同类型土壤中Sb毒性的差异,选取死亡率、逃避率、繁殖数三组个体水平的评价指标研究了3种典型土壤(海伦黑土、祁阳红壤、北京潮土)中外源添加Sb对模式生物——跳虫(Folsomia candida)的急性毒性和慢性毒性效应.结果表明,基于实测w(Sb_总)求得的上述3种土壤中Sb影响跳虫逃避的2 d-EC_(50)(EC_(50)为半数效应浓度)分别为298、>431[高于土壤中最高w(Sb_总)]和132 mg/kg;影响跳虫死亡的7 d-LC_(50)(LC_(50)为半数致死浓度)分别为3 352、4 007、2 105 mg/kg;影响跳虫死亡的28 d-LC_(50)分别为2 271、1 865、703 mg/kg,影响跳虫繁殖的28 d-EC_(50)分别为1 799、1 323、307 mg/kg.由上述毒性阈值大小可知,跳虫逃避率的敏感性高于死亡率和繁殖数的敏感性,不同土壤中Sb对跳虫的毒性大小具有显著差异,北京潮土中Sb对跳虫的毒性与海伦黑土、祁阳红壤相比最大差别接近6倍,表明不同土壤理化性质对Sb生态毒性效应具有显著影响.但基于w(Sb_(水提))求得的上述3种土壤中Sb的毒性阈值差异减小,说明水提态Sb与其毒性具有显著相关性,可以较好地解释不同土壤间Sb毒性的差异.该研究结果可为建立我国土壤中Sb的毒性预测模型及制订Sb的质量标准值提供依据.

Despite growing concern about the potential adverse effects of elevated antimony concentrations in soil,hardly any toxicity data are available for terrestrial invertebrates. To explore the toxicity of antimony to soil invertebrates and compare toxicity differences among different types of soil,the acute and chronic toxicity of antimony to Folsomia candida were assessed in three typical soils( i. e.,Hailun isohumosol,Qiyang ferrosol and Beijing primosol) using mortality,avoidance and reproduction as evaluation endpoints. The 2-day EC_(50)( i. e.,concentration causing 50% toxic effect) values expressed in measured total antimony concentrations for the avoidance of F.candida were 298, > 400( i. e.,avoidance rate did not reach 50% at the highest concentration) and 132 mg/kg,respectively. The 7-day LC_(50)( i. e.,median lethal concentration) values for the mortality of F. candida were 3352,4007 and 2105 mg/kg,respectively. The 28-day LC_(50) values for the mortality of F. candida were 2271,1865 and 703 mg/kg,respectively. The 28-day EC_(50) values for the reproduction of F. candida were 1799,1323 and 307 mg/kg,respectively. The results showed that avoidance was a more sensitive endpoint than reproduction and mortality,and the toxic effect of antimony on F. candida significantly varied with soil types. The toxicity of antimony in Beijing primosol was maximally nearly six times higher than that of in Hailunisohumosol and Qiyang ferrosol,indicating the distinct impact of soil physicochemical properties on the toxic effect of antimony. But the differences of LC_(50) or EC_(50)values expressed in water-extracted antimony concentrations among the three soils decreased,indicating that the water-extracted antimony consisted with the toxicity of antimony obviously and could explain the toxicity variations among the three soils.The study can provide the basis for establishing a prediction model of antimony toxicity as well as formulating the quality standard value of antimony in soil.