Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, 01003, USA.
Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, 01003, USA; College of Chemistry and Environment and Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000, China.
Environ Pollut. 2018 Jul;238:631-637. doi: 10.1016/j.envpol.2018.03.070. Epub 2018 Mar 31.
The effect of titanium dioxide nanoparticles (nano-TiO) on the bioaccumulation and biotransformation of arsenic (As) remains largely unknown. In this study, we exposed two freshwater algae (Microcystis aeruginosa and Scenedesmus obliquus) to inorganic As (arsenite and arsenate) with the aim of increasing our understanding on As bioaccumulation and methylation in the presence of nano-TiO. Direct evidence from transmission electron microscope (TEM) images show that nano-TiO (anatase) entered exposed algae. Thus, nano-TiO as carriers boosted As accumulation and methylation in these two algae species, which varied between inorganic As speciation and algae species. Specifically, nano-TiO could markedly enhance arsenate (As(V)) accumulation in M. aeruginosa and arsenite (As(III)) accumulation in S. obliquus. Similarly, we found evidence of higher As methylation activity in the M. aeruginosa of As(III) 2 mg L nano-TiO treatment. Although this was also true for the S. obliquus (As(V)) treatment, this species exhibited higher As methylation compared to M. aeruginosa, being more sensitive to As associated with nano-TiO compared to M. aeruginosa. Due to changes in pH levels inside these exposed algae, As dissociation from nano-TiO inside algal cells enhanced As methylation. Accordingly, the potential influence of nanoparticles on the bioaccumulation and biotransformation of their co-contaminants deserves more attention.
纳米二氧化钛（nano-TiO）对砷（As）的生物积累和生物转化的影响在很大程度上尚不清楚。在这项研究中，我们将两种淡水藻类（铜绿微囊藻和斜生栅藻）暴露于无机砷（亚砷酸盐和砷酸盐）中，旨在提高我们对纳米 TiO 存在下砷生物积累和甲基化的理解。透射电子显微镜（TEM）图像的直接证据表明，纳米 TiO（锐钛矿）进入了暴露的藻类。因此，纳米 TiO 作为载体促进了这两种藻类对砷的积累和甲基化，这取决于无机砷的形态和藻类的种类。具体而言，纳米 TiO 可以显著增强铜绿微囊藻对砷酸盐（As(V)）的积累和斜生栅藻对亚砷酸盐（As(III)）的积累。同样，我们发现纳米 TiO 处理的 As(III)2mg/L 铜绿微囊藻中的砷甲基化活性更高。尽管斜生栅藻（As(V)）处理也是如此，但与铜绿微囊藻相比，该种藻类的砷甲基化活性更高，与铜绿微囊藻相比，其对与纳米 TiO 结合的砷更为敏感。由于暴露的藻类内部 pH 值的变化，纳米 TiO 内部藻类细胞中砷的离解增强了砷的甲基化。因此，纳米颗粒对其共污染物生物积累和生物转化的潜在影响值得更多关注。
