本研究通过添加SuwanneeRiver天然有机物以及在测试前对原料和测试悬浮液进行老化,研究了工程纳米粒子(ENPs)的悬浮稳定性和生态毒性的变化。银(Ag)的急性毒性试验,氧化锌(ZnO),和二氧化钛(TiO2)ENPs与大型水蚤是按照经济合作与发展组织的测试指南进行的。发现大型水蚤对AgENPs非常敏感(48小时50%有效浓度33μgL(-1)),并且测试悬浮液在M7培养基中的老化(长达48小时)并未显着降低毒性。相反,Suwannee河天然有机物(NOM;20mgL(-1))的存在在所有测试方案中都完全减轻了AgENP的毒性,并且无助于稳定悬浮液。相比之下,添加SuwanneeRiverNOM稳定了ZnOENP悬浮液,并且没有降低毒性。在存在和不存在SuwanneeRiverNOM的情况下,老化48小时会产生单调的浓度-响应曲线。在任何测试条件下,浓度高达100mgL(-1)的TiO2ENPs均未导致D.magna固定。Suwannee河NOM的存在导致了种群悬浮液的聚集。作者的结果表明,SuwanneeRiverNOM的老化和存在是ENPs标准毒性测试的重要参数,在某些情况下,这可能有助于更好地控制暴露条件,但在其他情况下,可能有助于聚集或消除ENP毒性。因此,对当前ENPs测试指南的修改应根据具体情况进行评估.环境毒物化学2015;34:497-506。©2014SETAC。
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.