不同类型土壤中外源镍对赤子爱胜蚓的急性毒性

摘要

按照国际标准化组织(ISO)颁布的蚯蚓毒性试验方法,研究了镍离子在我国13种典型土壤中对赤子爱胜蚓(Eisenia fetida)的急性毒性,发现镍离子在不同类型土壤中对蚯蚓的半数致死浓度(LC50)变化范围为243.8-1970.6 mg·kg-1,镍离子在不同土壤中的毒性大小顺序为:湖南红壤＞重庆紫壤＞江西红壤＞河南潮土＞吉林黑土＞浙江水稻土＞新疆灰漠土＞北京潮土＞陕西黄土＞山东潮土＞河北潮土＞江苏水稻土＞黑龙江黑土,其中镍离子在湖南红壤和黑龙江黑土中的LC50值差异可达8倍以上.将土壤的主要理化性质(pH、有机质含量、阳离子交换量和黏土含量)与镍离子对蚯蚓的LC50值进行逐步多元回归分析,发现土壤pH值和有机质含量与LC50呈显著正相关关系,两种因子共同控制了LC50预测回归模型变异的79.4%.研究结果可为制订基于我国土壤类型的生态筛选值提供基础参考数据.%Acute toxicity of nickel to earthworm Eiseniafetida in 13 spiked soils was investigated using the methods of International Standardization Organization (ISO). The results show that nickel toxicity to E. feiida differs in different soils, and 50％ lethal concentrations (14 LC50) varies fiom 2438 to 1970.6 mg kg-1. Nickel toxicity to E. fetida in a range of Chinese soils can be ranked as red soil (Hunan) ＞ purple soil (Chongqing) ＞ red earth (Jiangxi) ＞ fluvo-aquic soil (Henan) ＞ black soil (Jilin) ＞ paddy soil (Zhejiang) ＞ grey desert soil (Xinjiang) ＞ fluvo-aquic soil (Beijing) ＞ loessal soil (Shaanxi) ＞ fluvo-aquic soil (Shandong) ＞ fluvo-aquic soil (Htebei) ＞ paddy soil (Jiangsu) ＞ black soil (Heilongjiang). An eight-fold difference of nickel LC50 exists between red soil (Hunan) and black soil (Heilongjiang). Stepwise multiple regressions are carried out to determine the relative contributions of some soil properties (pH, organic matter capacity, cation exchange content and clay content) to nickel LC50. Significant positive correlations were observed between soil pH, organic matter content and nickel LC50. Soil pH and organic matter content can account for 79.4％ variance for nickel LC50. The ecotoxicity data generated in the current study may provide useful reference information for the development of ecological soft screening values in China.