Ramskov Tina, Thit Amalie, Croteau Marie-Noële, Selck Henriette
Department of Environmental, Social and Spatial Change, Roskilde University, PO Box 260, Universitetsvej 1, DK-4000 Roskilde, Denmark; US Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States.
Department of Environmental, Social and Spatial Change, Roskilde University, PO Box 260, Universitetsvej 1, DK-4000 Roskilde, Denmark.
Aquat Toxicol. 2015 Jul;164:81-91. doi: 10.1016/j.aquatox.2015.04.022. Epub 2015 Apr 22.
Copper oxide (CuO) nanoparticles (NPs) are widely used, and likely released into the aquatic environment. Both aqueous (i.e., dissolved Cu) and particulate Cu can be taken up by organisms. However, how exposure routes influence the bioavailability and subsequent toxicity of Cu remains largely unknown. Here, we assess the importance of exposure routes (water and sediment) and Cu forms (aqueous and nanoparticulate) on Cu bioavailability and toxicity to the freshwater oligochaete, Lumbriculus variegatus, a head-down deposit-feeder. We characterize the bioaccumulation dynamics of Cu in L. variegatus across a range of exposure concentrations, covering both realistic and worst-case levels of Cu contamination in the environment. Both aqueous Cu (Cu-Aq; administered as Cu(NO3)2) and nanoparticulate Cu (CuO NPs), whether dispersed in artificial moderately hard freshwater or mixed into sediment, were weakly accumulated by L. variegatus. Once incorporated into tissues, Cu elimination was negligible, i.e., elimination rate constants were in general not different from zero for either exposure route or either Cu form. Toxicity was only observed after waterborne exposure to Cu-Aq at very high concentration (305μgL(-1)), where all worms died. There was no relationship between exposure route, Cu form or Cu exposure concentration on either worm survival or growth. Slow feeding rates and low Cu assimilation efficiency (approximately 30%) characterized the uptake of Cu from the sediment for both Cu forms. In nature, L. variegatus is potentially exposed to Cu via both water and sediment. However, sediment progressively becomes the predominant exposure route for Cu in L. variegatus as Cu partitioning to sediment increases.
氧化铜（CuO）纳米颗粒（NPs）被广泛使用，并可能释放到水生环境中。生物体可以吸收水溶态（即溶解态铜）和颗粒态铜。然而，暴露途径如何影响铜的生物有效性及后续毒性在很大程度上仍不清楚。在此，我们评估暴露途径（水和沉积物）以及铜的形态（水溶态和纳米颗粒态）对铜的生物有效性和对淡水寡毛类动物颤蚓（一种头向下的沉积物摄食者）毒性的重要性。我们描述了颤蚓在一系列暴露浓度下铜的生物累积动态，涵盖了环境中铜污染的实际水平和最坏情况水平。水溶态铜（Cu-Aq；以硝酸铜形式施用）和纳米颗粒态铜（CuO NPs），无论分散在人工中硬淡水中还是混入沉积物中，颤蚓对其的累积都很微弱。一旦进入组织，铜的消除可忽略不计，即对于任何一种暴露途径或任何一种铜形态，消除速率常数通常都与零无差异。仅在高浓度（305μg L⁻¹）的水溶态铜水暴露后观察到毒性，此时所有蠕虫死亡。暴露途径、铜形态或铜暴露浓度与蠕虫的存活或生长之间均无关联。两种铜形态从沉积物中摄取铜的特征均为摄食速率缓慢和铜同化效率低（约30%）。在自然界中，颤蚓可能通过水和沉积物两种途径接触铜。然而，随着铜在沉积物中的分配增加，沉积物逐渐成为颤蚓接触铜的主要暴露途径。
