Hoang Tham C, Brausch John M, Cichra Mary F, Phlips Edward J, Van Genderen Eric, Rand Gary M
Ecotoxicology & Risk Assessment Laboratory, Department of Earth & Environment, Southeast Environmental Research Center, Florida International University, N. Miami, Florida, USA.
School of Environmental Sustainability, Loyola University Chicago, Chicago, Illinois, USA.
Environ Toxicol Chem. 2021 Jul;40(7):2053-2072. doi: 10.1002/etc.5050. Epub 2021 May 25.
A long-term exposure outdoor microcosm study was conducted to evaluate the effects of zinc (Zn) on zooplankton, phytoplankton, and periphyton in a freshwater system. Five Zn treatment concentrations (nominal: 8, 20, 40, 80, and 160 μg/L Zn) and an untreated control with 3 replicates each were used. Various physical and chemical characteristics of the microcosms and biological assessment endpoints (e.g., total abundance, group abundance, species richness, chlorophyll a, etc.) were measured to determine the effects of Zn over time. In general, physical and chemical characteristics (e.g., total dissolved solids, total suspended solids, dissolved oxygen, pH, dissolved organic carbon) of water fluctuated over time, but they were not significantly different within treatments and controls during the study. Zinc significantly affected the population dynamics and community structure of plankton. The effects occurred 7 d after initial treatment exposures began and continued to the end of the treatment phase, especially at the high treatment concentrations. Total and group abundance, species richness, the Shannon index, and chlorophyll a concentrations for high Zn treatment concentrations were significantly lower than the controls during the treatment phase. The no-observed-effect, lowest-observed-effect, and median effect concentrations were generally lower than the literature-reported results from single-species toxicity tests for fish and invertebrates, suggesting that plankton are more sensitive to Zn than planktivores. Although primary producers play an important role in the ecosystem, they have not been consistently incorporated into numerical environmental quality criteria for freshwater organisms, at least in the United States. The results of the present study are useful for development of environmental quality guidelines for freshwater ecosystems and ecological risk assessment. Environ Toxicol Chem 2021;40:2053-2072. © 2021 SETAC.
进行了一项长期室外微观世界研究，以评估锌（Zn）对淡水系统中浮游动物、浮游植物和周丛生物的影响。使用了五个锌处理浓度（标称值：8、20、40、80和160μg/L Zn）以及一个未处理的对照组，每组有3个重复。测量了微观世界的各种物理和化学特性以及生物评估终点（如总丰度、类群丰度、物种丰富度、叶绿素a等），以确定锌随时间的影响。总体而言，水的物理和化学特性（如总溶解固体、总悬浮固体、溶解氧、pH值、溶解有机碳）随时间波动，但在研究期间，处理组和对照组内部没有显著差异。锌显著影响浮游生物的种群动态和群落结构。这些影响在初始处理暴露开始7天后出现，并持续到处理阶段结束，尤其是在高处理浓度下。在处理阶段，高锌处理浓度下的总丰度和类群丰度、物种丰富度、香农指数和叶绿素a浓度显著低于对照组。未观察到影响浓度、最低观察到影响浓度和半数效应浓度通常低于文献报道的鱼类和无脊椎动物单物种毒性试验结果，这表明浮游生物比食浮游生物的动物对锌更敏感。尽管初级生产者在生态系统中起着重要作用，但至少在美国，它们尚未被一致纳入淡水生物的数值环境质量标准中。本研究结果有助于制定淡水生态系统的环境质量指南和生态风险评估。《环境毒理学与化学》2021年；40:2053 - 2072。© 2021 SETAC。
