Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, the Netherlands; Department of Aquatic Ecology and Water Quality Management, Wageningen University, P.O. Box 47, 6700 AA Wageningen, the Netherlands.
Thailand Institute of Scientific and Technological Research 35 Moo 3, Tambon Klong five, Klong Laung, PathumThani 12120, Thailand; Department of Animal and Plant Sciences, The University of Sheffield, Sheffield S10 2TN, UK.
Sci Total Environ. 2014 Aug 15;490:1002-11. doi: 10.1016/j.scitotenv.2014.05.073. Epub 2014 Jun 7.
Aquatic ecological risk assessment of fungicides in Europe under Regulation 1107/2009/EC does not currently assess risk to non-target bacteria and fungi. Rather, regulatory acceptable concentrations based on ecotoxicological data obtained from studies with fish, invertebrates and primary producers (including algae) are assumed to be protective to all other aquatic organisms. Here we explore the validity of this assumption by investigating the effects of a fungicide (tebuconazole) applied at its "non-microbial" HC5 concentration (the concentration that is hazardous to 5% of the tested taxa) and derived from acute single species toxicity tests on fish, invertebrates and primary producers (including algae) on the community structure and functioning of heterotrophic microbes (bacteria and aquatic fungi) in a semi-field study, using novel molecular techniques. In our study, a treatment-related effect of tebuconazole (238 μg/L) on either fungal biomass associated with leaf material or leaf decomposition or the composition of the fungal community associated with sediment could not be demonstrated. Moreover, treatment-related effects on bacterial communities associated with sediment and leaf material were not detected. However, tebuconazole exposure did significantly reduce conidia production and altered fungal community composition associated with leaf material. An effect on a higher trophic level was observed when Gammarus pulex were fed tebuconazole-exposed leaves, which caused a significant decrease in their feeding rate. Therefore, tebuconazole may affect aquatic fungi and fungally mediated processes even when applied at its "non-microbial" HC5 concentration.
欧洲 1107/2009/EC 法规下的杀菌剂水生生态风险评估目前并未评估其对非靶标细菌和真菌的风险。相反，基于鱼类、无脊椎动物和初级生产者（包括藻类）的生态毒理学数据得出的监管可接受浓度被假定对所有其他水生生物都具有保护作用。在这里，我们通过调查在半野外研究中，以其“非微生物” HC5 浓度（对 5%测试分类群具有危害性的浓度）应用一种杀菌剂（戊唑醇），以及源自鱼类、无脊椎动物和初级生产者（包括藻类）的急性单物种毒性试验对异养微生物（细菌和水生真菌）群落结构和功能的影响，来探讨这一假设的有效性，使用了新颖的分子技术。在我们的研究中，戊唑醇（238μg/L）对叶片物质相关真菌生物量或叶片分解或与沉积物相关的真菌群落组成没有表现出处理相关的影响。此外，也未检测到与沉积物和叶片物质相关的细菌群落的处理相关影响。然而，戊唑醇暴露确实显著减少了与叶片物质相关的分生孢子产生，并改变了真菌群落组成。当食蚊鱼被喂食戊唑醇暴露的叶片时，观察到了对更高营养级的影响，这导致它们的摄食率显著下降。因此，即使在应用其“非微生物” HC5 浓度时，戊唑醇也可能会影响水生真菌和真菌介导的过程。
