The present study examined the effect of titanium dioxide nanoparticles (nanoTiO₂) and mercury (Hg) compounds on the green alga, Chlamydomonas reinhardtii. Mixtures containing nanoTiO₂ of different primary sizes (5 nm, 15 nm and 20 nm), inorganic Hg (IHg) or monomethyl Hg (CH₃Hg⁺, MeHg) were studied and compared with individual treatments. Oxidative stress and membrane damage were examined. Stability of nanoTiO₂ materials in terms of hydrodynamic size and surface charge as well as Hg adsorption on different nanoTiO₂ materials were characterized. The uptake of Hg compounds in the absence and presence of nanoTiO₂ was also quantified. Results show that increasing concentrations of nanoTiO₂ with different primary size diminished oxidative stress and membrane damage induced by high concentrations of IHg or MeHg, due to the adsorption of Hg on the nanoTiO₂ aggregates and consequent decrease of cellular Hg concentrations. The observed alleviation effect of nanoTiO₂ materials on Hg biouptake and toxicity was more pronounced for the materials with smaller primary size. IHg adsorbed onto the nanoTiO₂ materials to a higher extent than MeHg. The present study highlights that the effects of contaminants are modulated by the co-existing engineered nanomaterials; therefore, it is essential to get a better understanding of their combined effect in the environment.

本研究检查了二氧化钛纳米颗粒（nanoTiO ₂）和汞（Hg）化合物对绿藻莱茵衣藻的影响。研究了包含不同主要尺寸（5 nm，15 nm和20 nm），无机Hg（IHg）或一甲基Hg（CH ₃ Hg ⁺，MeHg）的nanoTiO ₂的混合物，并将其与单独处理进行了比较。检查了氧化应激和膜损伤。表征了纳米TiO ₂材料在流体动力学尺寸和表面电荷以及汞在不同纳米TiO ₂材料上的吸附方面的稳定性。在不存在和存在纳米TiO ₂的情况下对汞化合物的吸收也被量化了。结果表明，由于高浓度的IHg或MeHg引起的纳米级TiO ₂浓度的增加，降低了氧化应激和膜损伤，这是由于Hg在纳米级TiO ₂聚集体上的吸附并因此降低了细胞中Hg的浓度。对于具有较小初级尺寸的材料，观察到的纳米TiO ₂材料对汞生物吸收和毒性的缓解作用更加明显。IHg吸附到纳米TiO _2上材料的含量比甲基汞更高。本研究强调污染物的影响是由共存的工程纳米材料调节的。因此，有必要更好地了解它们在环境中的综合作用。