Cupi Denisa, Hartmann Nanna B, Baun Anders
Department of Environmental Engineering, Technical University of Denmark, Lyngby, Denmark.
Environ Toxicol Chem. 2015 Mar;34(3):497-506. doi: 10.1002/etc.2855. Epub 2015 Feb 10.
The present study investigated changes in suspension stability and ecotoxicity of engineered nanoparticles (ENPs) by addition of Suwannee River natural organic matter and aging of stock and test suspensions prior to testing. Acute toxicity tests of silver (Ag), zinc oxide (ZnO), and titanium dioxide (TiO2 ) ENPs with Daphnia magna were carried out following Organisation for Economic Co-operation and Development test guidelines. Daphnia magna was found to be very sensitive to Ag ENPs (48-h 50% effective concentration 33 μg L(-1) ), and aging of the test suspensions in M7 medium (up to 48 h) did not decrease toxicity significantly. Conversely, the presence of Suwannee River natural organic matter (NOM; 20 mg L(-1) ) completely alleviated Ag ENP toxicity in all testing scenarios and did not aid in stabilizing suspensions. In contrast, addition of Suwannee River NOM stabilized ZnO ENP suspensions and did not decrease toxicity. Aging for 48 h generated monotonous concentration-response curves in the presence and absence of Suwannee River NOM. At concentrations up to 100 mg L(-1) TiO2 ENPs did not cause immobilization of D. magna under any of the tested conditions. Presence of Suwannee River NOM caused agglomeration in stock suspensions. The authors' results suggest that aging and presence of Suwannee River NOM are important parameters in standard toxicity testing of ENPs, which in some cases may aid in gaining better control over the exposure conditions but in other cases might contribute to agglomeration or elimination of ENP toxicity. Therefore, modifications to the current guidelines for testing ENPs should be evaluated on a case-by-case basis. Environ Toxicol Chem 2015;34:497-506. © 2014 SETAC.
本研究通过添加苏万尼河天然有机物以及在测试前对储备液和测试悬浮液进行老化处理，研究了工程纳米颗粒（ENPs）的悬浮稳定性和生态毒性变化。按照经济合作与发展组织的测试指南，对银（Ag）、氧化锌（ZnO）和二氧化钛（TiO₂）ENPs进行了大型溞急性毒性试验。结果发现大型溞对Ag ENPs非常敏感（48小时半数有效浓度为33μg L⁻¹），在M7培养基中测试悬浮液老化（长达48小时）并未显著降低毒性。相反，在所有测试场景中，苏万尼河天然有机物（NOM；20mg L⁻¹）的存在完全缓解了Ag ENP的毒性，且无助于稳定悬浮液。相比之下，添加苏万尼河NOM可稳定ZnO ENP悬浮液且不会降低毒性。在有和没有苏万尼河NOM的情况下，老化48小时产生了单调的浓度-反应曲线。在高达100mg L⁻¹的浓度下，TiO₂ ENPs在任何测试条件下均未导致大型溞固定不动。苏万尼河NOM的存在导致储备悬浮液中出现团聚。作者的结果表明，老化和苏万尼河NOM的存在是ENPs标准毒性测试中的重要参数，在某些情况下可能有助于更好地控制暴露条件，但在其他情况下可能导致ENP团聚或毒性消除。因此，应逐案评估对当前ENPs测试指南的修改。《环境毒理学与化学》2015年；34：497 - 506。©2014 SETAC。
