Although the risk of graphene materials to aquatic organisms has drawn wide attention, the combined effects of graphene materials with other contaminants such as toxic metals, which may bring about more serious effects than graphene materials alone, have seldom been explored. Herein, the effects of graphene (GN) and graphene oxide (GO, an important oxidized derivative of graphene) on copper (Cu) toxicity to Daphnia magna were systematically investigated. The results indicated that GN remarkably increased the Cu accumulation in D. magna and enhanced the oxidative stress injury caused by Cu, whereas did not significantly alter D. magna acute mortality within the tested Cu concentrations (0–200 μg L⁻¹). On the contrary, GO significantly decreased the Cu accumulation in D. magna and alleviated the oxidative stress injury caused by Cu. Meanwhile, the presence of GO significantly reduced the mortality of D. magna when Cu concentration exceeded 50 μg L⁻¹. The different effects of GN and GO on Cu toxicity were possibly dependent on the action of surface oxygenic functional group. Because of the introduction of surface oxygenic functional groups, the adsorption ability to metal ions, stability in water and interaction mode with organisms of GO are quite different from that of GN, causing different effects on Cu toxicity. This study provides important information on the bioavailability and toxicity of heavy metals as affected by graphene materials in natural water.

尽管石墨烯材料对水生生物的危险已引起广泛关注，但很少研究石墨烯材料与其他污染物（例如有毒金属）的组合作用，这种作用可能比单独使用石墨烯材料带来更严重的影响。在本文中，系统地研究了石墨烯（GN）和氧化石墨烯（GO，石墨烯的重要氧化衍生物）对铜（Cu）对大型蚤（Daphnia magna）毒性的影响。结果表明，GN显着增加了D. magna中Cu的积累，并增强了Cu引起的氧化应激损伤，而在所测试的Cu浓度（0-200μgL ^-1内）并未明显改变D. magna的急性死亡率。）。相反，GO显着降低了D. magna中的Cu积累，减轻了Cu引起的氧化应激损伤。同时，当Cu浓度超过50μgL ^-1时，GO的存在显着降低了D. magna的死亡率。。GN和GO对Cu毒性的不同影响可能取决于表面氧官能团的作用。由于引入了表面氧官能团，GO对金属离子的吸附能力，在水中的稳定性以及与GO有机体的相互作用方式与GN完全不同，从而对Cu毒性产生不同的影响。这项研究提供了有关天然水中石墨烯材料影响的重金属的生物利用度和毒性的重要信息。