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Recently, there has been significant focus on microplastics in the environment, especially regarding their role in sorption–desorption processes of emerging contaminants, impacting pollutant migration between aquatic and terrestrial ecosystems. Notably, the newest pollutants in such environments are the herbicide formulations known as ionic liquids (ILs), which integrate the structure of classic herbicidal anion with surface-active cations acting as an adjuvant. In our study, we synthesized herbicidal ILs by combining 2,4-D anion with cetyltrimethylammonium [CTA] and didecyldimethylammonium [DDA] cations. We investigated whether ILs and the mixture of salts, when exposed to polyethylene (PE) microplastics, differ in properties. We analyzed their sorption on defined PE particles, evaluated toxicity on Pseudomonas putida KT2440 using trans/cis ratio of unsaturated fatty acids, and assessed biodegradability with OECD 301F standard test. Results indicate IL cations and anions behave as distinct entities, questioning IL synthesis feasibility. Hydrophobic adjuvants were found to adsorb onto PE microplastic surfaces (5–60% [CTA] > [DDA]), posing potential threats of surface-active xenobiotic accumulation. This highlights the need to explore microplastics' role as sorbents of hazardous adjuvants in agriculture, potentially competing with humic acids and affecting xenobiotic bioavailability. Consequently, xenobiotics may persist longer in the environment, facilitated by microplastic mobility between aquatic and terrestrial ecosystems. Key points: • Microplastics act as sorbents, accumulating xenobiotics and limiting biodegradation. • Sorption of surfactant cations on microplastics reduces soil bacteria toxicity. • Research confirms independent action of ions from ionic liquids in the environment. [ABSTRACT FROM AUTHOR]

This study aimed to compare the impact of iodosulfuron-methyl-sodium and an iodosulfuron-based herbicidal ionic liquid (HIL) on the microbiomes constituting the epiphytes and endophytes of cornflower (Centaurea cyanus L.). The experiment involved biotypes of cornflower susceptible and resistant to acetolactate synthase inhibition, examining potential bacterial involvement in sulfonylurea herbicide detoxification. We focused on microbial communities present on the surface and in the plant tissues of roots and shoots. The research included the synthesis and physicochemical analysis of a novel HIL, evaluation of shifts in bacterial community composition, analysis of the presence of catabolic genes associated with sulfonylurea herbicide degradation and determination of their abundance in all experimental variants. Overall, for the susceptible biotype, the biodiversity of the root microbiome was higher compared to shoot microbiome; however, both decreased notably after herbicide or HIL applications. The herbicide-resistant biotype showed lower degree of biodiversity changes, but shifts in community composition occurred, particularly in case of HIL treatment. [ABSTRACT FROM AUTHOR]

Surfactants not only are widely used in biotechnological processes but also constitute significant contaminants of the modern world. Among many reports, there is a shortage of works which summarize the issue of surfactant sorption to biomass in a way that would elucidate the biological factors for analysts and analytical factors for microbiologists. The main factor, which is not as obvious as one would expect, is associated with the susceptibility of analytical approaches to errors resulting from incorrect handling of biomass. In case of several publications reviewed in the framework of this study, it was not possible to establish whether the decrease of the analytical signal observed by the authors actually resulted from biodegradation of the surfactant. This review emphasizes the necessity to consider the possibility of surfactant sorption to microbial cells, which may result in significant detection errors as well as conceptual inconsistency. In addition, a reference study regarding representative surfactants (cationic, anionic and non-ionic) as well as yeast, Gram-negative, Gram-positive bacteria, and activated sludge was provided to highlight the possible errors which may arise from disregarding sorption processes when determining degradation of surfactants. This particularly applies to systems which include ionic surfactants and activated sludge as sorption may account for 90% of the observed depletion of the surfactant. Therefore, a systematic approach was proposed in order to improve the credibility of the obtained results. Finally, the need to employ additional procedures was highlighted which may be required in order to verify that the decrease of surfactant concentration results from biodegradation processes. [ABSTRACT FROM AUTHOR]