Biocides in hydraulic fracturing fluids: a critical review of their usage, mobility, degradation, and toxicity

Rising Tide to Silent Tsunami: Unveiling the role of plastics in driving antimicrobial resistance

Pollution caused by plastic production and waste has severe consequences on global economies, social inequalities, and ecosystems. Likewise, antimicrobial resistance (AMR) is one of the greatest One Health challenges. These threats are typically considered in isolation, but there is likely a complex interplay between the two. By adopting a systems approach and looking across the whole life cycle of plastics, we propose the range of ways in which plastic may influence AMR. Starting with raw material extraction processes where the leaching of potentially AMR co-selective chemicals used in pumping or piping of plastic feedstocks may influence AMR development in environmental microbial communities. Then, during production and manufacture, the use of plastic additives may impose selection for AMR. Finally, during use, collection or disposal, plastics can transport AMR biofilms in the community, clinical, agricultural, or aquatic settings. By linking these two important One Health threats, we may be better equipped and informed to combat them.

[P(CH2OH)4]Cl induced natural shift of methanogenic pathway through disrupting bacterial disulfide bonds and reshaping microbial community structure

Ionic liquids (ILs), which are expanding produced and applied as alternatives to volatile organic solvents, have shown the ability to deteriorate the anaerobic biotransformation of organics. It is unclear, nevertheless, how ILs affect different functional anaerobes during anaerobic digestion, leaving a knowledge gap in the environmental risks of ILs. Here, we revealed that the differences of Gram-staining bacteria probably were the part drivers of a shift in methanogenic pathway from acetoclastic to hydrogenotrophic methanogenesis in anaerobic microcosms exposed to a typical IL (Tetrakis (hydroxymethyl) phosphonium chloride, [P(CH2OH)4]Cl). The results showed that 0.1-4 mg/L [P(CH2OH)4]Cl respectively decreased methane production rate and carbon-use efficiency by 4.43-43.90 % and 0.52-57.23 % during anaerobic digestion. Microbial community and microscopic examination analysis indicated that most Gram-positive bacteria were more likely to survive in the [P(CH2OH)4]Cl-present environment than Gram-negative bacteria. Mechanistically, [P(CH2OH)4]Cl distorted cell walls of anaerobes, and then perturbed protein homeostasis in the periplasm by breaking disulfide bonds and disrupting disulfide-bond-forming pathways. Moreover, Gram-positive bacteria exhibited a higher tolerance than Gram-negative bacteria, potentially due to their thicker peptidoglycan structures and reliance less on disulfide bonds to stabilize proteins, leading to the remodeling of microbiome function and carbon-transport pathway. This study is the first to reveal the differential impact of [P(CH2OH)4]Cl on Gram-positive vs. Gram-negative anaerobes during methanogenesis, providing new insights into the ecological risks of ILs and contributing to their optimal design.

Bacteriophage application in inhibiting corrosion- producing bacteria

Sulfate-reducing bacteria (SRB) are a major cause of microbially-induced corrosion (MIC) and souring (MIS), leading to significant challenges in industries like oil recovery and wastewater treatment. Due to SRB's resistance to antimicrobial agents, bacteriophage (phage) therapy offers a promising alternative for SRB control. In this study, a novel lytic phage, SRB7757, targeting Desulfovibrio vulgaris, was isolated from sewage. SRB7757 inhibited sulfide production by 92.3% within 24 h and significantly reduced corrosion on metal specimens after 28 days, highlighting its potential in controlling MIC and MIS. Genome analysis revealed SRB7757 has a genome size of 142,573 bp, 217 ORFs, and 6 tRNAs, and belongs to the Chaseviridae family. SRB7757 exhibits a latent period of 4 h, a burst size of ~ 100 PFU/cell, and is stable between 4 °C and 60 °C across a pH range of 2.0-12.0. Two predicted lytic enzymes of SRB7757 demonstrated higher inactivation and biofilm removal rates.

Photoinactivation of sulfate-reducing bacteria using 1,9-dimethyl-methylene blue - DMMB and laser light

Annually, the oil and gas industry faces equipment losses and product quality degradation due to the presence of sulfate-reducing bacteria (SRB). Given the negative impact of SRB, this study evaluates the use of photoinactivation (PI) with zinc chloride double salt of 1,9-Dimethyl-Methylene Blue (DMMB) as a photosensitizer (PS) in varying concentrations and combined with Laser light at different exposures in an SRB consortium. For culture growth, a modified Postgate C medium (without ferrous sulfate) was used, and cell quantification was performed on 100 μL aliquots of the consortium, read on a spectrophotometer (λ600 nm) in an oxygen- and light-free environment at room temperature. Statistical analyses included two-way ANOVA and ANOVA with interaction to separately and jointly evaluate the effects of PS and light in PI. Results indicated microbial activity in all groups, with an antimicrobial inhibition rate exceeding 50 % (p < 0.05) for concentrations above 1.5 μg/mL of DMMB. PI efficacy significantly depended on DMMB concentration and light density, achieving a 70.58 % (55.73-70.58, with a mean of 66.71 %) reduction (p < 0.05) with 1.5 μg/mL of DMMB and a 70.15 % (65-70.15, with a mean of 68.21 %) reduction with 2.0 μg/mL at an intensity of 21.6 J/cm2. In conclusion, PI presents a promising alternative to biocides in the oil and gas industry, offering easy application, avoiding bacterial resistance, being environmentally safe, and compatible with other SRB population control techniques.

Review of the environmental and health risks of hydraulic fracturing fluids

The composition of hydraulic fracturing (HF) fluid poses risks to human health and the environment by impacting drinking water sources. Fracturing fluid recovery rate is highly variable, and the fact that a high percentage of the injected HF fluid is not produced back to the surface in some areas raises questions about its fate and possible migration into aquifers. In this paper, the composition of the HF fluid and related toxicity are described, along with insights about the environmental impact linked with HF fluid, synthesized spill data, main factors affecting the flow-back ratio, and induced seismicity related to HF activities. The environmental and health hazards posed by HF fluid are concerning due to the high concentration of toxic chemicals, the limited data on toxicity, the high probability of spills, and the reported cases of aquifer contamination. Furthermore, low load recovery values (10%-50 %) suggest that a significant volume of fracturing fluids may remain in the subsurface, thereby potentially increasing the likelihood of fluid migration towards drinking water sources under certain conditions. Hence, the fate of HF fluid is explained by establishing correlations between fluid flow (i.e., flow-back and migration to the subsurface) and different operation and formation parameters. For example, a negative correlation was detected between HF fluid recovery and shut-in period, fracture network complexity, and induced seismicity, while a positive correlation was observed between HF fluid migration speed and permeable pathways. Moreover, it is shown that the main handicap in assessing related risks is the scarcity of disclosure and monitoring data. Consequently, future work must focus on imposing strict disclosure and incident-reporting regulations, and more publications should be dedicated to inspecting the composition and impact of HF fluid.

Healthcare waste management and antimicrobial resistance: a critical review

The rapid growth of populations and urbanization has led to a significant increase in healthcare waste, posing serious health risks. A search on Google Scholar identified seven relevant articles from Ethiopia that examine the relationship between improper waste management in healthcare facilities (HCFs) and the rise of antimicrobial resistance (AMR) genes. This review aims to highlight key concepts, evidence sources, and knowledge gaps specific to the Ethiopian context. The unsafe disposal of antibiotics through leaks and solid waste has contributed to what some are calling a 'silent pandemic,' raising concerns about emerging infectious diseases. Studies have revealed alarming rates of infectious agents and AMR in healthcare wastewater. Isolates of C. jejuni, Escherichia coli, Enterococcus faecalis, and Enterococcus faecium from various healthcare waste sites in Ethiopia demonstrate high levels of AMR genes. Additionally, research indicates that HCFs produce significant amounts of waste, with high per-person daily waste production rates. Leachate from landfills containing this waste can negatively affect soil health, biological activity, water quality, agriculture, animal health, and human well-being. To mitigate these risks, effective waste management practices and the promotion of alternative antimicrobial use are essential strategies for reducing the emergence of pandemic diseases in developing countries.

Distribution and Characterization of Quaternary Ammonium Biocides Resistant Bacteria in Different Soils, in South-Western China

Quaternary ammonium compounds (QACs) are active ingredients in hundreds of disinfectants for controlling the epidemic of infectious diseases like SARS-CoV-2 (COVID-19), and are also widely used in shale gas exploitation. The occurrence of QAC-resistant bacteria in the environment could enlarge the risk of sterilization failure, which is not fully understood. In this study, QAC-resistant bacteria were enumerated and characterized in 25 soils collected from shale gas exploitation areas. Total counts of QAC-resistant bacteria ranged from 6.81 × 103 to 4.48 × 105 cfu/g, accounting for 1.59% to 29.13% of the total bacteria. In total, 29 strains were further purified and identified as Lysinibacillus, Bacillus, and Klebsiella genus. There, bacteria covering many pathogenic bacteria showed different QACs tolerance with MIC (minimum inhibition concentration) varying from 4 mg/L to 64 mg/L and almost 58.6% of isolates have not previously been found to tolerate QACs. Meanwhile, the QAC-resistant strains in the produced water of shale gas were also identified. Phylogenetic trees showed that the resistant species in soil and produced water are distinctly different. That is the first time the distribution and characterization of QAC-resistant bacteria in the soil environment has been analyzed.

Metabolite analysis of 14C-labeled chloromethylisothiazolinone/methylisothiazolinone for toxicological consideration of inhaled isothiazolinone biocides in lungs

5-Chloro-2-methyl-4-isothiazolin-3-one (CMIT) and 2-methyl-4-isothiazolin-3-one (MIT) used as preservatives in various products, including humidifier disinfectants, presents substantial health hazards. This research delves into the toxicological assessments of CMIT/MIT in the respiratory system using animal models. Through the synthesis of radiolabeled [14C]CMIT and [14C]MIT, we investigated the biological uptake and in vivo behaviors of CMIT/MIT in the respiratory tissues following intratracheal exposure. Quantitative whole-body autoradiography (QWBA) revealed significant persistence of CMIT/MIT in lung tissue. In addition, radio high-performance liquid chromatography (radio-HPLC) with tandem mass spectrometry (LC-MS/MS) was employed for metabolite profiling and identification. Notably, around 28% of the radiolabel was retained in tissue after the extraction step, suggesting covalent binding of CMIT/MIT and their metabolites with pulmonary biomolecules. This observation demonstrates the propensity of the electrophilic isothiazolinone ring in CMIT/MIT to undergo chemical interactions with biothiols in proteins and enzymes, fostering irreversible alterations of biomolecules. Such accumulations of transformations could result in direct toxicity at both cellular and organ levels. Additionally, the detection of metabolites, including a MIT dimer conjugated with glutathione (GSH), as analyzed by mass spectrometry indicates the possible reduction of cellular GSH levels and subsequent oxidative stress. This investigation offers an in-depth insight into the toxic mechanisms of CMIT/MIT, underlying their capability to engage in complex formations with biomacromolecules and induce pronounced respiratory toxicity. These results highlight the imperative for stringent safety assessments of these chemicals, advocating for improved public health and safety measures in the use of chemicals.

Inhibition of Microbial Growth and Biofilm Formation in Pure and Mixed Bacterial Samples

Hydraulic fracturing, or fracking, requires large amounts of water to extract fossil fuel from rock formations. As a result of hydraulic fracturing, the briny wastewater, often termed back-produced fracturing or fracking water (FW), is pumped into holding ponds. One of the biggest challenges with produced water management is controlling microbial activity that could reduce the pond water's reusable layer and pose a significant environmental hazard. This study focuses on the characterization of back-produced water that has been hydraulically fractured using chemical and biological analysis and the development of a high-throughput screening method to evaluate and predict the antimicrobial effect of four naturally and commercially available acidic inhibitors (edetic acid, boric acid, tannic acid, and lactic acid) on the growth of the FW microbiome. Liquid cultures and biofilms of two laboratory model strains, the vegetative Escherichia coli MG1655, and the spore-forming Bacillus atrophaeus (also known as Bacillus globigii, BG) bacteria, were used as reference microorganisms. Planktonic bacteria in FW were more sensitive to antimicrobials than sessile bacteria in biofilms. Spore-forming BG bacteria exhibited more sensitivity to acidic inhibitors than the vegetative E. coli cells. Organic acids were the most effective bacterial growth inhibitors in liquid culture and biofilm.

Interactions between microbial communities and polymers in hydraulic fracturing water cycle: A review

Hydraulic fracturing (HF) has substantially boosted global unconventional hydrocarbon production but has also introduced various environmental and operational challenges. Understanding the interactions between abundant and diverse microbial communities and chemicals, particularly polymers used for proppant delivery, thickening, and friction reduction, in HF water cycles is crucial for addressing these challenges. This review primarily examined the recent studies conducted in China, an emerging area for HF activities, and comparatively examined studies from other regions. In China, polyacrylamide (PAM) and its derivatives products became key components in hydraulic fracturing fluid (HFF) for unconventional hydrocarbon development. The microbial diversity of unconventional HF water cycles in China was higher compared to North America, with frequent detection of taxa such as Shewanella, Marinobacter, and Desulfobacter. While biodegradation, biocorrosion, and biofouling were common issues across regions, the mechanisms underlying these microbe-polymer interactions differed substantially. Notably, in HF sites in the Sichuan Basin, the use of biocides gradually decreased its efficiency to mitigate adverse microbial activities. High-throughput sequencing proved to be a robust tool that could identify key bioindicators and biodegradation pathways, and help select optimal polymers and biocides, leading to more efficient HFF systems. The primary aim of this study is to raise awareness about the interactions between microorganisms and polymers, providing fresh insights that can inform decisions related to enhanced chemical use and biological control measures at HF sites.

Mitigation of Desulfovibrio ferrophilus IS5 degradation of X80 carbon steel mechanical properties using a green biocide

Most microbiologically influenced corrosion (MIC) studies focus on the threat of pinhole leaks caused by MIC pitting. However, microbes can also lead to structural failures. Tetrakis hydroxymethyl phosphonium sulfate (THPS) biocide mitigated the microbial degradation of mechanical properties of X80 steel pipeline by Desulfovibrio ferrophilus (IS5 strain), a very corrosive sulfate reducing bacterium. It was found that 100 ppm (w/w) THPS added to the enriched artificial seawater (EASW) culture medium before incubation resulted in 2.8-log reduction in sessile cell count after a 7-d incubation at 28 °C under anaerobic conditions, leading to 94% uniform corrosion rate reduction (from 1.3 to 0.07 mm/a), and 84% pitting corrosion rate reduction (from 0.70 to 0.11 mm/a). The X80 dogbone coupon incubated with 100 ppm THPS for 7 d suffered 3% loss in ultimate tensile strain and 0% loss in ultimate tensile strength compared with the abiotic control in EASW. In comparison, the no-treatment X80 dogbone coupon suffered losses of 13% in ultimate tensile strain and 6% in ultimate tensile stress, demonstrating very good THPS efficacy.

Long-term disinfectant exposure on intestinal immunity and microbiome variation of grass carp

The gut microbiome is crucial in maintaining fish health homeostasis. Disinfectants can kill important pathogens and disinfect fish eggs, yet their effect on the immune pathways and intestinal microbiome in healthy fish remains unknown. In this study, we investigated the effects of two disinfectants on the transcriptome profiles, immunological response, and gut microbiota dynamics of grass carp over a four-week trial. In particular, aquatic water was disinfected with 80 μg/L glutaraldehyde or 50 μg/L povidone-iodine. We found that glutaraldehyde and povidone-iodine induced gut antioxidant system and depressed the function of grass carp digestive enzymes. The results of the 16S rDNA high-throughput sequencing identified a reduction in the diversity of grass carp gut microbiota following the disinfectant treatment. Moreover, transcriptome profiling revealed that disinfectant exposure altered the immune-related pathways of grass carp and inhibited the expression of inflammation and tight junction related genes. Finally, the histopathological observation and apoptosis detection results suggested that the long-term diet of disinfectant destroyed intestinal structural integrity and promoted apoptosis. In conclusion, long-term exposure to disinfectants was observed to reduce oxidation resistance, suppress the immune response, dysbiosis of the intestinal flora, and resulted in increasing the apoptosis in intestinal of grass carp.

Metagenome-assembled genomes provide insight into the metabolic potential during early production of Hydraulic Fracturing Test Site 2 in the Delaware Basin

Demand for natural gas continues to climb in the United States, having reached a record monthly high of 104.9 billion cubic feet per day (Bcf/d) in November 2023. Hydraulic fracturing, a technique used to extract natural gas and oil from deep underground reservoirs, involves injecting large volumes of fluid, proppant, and chemical additives into shale units. This is followed by a "shut-in" period, during which the fracture fluid remains pressurized in the well for several weeks. The microbial processes that occur within the reservoir during this shut-in period are not well understood; yet, these reactions may significantly impact the structural integrity and overall recovery of oil and gas from the well. To shed light on this critical phase, we conducted an analysis of both pre-shut-in material alongside production fluid collected throughout the initial production phase at the Hydraulic Fracturing Test Site 2 (HFTS 2) located in the prolific Wolfcamp formation within the Permian Delaware Basin of west Texas, USA. Specifically, we aimed to assess the microbial ecology and functional potential of the microbial community during this crucial time frame. Prior analysis of 16S rRNA sequencing data through the first 35 days of production revealed a strong selection for a Clostridia species corresponding to a significant decrease in microbial diversity. Here, we performed a metagenomic analysis of produced water sampled on Day 33 of production. This analysis yielded three high-quality metagenome-assembled genomes (MAGs), one of which was a Clostridia draft genome closely related to the recently classified Petromonas tenebris. This draft genome likely represents the dominant Clostridia species observed in our 16S rRNA profile. Annotation of the MAGs revealed the presence of genes involved in critical metabolic processes, including thiosulfate reduction, mixed acid fermentation, and biofilm formation. These findings suggest that this microbial community has the potential to contribute to well souring, biocorrosion, and biofouling within the reservoir. Our research provides unique insights into the early stages of production in one of the most prolific unconventional plays in the United States, with important implications for well management and energy recovery.

Prioritizing Organic Pollutants for Shale Gas Exploitation: Life Cycle Environmental Risk Assessments in China and the US

Environmental impacts associated with shale gas exploitation have been historically underestimated due to neglecting to account for the production or the release of end-of-pipe organic pollutants. Here, we assessed the environmental impacts of shale gas production in China and the United States using life cycle assessment. Through data mining, we compiled literature information on organic pollutants in flowback and produced water (FPW), followed by assessments using USEtox to evaluate end-of-pipe risks. Results were incorporated to reveal the life cycle risks associated with shale gas exploitation in both countries. China exhibited higher environmental impacts than the US during the production phase. Substantially different types of organic compounds were observed in the FPW between two countries. Human carcinogenic and ecological toxicity attributed to organics in FPW was 3 orders of magnitude higher than that during the production phase in the US. Conversely, in China, end-of-pipe organics accounted for approximately 52%, 1%, and 47% of the overall human carcinogenic, noncarcinogenic, and ecological impacts, respectively. This may be partially limited by the quantitative data available. While uncertainties exist associated with data availability, our study highlights the significance of integrating impacts from shale gas production to end-of-pipe pollution for comprehensive environmental risk assessments.

Bromine contamination and risk management in terrestrial and aquatic ecosystems

Bromine (Br) is widely distributed through the lithosphere and hydrosphere, and its chemistry in the environment is affected by natural processes and anthropogenic activities. While the chemistry of Br in the atmosphere has been comprehensively explored, there has never been an overview of the chemistry of Br in soil and aquatic systems. This review synthesizes current knowledge on the sources, geochemistry, health and environmental threats, remediation approaches, and regulatory guidelines pertaining to Br pollution in terrestrial and aquatic environments. Volcanic eruptions, geothermal streams, and seawater are the major natural sources of Br. In soils and sediments, Br undergoes natural cycling between organic and inorganic forms, with bromination reactions occurring both abiotically and through microbial activity. For organisms, Br is a non-essential element; it is passively taken up by plant roots in the form of the Br- anion. Elevated Br- levels can limit plant growth on coastal soils of arid and semi-arid environments. Br is used in the chemical industry to manufacture pesticides, flame retardants, pharmaceuticals, and other products. Anthropogenic sources of organobromine contaminants in the environment are primarily wastewater treatment, fumigants, and flame retardants. When aqueous Br- reacts with oxidants in water treatment plants, it can generate brominated disinfection by-products (DBPs), and exposure to DBPs is linked to adverse human health effects including increased cancer risk. Br- can be removed from aquatic systems using adsorbents, and amelioration of soils containing excess Br- can be achieved by leaching, adding various amendments, or phytoremediation. Developing cost-effective methods for Br- removal from wastewater would help address the problem of toxic brominated DBPs. Other anthropogenic organobromines, such as polybrominated diphenyl ether (PBDE) flame retardants, are persistent, toxic, and bioaccumulative, posing a challenge in environmental remediation. Future research directives for managing Br pollution sustainably in various environmental settings are suggested here.

Review of techniques for the in-situ sterilization of soil contaminated with Bacillus anthracis spores or other pathogens

This review summarizes the literature on efficacy of techniques to sterilize soil. Soil may need to be sterilized if contaminated with pathogens such as Bacillus anthracis. Sterilizing soil in-situ minimizes spread of the bio-contaminant. Soil is difficult to sterilize, with efficacy generally diminishing with depth. Methyl bromide, formaldehyde, and glutaraldehyde are the only soil treatment options that have been demonstrated at full-scale to effectively inactivate Bacillus spores. Soil sterilization modalities with high efficacy at bench-scale include wet and dry heat, metam sodium, chlorine dioxide gas, and activated sodium persulfate. Simple oxidants such as chlorine bleach are ineffective in sterilizing soil.

Role of Carbonyl Compounds for N-Nitrosamine Formation during Nitrosation: Kinetics and Mechanisms

N-Nitrosamines are potential human carcinogens frequently detected in natural and engineered aquatic systems. This study sheds light on the role of carbonyl compounds in the formation of N-nitrosamines by nitrosation of five secondary amines via different pathways. The results showed that compared to a control system, the presence of formaldehyde enhances the formation of N-nitrosamines by a factor of 5-152 at pH 7, depending on the structure of the secondary amines. Acetaldehyde showed a slight enhancement effect on N-nitrosamine formation, while acetone and benzaldehyde did not promote nitrosation reactions. For neutral and basic conditions, the iminium ion was the dominant intermediate for N-nitrosamine formation, while carbinolamine became the major contributor under acidic conditions. Negative free energy changes (<-19 kcal mol-1) and relatively low activation energies (<18 kcal mol-1) of the reactions of secondary amines with N2O3, iminium ions with nitrite and carbinolamines with N2O3 from quantum chemical computations further support the proposed reaction pathways. This highlights the roles of the iminium ion and carbinolamine in the formation of N-nitrosamines during nitrosation in the presence of carbonyl compounds, especially in the context of industrial wastewater.

Toxicity and chemical characterization of shale gas wastewater discharged to the receiving water: Evidence from toxicity identification evaluation

Flowback and produced water (FPW) generated from shale gas extraction is a complex mixture consisting of injected drilling fluid, deep formation water, and byproducts of downhole reactions. Limited knowledge is available regarding the impact of discharged FPW on surface water in China. With the development of shale gas exploitation, this emphasizes an urgent need for comprehensive assessments and stringent regulations to ensure the safe disposal of shale gas extraction-related wastewater. Herein, we explored potential impacts of treated shale gas wastewater discharged into a local river in southwest China through toxicity identification evaluation (TIE). Results revealed that organics and particulates significantly contributed to the overall toxicity of the treated FPW wastewater. Through target and suspect chemical analyses, various categories of organic contaminants were detected, including alkanes, aromatic hydrocarbons, biocides, phenols, and phthalates. Furthermore, non-target analysis uncovered the presence of surfactant-related contaminants in tissues of exposed organisms, but their contribution to the observed toxicity was unclear due to the lack of effect data for these compounds. Higher toxicity was found at the discharge point compared with upstream sites; however, the toxicity was rapidly mitigated due to dilution in the receiving river, posing little impact on downstream areas. Our study highlighted the importance of monitoring toxicity and water quality of FPW effluent even though dilution could be a viable approach when the water volume in the discharge was small.

Increases in trade secret designations in hydraulic fracturing fluids and their potential implications for environmental health and water quality

Hydraulic fracturing is an increasingly common method of oil and gas extraction across the United States. Many of the chemicals used in hydraulic fracturing processes have been proven detrimental to human and environmental health. While disclosure frameworks have advanced significantly in the last 20 years, the practice of withholding chemical identities as "trade secrets" or "proprietary claims" continues to represent a major absence in the data available on hydraulic fracturing. Here, we analyze rates of trade secret claims using FracFocus, a nationwide database of hydraulic fracturing data, from January 1, 2014 to December 31, 2022. We use the open-source tool Open-FF, which collates FracFocus data, makes it accessible for systematic analysis, and performs several quality-control measures. We found that the use by mass of chemicals designated as trade secrets has increased over the study time period, from 728 million pounds in 2014 to 2.96 billion pounds in 2022 (or a 43.7% average yearly increase). A total of 10.4 billion pounds of chemicals were withheld as trade secrets in this time period. The water volume used (and therefore total mass of fracturing fluid) per fracturing job has shown a large increase from 2014 to 2022, which partly explains the increase in mass of chemicals withheld as trade secrets over this time period, even as total fracturing jobs and individual counts of proprietary records have decreased. Our analysis also shows increasing rates of claiming proppants (which can include small grains of sand, ceramic, or other mineral substances used to prop open fractures) as proprietary. However, the mean and median masses of non-proppant constituents designated as trade secrets have also increased over the study period. We also find that the total proportion of all disclosures including proprietary designations has increased by 1.1% per year, from 79.3% in 2014 to 87.5% in 2022. In addition, most disclosures designate more than one chemical record as proprietary: trade secret withholding is most likely to apply to 10-25% of all records in an individual disclosure. We also show the top ten reported purposes that most commonly include proprietary designations, after removing vague or multiple entries, the first three of which are corrosion inhibitors, friction reducers, and surfactants. Finally, we report the top ten operators and suppliers using and supplying proprietary chemicals, ranked by mass used or supplied, over our study period. These results suggest the importance of revisiting the role of proprietary designations within state and federal disclosure mechanisms.

Enhancing microbiologically influenced corrosion protection of carbon steels with silanized epoxy-biocide hybrid coatings

Microbial biofilms and microbiologically influenced corrosion (MIC) pose serious problems in pipelines transporting freshwater from the reservoir to service water systems and fire water systems of power reactors. The present work aims to design a silane-based epoxy-biocide hybrid coating along with antibacterial compounds on carbon steels (CS) for controlling the MIC of pipeline materials. The optimal inhibitory concentrations of biocides are identified and a robust protocol has been developed to prepare epoxy-based coatings impregnated with three biocides (25 ppm each of benzalkonium chloride, bronopol, and isothiazoline). Microbiological and accelerated corrosion studies were carried out by exposing the coated CS specimens to the enriched freshwater bacterial culture (FWC). As compared to the impedance value of 102 Ohms for the polished CS, the values were 106 and 105 Ohms, respectively, for epoxy-coated specimens (CSE) and epoxy-coated specimens impregnated with biocides (CSEB). The corrosion protection efficiency of CSE and CSEB coated specimens exposed to FWC was 99.9% and 98.1%, respectively. Confocal microscopic analysis showed the average biomass thickness was 51.3 ± 0.6 µm and 24.4 ± 0.5 µm, respectively, for CSE and CSEB specimens in comparison to 94.1 ± 0.2 µm on CS specimens. The improved anticorrosion and antifouling behaviors observed in the CSEB specimens suggest that the new coating strategy has the potential for the development of multifunctional hybrid epoxy coatings for pipeline materials to mitigate MIC-related issues in water-transporting pipeline systems.

Bioconcentration Assessment of Three Cationic Surfactants in Permanent Fish Cell Lines

Cationic surfactants are used in many industrial processes and in consumer products with concurrent release into the aquatic environment, where they may accumulate in aquatic organisms to regulatoryly relevant thresholds. Here, we aimed to better understand the bioconcentration behavior of three selected cationic surfactants, namely N,N-dimethyldecylamine (T10), N-methyldodecylamine (S12), and N,N,N-trimethyltetradecylammonium cation (Q14), in the cells of fish liver (RTL-W1) and gill (RTgill-W1) cell lines. We conducted full mass balances for bioconcentration tests with the cell cultures, in which the medium, the cell surface, the cells themselves, and the plastic compartment were sampled and quantified for each surfactant by HPLC MS/MS. Accumulation in/to cells correlated with the surfactants' alkyl chain lengths and their membrane lipid-water partitioning coefficient, DMLW. Cell-derived bioconcentration factors (BCF) of T10 and S12 were within a factor of 3.5 to in vivo BCF obtained from the literature, while the cell-derived BCF values for Q14 were >100 times higher than the in vivo BCF. From our experiments, rainbow trout cell lines appear as a suitable conservative in vitro screening method for bioconcentration assessment of cationic surfactants and are promising for further testing.

Changes in environmental and engineered conditions alter the plasma membrane lipidome of fractured shale bacteria

IMPORTANCE

Microorganisms inadvertently introduced into the shale reservoir during fracturing face multiple stressors including brine-level salinities and starvation. However, some anaerobic halotolerant bacteria adapt and persist for long periods of time. They produce hydrogen sulfide, which sours the reservoir and corrodes engineering infrastructure. In addition, they form biofilms on rock matrices, which decrease shale permeability and clog fracture networks. These reduce well productivity and increase extraction costs. Under stress, microbes remodel their plasma membrane to optimize its roles in protection and mediating cellular processes such as signaling, transport, and energy metabolism. Hence, by observing changes in the membrane lipidome of model shale bacteria, Halanaerobium congolense WG10, and mixed consortia enriched from produced fluids under varying subsurface conditions and growth modes, we provide insight that advances our knowledge of the fractured shale biosystem. We also offer data-driven recommendations for improving biocontrol efficacy and the efficiency of energy recovery from unconventional formations.

Main Control Factors of Fracture Propagation in Reservoir: A Review

The fracture distribution and internal control factors after the fracturing of unconventional oil and gas reservoirs determine the reservoir reforming effect to a large extent. Based on the research of global scholars on the influencing factors of fracture propagation, comprehensive theoretical model, and numerical simulation, this Review systematically discusses the influence of internal geological factors and external engineering factors of unconventional oil and gas reservoir on fracture propagation behavior and summarizes the current problems and development trends in fracture research. The results show the following: (1) The fracture propagation is a comprehensive process constrained by lithology and mineral composition, water saturation, nonhomogeneity, natural weak surface, and ground stress. (2) External engineering factors have a meaningful control effect on fracture propagation; the type and temperature of fracturing fluids can also change the mechanical properties of different rocks, thus affecting the fracture propagation pattern. (3) The existing fracture propagation models have certain limitations, and their computational reliability still needs to be further verified. (4) Numerical simulation can break through the limitations of physical simulation, but different simulation methods have different shortcomings and applicability. In the future, we should focus on: (1) finding parameters to quantitatively characterize heterogeneity at the 3D level, which is an important direction to study the effect of heterogeneity on fracture propagation; (2) introducing computerized methods to establish a geological model that considers multiple factors and combining it with numerical simulation software to study fracture propagation; (3) considering the characteristics of fluid-liquid-solid phase comprehensively, establishing a suitable THL coupling equation; (4) how the interaction mode of fracturing fracture is combined with the natural fracture geometry, and how the fracture is affected by fracturing engineering parameters such as fluid injection rate and viscosity of fracturing fluid; and (5) geology-engineering dynamic integration, which is an important direction to be carried out in the future.

Changes in community structure and microbiological risks in a small stream after receiving treated shale gas wastewater for two years

Discharge of treated shale gas wastewater is becoming prevalent in the Sichuan Basin in China, and the resulting potential environmental impacts have raised concern. In this study, the responses of microbial community in the receiving water to discharge of treated shale gas wastewater were assessed during a two-year study period, covering two wet seasons and one dry season. The results showed that the discharge of treated shale gas wastewater had no significant effects on alpha diversity in the two wet seasons, but had significant effects in the dry season after 15 months of discharge. Obvious changes in microbial community structure were observed in all three seasons at the downstream sites near the wastewater outfall, as compared to the control site. Multimetric indices indicated that the impacts of wastewater discharge on microbial ecosystem occurred with the extension of the discharge period. Moreover, special attention was given to the microbiological risks associated with antibiotic resistance genes (ARGs), virulence factor genes (VFGs), and pathogenic antibiotic resistant bacteria (PARBs) in the dry season in sediments of the receiving water. At downstream sites near the outfall, five subtypes of ARGs and seven VFGs showed a significant increase in relative abundance. Forty-two PARBs carrying ARGs and VFGs were detected, and three PARBs (Pseudomonas aeruginosa, Pseudomonas stutzeri and Pseudomonas fluorescens) increased obviously in relative abundance at the downstream site near the outfall. In conclusion, long-term wastewater discharge had effects on the microbial community, and limited microbiological risks existed in the receiving waters.

Aromatic amino acid metabolism and active transport regulation are implicated in microbial persistence in fractured shale reservoirs

Hydraulic fracturing has unlocked vast amounts of hydrocarbons trapped within unconventional shale formations. This large-scale engineering approach inadvertently introduces microorganisms into the hydrocarbon reservoir, allowing them to inhabit a new physical space and thrive in the unique biogeochemical resources present in the environment. Advancing our fundamental understanding of microbial growth and physiology in this extreme subsurface environment is critical to improving biofouling control efficacy and maximizing opportunities for beneficial natural resource exploitation. Here, we used metaproteomics and exometabolomics to investigate the biochemical mechanisms underpinning the adaptation of model bacterium Halanaerobium congolense WG10 and mixed microbial consortia enriched from shale-produced fluids to hypersalinity and very low reservoir flow rates (metabolic stress). We also queried the metabolic foundation for biofilm formation in this system, a major impediment to subsurface energy exploration. For the first time, we report that H. congolense WG10 accumulates tyrosine for osmoprotection, an indication of the flexible robustness of stress tolerance that enables its long-term persistence in fractured shale environments. We also identified aromatic amino acid synthesis and cell wall maintenance as critical to biofilm formation. Finally, regulation of transmembrane transport is key to metabolic stress adaptation in shale bacteria under very low well flow rates. These results provide unique insights that enable better management of hydraulically fractured shale systems, for more efficient and sustainable energy extraction.

Synthesis of Mesoporous Lanthanum-Doped SnO2 Spheres for Sensitive and Selective Detection of the Glutaraldehyde Disinfectant

Glutaraldehyde disinfectant has been widely applied in aquaculture, farming, and medical treatment. Excessive concentrations of glutaraldehyde in the environment can lead to serious health hazards. Therefore, it is extremely important to develop high-performance glutaraldehyde sensors with low cost, high sensitivity, rapid response, fabulous selectivity, and low limit of detection. Herein, mesoporous lanthanum (La) doped SnO2 spheres with high specific surface area (52-59 m2 g-1), uniform mesopores (with a pore size concentrated at 5.7 nm), and highly crystalline frameworks are designed to fabricate highly sensitive gas sensors toward gaseous glutaraldehyde. The mesoporous lanthanum-doped SnO2 spheres exhibit excellent glutaraldehyde-sensing performance, including high response (13.5@10 ppm), rapid response time (28 s), and extremely low detection limit of 0.16 ppm. The excellent sensing performance is ascribed to the high specific surface area, high contents of chemisorbed oxygen species, and lanthanum doping. DFT calculations suggest that lanthanum doping in the SnO2 lattice can effectively improve the adsorption energy toward glutaraldehyde compared to pure SnO2 materials. Moreover, the fabricated gas sensors can effectively detect commercial glutaraldehyde disinfectants, indicating a potential application in aquaculture, farming, and medical treatment.

High Chlorine Concentrations in an Unconventional Oil and Gas Development Region and Impacts on Atmospheric Chemistry

Growth in unconventional oil and gas development (UOGD) in the United States has increased airborne emissions, raising environmental and human health concerns. To assess the potential impacts on air quality, we deployed instrumentation in Karnes City, Texas, a rural area in the middle of the Eagle Ford Shale. We measured several episodes of elevated Cl2 levels, reaching maximum hourly averages of 800 ppt, the highest inland Cl2 concentration reported to date. Concentrations peak during the day, suggesting a strong local source (given the short photolysis lifetime of Cl2) and/or a photoinitiated production mechanism. Well preproduction activity near the measurement site is a plausible source of these high Cl2 levels via direct emission and photoactive chemistry. ClNO2 is also observed, but it peaks overnight, consistent with well-known nocturnal formation processes. Observations of organochlorines in the gas and particle phases reflect the contribution of chlorine chemistry to the formation of secondary pollutants in the area. Box modeling results suggest that the formation of ozone at this location is influenced by chlorine chemistry. These results suggest that UOGD can be an important source of reactive chlorine in the atmosphere, impacting radical budgets and the formation of secondary pollutants in these regions.

Comprehensive Review on the Use of Biocides in Microbiologically Influenced Corrosion

A microbiologically influenced corrosion (MIC) causes huge economic losses and serious environmental damage every year. The prevention and control measures for MIC mainly include physical, chemical, and biological methods. Among them, biocide application is the most cost-effective method. Although various biocides have their own advantages in preventing and treating MIC, most biocides have the problem of polluting the environment and increasing microorganism resistance. Therefore, it has stimulated the exploration of continuously developing new environmentally friendly and efficient biocides. In this review, the application advantages and research progress of various biocides used to prevent and control MIC are discussed. Also, this review provides a resource for the research and rational use of biocides regarding MIC mitigation and prevention.

Application of Hydrogels and Hydrocarbon-Based Gels in Oil Production Processes and Well Drilling

The use of gels in oil production processes has become a regular practice in oilfield operations and is constantly developing in all oil-producing countries of the world, as evidenced by the growth of publications and patent activity on this topic. Many oil production processes, such as hydraulic fracturing, conformance control, water, and gas shutoff, cannot be imagined without the use of gel technologies. Inorganic, organic, and hybrid gels are used, as well as foams, gel-forming, and gel-dispersed systems. The possibility of a broad control of structural and mechanical properties, thermal stability, and shear resistance by introducing microscale and nanoscale additives made hydrogels and hydrocarbon-based gels indispensable tools for oil engineers.

Removal of organic pollutants in shale gas fracturing flowback and produced water: A review

Shale gas has been developed as an alternative to conventional energy worldwide, resulting in a large amount of shale gas fracturing flowback and produced water (FPW). Previous studies focus on total dissolved solids reduction using membrane desalination. However, there is a lack of efficient and stable techniques to remove organic pollutants, resulting in severe membrane fouling in downstream processes. This review focuses on the concentration and chemical composition of organic matter in shale gas FPW in China, as well as the hazards of organic pollutants. Organic removal techniques, including advanced oxidation processes, coagulation, sorption, microbial degradation, and membrane treatment are systematically reviewed. In particular, the influences of high salt on each technique are highlighted. Finally, different treatment techniques are evaluated in terms of energy consumption, cost, and organic removal efficiency. It is concluded that integrated coagulation-sorption-Fenton-membrane filtration represents a promising treatment process for FPW. This review provides valuable information for the feasible design, practical operation, and optimization of FPW treatment.

Impacts of hydraulic fracturing wastewater from oil and gas industries on drinking water: Quantification of 69 disinfection by-products and calculated toxicity

Oil and gas production generates large amounts of brine wastewater called "produced water" with various geogenic and synthetic contaminants. These brines are generally used in hydraulic fracturing operations to stimulate production. They are characterized by elevated halide levels, particularly geogenic bromide and iodide. Such salt concentrations in produced water may be as high as thousands of mg/L of bromide and tens of mg/L of iodide. Large volumes of produced water are stored, transported, reused in production operations, and ultimately disposed of by deep well injection into saline aquifers. Improper disposal may potentially contaminate shallow freshwater aquifers and impact drinking water sources. Because conventional produced water treatment typically does not remove halides, produced water contamination of groundwater aquifers may cause the formation of brominated and iodinated disinfection by-products (I-DBPs) at municipal water treatment plants. These compounds are of interest because of their higher toxicity relative to their chlorinated counterparts. This study reports a comprehensive analysis of 69 regulated and priority unregulated DBPs in simulated drinking waters fortified with 1 % (v/v) oil and gas wastewater. Impacted waters produced 1.3×-5× higher levels of total DBPs compared to river water after chlorination and chloramination. Individual DBP levels ranged from (<0.1-122 μg/L). Overall, chlorinated waters formed highest levels, including trihalomethanes that would exceed the U.S. EPA regulatory limit of 80 μg/L. Chloraminated waters had more I-DBP formation and highest levels of haloacetamides (23 μg/L) in impacted water. Calculated cytotoxicity and genotoxicity were higher for impacted waters treated with chlorine and chloramine than corresponding treated river waters. Chloraminated impacted waters had the highest calculated cytotoxicity, likely due to higher levels of more toxic I-DBPs and haloacetamides. These findings demonstrate that oil and gas wastewater if discharged to surface waters could adversely impact downstream drinking water supplies and potentially affect public health.

Toxicity identification evaluation for hydraulic fracturing flowback and produced water during shale gas exploitation in China: Evidence from tissue residues and gene expression

Hydraulic fracturing flowback and produced water (HF-FPW) from shale gas extraction processes is a highly complex medium with potential threats to the environment. Current research on ecological risks of FPW in China is limited, and the link between major components of FPW and their toxicological effects on freshwater organisms is largely unknown. By integrating chemical and biological analyses, toxicity identification evaluation (TIE) was used to reveal causality between toxicity and contaminants, potentially disentangling the complex toxicological nature of FPW. Here, FPW from different shale gas wells, treated FPW effluent, and a leachate from HF sludge were collected from southwest China, and TIE was applied to obtain a comprehensive toxicity evaluation in freshwater organisms. Our results showed that FPW from the same geographic zone could cause significantly different toxicity. Salinity, solid phase particulates, and organic contaminants were identified as the main contributors to the toxicity of FPW. In addition to water chemistry, internal alkanes, PAHs, and HF additives (e.g., biocides and surfactants) were quantified in exposed embryonic fish by target and non-target tissue analyses. The treated FPW failed to mitigate the toxicity associated with organic contaminants. Transcriptomic results illustrated that organic compounds induced toxicity pathways in FPW-exposed embryonic zebrafish. Similar zebrafish gene ontologies were affected between treated and untreated FPW, again confirming that sewage treatment did not effectively remove organic chemicals from FPW. Thus, zebrafish transcriptome analyses revealed organic toxicant-induced adverse outcome pathways and served as evidence for TIE confirmation in complex mixtures under data-poor scenarios.

Trans- and Multigenerational Effects of Isothiazolinone Biocide CMIT/MIT on Genotoxicity and Epigenotoxicity in Daphnia magna

The mixture of 5-chloro-2-methylisothiazol-3(2H)-one and 2-methylisothiazol-3(2H)-one, CMIT/MIT, is an isothiazolinone biocide that is consistently detected in aquatic environments because of its broad-spectrum usage in industrial fields. Despite concerns about ecotoxicological risks and possible multigenerational exposure, toxicological information on CMIT/MIT is very limited to human health and within-generational toxicity. Furthermore, epigenetic markers altered by chemical exposure can be transmitted over generations, but the role of these changes in phenotypic responses and toxicity with respect to trans- and multigenerational effects is poorly understood. In this study, the toxicity of CMIT/MIT on Daphnia magna was evaluated by measuring various endpoints (mortality, reproduction, body size, swimming behavior, and proteomic expression), and its trans- and multigenerational effects were investigated over four consecutive generations. The genotoxicity and epigenotoxicity of CMIT/MIT were examined using a comet assay and global DNA methylation measurements. The results show deleterious effects on various endpoints and differences in response patterns according to different exposure histories. Parental effects were transgenerational or recovered after exposure termination, while multigenerational exposure led to acclimatory/defensive responses. Changes in DNA damage were closely associated with altered reproduction in daphnids, but their possible relationship with global DNA methylation was not found. Overall, this study provides ecotoxicological information on CMIT/MIT relative to multifaceted endpoints and aids in understanding multigenerational phenomena under CMIT/MIT exposure. It also emphasizes the consideration of exposure duration and multigenerational observations in evaluating ecotoxicity and the risk management of isothiazolinone biocides.

Pronounced temporal changes in soil microbial community and nitrogen transformation caused by benzalkonium chloride

As one typical cationic disinfectant, quaternary ammonium compounds (QACs) were approved for surface disinfection in the coronavirus disease 2019 pandemic and then unintentionally or intentionally released into the surrounding environment. Concerningly, it is still unclear how the soil microbial community succession happens and the nitrogen (N) cycling processes alter when exposed to QACs. In this study, one common QAC (benzalkonium chloride (BAC) was selected as the target contaminant, and its effects on the temporal changes in soil microbial community structure and nitrogen transformation processes were determined by qPCR and 16S rRNA sequencing-based methods. The results showed that the aerobic microbial degradation of BAC in the two different soils followed first-order kinetics with a half-life (4.92 vs. 17.33 days) highly dependent on the properties of the soil. BAC activated the abundance of N fixation gene (nifH) and nitrification genes (AOA and AOB) in the soil and inhibited that of denitrification gene (narG). BAC exposure resulted in the decrease of the alpha diversity of soil microbial community and the enrichment of Crenarchaeota and Proteobacteria. This study demonstrates that BAC degradation is accompanied by changes in soil microbial community structure and N transformation capacity.

Outcomes of the Halliburton Loophole: Chemicals regulated by the Safe Drinking Water Act in US fracking disclosures, 2014-2021

Hydraulic fracturing (fracking) has enabled the United States to lead the world in gas and oil production over the past decade; 17.6 million Americans now live within a mile of an oil or gas well (Czolowski et al., 2017). This major expansion in fossil fuel production is possible in part due to the 2005 Energy Policy Act and its "Halliburton Loophole," which exempts fracking activity from regulation under the Safe Drinking Water Act (SDWA). To begin quantifying the environmental and economic impacts of this loophole, this study undertakes an aggregate analysis of chemicals that would otherwise be regulated by SDWA within FracFocus, an industry-sponsored fracking disclosure database. This paper quantifies the total disclosures and total mass of these chemicals used between 2014 and 2021, examines trends in their use, and investigates which companies most use and supply them. We find that 28 SDWA-regulated chemicals are reported in FracFocus, and 62-73% of all disclosures (depending on year) report at least one SDWA-regulated chemical. Of these, 19,700 disclosures report using SDWA-regulated chemicals in masses that exceed their reportable quantities as defined under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Finally, while the most common direct-supplier category is "company name not reported," Halliburton is the second-most named direct supplier of SWDA regulated chemicals. Halliburton is also the supplier most frequently associated with fracks that use SDWA regulated chemicals. These results show the necessity of a more robust and federally mandated disclosure system and suggest the importance of revisiting exemptions such as the Halliburton Loophole.

Investigating the bioaccumulation potential of anionic organic compounds using a permanent rainbow trout liver cell line

Permanent rainbow trout (Oncorhynchus mykiss) cell lines represent potential in vitro alternatives to experiments with fish. We here developed a method to assess the bioaccumulation potential of anionic organic compounds in fish, using the rainbow trout liver-derived RTL-W1 cell line. Based on the availability of high quality in vivo bioconcentration (BCF) and biomagnification (BMF) data and the substances' charge state at physiological pH, four anionic compounds were selected: pentachlorophenol (PCP), diclofenac (DCF), tecloftalam (TT) and benzotriazol-tert-butyl-hydroxyl-phenyl propanoic acid (BHPP). The fish cell line acute toxicity assay (OECD TG249) was used to derive effective concentrations 50 % and non-toxic exposure concentrations to determine exposure concentrations for bioaccumulation experiments. Bioaccumulation experiments were performed over 48 h with a total of six time points, at which cell, medium and plastic fractions were sampled and measured using high resolution tandem mass spectrometry after online solid phase extraction. Observed cell internal concentrations were over-predicted by KOW-derived predictions while pH-dependent octanol-water partitioning (DOW) and membrane lipid-water partitioning (DMLW) gave better predictions of cell internal concentrations. Measured medium and cell internal concentrations at steady state were used to calculate RTL-W1-based BCF, which were compared to DOW- or DMLW-based model approaches and in vivo data. With the exception of PCP, the cell-derived BCF best compared to DOW-based model predictions, which were higher than predictions based on DMLW. All methods predicted the in vivo BCF for diclofenac well. For PCP, the cell-derived BCF was lowest although all BCF predictions underestimated the in vivo BCF by ≥ 1 order of magnitude. The RTL-W1 cells, and all other prediction methods, largely overestimated in vivo BMF, which were available for PCP, TT and BHPP. We conclude that the RTL-W1 cell line can supplement BCF predictions for anionic compounds. For BMF estimations, however, in vitro-in vivo extrapolations need adaptation or a multiple cell line approach.

From Minerals to Simplest Living Matter: Life Origination Hydrate Theory

Long since, people tried to solve the mystery of the way that led to the appearance and propagation of living entities. However, no harmonious understanding of this mystery existed, because neither the scientifically grounded source minerals nor the ambient conditions were proposed and because it was groundlessly taken that the process of living matter origination is endothermal. The Life Origination Hydrate Theory (LOH-Theory) first suggests the chemical way capable of leading from the specified abundant natural minerals to origination of multitudes of multitudes of simplest living entities and gives an original explanation for the phenomena of chirality and racemization delay. The LOH-Theory covers the period up to origination of the genetic code. The LOH-Theory is grounded on the following three discoveries based on the available information and on the results of our experimental works performed using original instrumentation and computer simulations. (1) There is the only one triad of natural minerals applicable for exothermal thermodynamically possible chemical syntheses of simplest living-matter components. (2) N-base, ribose, and phosphdiester radicals and nucleic acids as whole are size-compatible with structural gas-hydrate cavities. (3) The gas-hydrate structure arises around amido-groups in cooled undisturbed systems consisting of water and highly-concentrated functional polymers with amido-groups.The natural conditions and historic periods favorable for simplest living matter origination are revealed. The LOH-Theory is supported by results of observations, biophysical and biochemical experiments, and wide application of original three-dimensional and two-dimensional computer simulations of biochemical structures within gas-hydrate matrix. The instrumentation and procedures for experimental verification of the LOH-Theory are suggested. If future experiments are successful, they, possibly, could be the first step on the way to industrial synthesis of food from minerals, i.e., to execution of the work that is performed by plants.

In silico and in vivo hepatoprotective activity of the synthesized 5-benzylidene-2-thiohydantoin against diethylnitrosamine-induced liver injury in a rat model

In the present study, the hepatoprotective effect of 5-benzylidine-2-thiohydantoin (5B2T), a unique derivative of the thiohydantoin group, on liver injury induced by diethylnitrosamine (DEN) in male rats was investigated. The experimental animals were divided into three groups, each with 14 rats. Rats in group I were considered to be controls and received only 10% Tween 80. Rats in group II were injected with 200 mg/kg DEN intraperitoneally. Rats in group III were injected with a single dose of DEN 200 mg/kg intraperitoneally and received the treatment orally (50 mg/kg, 5B2T) for two durations, 3 and 6 weeks. At the end of the experiment, blood was collected for the analysis of liver function and pro-inflammatory cytokine IL-6 and tumor necrosis factor α (TNF-α) levels. Additionally, liver specimens were used for histopathological examination and immunohistochemistry. The single intraperitoneal injection of 200 mg/kg DEN into rats resulted in significant elevation of serum enzyme levels of AST, ALT and ALP, which are indicators of hepatocellular damage, along with elevation in TNF-α and IL-6 in the DEN group. The results of both LFTs and ELISA in the treatment group showed improvements and a decline in the levels of the markers. Histopathological examination showed fibrosis, necrosis and infiltration of inflammatory cells in the DEN group, with lower intensity in the treatment group. The results of immunohistochemical staining revealed strong positive staining of both HSA and Ki-67 antibodies in the DEN group, with much lower intensity in the treatment group. The results of the docking study indicated that 5B2T has a remarkable interaction with TNF-α (PDB ID: 1TNF) and human IL-6 (PDB ID: 1IL6) with binding site energies of - 7.1 and - 6.1 (kcal/mol), respectively. The correct absorption and binding between the drug and the receptor was evaluated through computerized molecular docking by using the AutoDock program. The conclusion of the results from the current study reflected the interesting hepatoprotective abilities of 5B2T against DEN-induced hepatocellular damage and cancer in experimental rats.

Coupling iron-carbon micro-electrolysis with persulfate advanced oxidation for hydraulic fracturing return fluid treatment

Improving the sustainability of the hydraulic fracturing water cycle of unconventional oil and gas development needs an advanced water treatment that can efferently treat flowback and produced water (FPW). In this study, we developed a robust two-stage process that combines flocculation, and iron-carbon micro-electrolysis plus sodium persulfate (ICEPS) advanced oxidation to treat field-based FPW from the Sulige tight gas field, China. Influencing factors and optimal conditions of the flocculation-ICEPS process were investigated. The flocculation-ICEPS system at optimal conditions sufficiently removed the total organic contents (95.71%), suspended solids (92.4%), and chroma (97.5%), but the reaction stoichiometric efficiency (RSE) value was generally less than 5%. The particles and chroma were effectively removed by flocculation, and the organic contents was mainly removed by the ICEPS system. Fourier-transform infrared spectroscopy (FTIR) analysis was performed to track the changes in FPW chemical compositions through the oxidation of the ICEPS process. Multiple analyses demonstrated that PS was involved in the activation of Fe oxides and hydroxides accreted on the surface of the ICE system for FPW treatment, which led to increasing organics removal rate of the ICEPS system compared to the conventional ICE system. Our study suggests that the flocculation-ICEPS system is a promising FPW treatment process, which provides technical and mechanistic foundations for further field application.

Foamed glass ceramics-an upcycled scaffold for microbial biofilm development

Glass, a near infinitely recyclable material, can be upcycled to create new products such as foamed glass ceramics, which are essentially a synthetic pumice-like material. This material has been demonstrated to sustain preserved biofilms which have application in various fields based on the deployability of the product and the preserved microbes. Foamed glass ceramics have increased surface area compared to typical soda-lime glass cullet. This material has been explored for variety of applications including the growth, storage and transport of biofilms and microbial colonies which can be preserved and deployed later. Here, we demonstrate the ability for microbial cultures including BioTiger™, Escherichia coli K-12, Bacillus thuringiensis, and two environmental eukaryotic cells to colonize the upcycled glass products, undergo preservation, and regrow after 84 days of storage. The growth of preserved samples is correlated to the time spent incubating prior to preservation. These results demonstrate the applicability of this novel glass-biofilm combination in which various preserved microorganisms are able to be rapidly grown after storage on an upcycled glass product.

Electrochemical Characterization and Voltammetric Determination of Methylisothiazolinone on a Boron-Doped Diamond Electrode

The electrochemical properties of methylisothiazolinone (MIT), the most widely used preservative, were investigated by cyclic (CV) and differential pulse voltammetry (DPV) to develop a new method for its determination. To our knowledge, this is the first demonstration of a voltammetric procedure for the determination of MIT on a boron-doped diamond electrode (BDDE) in a citrate-phosphate buffer (C-PB) environment. The anodic oxidation process of methylisothiazolinone, which is the basis of this method, proved to be diffusion-controlled and proceeded with an irreversible two-electron exchange. The radical cations, as unstable primary products, were converted in subsequent chemical reactions to sulfoxides and sulfones, and finally to more stable final products. Performed determinations were based on the DPV technique. A linear calibration curve was obtained in the concentration range from 0.7 to 18.7 mg L^-1, with a correlation coefficient of 0.9999. The proposed procedure was accurate and precise, allowing the detection of MIT at a concentration level of 0.24 mg L^-1. It successfully demonstrated its suitability for the determination of methylisothiazolinone in household products without the need for any separation steps. The proposed method can serve as an alternative to the prevailing chromatographic determinations of MIT in real samples.

Geochemistry and Multiomics Data Differentiate Streams in Pennsylvania Based on Unconventional Oil and Gas Activity

Unconventional oil and gas (UOG) extraction is increasing exponentially around the world, as new technological advances have provided cost-effective methods to extract hard-to-reach hydrocarbons. While UOG has increased the energy output of some countries, past research indicates potential impacts in nearby stream ecosystems as measured by geochemical and microbial markers. Here, we utilized a robust data set that combines 16S rRNA gene amplicon sequencing (DNA), metatranscriptomics (RNA), geochemistry, and trace element analyses to establish the impact of UOG activity in 21 sites in northern Pennsylvania. These data were also used to design predictive machine learning models to determine the UOG impact on streams. We identified multiple biomarkers of UOG activity and contributors of antimicrobial resistance within the order Burkholderiales. Furthermore, we identified expressed antimicrobial resistance genes, land coverage, geochemistry, and specific microbes as strong predictors of UOG status. Of the predictive models constructed (n = 30), 15 had accuracies higher than expected by chance and area under the curve values above 0.70. The supervised random forest models with the highest accuracy were constructed with 16S rRNA gene profiles, metatranscriptomics active microbial composition, metatranscriptomics active antimicrobial resistance genes, land coverage, and geochemistry (n = 23). The models identified the most important features within those data sets for classifying UOG status. These findings identified specific shifts in gene presence and expression, as well as geochemical measures, that can be used to build robust models to identify impacts of UOG development. IMPORTANCE The environmental implications of unconventional oil and gas extraction are only recently starting to be systematically recorded. Our research shows the utility of microbial communities paired with geochemical markers to build strong predictive random forest models of unconventional oil and gas activity and the identification of key biomarkers. Microbial communities, their transcribed genes, and key biomarkers can be used as sentinels of environmental changes. Slight changes in microbial function and composition can be detected before chemical markers of contamination. Potential contamination, specifically from biocides, is especially concerning due to its potential to promote antibiotic resistance in the environment. Additionally, as microbial communities facilitate the bulk of nutrient cycling in the environment, small changes may have long-term repercussions. Supervised random forest models can be used to identify changes in those communities, greatly enhance our understanding of what such impacts entail, and inform environmental management decisions.

Antimicrobial Resistance and Its Drivers-A Review

Antimicrobial resistance (AMR) is a critical issue in health care in terms of mortality, quality of services, and financial damage. In the battle against AMR, it is crucial to recognize the impacts of all four domains, namely, mankind, livestock, agriculture, and the ecosystem. Many sociocultural and financial practices that are widespread in the world have made resistance management extremely complicated. Several pathways, including hospital effluent, agricultural waste, and wastewater treatment facilities, have been identified as potential routes for the spread of resistant bacteria and their resistance genes in soil and surrounding ecosystems. The overuse of uncontrolled antibiotics and improper treatment and recycled wastewater are among the contributors to AMR. Health-care organizations have begun to address AMR, although they are currently in the early stages. In this review, we provide a brief overview of AMR development processes, the worldwide burden and drivers of AMR, current knowledge gaps, monitoring methodologies, and global mitigation measures in the development and spread of AMR in the environment.

Hazard assessment of chemical constituents in biocide formulations used in offshore oil and gas operations

Biocides used in offshore oil and gas operations could be present in water discharges, and thus identifying such chemicals and their hazard could help address concerns regarding non-target organisms. Aquatic toxicity data, queried from different sources and augmented with predictive models, were used to develop species sensitivity distributions and their corresponding 5th percentile hazard concentrations (HC5s). Curated data, including over 1000 empirical records for 137 species, indicated no evidence of bias when comparing sensitivity between marine and freshwater species, even when predicted data were used. HC5s facilitated estimation of an acute-to-chronic ratio (ACR = 10), appropriate for most chemicals and useful in filling data gaps. Comparison of chronic-HC5s with the default approach for deriving predicted no effect concentrations showed that the latter systematically overstates aquatic hazard. The present approach shows promise of using acute-to-chronic HC5 ratios for defining assessment factors for different chemical classes, instead of the use of generic assessment factors.

Sorption, degradation and microbial toxicity of chemicals associated with hydraulic fracturing fluid and produced water in soils

Spills of hydraulic fracturing (HF) fluids and of produced water during unconventional gas extraction operations may cause soil contamination. We studied the degradation and microbial toxicity of selected HF chemical components including two biocides (methylisothiozolinone- MIT, chloromethylisothiozolinone- CMIT), a gel-breaker aid (triethanolamine -TEA), and three geogenic chemicals (phenol, m-cresol and p-cresol) in ultrapure water, HF fluid and produced water in five different soil types (surface and subsurface soils). The degradation of the two biocides (in soils treated with HF fluid or ultrapure water) and of the three geogenic chemicals (in soils treated with produced water) was rapid (in all cases DT₅₀ values < 2 days in surface soils). In contrast, the loss of TEA was much slower in soils, especially in those treated with HF fluid (DT₅₀ > 30 days). Sorption coefficients (K_oc in L/Kg) in these soils ranged from 71 to 733 for TEA, 64-408 for MIT and 11-72 for CMIT. In terms of soil microbial toxicity, exposure to HF fluid and produced water reduced microbial respiration, albeit temporarily. The overall microbial activities in surface soils contaminated with produced water had fully recovered in most soils. In contrast, the HF fluid addition to soils completely inhibited the nitrification in all soils, with little recovery over the 60 day experimental period. In the case of produced water exposure, three out of five surface soils showed complete recovery in nitrification during the study period. The functional genes for nitrogen fixation (nifH) and carbon cycling (GA1) and microbial community composition (16 S rRNA) were significantly affected by HF fluid in some soils. Overall, the study shows that the HF fluid can have significant detrimental impact on soil microbial functions, especially on nitrogen cycling. More work is needed to identify the exact cause of microbial toxicity in soils contaminated with HF fluid.

Degradation of chloromethylisothiazolinone antimicrobial by Vacuum-Ultraviolet/Ultraviolet irradiation: Reactive species, degradation pathway and toxicity evaluation

Chloromethylisothiazolinone (CMIT) has been extensively used as antimicrobial in cosmetics, detergents, wall paints, and anti-fouling products. To prevent the potential ecological and health risks, the degradation mechanisms and toxicity changes of CMIT by Vacuum-Ultraviolet/Ultraviolet (VUV/UV) irradiation were investigated in this study. VUV/UV irradiation showed better performance on CMIT degradation compared to sole UV photolysis. The removal efficiency of CMIT with photon fluence of 0.6 μEinstein/cm² was 8% and 100% by UV or VUV/UV irradiation, respectively. Radical quenching experiments indicated that 254 nm photolysis, 185 nm photolysis, and •OH oxidation contributed to CMIT degradation during VUV/UV process, with fluence-based apparent rate constants of 0.16, 0.13, and 4.9 μEinstein^-1cm², respectively. The formation of H₂O₂ during VUV/UV process increased to 0.7 mg/L at 4.5 min, and the concentration of •OH ranged within 1.0-3.8 × 10^-12 M. The degradation of CMIT by VUV/UV irradiation in neutral condition was slightly higher than that in acidic and basic conditions. The removal efficiency of CMIT with reaction time of 2 min decreased from 92.2% to 34.3% when the concentration of HCO₃^-/CO₃^2- increased to 1 mM. The degradation of CMIT by VUV/UV irradiation in secondary effluents was lower than that in ultrapure water because of the •OH scavenging effects, but still 2.9 times higher than that by UV photolysis. Four main degradation mechanisms of CMIT were observed during VUV/UV process, including the oxidation of sulfur, addition of hydroxyl groups on the double-carbon-bond, demethylation on the nitrogen, and substitution of organochlorine atom by hydroxyl group. Based on the quantitative structure activity relationship analysis, most products of CMIT underwent complete detoxification to fish and daphnia. 40% of products still showed acute toxicity to algae, but most of them were less toxic than CMIT.

The Microbial Community and Functional Potential in the Midland Basin Reveal a Community Dominated by Both Thiosulfate and Sulfate-Reducing Microorganisms

The Permian Basin is the highest producing oil and gas reservoir in the United States. Hydrocarbon resources in this region are often accessed by unconventional extraction methods, including horizontal drilling and hydraulic fracturing. Despite the importance of the Permian Basin, there is no publicly available microbiological data from this region. We completed an analysis of Permian produced water samples to understand the dynamics present in hydraulically fractured wells in this region. We analyzed produced water samples taken from 10 wells in the Permian region of the Midland Basin using geochemical measurements, 16S rRNA gene sequencing, and metagenomic sequencing. Compared to other regions, we found that Permian Basin produced water was characterized by higher sulfate and lower total dissolved solids (TDS) concentrations, with a median of 1,110 mg/L and 107,000 mg/L. Additionally, geochemical measurements revealed the presence of frac hits, or interwell communication events where an established well is affected by the pumping of fracturing fluid into a new well. The occurrence of frac hits was supported by correlations between the microbiome and the geochemical parameters. Our 16S rRNA gene sequencing identified a produced water microbiome characterized by anaerobic, halophilic, and sulfur reducing taxa. Interestingly, sulfate and thiosulfate reducing taxa including Halanaerobium, Orenia, Marinobacter, and Desulfohalobium were the most prevalent microbiota in most wells. We further investigated the metabolic potential of microorganisms in the Permian Basin with metagenomic sequencing. We recovered 15 metagenome assembled genomes (MAGs) from seven different samples representing 6 unique well sites. These MAGs corroborated the high presence of sulfate and thiosulfate reducing genes across all wells, especially from key taxa including Halanaerobium and Orenia. The observed microbiome composition and metabolic capabilities in conjunction with the high sulfate concentrations demonstrate a high potential for hydrogen sulfide production in the Permian Basin. Additionally, evidence of frac hits suggests the possibility for the exchange of microbial cells and/or genetic information between wells. This exchange would increase the likelihood of hydrogen sulfide production and has implications for the oil and gas industry. IMPORTANCE The Permian Basin is the largest producing oil and gas region in the United States and plays a critical role supplying national energy needs. Previous work in other basins has demonstrated that the geochemistry and microbiology of hydrocarbon regions can have a major impact on well infrastructure and production. Despite that, little work has been done to understand the complex dynamics present in the Permian Basin. This study characterizes and analyzes 10 unique wells and one groundwater sample in the Permian Basin using geochemical and microbial techniques. Across all wells we found a high number of classic and thiosulfate reducers, suggesting that hydrogen sulfide production may be especially prevalent in the Permian Basin. Additionally, our analysis revealed a biogeochemical signal impacted by the presence of frac hits, or interwell communication events where an established well is affected by the pumping of fracturing fluid into a new well. This information can be utilized by the oil and gas industry to improve oil recovery efforts and minimize commercial and environmental costs.

Stable Porous Organic Polymers Used for Reversible Adsorption and Efficient Separation of Trace SO2

The development of porous solid adsorbents for selective adsorption and separation of SO₂ has attracted much attention recently. Herein, we design porous organic polymers (POPs) decorated with pyridine ligands as building units (POP-Py) through a radical polymerization of the 2,5-divinylpyridine (v-Py) monomer. Due to its high BET surface area, nanoporosity, and excellent stability, the prepared POP-Py can be used for reversible adsorption and efficient separation of SO₂. The POP-Py possesses a SO₂ capacity of 10.8 mmol g^-1 at 298 K and 1.0 bar, which can be well retained after 6 recycles, showing an excellent reversible adsorption capacity. The POP-Py also shows superior separation performance for SO₂ from a ternary SO₂/CO₂/N₂ mixture (0.17/15/84.83v%), giving a breakthrough time and a saturated SO₂ capacity at 178 min g^-1 and 0.4 mmol g^-1. The retention time was well maintained even under high moisture conditions, confirming its superior water resistance. Furthermore, when other vinyl-functionalized organic ligand monomers (bipyridine, pyrimidine, and pyrazine) were employed for radical polymerization, all of the resultant porous organic ligand polymers (POP-BPy, POP-PyI, and POP-PyA) exhibited superior performance for reversible adsorption and efficient separation of SO₂. The combined features of reversible adsorption, efficient separation, and water resistance are important for the industrial applications of these materials as SO₂ adsorbents.

Occurrence and Transport of Isothiazolinone-Type Biocides from Commercial Products to Aquatic Environment and Environmental Risk Assessment

This study investigated the occurrence and transport of four isothiazolinone-type biocides from commercial products to wastewater treatment plants (influents, sludges, and effluents) and to natural emissaries (upstream and downstream the wastewater treatment plants) in Romania. All four biocides were determined in personal care and household products, with the highest concentration of 76.4 µg/L OIT (2-octyl-4-isothiazolin-3-one). For environmental samples, three of the four isothiazolinones were determined, CMI (5-chloro-2-methyl-4-isothiazolin-3-one) being the prominent compound for water samples. The maximum concentration of 84.0 µg/L in influent, 122 µg/L upstream, and 144 µg/L downstream the wastewater treatment plants were obtained for CMI. Unlike water samples, in the sewage sludge samples, OIT proved to be the dominant compound, with concentration up to 5.80 µg/g d.w. The extremely high levels of isothiazolinone determined in different WWTPs from Romania may be due to the COVID-19 pandemic situation, during which a much larger amount of cleaning, hygiene, and personal care products was used. The isothiazolinone-type biocides were readily removed from the influents of the five WWTPs, with the mean removal rate up to 67.5%. The mean mass loading value for the targeted biocides based on influent was 20.4 μg/day/1000 people, while the average environmental emissions were 6.93 μg/day/1000 people for effluents. The results obtained for riverine water combine with statistical analysis showed that the anthropogenic activities are the major contamination sources of the surface waters. Preliminary ecological risk evaluation showed that BIT (1,2-benzisothiazol-3(2H)-one), OIT, and CMI could pose a very high risks to different aquatic species living in the receiving aquatic environments.