Wang Jing, Zhou Qixing, Zhang Qianru, Zhang Ying
Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
J Environ Sci (China). 2008;20(1):68-74. doi: 10.1016/s1001-0742(08)60010-8.
Using the concentration gradient and combined pollutant exposure method, the single and joint effects of petroleum hydrocarbons (PHCs) and cadmium (Cd) on polychaete Perinereis aibuhitensis Grube, an ecologically keystone species in estuarine and coastal environment, have been investigated. The results indicate that the toxicity of PHCs to P. aibuhitensis is stronger than that of Cd to the organism. There are positive correlations between the mortality of worms and the exposed concentration of single Cd or PHCs in solution. Similarly, the accumulation of Cd or PHCs in worms increased with increasing Cd- or PHC-exposed concentrations. All the correlation relationships can be described using unitary quadratic equations (Y or Z = aX2 + bX + c). It is calculated, on the basis of these expressions, that the median lethal dose (LC50) of P. aibuhitensis exposed to a single Cd or PHCs is 793.4-13567.3 and 28.0-119.9 microg/L, respectively. The exposed time has some stimulative effect on the two pollutants and on the mortality of the worms. Thus, even a low concentration of a single Cd or PHCs may have strong toxic effects on the worms when the exposed time becomes longer. The accumulation of Cd or PHCs in worms differs with an increase in exposure time at the given exposed concentration of a single Cd or PHCs. Noticeably, the accumulation of PHCs in worms decreases with an increase in exposure time at the given high concentration of PHCs in solution. The joint effect of PHCs and Cd on P. aibuhitensis is very complicated and changes with the exposed concentrations of the two pollutants. At the given concentration of PHCs, the joint toxicity of the two pollutants on the worms changes from synergism to antagonism with an increase in Cd concentration. The accumulation of Cd in the worms significantly decreases with the addition of PHCs to exposure solution.
采用浓度梯度和复合污染物暴露方法，研究了石油烃（PHCs）和镉（Cd）对多毛类双齿围沙蚕（Perinereis aibuhitensis Grube）的单一和联合效应，双齿围沙蚕是河口和海岸环境中的生态关键物种。结果表明，PHCs对双齿围沙蚕的毒性强于Cd对该生物的毒性。蠕虫死亡率与溶液中单一Cd或PHCs的暴露浓度之间存在正相关关系。同样，蠕虫体内Cd或PHCs的积累量随Cd或PHCs暴露浓度的增加而增加。所有相关关系都可以用一元二次方程（Y或Z = aX2 + bX + c）来描述。根据这些表达式计算得出，双齿围沙蚕暴露于单一Cd或PHCs时的半数致死剂量（LC50）分别为793.4 - 13567.3和28.0 - 119.9 μg/L。暴露时间对这两种污染物以及蠕虫的死亡率有一定的刺激作用。因此，当暴露时间延长时，即使是低浓度的单一Cd或PHCs也可能对蠕虫产生强烈的毒性作用。在单一Cd或PHCs给定的暴露浓度下，蠕虫体内Cd或PHCs 的积累量随暴露时间的增加而不同。值得注意的是，在溶液中给定的高浓度PHCs条件下，蠕虫体内PHCs的积累量随暴露时间的增加而减少。PHCs和Cd对双齿围沙蚕的联合效应非常复杂，并且随着两种污染物的暴露浓度而变化。在给定的PHCs浓度下，随着Cd浓度的增加这两种污染物对蠕虫的联合毒性从协同作用转变为拮抗作用。向暴露溶液中添加PHCs后，蠕虫体内Cd的积累量显著降低。
