Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Via Vivaldi 43, I-81100 Caserta, Italy.
Medical University of Vienna, Center for Public Health, Department of Environmental Health, Kinderspitalgasse 15, 1090, Vienna, Austria.
Environ Pollut. 2022 Nov 15;313:120088. doi: 10.1016/j.envpol.2022.120088. Epub 2022 Sep 5.
Freshwater ecosystems are recognized as non-negligible sources of plastic contamination for the marine environment that is the final acceptor of 53 thousand tons of plastic per year. In this context, microplastic particles are well known to directly pose a great threat to freshwater organisms, they also indirectly affect the aquatic ecosystem by adsorbing and acting as a vector for the transport of other pollutants ("Trojan horse effect"). Polystyrene is one of the most widely produced plastics on a global scale, and it is among the most abundant microplastic particles found in freshwaters. Nevertheless, to date few studies have focused on the eco-genotoxic effects on freshwater organisms caused by polystyrene microplastic particles (PS-MPs) in combination with other pollutants such as pharmaceuticals and pesticides. The aim of this study is to investigate chronic and sub-chronic effects of the microplastic polystyrene beads (PS-MP, 1.0 μm) both as individual xenobiotic and in combination (binary/ternary mixtures) with the acicloguanosine antiviral drug acyclovir (AC), and the neonicotinoid broad-spectrum insecticide imidacloprid (IMD) in one of the most sensitive non-target organisms of the freshwater food chain: the cladoceran crustacean Ceriodaphnia dubia. Considering that the individually selected xenobiotics have different modes of action and/or different biological sites, the Bliss independence was used as reference model for this research. Basically, when C. dubia neonates were exposed for 24 h to the mixtures during Comet assay, mostly an antagonistic genotoxic effect was observed. When neonates were exposed to the mixtures for 7 days, mostly an additive chronic toxic effect occurred at concentrations very close or even overlapping to the environmental ones ranging from units to tens of ng/L for PS-MPs, from tenths/hundredths to units of μg/L for AC and from units to hundreds of μg/L for IMD, revealing great environmental concern.
淡水生态系统被认为是海洋环境中不可忽视的塑料污染来源，每年有 5.3 万吨塑料最终进入海洋环境。在这种情况下，微塑料颗粒众所周知会直接对淡水生物构成巨大威胁，它们还通过吸附并充当其他污染物的载体来间接影响水生生态系统（“特洛伊木马效应”）。聚苯乙烯是全球范围内产量最大的塑料之一，也是淡水中最常见的丰富微塑料颗粒之一。然而，迄今为止，很少有研究关注聚苯乙烯微塑料颗粒 (PS-MP) 与其他污染物（如药品和农药）结合对淡水生物的生态遗传毒性影响。本研究旨在研究微塑料聚苯乙烯珠（PS-MP，1.0 μm）作为单一异生物质以及与抗病毒药物阿昔洛韦 (AC) 和新烟碱类广谱杀虫剂噻虫啉 (IMD) 组合对淡水食物链中最敏感的非目标生物之一——桡足类甲壳动物大眼水蚤的慢性和亚慢性影响。考虑到单独选择的异生物质具有不同的作用方式和/或不同的生物部位，本研究使用 Bliss 独立性作为参考模型。基本上，当 C. dubia 幼虫在彗星试验中接触混合物 24 小时时，主要观察到拮抗遗传毒性作用。当幼虫接触混合物 7 天时，主要观察到在接近或甚至与环境浓度重叠的浓度下发生的加性慢性毒性作用，范围从单位到数十纳克/升的 PS-MPs，从十分之几/百分之几到单位微克/升的 AC 和从单位到数百微克/升的 IMD，这表明存在很大的环境问题。
