Submicron polymer particles may mask the presence of toxicants in wastewater effluents probed by reporter gene containing bacteria

Do microbial decomposers find micro- and nanoplastics to be harmful stressors in the aquatic environment? A systematic review of in vitro toxicological research

Microbial decomposers (bacteria and fungi) are likely to interact with plastic particles introduced into natural systems, particularly micro- and nanoplastics (MNPs), exposing them to a variety of risks. In vitro testing has proven to be an accessible and viable method for gaining insights into how microbial decomposers behave individually and systemically toward MNPs. Recent advances have enhanced our understanding of MNP interactions with organisms, revealing the molecular foundations of adaptive responses as well as the biological impact and potential risks to MNPs. Despite widespread attention, this topic has not yet been reviewed. Here, we conducted a systematic review of the available research to critically assess and highlight the most recent advances in two major areas: (1) methods for in vitro evaluation of environmentally relevant microbial decomposers to MNPs; and (2) current understanding of the underlying toxicity mechanisms gained from in vitro assessments. We also addressed the key considerations throughout and proposed available opportunities in the field. Our analysis revealed that MNPs' toxicity has been studied in vitro either alone or in combination with other contaminants (e.g., antibiotics and metallic nanoparticles), with Escherichia coli and polystyrene particles receiving the most attention. Moreover, there were methodological differences in terms of MNP size, shape, polymer, surface characteristics, exposure period, and concentrations. A combination of methods, including growth-viability tests, biochemical assays, and omics profiling (metabolomics and transcriptomics), were employed to detect the effects of MNP exposure and explain its toxicity mechanism. The current literature suggests that the impacts of MNPs on microbial decomposers include alterations in the antioxidative system, gene expression levels and cell-membrane permeability and oxidative damage, all of which can be further influenced by MNPs interaction with other contaminants. This review will thus provide critical insights and up-to-date knowledge to assist novices and experts in promoting advancements and research.

Illuminating Progress: The Contribution of Bioluminescence to Sustainable Development Goal 6-Clean Water and Sanitation-Of the United Nations 2030 Agenda

The United Nations Agenda 2030 Sustainable Development Goal 6 (SDG 6) aims at ensuring the availability and sustainable management of water and sanitation. The routine monitoring of water contaminants requires accurate and rapid analytical techniques. Laboratory analyses and conventional methods of field sampling still require considerable labor and time with highly trained personnel and transport to a central facility with sophisticated equipment, which renders routine monitoring cumbersome, time-consuming, and costly. Moreover, these methods do not provide information about the actual toxicity of water, which is crucial for characterizing complex samples, such as urban wastewater and stormwater runoff. The unique properties of bioluminescence (BL) offer innovative approaches for developing advanced tools and technologies for holistic water monitoring. BL biosensors offer a promising solution by combining the natural BL phenomenon with cutting-edge technologies. This review provides an overview of the recent advances and significant contributions of BL to SDG 6, focusing attention on the potential use of the BL-based sensing platforms for advancing water management practices, protecting ecosystems, and ensuring the well-being of communities.

The effect of polyethylene microplastics on the disinfection of Escherichia coli by sodium hypochlorite

The effect of polyethylene microplastics (PE-MPs) on the disinfection of Escherichia coli (E. coli) by sodium hypochlorite was investigated in different pH value, ionic strength, and NOM concentration to illustrate the impact of MPs on the pathogenic bacteria disinfection efficiency in nature water environment. The results showed that PE-MPs tended to agglomerate rather than disperse due to their strong hydrophobicity in water. Within 30 s, about 1.5 log₁₀ of E. coli was adsorbed on the surface of PE-MPs, forming subsequent protection for E. coli. Thus, the presence of PE-MPs reduced the inactivation rate of E. coli. As for the particle-free solutions, the higher solution pH, the presence of natural organic matter (NOM), and the higher concentrations of cations (monovalent Na⁺ and divalent Ca²⁺) were confirmed as the major influencing factors decreasing the E. coli disinfection efficiency. However, due to the adsorption and protection of PE-MPs on E. coli, the influences of complex chemistry factors on the inactivation of E. coli were reduced. The inactivation of E. coli in PE-MPs (20 NTU) solution was 1 log₁₀ lower than that in particle-free solution under the same water quality conditions. Therefore, considering the complex water chemistry, the existence of MPs could be a potential challenge for disinfection efficiency in the water treatment plants.

The Effect of Submicron Polystyrene on the Electrokinetic Potential of Cell Membranes of Red Blood Cells and Platelets

In recent years, many scientists have studied the effects of polymer micro- and nanostructures on living organisms. As it turns out, plastic can be a component of the blood of livestock, eaten by humans around the globe. Thus, it seems important to investigate possible changes in the physicochemical parameters and morphology of the cell membranes of blood morphotic elements (red blood cells and platelets) under the influence of polymer particles. The article presents research in which cell membranes were exposed to plain polystyrene (PS) and amino-functionalized polystyrene (PS-NH₂) of two different sizes. The polymers were characterized by infrared spectroscopy and dynamic light-scattering methods. To analyze possible changes caused by polymer exposure in the structure of the membranes, their zeta potentials were measured using the electrophoretic light-scattering technique. The concentration of the polymers, as well as the exposure time, were also taken into the consideration during the research. Based on the obtained results, we concluded that 100 and 200 nm PS, as well as 100 nm PS-NH₂, internalize into the cells. On the contrary, 200 nm PS-NH₂ particles attach to cell membranes. Our study clearly shows that particle size and surface chemistry determine the interaction with biological membranes.