Uwizeyimana Herman, Wang Meie, Chen Weiping
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, People's Republic of China.
Environ Sci Pollut Res Int. 2017 Feb;24(6):5349-5359. doi: 10.1007/s11356-016-8220-x. Epub 2016 Dec 24.
Environmental contaminants do not often occur as individual chemicals but rather in complex mixtures whose joint effects can create a strong toxicity to surrounding organisms. To determine the combined harmful effects of siduron (herbicide) and cadmium (heavy metal) toward Eisenia fetida earthworms, samples of worm's coelomocytes were subjected to siduron and cadmium (Cd) at sublethal concentrations (lower than LC)-siduron 0, 0.8, 2.4, and 7.2 μg cm Cd 0, 0.4, 0.8, and 1.6 μg cm in filter paper contact assay, both as individual compounds and combinations. The CI-isobologram model was utilized to reveal the types of toxicological interactions between siduron and cadmium in inducing DNA damage toward earthworms. The results indicated that tail DNA percentage (TDNA %) at individual siduron and cadmium concentrations (with the exception of the lowest concentration of Cd 0.04 μgcm ) were highly significant compared to those of the control (p < 0.01). Tail moments (TM) at individual Cd concentrations (0.8 and 1.6 μg cm ) were highly significant compared to those of the control (p < 0.05), while the increase of TM for individual siduron was only significant (p < 0.05) at 7.2 μg cm which is the highest dose/concentration of siduron used in this study. The combinations of siduron and Cd indicated a significant synergism (CI < 1) at the lower effect levels and a significant antagonism (CI > 1) at the higher effect levels. The synergistic effect for a particular combination of chemicals suggests that there might be a possible risk connected to the coincidence of these chemicals.
环境污染物通常并非以单一化学物质的形式存在，而是存在于复杂的混合物中，其联合效应可能会对周围生物产生强烈的毒性。为了确定西草净（除草剂）和镉（重金属）对赤子爱胜蚓的联合有害影响，在滤纸接触试验中，将蚯蚓体腔细胞样本分别置于亚致死浓度（低于半数致死浓度）的西草净和镉中——西草净浓度分别为0、0.8、2.4和7.2微克/厘米，镉浓度分别为0、0.4、0.8和1.6微克/厘米，二者均作为单一化合物及组合形式进行试验。采用共毒系数等值线图模型来揭示西草净和镉在诱导蚯蚓DNA损伤方面的毒理学相互作用类型。结果表明，除镉的最低浓度0.04微克/厘米外，单一西草净和镉浓度下的尾部DNA百分比（TDNA%）与对照组相比均具有高度显著性（p < 0.01）。单一镉浓度（0.8和1.6微克/厘米）下的尾矩（TM）与对照组相比具有高度显著性（p < 0.05），而单一西草净在7.2微克/厘米（本研究中使用的西草净最高剂量/浓度）时TM的增加才具有显著性（p < 0.05）。西草净和镉的组合在较低效应水平时显示出显著的协同作用（共毒系数<1），而在较高效应水平时则显示出显著的拮抗作用（共毒系数>1）。特定化学物质组合的协同效应表明，这些化学物质同时存在可能存在潜在风险。
