两种典型持久性有机污染物对草履虫急性毒性初探

摘要

Dichlorodiphenyltrichloroethane (DDT) and Benzo[a]pyrene (BaP) are ubiquitous contaminants in the environment. Acute toxic effects of DDT and BaP on a model unicellular eukaryotic organism Paramecium caudatum were studied and a dose-dependent increase in toxicities was observed. The median lethal concentration (LC50) of DDT in 1h is 126.012 mg·L- 1 and that of BaP is 180.167 mg·L- 1. There exists a good linear relationship between probit and logarithm of concentrations of contaminants. Exposed to DDT and BaP at different concentrations, Paramecia caudatum exhibited some shapes. Comparably, DDT is more toxic to Paramecium caudatum than that of BaP. Sensitive to both DDT and BaP suggests that Paramecium caudatum can be used as a sensitive indicator for early risk assessment of longterm hazards of POPs. These results provide a novel approach for developing a strategy for the abatement of water pollution and maintenance of ecosystem viability. Finally, the toxicity mechanism of two typical POPs in Paramecium caudatum is discussed.%滴滴涕和苯并芘这两种典型持久性有机污染物在环境中已广泛分布,因此,本研究利用单细胞真核模式生物-草履虫来研究其急性毒性效应,结果发现其毒性效应存在显著的剂量效应关系.DDT和BaP的半数致死浓度分别为126.012 mg·L-1和180.167 mg·L-1,且这两种污染物的浓度和概率间存在很好的线性关系.不同浓度的DDT和BaP对草履虫进行毒性作用时,草履虫呈现出不同的形态;比较而言,DDT的毒性作用更大.由于草履虫对这两种毒性物质作用的敏感性,因此,草履虫可作为一种敏感指示生物来评估POPs的长期危害.本研究为水污染的减排和生境的保护提供了一种新途径.最后,就这两种典型POPs对草履虫的毒性机理进行了讨论.