Manivannan Bhuvaneshwari, Eltzov Evgeni, Borisover Mikhail
Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, P.O. Box 15159, 7505101, Rishon LeZion, Israel.
Institute of Postharvest and Food Science, Department of Postharvest Science, Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel.
Sci Rep. 2021 Apr 1;11(1):7424. doi: 10.1038/s41598-021-86672-7.
Microplastics are ubiquitous in aquatic systems and break down into submicron particles that can interact with aquatic toxic chemicals. These interactions may affect the detection of toxicants when using bacteria as a biomonitoring tool. This study examined the effects of model polystyrene (PS)-based submicron particles on the detection of aqueous geno- and cytotoxicity by genetically modified bioluminescent (GMB) bacteria. The toxicities were tested in three treated wastewater (TWW) effluents before and after chlorination. The PS plastics included negatively charged sulfate-coated (S-PS) and pristine (P-PS) particles of different sizes (0.1, 0.5, and 1.0 µm) that were present at different concentrations. Chlorinated or not, the S-PS and P-PS particles per se were not toxic to the GMB bacteria. However, exposure of PS particles to TWW effluents can significantly reduce the measured geno- and cytotoxicity. Adsorption of toxic compounds to polymer particles can limit the ability of the bacteria to detect those compounds. This masking effect may be mitigated by TWW chlorination, possibly due to the formation of new toxic material. Due to interactions between toxic TWW constituents and the plastics particles, water samples containing particle-associated contaminants and/or their transformation products may be declared non-toxic, based on bacterial tests as a biomonitoring tool.
微塑料在水生系统中无处不在，并会分解成亚微米颗粒，这些颗粒可与水生有毒化学物质相互作用。在将细菌用作生物监测工具时，这些相互作用可能会影响有毒物质的检测。本研究考察了基于聚苯乙烯（PS）的模型亚微米颗粒对转基因生物发光（GMB）细菌检测水体基因毒性和细胞毒性的影响。在三种经过处理的废水（TWW）出水氯化前后对毒性进行了测试。PS塑料包括带负电荷的硫酸涂层（S-PS）和不同尺寸（0.1、0.5和1.0 µm）的原始（P-PS）颗粒，它们以不同浓度存在。无论是否氯化，S-PS和P-PS颗粒本身对GMB细菌无毒。然而，将PS颗粒暴露于TWW出水中会显著降低所测得的基因毒性和细胞毒性。有毒化合物吸附到聚合物颗粒上会限制细菌检测这些化合物的能力。这种掩盖效应可能会因TWW氯化而减轻，这可能是由于形成了新的有毒物质。由于有毒的TWW成分与塑料颗粒之间的相互作用，基于细菌测试作为生物监测工具，含有与颗粒相关的污染物和/或其转化产物的水样可能会被判定为无毒。
