Department of Environmental Engineering, Technical University of Denmark, Building 113, Kgs. Lyngby, Denmark.
Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
Aquat Toxicol. 2012 Aug 15;118-119:1-8. doi: 10.1016/j.aquatox.2012.03.008. Epub 2012 Mar 21.
The use of engineered nanoparticles (e.g. in industrial applications and consumer products) is increasing. Consequently, these particles will be released into the aquatic environment. Through aggregation/agglomeration and sedimentation, sediments are expected ultimately to be sinks for nanoparticles. Both in the water phase and in the sediments engineered nanoparticles will mix and interact with other environmental pollutants, including metals. In this study the toxicity of cadmium to two freshwater organisms, water column crustacean Daphnia magna and sediment oligochaete Lumbriculus variegatus, was investigated both in the absence and presence of titanium dioxide (TiO(2)) nanoparticles (P25 Evonic Degussa, d: 30 nm). The uptake of cadmium in sub-lethal concentrations was also studied in the absence and presence of 2 mg/L TiO(2) nanoparticles. Formation of larger nanoparticles aggregates/agglomerates was observed and sizes varied depending on media composition (358±13 nm in US EPA moderately hard synthetic freshwater and 1218±7 nm in Elendt M7). TiO(2) nanoparticles are potential carriers for cadmium and it was found that 25% and 6% of the total cadmium mass in the test system for L. variegatus and D. magna tests were associated to suspended TiO(2) particles, respectively. μXRF (micro X-ray fluorescence) analysis confirmed the uptake of TiO(2) in the gut of D. magna. For L. variegatus μXRF analysis indicated attachment of TiO(2) nanoparticles to the organism surface as well as a discrete distribution within the organisms. Though exact localisation in this organism was more difficult to assess, the uptake seems to be within the coelomic cavity. Results show that the overall body burden and toxicity of cadmium to L. variegatus was unchanged by addition of TiO(2) nanoparticles, showing that cadmium adsorption to TiO(2) nanoparticles did not affect overall bioavailability. Despite facilitated uptake of cadmium by TiO(2) nanoparticles in D. magna, resulting in increased total cadmium body burden, no change in toxicity was observed.
工程纳米粒子（例如，在工业应用和消费产品中）的使用正在增加。因此，这些粒子将被释放到水生环境中。通过聚集/团聚和沉降，沉积物预计最终将成为纳米粒子的汇。在水相和沉积物中，工程纳米粒子将与其他环境污染物（包括金属）混合并相互作用。在这项研究中，研究了在没有和存在二氧化钛（TiO(2)）纳米粒子（P25 Evonic Degussa，d：30nm）的情况下，两种淡水生物，水柱甲壳类动物大型溞（Daphnia magna）和底栖寡毛类蚯蚓（Lumbriculus variegatus）对镉的毒性。还研究了在没有和存在 2mg/L TiO(2)纳米粒子的情况下，亚致死浓度下镉的摄取情况。观察到较大的纳米粒子聚集/团聚的形成，并且尺寸取决于介质组成（在美国环保署中等硬度合成淡水中为 358±13nm，在 Elendt M7 中为 1218±7nm）。TiO(2)纳米粒子是镉的潜在载体，研究发现，在 L. variegatus 和 D. magna 试验的测试系统中，总镉质量的 25%和 6%分别与悬浮的 TiO(2)颗粒相关。μXRF（微 X 射线荧光）分析证实了 D. magna 肠道中 TiO(2)的摄取。对于 L. variegatus，μXRF 分析表明 TiO(2)纳米粒子附着在生物体表面以及在生物体内部的离散分布。尽管在这种生物体中更难确定其确切的定位，但摄取似乎在体腔中。结果表明，添加 TiO(2)纳米粒子不会改变镉对 L. variegatus 的整体体负荷和毒性，表明镉吸附到 TiO(2)纳米粒子不会影响其总体生物利用度。尽管 TiO(2)纳米粒子促进了 D. magna 对镉的摄取，导致总镉体负荷增加，但未观察到毒性变化。
