Nanosized Titanium Dioxide Reduces Copper Toxicity - The Role of Organic Material and the Crystalline Phase

作者：Rosenfeldt Ricki R^*; Seitz Frank; Senn Lilli; Schilde Carsten; Schulz Ralf; Bundschuh Mirco

来源：Environmental Science & Technology, 2015, 49(3): 1815-1822.

DOI：10.1021/es506243d

Titanium dioxide nanoparticles (nTiO(2)) are expected to interact with natural substances and other chemicals in the environment, however little is known about their combined effects. Therefore, this study assessed the toxicity of copper (Cu) in combination with varying crystalline phases (anatase, rutile, and the mixture) of nTiO(2) and differing organic materials on Daphnia magna. The nanoparticles reduced the Cu-toxicity depending on the product (0.3- to 2-fold higher 48-h EC50). This decrease in toxicity coincided with a lowered Cu-concentration in the water column, which was driven by the adsorption of Cu to nTiO(2)-depending on available surface area and structureand their subsequent sedimentation. In the presence of organic material and nTiO(2), the Cu-toxicity was further reduced (up to 7-fold higher 48-h EC50). This observation can be explained by a reduced Cu-bioavailability as a result of complexation and adsorption by the organic material and nTiO(2), respectively. Thus, the crystalline phase composition, which is determining the surface area and structure of nTiO(2), seems to be of major importance for the toxicity reduction of heavy metals, while the influence of the organic materials was mainly driven by the quantity and quality of humic substances.

• 出版日期2015-2-3