Engineered nanoparticles are increasingly discharged into the environment. After discharge, these nanoparticles can interact with co-existing organic contaminants, resulting in a phenomena referred to as ‘joint toxicity’. This study evaluated joint toxicities of TiO₂ nanoparticles (TiO₂NPs) with four different (atrazine, hexachlorobenzene, pentachlorobenzene, and 3,3′,4,4′-tetrachlorobiphenyl) organochlorine contaminants (OCs) toward algae (Chlorella pyrenoidosa). The potential mechanisms underlying the joint toxicity were discussed, including TiO₂NPs–OC interactions, effects of TiO₂NPs and OCs on biophysicochemical properties of algae and effects of TiO₂NPs and OCs on each other’s bioaccumulation in algae. The results indicate that coexposure led to a synergistic effect on the joint toxicity for TiO₂NPs–atrazine, antagonistic effect for TiO₂NPs–hexachlorobenzene and TiO₂NPs–3,3',4,4'-tetrachlorobiphenyl, and an additive effect for TiO₂NPs–pentachlorobenzene. There was nearly no adsorption of OCs by TiO₂NPs, and the physicochemical properties of TiO₂NPs were largely unaltered by the presence of OCs. However, both OCs and NPs affected the biophysicochemical properties of algal cells and thereby influenced the cell surface binding and/or internalization. TiO₂NPs significantly increased the bioaccumulation of each OC. However, with the exception of atrazine, the bioaccumulation of TiO₂NPs decreased when used with each OC. The distinct joint toxicity outcomes were a result of the balance between the increased toxicities of OCs (increased bioaccumulations) and the altered toxicity of TiO₂NPs (bioaccumulation can either increase or decrease). These results can significantly improve our understanding of the potential environmental risks associated with NPs.

中文翻译：

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TiO ₂纳米粒子与四种共存的有机氯污染物在藻类上的明显毒性相互作用

工程纳米颗粒越来越多地排放到环境中。放电后，这些纳米粒子可与共存的有机污染物相互作用，导致被称为“联合毒性”的现象。这项研究评估了TiO ₂纳米颗粒（TiO ₂ NPs）与四种不同的（阿特拉津，六氯苯，五氯苯和3,3'，4,4'-四氯联苯）有机氯污染物（OCs）对藻类（Chlorella pyrenoidosa）的联合毒性。讨论了共同毒性的潜在机制，包括TiO ₂ NPs–OC相互作用，TiO ₂ NPs和OCs对藻类生物物理化学特性的影响以及TiO _2的影响NP和OC对藻类中彼此生物富集的影响。结果表明，coexposure导致的协同效应上的TiO联合毒性₂ NPS-莠去津，二氧化钛为拮抗作用₂ NPS-六氯苯和TiO _2个纳米粒子，3,3' ，4,4'-四氯联苯，和添加剂的效果用于TiO ₂ NPs-五氯苯。TiO ₂ NPs几乎不吸附OCs ，并且OCs的存在基本上不会改变TiO ₂ NPs的理化性质。但是，OC和NP都影响藻类细胞的生物物理化学特性，从而影响细胞表面结合和/或内在化。二氧化钛₂NPs显着增加了每个OC的生物积累。但是，除of去津外，与每种OC一起使用时，TiO ₂ NP的生物蓄积都降低了。明显的联合毒性结果是OCs毒性增加（生物累积增加）与TiO ₂ NPs毒性改变（生物累积可以增加或减少）之间平衡的结果。这些结果可以显着提高我们对与NP相关的潜在环境风险的理解。