【摘要】 为了解DOM与AgNPs的相互作用及其对AgNPs毒性的影响,本文以菲律宾蛤仔为受试生物、以水环境广泛存在腐殖酸（Humic acid, HA）为代表性有机质。通过贝类体内抗氧化系统的生物标志物（过氧化氢酶（Catalase, CAT）、超氧化物歧化酶（Superoxide dismutase, SOD）、金属硫蛋白（Metallothionein, MT）和丙二醛（Malondialdehyde, MDA））的响应,研究了HA对AgNPs生物效应的影响。结果表明,HA显著增加了AgNPs的稳定性,抑制了AgNPs的聚集。AgNPs(20μg·L^-1)暴露3 d后,蛤仔鳃组织中Ag的蓄积显著上升,并随着时间的延长不断升高。AgNPs暴露第3、7天,不同浓度的HA条件下,鳃组织中Ag的蓄积无显著差异,但显著地低于无HA存在的AgNPs暴露组。CAT活性和MDA含量仅在无HA存在的AgNPs暴露组出现显著升高,其余各组之间无显著差异。表征DNA损伤程度的Olive尾矩（OTM）和尾长（TL）在无HA存在的AgNPs暴露组中随时间的延长不断上升。HA显著降低了AgNPs的对鳃组织细胞的遗传毒性。结果表明,HA通过增加AgNPs在介质中的稳定性而显著地抑制了鳃组织对Ag的蓄积,从而减弱了AgNPs对鳃组织的氧化胁迫和遗传毒性。结果证明了有机质含量等环境理化条件对纳米毒性存在显著影响。更多还原

【Abstract】 Dissolved organic matter（DOM） can significantly affect the dissolution and aggregation behavior and thus the bioavailability/toxicity of silver nanoparticles（AgNPs）. To understand the interaction between DOM and AgNPs and its influence on the toxicity of AgNPs, this study took the Ruditapes philippinarum as the test organism and humic acid（HA） as the representative DOM. And the influence of HA on the biological effects of AgNPs was studied by using the response of antioxidant system biomarkers(Catalase（CAT）, Superoxide dismutase（SOD）, Metallothionein（MT）, and Malondialdehyde（MDA） in clams. The results showed that HA significantly increased the stability of AgNPs and inhibited the aggregation of AgNPs. The accumulation of Ag in the gill increased obviously after 3 days of exposure to AgNPs(20 μg·L^-1) treatments without HA presence and rose over time. On the 3 rd and 7 th day of exposure to AgNPs treatments without HA presence, there was no significant difference in the accumulation of Ag in gill under different concentrations of HA, but it was significantly lower than that in AgNPs treatments without HA presence. CAT activity and MDA content in gills only increased significantly in AgNPs treatments without HA presence, but there was no significant difference among other treatments. The olive tail moment（OTM） and tail length（TL）, which were used to characterize the degree of DNA damage, increased over time on AgNPs treatments without HA presence. And HA significantly reduced the genotoxicity of AgNPs to histocytes of gills. The results indicated that HA significantly inhibited the accumulation of Ag in the gill by increasing the stability of AgNPs in the medium, thus alleviating the oxidative stress and genotoxicity of AgNPs to gill. The results proved that environmental physical and chemical factors such as DOM had a significant impact on nanotoxicity.更多还原