Laboratory of Aquatic Ecology & Evolutionary Biology, University of Leuven, Deberiotstraat 32, B-3000, Leuven, Belgium.
Environ Pollut. 2012 Apr;163:127-33. doi: 10.1016/j.envpol.2011.12.011. Epub 2012 Jan 11.
Next to imposing direct lethal effects, pollutants may also indirectly impose mortality by making prey organisms more vulnerable to predation. We report that four water boatmen species differed strongly in direct endosulfan-imposed mortality, and only the species that suffered highest mortality, Sigara iactans, also showed a reduction in escape swimming speed. While head AChE activity was inhibited in all four species, body ChE was only inhibited in S. iactans where it covaried with escape swimming speed, indicating a mechanistic link between body ChE and swimming speed. Our study underscores the need for risk assessment to consider sublethal pollutant effects, which may considerably affect survival rates under natural conditions, also when testing concentrations of a pesticide that cause direct mortality. Such sublethal effects may generate discrepancies between laboratory and field studies and should be considered when designing safety factors for toxicants where the risk assessment is solely based on LC50 values.
除了直接致命效应外，污染物还可能通过使猎物更容易被捕食而间接导致死亡。我们报告说，有四种水黾物种在直接施用硫丹方面表现出强烈的死亡率差异，只有死亡率最高的 Sigara iactans 物种也表现出逃避游泳速度的降低。虽然四种物种的头部 AChE 活性均受到抑制，但只有在 S.iactans 中，身体 ChE 受到抑制，且与逃避游泳速度相关，表明身体 ChE 与游泳速度之间存在机制联系。我们的研究强调了风险评估需要考虑亚致死污染物效应的必要性，这些效应可能会在自然条件下对存活率产生重大影响，即使在测试直接导致死亡率的农药浓度时也是如此。这种亚致死效应可能会在实验室和野外研究之间产生差异，并且在仅基于 LC50 值进行毒剂风险评估时，应该考虑这些效应。
