Université de Lorraine, CNRS, LIEC, F-57000 Metz, France.
Université de Lorraine, CNRS, LIEC, F-57000 Metz, France; Laboratoire de Bio-surveillance de l'Environnement (LBE), Université de Carthage, Faculté des Sciences de Bizerte, 7021 Zarzouna, Bizerte, Tunisia.
Sci Total Environ. 2020 Apr 20;714:136567. doi: 10.1016/j.scitotenv.2020.136567. Epub 2020 Jan 11.
The aim of the study was to investigate the influence of microplastics (MPs) on the ecotoxicity of common contaminants of aquatic ecosystems. As a model contaminant, the hydrophobic pesticide deltamethrin (DM) was chosen, and its effects on life history traits of Daphnia magna were studied in the presence or absence of polyethylene MPs. Commercialized DM and MPs obtained as dry powder were used in the experiment. According the manufacturer (Cospheric, Santa Barbara, CA, USA) MPs were spherical (1-4 μm in diameter), had a density of 0.96 g/cm and were without any solvent. Three concentrations of polyethylene MPs were tested (0, 1, 10 mg/L) with two realistic concentrations of DM (0 and 40 ng/L) and a solvent control (acetone). During the 21 d experiment, D. magna neonates were individually exposed to the treatments, and the effects of MPs and DM alone and together were evaluated by assessing survival, number of cumulative molts, days to first brood, number of broods, number of neonates per surviving adult, and body length. Significant detrimental effects on survival were only observed for the two mixture treatments. DM alone (40 ng/L) delayed the days to first brood and reduced the number of neonates per surviving adult, whereas MPs alone (10 mg/L) induced significant reduction in the number of juveniles by surviving adults. The combined exposure to DM and MPs clearly had a synergistic effect on survival, brood number, and number of neonates per surviving female. For example, compared to exposure to 40 ng/L of DM alone, the addition of 1 mg/L of MPs resulted in a 51.1% reduction in number of neonates per surviving female and a 46% reduction in brood number. These results suggest the potential drastic effects of this kind of mixed exposure on daphnid populations, which are key components of freshwater food webs.
本研究旨在探讨微塑料（MPs）对水生生态系统常见污染物的生态毒性的影响。选择疏水性农药氯菊酯（DM）作为模式污染物，研究了在存在或不存在聚乙烯 MPs 的情况下，DM 对大型溞（Daphnia magna）生活史特征的影响。实验中使用了商业化的 DM 和作为干粉获得的 MPs。根据制造商（美国加利福尼亚州圣巴巴拉市 Cospheric）的说法，MPs 呈球形（直径为 1-4μm），密度为 0.96g/cm³，且不含任何溶剂。实验测试了 3 种浓度的聚乙烯 MPs（0、1、10mg/L），以及 2 种实际浓度的 DM（0 和 40ng/L）和溶剂对照（丙酮）。在 21d 的实验过程中，将大型溞的幼体单独暴露于处理组中，并通过评估存活率、累计蜕皮次数、首次产卵天数、产卵次数、每只存活成年个体的幼体数量和体长来评估 MPs 和 DM 单独及共同作用的影响。仅在两种混合物处理中观察到对存活率的显著不利影响。单独的 DM（40ng/L）延迟了首次产卵的时间，并减少了每只存活成年个体的幼体数量，而单独的 MPs（10mg/L）则导致通过存活的成年个体产生的幼体数量显著减少。DM 和 MPs 的联合暴露对存活率、产卵次数和每只存活雌性个体的幼体数量显然具有协同作用。例如，与单独暴露于 40ng/L 的 DM 相比，添加 1mg/L 的 MPs 导致每只存活雌性个体的幼体数量减少 51.1%，产卵次数减少 46%。这些结果表明，这种混合暴露对水蚤种群（淡水食物网的关键组成部分）可能产生严重影响。
