Mohr S, Berghahn R, Feibicke M, Meinecke S, Ottenströer T, Schmiedling I, Schmiediche R, Schmidt R
Federal Environment Agency, Schichauweg 58, D-12307 Berlin, Germany.
Aquat Toxicol. 2007 May 1;82(2):73-84. doi: 10.1016/j.aquatox.2007.02.001. Epub 2007 Feb 11.
The chloroacetamide metazachlor is a commonly used pre-emergent herbicide to inhibit growth of plants especially in rape culture. It occurs in surface and ground water due to spray-drift or run-off in concentrations up to 100 microgL(-1). Direct and indirect effects of metazachlor on aquatic macrophytes were investigated at oligo- to mesotrophic nutrient levels employing eight stream and eight pond indoor mesocosms. Five systems of each type were dosed once with 5, 20, 80, 200 and 500 microgL(-1) metazachlor and three ponds and three streams served as controls. Pronounced direct negative effects on macrophyte biomass of Potamogeton natans, Myriophyllum verticillatum and filamentous green algae as well as associated changes in water chemistry were detected in the course of the summer 2003 in both pond and stream mesocosms. Filamentous green algae dominated by Cladophora glomerata were the most sensitive organisms in both pond and stream systems with EC(50) ranging from 3 (streams) to 9 (ponds) microgL(-1) metazachlor. In the contaminated pond mesocosms with high toxicant concentrations (200 and 500 microgL(-1)), a species shift from filamentous green algae to the yellow-green alga Vaucheria spec. was detected. The herbicide effects for the different macrophyte species were partly masked by interspecific competition. No recovery of macrophytes was observed at the highest metazachlor concentrations in both pond and stream mesocosms until the end of the study after 140 and 170 days. Based on the lowest EC(50) value of 4 microgL(-1) for total macrophyte biomass, it is argued that single exposure of aquatic macrophytes to metazachlor to nominal concentrations >5 microgL(-1) is likely to have pronounced long-term effects on aquatic biota and ecosystem function.
氯乙酰胺类除草剂异丙甲草胺是一种常用的芽前除草剂，用于抑制植物生长，尤其是在油菜种植中。由于喷雾漂移或径流，它会以高达100微克/升的浓度出现在地表水和地下水中。在贫营养至中营养水平下，利用八个溪流和八个池塘室内中宇宙研究了异丙甲草胺对水生大型植物的直接和间接影响。每种类型的五个系统分别用5、20、80、200和500微克/升的异丙甲草胺处理一次，三个池塘和三条溪流作为对照。2003年夏季期间，在池塘和溪流中宇宙中均检测到异丙甲草胺对苦草、轮叶黑藻和丝状绿藻的大型植物生物量有明显的直接负面影响，以及相关的水化学变化。以团集刚毛藻为主的丝状绿藻是池塘和溪流系统中最敏感的生物，异丙甲草胺的半数有效浓度（EC50）范围为3（溪流）至9（池塘）微克/升。在高毒浓度（200和500微克/升）的受污染池塘中宇宙中，检测到从丝状绿藻到黄绿藻丝状绿藻的物种转变。不同大型植物物种的除草剂效应部分被种间竞争所掩盖。在研究结束时（140天和170天后），在池塘和溪流中宇宙中，在最高异丙甲草胺浓度下均未观察到大型植物的恢复。基于总大型植物生物量的最低EC50值为4微克/升，有人认为水生大型植物单次接触异丙甲草胺的标称浓度>5微克/升可能会对水生生物群和生态系统功能产生明显的长期影响。
