Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX 79416, USA.
Arch Environ Contam Toxicol. 2011 Aug;61(2):272-9. doi: 10.1007/s00244-010-9617-z. Epub 2010 Nov 11.
Daphnia magna were exposed under semistatic conditions (i.e., conditions taking natural degradation into account) to a pesticide mixture consisting of a pyrethroid insecticide (cyfluthrin) and a pre-emergent herbicide (diuron) as well as pesticides individually using a full life cycle exposure (21 days). Subsequently, offspring from the second reproductive brood were used to continue exposure for a second generation. Survival, time to first brood, total number of offspring produced, number of broods produced, growth rate, and population growth rate were recorded for each generation and concentration. Significant differences existed between F0 and F1 D. magna for survival, in which F1 were less sensitive to pesticide mixtures than F0. In addition, F1 D. magna were significantly smaller than F0, which resulted in longer time to first brood. There were no differences in any end point examined between D. magna exposed to the pesticide mixture and diuron alone, although differences existed in survival, total number of offspring, total number of broods, and population growth rate when F0 D. magna were exposed to cyfluthrin alone. This study illustrates the utility of a two-generation study design that may more fully reflect, and more accurately predict, population level effects of pesticide exposures to short-lived aquatic organisms.
大型溞在半静态条件下（即考虑自然降解的条件）暴露于由拟除虫菊酯杀虫剂（氯氟氰菊酯）和芽前除草剂（敌草隆）组成的农药混合物以及单独使用农药的情况下进行了全生命周期暴露（21 天）。随后，第二代繁殖后代被用于继续进行第二代暴露。每一代和每个浓度都记录了存活率、首次产卵时间、产生的后代总数、产卵次数、增长率和种群增长率。F0 和 F1 大型溞在存活率方面存在显著差异，其中 F1 对农药混合物的敏感性低于 F0。此外，F1 大型溞明显小于 F0，这导致首次产卵时间延长。暴露于农药混合物和单独敌草隆的大型溞在任何检查终点均无差异，尽管单独暴露于氯氟氰菊酯的 F0 大型溞的存活率、总后代数、总产卵次数和种群增长率存在差异。本研究说明了两代研究设计的实用性，该设计可能更充分地反映和更准确地预测短期水生生物暴露于农药的种群水平效应。
