School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Nanjing University of Information Science and Technology, Nanjing, 210044, PR China.
School of Environmental Science and Engineering, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Nanjing University of Information Science and Technology, Nanjing, 210044, PR China.
Environ Pollut. 2020 Feb;257:113451. doi: 10.1016/j.envpol.2019.113451. Epub 2019 Oct 24.
Novel metal-oxide-doped microplastic particles (MMPs) have become emerging particulate plastics. The toxicity of MMPs in the aquatic environment remains unknown yet. In this study, toxicological effects of a representative MMP (iron-oxide core) with the nominal diameter of 1 μm and two different surface functional groups, amine-modified (MPS (Fe)-NH) and carboxyl-modified (MPS (Fe)-COOH) polystyrene, were investigated by toxicity testing using Chlorella pyrenoidosa and Daphnia magna. The aquatic toxicity of two microplastic particles (MPS-NH and MPS-COOH) with the same particle size and surface modification in the absence of iron-oxide core was also observed and compared. Results show that the toxicity of MPS (Fe)-NH to the studied organisms (in terms of median effective concentration) was greater than the MPS (Fe)-COOH and non-iron-oxide-doped microplastic particles. Moreover, the MMPs mainly contributed to the toxicity rather than their dissolved fraction. The accumulation (based on total Fe) of MPS (Fe)-NH in C. pyrenoidosa was higher than the MPS (Fe)-COOH at low effect concentrations. The observations by optical microscopy indicated that the MPS (Fe)-NH was heavily adsorbed on the surface and distributed over the antennae, carapace, and apical spine of D. magna body whereas the MPS (Fe)-COOH was mainly accumulated inside the digestive tract of the daphnia. Furthermore, the analysis of intracellular reactive oxygen species level and antioxidant capacity confirmed that the intensities of the toxic effects cannot be linked to oxidative stress induced by the particles in the algae and daphnids. This work provides valuable insights into the ecological effects of MMPs, which is helpful for the quantitative assessment of food chain transfer of microplastics.
新型金属氧化物掺杂微塑料颗粒（MMPs）已成为新兴的颗粒状塑料。然而，其在水生环境中的毒性仍不清楚。在这项研究中，通过使用栅藻和大型溞进行毒性测试，研究了具有名义直径 1μm 和两种不同表面官能团的代表性 MMP（氧化铁核）的毒理学效应，即胺改性（MPS（Fe）-NH）和羧基改性（MPS（Fe）-COOH）聚苯乙烯。还观察并比较了具有相同粒径和表面修饰但不含氧化铁核的两种微塑料颗粒（MPS-NH 和 MPS-COOH）在水中的毒性。结果表明，MPS（Fe）-NH 对研究生物（以中效浓度表示）的毒性大于 MPS（Fe）-COOH 和非氧化铁掺杂微塑料颗粒。此外，MMPs 主要导致毒性，而不是其溶解部分。在低效应浓度下，MPS（Fe）-NH 在栅藻中的积累（基于总铁）高于 MPS（Fe）-COOH。光学显微镜观察表明，MPS（Fe）-NH 被大量吸附在表面上，并分布在大型溞的触角、甲壳和顶刺上，而 MPS（Fe）-COOH 主要积累在溞的消化道内。此外，细胞内活性氧水平和抗氧化能力的分析证实，毒性效应的强度不能与藻类和溞体内颗粒诱导的氧化应激联系起来。这项工作为 MMPs 的生态效应提供了有价值的见解，有助于对食物链中微塑料转移进行定量评估。
