The effects of zinc on the structure and functioning of a freshwater community: A microcosm experiment

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• 作者：Dimitri Van de Perre ; Ivo Roessink ; Colin R. Janssen ; Erik Smolders ; Tina Van Regenmortel ; Jeroen Van Wichelen ; Wim Vyverman ; Paul J. Van den Brink and Karel A.C. De Schamphelaere
• 刊名：Environmental Toxicology and Chemistry
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：35
• 期：11
• 页码：2698-2712
• 全文大小：1363K
• ISSN：1552-8618

文摘

A major problem with risk assessment of chemicals is the extrapolation of laboratory single-species toxicity tests, which oversimplify the actual field situation by ignoring species interactions, to natural communities. The authors tested if the bioavailability-normalized 5% hazardous concentration (HC5) estimated from chronic planktonic single-species toxicity data (HC5_plankton) for zinc (Zn) is protective for a plankton community and investigated the direct and indirect effects of Zn (at HC5 and HC50) on a freshwater community's structure and function. Microcosms were exposed to 3 different Zn concentrations (background, HC5_plankton = 75 μg Zn/L and HC50_plankton = 300 μg Zn/L) for 5 wk. The planktonic groups revealed a consistent no-observed-effect concentration for the community of 75 μg Zn/L, similar to or higher than the HC5_plankton, thus suggesting its protectiveness in the present study. At 300 μg Zn/L a significant reduction in cladocerans resulted in increases of rotifer, ciliate, and phytoplankton abundance. In addition, the phytoplankton community shifted in dominance from grazing-resistant to edible species. Contrary to the species sensitivity distribution (SSD) prediction, which identified phytoplankton as the most sensitive group, only the total chlorophyll and the abundance of 2 phytoplankton species were adversely affected at 300 μg Zn/L. Thus, although the HC5 estimated from the bioavailability-normalized SSD was overall protective for the plankton community, the SSD was not able to correctly predict the species sensitivity ranking within their community context at the HC50. Environ Toxicol Chem 2016;35:2698–2712.