The potential of TiO₂ nanoparticles as carriers for cadmium uptake in Lumbriculus variegatus and Daphnia magna

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• 作者：Nanna B. Hartmann^a ; ^{Nanna.Hartmann@ec.europa.eu} ; ^{nannahartmann@gmail.com} ; Samuel Legros^b ; Frank Von der Kammer^b ; Thilo Hofmann^b ; Anders Baun^a
• 关键词：Facilitated transport ; Bioaccumulation ; Cadmium ; Titanium dioxide ; Nanomaterials
• 刊名：Aquatic Toxicology
• 出版年：2012
• 期刊代码：19_0166445x
• 类别：abs
• 出版时间：15 August, 2012
• 卷：118-119
• 期：Complete
• 页码：1-8
• 文件大小：748 K

摘要

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 (TiO₂) 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 TiO₂ nanoparticles. Formation of larger nanoparticles aggregates/agglomerates was observed and sizes varied depending on media composition (358 卤 13 nm in US EPA moderately hard synthetic freshwater and 1218 卤 7 nm in Elendt M7). TiO₂ 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 TiO₂ particles, respectively. 渭XRF (micro X-ray fluorescence) analysis confirmed the uptake of TiO₂ in the gut of D. magna. For L. variegatus 渭XRF analysis indicated attachment of TiO₂ 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 TiO₂ nanoparticles, showing that cadmium adsorption to TiO₂ nanoparticles did not affect overall bioavailability. Despite facilitated uptake of cadmium by TiO₂ nanoparticles in D. magna, resulting in increased total cadmium body burden, no change in toxicity was observed.