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This work presents results from a pilot-scale drinking water treatment plant used to investigate the performance of ozone oxidation and granulated activated carbon (GAC) adsorption in removing natural organic matter (NOM) and specific organic micropollutants from groundwater. The investigated groundwater has a relatively low NOM content (1.83±1.01 mg C/L total organic carbon, TOC). Using gas chromatography/mass spectrometry (GC/MS) screening analysis, a variety of different organic compounds were identified, including benzophenone, 2-phenoxyethanol, butylated hydroxytoluene and benzoic acid, all contaminants of emerging concern (CEC) identified by NORMAN. The application of the ozonation process resulted in a 4-20% NOM reduction, based on the TOC values. Estimated removal of CECs by ozone increased with increasing ozone dose (up to 1.0 g O3/m3) and was in the range 24-70%. Adsorption on GAC further improves total NOM and CECs removal compared to the ozonation alone. Combined use of ozone and GAC provides up to 16-33% TOC reduction as well as 70-82% CECs removal. UV absorbance values at 254 nm can serve as an indicator of aromatic carbon content in water, and were significantly reduced after ozonation and GAC filtration (by up to 50%). Among the CECs investigated, benzophenone was the most prone to oxidation/adsorption treatment. In addition to the naturally present organic matter, CECs detected can serve as indicators of anthropogenic pollution which may alter drinking water quality. Tracking their behaviour during treatment allows assessment of the efficiency of the technological line and optimization of the oxidation process in the case of groundwater pollution by infiltration.

The role of microplastics (MPs) on the fate and transport of various pollutants in water matrices is of major concern, but it is still relatively under investigated. In order to consider the conditions in real aquatic environments, the changes to polyethylene (PE) structure during the fabrication of microplastic particles for specific uses should not be neglected. Thus, this work considers isolated PE from two types of personal care products, which are possible sources of microplastic contamination in aquatic environments. The adsorption affinity of these PE microplastics towards ionisable compounds was compared with those of standards of PE and polyethylene terephthalate (PET), using chlorinated phenols (4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol) as adsorbates. The pseudo-second order kinetic model described well the sorption process for all chlorinated phenols on all four types of MPs (R2 range: 0.900–0.998). The kinetic study showed that sorption rates are mainly controlled by hydrophobic interactions and molecule size. Adsorption isotherms were best described by the Freundlich model for all MPs. The obtained results indicate that MPs could serve for the transport of chlorinated phenols through ambient waters. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III43005]

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The rapid global population growth since the early 2000s has significantly increased the demand for agricultural products, leading to widespread pesticide use, particularly organophosphorus pesticides (OPPs). This extensive application poses severe environmental risks by contaminating air, soil, and water resources. To protect groundwater quality, it is crucial to understand the transport and fate of these pesticides in soil and sediment. This study investigates the effects of hydrochars and biochars derived from sugar beet shreds (SBS) and Miscanthus×giganteus (MIS) on the retardation and biodegradation of OPPs in alluvial Danube sandy soil. The research is novel in its approach, isolating native OPP-degrading bacteria from natural alluvial sandy soil, inoculating them onto chars, and reapplying these bioaugmented chars to the same soil to enhance biodegradation and reduce pesticide leaching. The amendment of chars with immobilized Bacillus megaterium BD5 significantly increased bacterial abundance and activity. Metabarcoding of the 16S rRNA gene revealed a dominance of Proteobacteria (48.0-84.8 %) and Firmicutes (8.3-35.6 %). Transport modeling showed retardation coefficients (R d ) for OPPs ranging from 10 to 350, with biodegradation rates varying between 0.05 % and 75 %, indicating a positive correlation between retardation and biodegradation. The detection of biodegradation byproducts, including derivatives of phosphin, pyridine, and pyrazole, in the column leachate confirmed that biodegradation had occurred. Additionally, principal component analysis (PCA) revealed positive correlations among retardation, biodegradation, specific surface area (SSA), aldehyde/ketone groups, and bacterial count. These findings demonstrate the potential of biochar and hydrochar amendments to enhance OPP immobilization in contaminated soils, thereby reducing their leaching into groundwater. This study offers a comprehensive approach to the remediation of pesticide-contaminated soils, advancing both our fundamental understanding and the practical applications of environmental remediation techniques., Competing Interests: Declaration of Competing Interest The authors would like to declare that they have no conflicts of interest associated with this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Microplastics are ubiquitous in aqueous media, and the importance of considering their impact on the behaviour of other compounds in water has often been highlighted. This work thus investigates the adsorption mechanism of six priority substances (as defined by European Union legislation: trichlorobenzenes (1,2,3-TeCB, 1,3,5-TeCB, 1,2,4-TeCB), pentachlorobenzene (PeCB), hexachlorobenzene (HeCB), and trifluralin (TFL)) on primary polyethylene (PE) microplastics (polyethylene standard and polyethylene microparticles isolated from two personal care products) in Danube river water and a synthetic matrix. The maximum adsorbed amounts of the compounds investigated on PEs ranged from 227 μg/g for 1,2,3-TeCB to 333 μg/g for TFL. Equilibrium data was analysed using five isotherm models, with the best fit being described by the Langmuir model and the Dubinin-Radushkevich model indicating chemisorption as the likely sorption mechanism. In general, the Langmuir model showed that the investigated compounds will be better adsorbed on PEs in real river water, with the exception of 1,3,5-TeCB on all studied PEs, where the model predicts better sorption in the synthetic matrix. Compound characteristics and the polymer properties were the most important factors affecting the sorption process, while a significant matrix effect was also observed on PE behaviour. The fact that polyethylene particles derived from personal care products showed greater adsorption capacities than virgin PE demonstrates the necessity of investigating real-world PE samples when assessing the potential impact of MPs in the environment., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

The characteristics of the Danube river alluvial sediment are of great importance in assessing the risk for transport of pollutants to drinking water sources. Characterization of the sediment column layers has shown that the alluvial sediment, sampled near the city of Novi Sad, is a mesoporous sandy material with certain differences in the properties of individual layers. In order to investigate the sorption mechanisms of four chlorinated phenols (CPs) on the alluvial deposit, static sorption experiments were performed at pH 4, 7 and 10. The results of sorption experiments, confirmed by principal components analysis sugest different mechanisms govern the sorption process at different pH conditions. This can be attributed to the molecular characteristics of CPs, geosorbent properties and to variations in the surface charge of the sorbent at different pH conditions., Competing Interests: Declaration of Competing Interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

This work investigates the transport behaviour of selected organophosphorus pesticides, OPPs (chlorpyrifos, CP; chlorpyrifos-methyl, CPM; chlorfenvinphos, CF) through Danube alluvial sediment in the presence of hydrochars and biochars. The investigated hydrochar, obtained at three different temperatures (180 °C, 200 °Cand 220 °C), originated from sugar beet shreds (SBS) and Miscanthus×giganteus (MIS). Results are described by conventional advective-dispersive equation (ADE). Retardation coefficients (R d ) for all OPPs were in the range 6.2-16. Biodegradation was 4.15 and 1.80 for CPM and CP, respectively, while for CF biodegradation did not occur. The addition of carbon rich materials increases retardation of all OPPs in the range from 4 to 18 times depending on the material. Column experiment results indicated that biodegradation of OPPs occurred (up to λ = 13). In order to confirm that biodegradation occurred in the column experiments, we isolated OPPs degrading microorganisms for the first time from the alluvial sediment. A strain capable of degrading CP and CPM was isolated and identified as Bacillus megaterium BD5 based on biochemical properties, MALDI TOF and 16S rRNA analysis (99.54% identity). The results demonstrate that hydrochars, biochars and isolated degrading bacteria may be effective agents for reducing the mobility of or removing OPPs in contaminated soils or sediments., (Copyright © 2020 Elsevier Ltd. All rights reserved.)