CESAM and Department of Biology, University of Aveiro, Campus Universitário de Santiago 3810-193, Aveiro, Portugal.
Sci Total Environ. 2011 Aug 15;409(18):3370-4. doi: 10.1016/j.scitotenv.2011.04.033. Epub 2011 Jun 8.
Effect assessment is usually based on responses obtained from standard tests, in which organisms are well fed and in an optimal population density. For a more thorough assessment of ecotoxicological risk, information is needed for chemical effects in systems that closer reflect the potential exposure in the field systems. Responses measured in standard density experiments do not fully reflect the field scenario, where populations' size fluctuate with environmental conditions, leading to very low organism number in certain season/conditions and high number in others. In the present study, the possible interaction between density and Cu-pollution was investigated in regard to population growth, using Enchytraeus crypticus, and for individual juvenile growth, using Eisenia fetida. The standardized ISO and OECD guidelines for enchytraeids and earthworms were adapted to test four densities and four Cu concentrations. The final population number was used to assess the effects and possible interaction between densities and Cu toxicity for population responses and the increase in individual organism wet weight was used as growth response. The study showed that although initial density itself had tremendous impact on population and individual growth, organisms under different densities had the same sensitivity to Cu.
效果评估通常基于从标准测试中获得的响应，其中生物体得到充分的喂养并处于最佳种群密度下。为了更全面地评估生态毒理学风险，需要了解更接近实际暴露于野外系统的化学效应的信息。在标准密度实验中测量的反应不能完全反映野外情况，在野外情况下，种群数量随环境条件而波动，导致某些季节/条件下的生物体数量非常低，而其他条件下的数量则很高。在本研究中，使用了食颤蚓（Enchytraeus crypticus）研究了密度和铜污染之间的可能相互作用对种群生长的影响，以及使用赤子爱胜蚓（Eisenia fetida）研究了个体幼体生长的影响。对国际标准化组织（ISO）和经济合作与发展组织（OECD）针对食颤蚓和蚯蚓的指南进行了改编，以测试四种密度和四种铜浓度。最终种群数量用于评估种群反应中密度和铜毒性之间的相互作用及其可能的影响，而个体生物体湿重的增加则用作生长反应。研究表明，尽管初始密度本身对种群和个体生长有巨大影响，但不同密度下的生物体对铜的敏感性相同。
