Bi Chunqing, Junaid Muhammad, Liu Yan, Guo Wenjing, Jiang Xilin, Pan Baozhu, Li Zhengguoshen, Xu Nan
Key Laboratory for Heavy Metal Pollution Control and Reutilization, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, 710048, Shaanxi, China.
Chemosphere. 2022 Jun;297:134242. doi: 10.1016/j.chemosphere.2022.134242. Epub 2022 Mar 5.
Graphene oxide (GO), a frequently utilized graphene family nanomaterial, is inevitably released into the aquatic environment and interacts with organic pollutants, including perfluorooctane sulfonate (PFOS), a well-known persistent organic pollutant. To determine the adverse effects of GO chronic exposure on PFOS bioaccumulation and toxicity, adult freshwater bivalves, namely Asian clams (Corbicula fluminea) were treated for 28 days with PFOS (500 ng/L) and different concentrations of GO (0.2, 1, 5 mg/L) as PFOS single and GO single exposure groups, as well as PFOS-GO mixture exposure groups. Our results demonstrated that the bioaccumulation of PFOS was significantly enhanced by co-exposure in gills and visceral masses, which was 1.64-2.91 times higher in gills than in visceral masses. Both single, as well as co-exposure, caused a significant reduction in clams' siphoning behavior, compared to the controls. Further, the co-exposure significantly increased the production of reactive oxygen species (ROS), exacerbating malondialdehyde (MDA) content, enhancing superoxide dismutase (SOD) and catalase (CAT), while decreasing glutathione reductase (GR) and glutathione S-transferase (GST) enzymatic activities in clam tissues. And co-exposure significantly altered the expressions of se-gpx, sod, cyp30, hsp40, and hsp22 genes (associated with oxidative stress and xenobiotic metabolism) both in gills and visceral masses. Moreover, co-exposure caused significant histopathological changes such as cilia degradation in the gills, expansion of tubule lumens in digestive glands, and oocyte shrinkage in gonads. Finally, the enhanced integrated biomarker response (EIBR) index revealed that co-exposure to 500 ng/L PFOS + 1 mg/L/5 mg/L GO was the most stressful circumstance. Overall, our findings suggested that the presence of GO increased PFOS bioaccumulation in tissues, inducing multifaceted negative implications at molecular and behavioral levels through oxidative stress generation in Asian clams.
氧化石墨烯（GO）是一种常用的石墨烯家族纳米材料，不可避免地会释放到水生环境中，并与有机污染物相互作用，包括全氟辛烷磺酸（PFOS），一种著名的持久性有机污染物。为了确定长期暴露于GO对PFOS生物累积和毒性的不利影响，将成年淡水双壳贝类，即亚洲蛤（河蚬），分别作为PFOS单一暴露组、GO单一暴露组以及PFOS - GO混合暴露组，用PFOS（500纳克/升）和不同浓度的GO（0.2、1、5毫克/升）处理28天。我们的结果表明，鳃和内脏团中PFOS的生物累积在共同暴露时显著增强，鳃中的累积量比内脏团高1.64至2.91倍。与对照组相比，单一暴露和共同暴露均导致蛤的虹吸行为显著减少。此外，共同暴露显著增加了活性氧（ROS）的产生，加剧了丙二醛（MDA）含量，增强了超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的活性，同时降低了蛤组织中谷胱甘肽还原酶（GR）和谷胱甘肽S - 转移酶（GST）的酶活性。并且共同暴露显著改变了鳃和内脏团中与氧化应激和异生物质代谢相关的se - gpx、sod、cyp30、hsp40和hsp22基因的表达。此外，共同暴露导致了显著的组织病理学变化，如鳃中纤毛退化、消化腺中小管腔扩张以及性腺中卵母细胞萎缩。最后，增强的综合生物标志物反应（EIBR）指数表明，共同暴露于500纳克/升PFOS + 1毫克/升/5毫克/升GO是最具压力的情况。总体而言，我们的研究结果表明，GO的存在增加了组织中PFOS的生物累积，通过在亚洲蛤中产生氧化应激在分子和行为水平上引发多方面的负面影响。
