Brominated dioxins and furans in a cement kiln co-processing municipal solid waste

Environmental impacts of cement kiln co-incineration sewage sludge biodried products in a scale-up trial

The biodrying technology as a pretreatment technology can overcome the limitations of cement kilns co-incineration sewage sludge (SS) on energy consumption. But the impact of SS biodried products on cement kilns and the route carbon reduction potential of biodrying + cement kilns have not been studied. In this study, SS biodrying and cement kiln co-incineration biodried product trials were conducted to highlight the matrix combustion characteristics, and the impact of biodried products on cement kilns (clinker capacity, coal consumption, and pollutant discharge). The carbon emissions of the four scenarios were assessed based on these results. The results showed that water removal rate reached 65.5 % after 11-day biodrying, and the wet-based lower heating value of the biodried product increased by 76.0 % compared with the initial matrix. Comprehensive combustibility index of the biodried product (0.745 × 10-7 %2℃-3min-2) was better than that of SS (0.433 × 10-7 %2℃-3min-2) although a portion of the organic matter was degraded. Cement kiln co-incineration of biodried products (150 t/d) resulted in per tonne of clinker saved 5.61 kg of coal due to the heat utilization efficiency of biodried products reached to 93.7 %. However, it led to an increase in the emission concentrations of NOX and SO2. Assessment results indicated that the biodrying + cement kiln pathway reduced CO2 emissions by 385.7 kg/t SS. Biodried products have greater potential to reduce emissions as alternative fuels than as fertilizers. This study indicated the advantages of SS biodrying + cement kiln co-incineration route.

Occurrence and carcinogenic potential of airborne PBDD/Fs and PCDD/Fs around a large-scale municipal solid waste incinerator: A long-term passive air sampling study

Municipal solid waste incinerator (MSWI) not only is deemed one of the uppermost sources of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), but also produces substantial amount of polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) owing to the existence of brominated flame retardants (BFRs) in the waste. So far, however, PBDD/Fs in the vicinal environments of MSWI and their associated risks remain rarely studied. Based on a one-year passive air sampling (PAS) scheme, we investigated airborne PBDD/Fs and PCDD/Fs around a large-scale MSWI that has been operated for multi-years. Both the concentrations of PBDD/Fs and PCDD/Fs showed spatially decreasing trends with the distance away from the MSWI, confirming the influence of the MSWI on the dioxin levels in its ambient air. But its influence on PBDD/Fs was less because PBDD/Fs exhibit lower volatility and therefore lower gaseous concentrations than PCDD/Fs. Compared to the existing global data of airborne PCDD/Fs and PBDD/Fs, our data of the MSWI vicinity were at medium levels, despite PAS samples only represent the concentrations of gaseous dioxins in theory. The seasonal data suggest that meteorological conditions exerted apparent influences over the concentrations and sources of airborne dioxins around the MSWI. As for PCDD/Fs, the MSWI was diagnosed as their uppermost source, followed by local traffic and volatilization/deposition. Whereas the top three PBDD/F sources were related to PBDEs, bromophenol/bromobenzene, and traffic vehicles, respectively. The bioassay-derived TEQs based on the aryl hydrocarbon receptor activation of airborne dioxins around the MSWI were one or two orders of magnitudes higher than their concentration-based TEQs, and the corresponding carcinogenic risks at some MSWI-vicinal sites exceeded the acceptable threshold proposed by the U. S. EPA (10-6 ∼ 10-4) and deserve continuous attention.

Advances in the management of radioactive wastes and radionuclide contamination in environmental compartments: a review

Several anthropogenic activities produce radioactive materials into the environment. According to reports, exposure to high concentrations of radioactive elements such as potassium (⁴⁰K), uranium (²³⁸U and ²³⁵U), and thorium (²³²Th) poses serious health concerns. The scarcity of reviews addressing the occurrence/sources, distribution, and remedial solutions of radioactive contamination in the ecosystems has fueled data collection for this bibliometric survey. In rivers and potable water, reports show that several parts of Europe and Asia have recorded radionuclide concentrations much higher than the permissible level of 1 Bq/L. According to various investigations, activity concentrations of gamma-emitting radioactive elements discovered in soils are higher than the global average crustal values, especially around mining activities. Adsorption technique is the most prevalent remedial method for decontaminating radiochemically polluted sites. However, there is a need to investigate integrated approaches/combination techniques. Although complete radionuclide decontamination utilizing the various technologies is feasible, future research should focus on cost-effectiveness, waste minimization, sustainability, and rapid radionuclide decontamination. Radioactive materials can be harnessed as fuel for nuclear power generation to meet worldwide energy demand. However, proper infrastructure must be put in place to prevent catastrophic disasters.

Framework of the Integrated Approach to Formation Mechanisms of Typical Combustion Byproducts─Polyhalogenated Dibenzo-p-dioxins/Dibenzofurans (PXDD/Fs)

Understanding the mechanisms through which persistent organic pollutants (POPs) form during combustion processes is critical for controlling emissions of POPs, but the mechanisms through which most POPs form are poorly understood. Polyhalogenated dibenzo-p-dioxins and dibenzofurans (PXDD/Fs) are typical toxic POPs, and the formation mechanisms of PXDD/Fs are better understood than the mechanisms through which other POPs form. In this study, a framework for identifying detailed PXDD/Fs formation mechanisms was developed and reviewed. The latest laboratory studies in which organic free radical intermediates of PXDD/Fs have been detected in situ and isotope labeling methods have been used to trace transformation pathways were reviewed. These studies provided direct evidence for PXDD/Fs formation pathways. Quantum chemical calculations were performed to determine the rationality of proposed PXDD/Fs formation pathways involving different elementary reactions. Many field studies have been performed, and the PXDD/Fs congener patterns found were compared with PXDD/Fs congener patterns obtained in laboratory simulation studies and theoretical studies to mutually verify the dominant PXDD/Fs formation mechanisms. The integrated method involving laboratory simulation studies, theoretical calculations, and field studies described and reviewed here can be used to clarify the mechanisms involved in PXDD/Fs formation. This review brings together information about PXDD/Fs formation mechanisms and provides a methodological framework for investigating PXDD/Fs and other POPs formation mechanisms during combustion processes, which will help in the development of strategies for controlling POPs emissions.

Concentrations, congener patterns, and correlations of unintentional persistent organic pollutants in cement kilns co-processing hazardous waste

Emissions from two typical cement kilns co-processing different kind of hazardous waste were analyzed for 143 congeners of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls, polychlorinated naphthalenes, polybrominated dibenzo-p-dioxins and dibenzofurans, and polybrominated diphenyl ethers. The congener distributions in different process stages were investigated. One of the plants co-processed waste chemical reagents from laboratories. The emission factor (TEQ basis) for the plant was 2.09 ng WHO2005 TEQ/t, with the kiln head and the kiln back end contributing 1.18, 0.91 ng WHO2005 TEQ/t, respectively. The other plant co-processed municipal waste incineration fly ash. The emission factor for the plant was 0.12 ng WHO2005 TEQ/t, with the kiln head and the kiln back end contributing 0.022, and 0.10 ng WHO2005 TEQ/t. These results indicate that co-processing of waste containing reagents from laboratories may lead to higher emission levels than co-processing of other types of waste. The congener patterns of persistent organic pollutants (POPs) in ash samples from the humidifier tower were similar to those in samples from the bag filter at the kiln back end. The correlation coefficients of five pollutants between the humidifier and bag filters samples were generally high, which indicated that conditions in those two stages similarly favored the formation of these POPs. Comparison of the concentrations for different process stages suggested that the main stage for formation of unintentional POPs was the humidifier tower. These results improve our understanding of emission characteristics and could be used for simultaneous control of multiple POPs.

Advances in the treatment of multi-pollutant flue gas in China's building materials industry

In most of the world's building material industries, the control of flue gas pollutants mainly focuses on a single pollutant. However, given the large capacity and high contribution of China's building materials industry to global air pollution, the need to develop multi-pollutant emission reduction technology is urgent. Recently, China has focused on reducing the emissions of flue gas pollutants in the building materials industry, established many key research and development projects, and gradually implemented more stringent pollutant emission limits. This project focuses on the most recent advances in flue gas emission control technology in China's building materials industry, including denitration, dust removal, desulfurization, synergistic multi-pollutant emission reduction, and the construction of pilot research and demonstration projects for pollutant removal in several building material industries. On this basis, revised pollutant limits in flue gas emitted in China's building material industry are proposed.

Variation in the formation characteristics of PBDD/F, brominated PAH, and PBDE congeners along the secondary copper smelting processes

Simultaneous determination of 58 congeners of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), brominated polycyclic aromatic hydrocarbons (Br-PAHs), and polybrominated diphenyl ethers (PBDEs) from multiple stages of industrial-scale secondary copper smelting plants was conducted with the aim of understanding their variations and control. In addition to the historical manufacture of PBDEs as brominated flame retardants, this study confirmed that PBDEs can be unintentionally produced and released from the secondary copper industry. The average mass emission factors of PBDD/Fs, PBDEs, and Br-PAHs from different sources were 10.0, 5.21 × 10³, and 7.24 × 10³ μg t^-1, respectively. Therefore, the emission of brominated persistent organic pollutants (POPs) in the secondary copper industry should be of concern. The concentration of brominated POPs increased from the gas cooling stage to stack outlet due to the possible "memory effect" and the regenerated POPs were mainly low-brominated homologs. A comparison of brominated POPs with corresponding chlorinated analogs in the same process indicated that the formation pathway of Br-PAHs was consistent with that of chlorinated PAHs. However, unlike chlorinated dioxins and furans, PBDD/Fs can also be formed from PBDEs as precursors, leading to obvious increases in highly brominated furans. Therefore, inhibiting the unintentional formation of PBDEs is important for controlling brominated POPs emissions.

Polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) in soil around municipal solid waste incinerator: A comparison with polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs)

Polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) share similar toxicities and thermal origins, e.g., municipal solid waste incinerator (MSWI). Recently, PBDD/Fs from MSWI attracted rising concern because their important precursors, i.e., brominated flame retardants (BFRs), were frequently found in various wastes for landfill or MSWI feedstock. So far, however, little is known about PBDD/Fs and their associated risks in the vicinal environments of MSWI. Here we analyzed PBDD/Fs and PCDD/Fs in 29 soil samples collected around a multiyear large-scale MSWI, and compared their spatial distributions, sources and risks. PBDD/Fs demonstrated comparable concentrations and toxic equivalent quantities (TEQs) to PCDD/Fs in these samples. Spatially, both the concentrations of PBDD/Fs and PCDD/Fs decreased outwards from the MSWI, and exhibited significant linear correlations with the distances from the MSWI in the southeast downwind soil, suggesting the influence of the MSWI on its vicinal soil environment. However, the existence of other dioxin sources concealed its influence beyond 6 km. PBDD/Fs in the soils were characterized by highly-brominated PBDFs, especially Octa-BDF, and their sources were diagnosed as the MSWI and diesel exhaust; PCDD/Fs, however, were dominated by highly-chlorinated PCDDs, particularly Octa-CDD, and were contributed individually or jointly by the MSWI, automobile exhaust and pentachlorophenol (PCP)/Na-PCP. The non-carcinogenic risks of dioxins in all the soil samples were acceptable, but their carcinogenic risks in 17% of the samples were unacceptable. These samples were all located close to the MSWI and highways, therefore, the land use of these two high-risk zones should be cautiously planed.

Environmental characteristics and formations of polybrominated dibenzo-p-dioxins and dibenzofurans

Polybrominated dibenzo-p-dioxins and furans (PBDD/Fs) are emerging persistent organic pollutants (POPs) that have similar or higher toxicities than the notorious dioxins. Toxicities, formation mechanisms, and environmental fates of PBDD/Fs are lacking because accurate quantification, especially of higher brominated congeners, is challenging. PBDD/F analysis is difficult because of photolysis and thermal degradation and interference from polybrominated diphenyl ethers. Here, literatures on PBDD/F analysis and environmental occurrences are reviewed to improve our understanding of PBDD/F environmental pollution and human exposure levels. Although PBDD/Fs behave similarly to dioxins, different congener profiles between PBDD/Fs and dioxins in the environment indicates their different sources and formation mechanisms. Herein, potential sources and formation mechanisms of PBDD/Fs were critically discussed, and current knowledge gaps and future directions for PBDD/F research are highlighted. An understanding of PBDD/F formation pathways will allow for development of synergistic control strategies for PBDD/Fs, dioxins, and other dioxin-like POPs.

Occurrence, profiles, and control of unintentional POPs in the steelmaking industry: A review

The steelmaking industry is an important source of unintentionally produced persistent organic pollutants (UP-POPs). This review summarizes the emission levels, characteristics, and formation mechanisms of UP-POPs, including halogenated dioxins, polychlorinated biphenyls, polychlorinated naphthalenes, and penta- and hexa- chlorobenzenes in the steelmaking industry to improve our understanding of the emissions of UP-POPs from the steelmaking industry. The factors influencing UP-POP formation during the iron ore sintering (IOS) process are also reviewed. The raw materials and temperature during the steelmaking process are important factors influencing UP-POP generation. Raw materials containing plastics, paints, cutting oil, rubber, and iron from electronic waste recycling can contribute to high emissions of UP-POPs during steelmaking processes. Electrostatic precipitator dust contains chlorine, carbon, and metals, which are usually recycled as a component of the raw material, and could also promote dioxin formation and emissions from IOS. Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are easily formed in high concentrations at temperatures in the range of 200 °C-650 °C. This review also provides a comprehensive summary of the UP-POP emission limits in the steel industry worldwide and the best available techniques and environmental practices for UP-POP emission reduction. The information in this review will be useful for the reduction of UP-POPs in the steelmaking process.

Field-scale study of co-processing dichlorodiphenyltrichloroethane-contaminated soil in a cement kiln

Persistent organic pollutants in soil are not readily degraded in the short term. The utilization of co-processing solid waste in cement kilns has received increasing attention in recent years. Co-processing may be a good way of disposing of dichlorodiphenyltrichloroethane-contaminated soil (CS). The feasibility of co-processing CS pretreated to desorb dichlorodiphenyltrichloroethane, was assessed by performing an industrial-scale trial, focusing on the risks posed by emissions to the environment. Samples of the input and output in cement kiln were collected for determining clinker quality, production operation, pollutant emissions, cement kiln system destruction efficiency, and distribution profiles of persistent organic pollutants unintentionally produced from kiln. The destruction efficiency and destruction removal efficiency both were > 99.99% in cement kiln system at the appropriate CS feeding rate. Emissions of stack gases produced by cement kilns co-processing CS were within the reasonable range set in China. Dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs) concentrations and distribution profiles in flue gases and particulate samples from two tests showed PCBs mainly formed at the same sites as PCDD/Fs, indicating they are may formed in a similar way in cement kiln. A comparison with the processing parameters in the clinker, cement kiln dust, and flue gas under baseline and co-processing conditions, manifested that co-processing had no effect on the operation or cement quality of the cement kiln. Thus co-processing CS at a rate of 20 t/h with pretreatment process, is an environmentally sound and highly efficient treatment for CS.

Ca2+ mediated mechanism of octa-brominated dioxin/furan formation via BDE-209 thermolysis: Introducing the Mayer bond order difference

Polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs) that form during industrial thermal processes, such as the cement kiln co-processing of BDE-209, are highly toxic contaminants. Nevertheless, the formation mechanisms of octa-brominated dioxins/furans (OBDD/Fs), most PBDD/F congeners, and one precursor of the more toxic lower PBDD/Fs from BDE-209 have received little attention. In cement kiln co-processes, the Ca²⁺-mediated regulation of OBDD/F formation is still debated. In this study, simulation experiments revealed that the average brominating degree of PBDD/Fs was 7.8, indicating that OBDD/Fs are dominant congeners (93.6 % median). Density functional theory (DFT) calculations found a new transition state (TS1) with a lower energy barrier than that found in a previous study. Three major OBDD/F formation reactions suggested that the presence of Ca²⁺ was thermodynamically beneficial to the formation of OBDD/Fs. This promotion effect can be attributed to the transfer of electron density leading to a change in the Mayer bond order (MBO) among elements when Ca²⁺ was bound. Intriguingly, in the transition state structures of the Ca²⁺-bound and Ca²⁺-free systems, the MBO difference among the old and new bonds can reveal the difficulty of Ca²⁺-mediated OBDD/F formation reactions from BDE-209.

A geospatially resolved database of hydraulic fracturing wells for chemical transformation assessment

Hydraulically fractured wells with horizontal drilling (HDHF) accounted for 69% of all oil and gas wells drilled and 670 000 of the 977 000 producing wells in 2016. However, only 238 flowback and produced water samples have been analyzed to date for specific organic chemicals. To aid the development of predictive tools, we constructed a database combining additive disclosure reports and physicochemical conditions at respective well sites with the goal of making synthesized analyses accessible. As proof-of-concept, we used this database to evaluate transformation pathways through two case studies: (1) a filter-based approach for flagging high-likelihood halogenation sites according to experimental criteria (e.g., for a model compound, cinnamaldehyde) and (2) a semi-quantitative, regionally comparative trihalomethane formation model that leverages an empirically derived equation. Study (1) highlighted 173 wells with high cinnamaldehyde halogenation likelihood based on combined criteria related to subsurface conditions and oxidant additive usage. Study (2) found that trihalomethane formation in certain wells within five specific basins may exceed regulatory limits for drinking water based on reaction-favorable subsurface conditions, albeit with wide uncertainty. While experimentation improves our understanding of subsurface reaction pathways, this database has immediate applications for informing environmental monitors and engineers about potential transformation products in residual fluids, guiding well operators' decisions to avoid unwanted transformations. In the future, we envision more robust components incorporating transformation, transport, toxicity, and other physicochemical parameters to predict subsurface interactions and flowback composition.

Pathways and influential factors study on the formation of PBDD/Fs during co-processing BDE-209 in cement kiln simulation system

The thermal processes of cement kilns are sources of polybrominated dibenzofurans and dioxins (PBDD/Fs); however, when co-processing decabromodiphenyl ether (BDE-209) soil in cement kilns, very few reports have investigated the mechanism of PBDD/Fs formation from BDE-209. Therefore, the pathways and factors that influence the formation of PBDD/Fs were investigated using Box-Behnken design (BBD) of the response surface methodology (RSM) at lab-scale. The PBDEs, HBr/Br₂ and PBDD/Fs emissions in flue gas from the simulated thermal process were analyzed using gas chromatography/mass spectroscopy (GC/MS), high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS), and ion chromatography (IC). Density functional theory (DFT) was also used to further discuss the formation of PBDD/Fs. The major products of BDE-209 thermal decomposition in flue gas were 97.1% HBr/Br₂ (a.v. 26.6%/70.6%) > 2.7% PBDEs >0.2% PBDD/Fs. Formation of precursors were the main pathways for PBDD/Fs, and those precursors were dominated by higher-brominated PBDEs (heptã deca-BDEs); debromination of BDE-209 was also a crucial pathway for the formation of PBDD/Fs throughout the thermal process. Interestingly, it was easier to form HpBDD/Fs from OBDD/Fs than from PBDEs. The O₂ percentage and interaction factors of O₂ percentage, temperature, and CaCO₃ percentage have the largest influence on PBDD/Fs emissions and formation.

Metabolomics and transcriptomics reveal defense mechanism of rice (Oryza sativa) grains under stress of 2,2',4,4'-tetrabromodiphenyl ether

2,2',4,4'-Tetrabromodiphenyl ether (BDE-47), a predominant polybrominated diphenyl ether (PBDE), has received extensive attention for its potential environmental impact. An integrated study of metabolomics and transcriptomics was conducted on two rice (Oryza sativa) cultivars, Lianjing-7 (LJ-7) and Yongyou-9 (YY-9), which have been identified as tolerant and sensitive cultivars to BDE-47, respectively. The objective was to investigate the molecular mechanisms of their different ability to tolerate BDE-47. Both rice plants were cultivated to maturity in soils containing three concentrations of BDE-47 (10, 20, and 50 mg/kg). Metabolomic analyses of rice grains identified 65 metabolites in LJ-7 and 45 metabolites in YY-9, including amino acids, saccharides, organic acids, fatty acids, and secondary metabolites. In the tolerant cultivar LJ-7 exposed to 50 mg/kg BDE-47, concentrations of most of the metabolites increased significantly, with α-ketoglutaric acid increased by 20-fold and stigmastanol increased by 12-fold. In the sensitive cultivar YY-9, the concentrations of most metabolites increased after the plant was exposed to 1 and 10 mg/kg BDE-47 but decreased after the plant was exposed to 50 mg/kg BDE-47. Transcriptomic data demonstrated that regulation of gene expressions was affected most in LJ-7 exposed to 50 mg/kg BDE-47 (966 genes up-regulated and 620 genes down-regulated) and in YY-9 exposed to 10 mg/kg BDE-47 (85 genes up-regulated and 291 genes down-regulated), in good accordance with the observed metabolic alternation in the two cultivars. Analyses of metabolic pathways and KEGG enrichment revealed that many biological processes, including energy consumption and biosynthesis, were perturbed in the two rice cultivars by BDE-47. A majority of metabolites and genes involved in dominating pathways of energy consumption (e.g., tricarboxylic acid cycle) and the biosynthesis (e.g., metabolism of saccharides and amino acids) were enhanced in LJ-7 by BDE-47. In contrast, energy consumption was increased while biosynthetic processes were inhibited in YY-9 by BDE-47, which could lead to the sensitivity of YY-9 to BDE-47. The combined results suggest that the different defensive abilities of these two rice cultivars in response to BDE-47 could be attributed to their differences in energy-consumption strategy and biosynthesis of nutritional components in grains. This study provides a useful reference for rice cultivation in PBDE-polluted areas.

Emission characteristics of polychlorinated, polybrominated and mixed polybrominated/chlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, PBDD/Fs, and PBCDD/Fs) from waste incineration and metallurgical processes in China

Typical thermal processes are common sources of polychlorinated, polybrominated and mixed polybrominated/chlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, PBDD/Fs, and PBCDD/Fs); however, very few reports have investigated their coemission. To clarify the emission characteristics of these DD/Fs, two municipal waste incinerators (MWIs), three hazardous waste incinerators (HWIs), one cement kiln coprocessing municipal waste incinerator (CMWI), one secondary copper smelter (SCu), and one iron and steel sintering smelter (ISS) in China were investigated. In total, 17 congeners of PCDD/Fs, 14 congeners of PBDD/Fs, and 12 congeners of PBCDDs in stack flue gases from these thermal processes were analyzed using a high-resolution gas chromatograph/high-resolution mass spectrometer (HRGC/HRMS) in this study. PCDD/Fs, PBDD/Fs and PBCDD/Fs were detectable in all samples, with total concentrations of 911-5.15 × 10³ pg/Nm³ (80.2-414 pg TEQ/Nm³). The concentrations of each DD/F were similar within the same type of facility and varied among different types of facilities. The contributions of PBDD/Fs and PBCDD/Fs to the total concentrations exceeded that of PCDD/Fs in some cases, such as in HWIs and SCu. In general, the ∑Cl_4-7 CDFs and ∑Cl_7-8 CDDs, 1,2,3,4,6,7,8-HpBDF, and 1-B-2,3,7,8-TeCDD and 2-B-1,3,7,8-TeCDD were the dominant congeners in the PCDD/F, PBDD/F, and PBCDD/F mass concentrations, respectively. Several other congeners present at low mass concentrations, such as 1,2,3,4,7,8-HxBDF, have potential as major contributors to the TEQs due to their high toxic equivalency factors. These results reveal the necessity of synergistically inhibiting the occurrences of PCDD/Fs, PBDD/Fs, and PBCDD/Fs from these sources and provide valuable information for use in the source identification of these pollutants in the environment.

Effect of maturity and mineralogy on fluid-rock reactions in the Marcellus Shale

Natural gas extraction from the Appalachian Basin has significantly increased in the past decade. The push to properly dispose, reuse, or recycle the large amounts of produced fluids associated with hydraulic fracturing operations and design better fracturing fluids has necessitated a better understanding of the subsurface chemical reactions taking place during hydrocarbon extraction. Using autoclave reactors, this study mimics the conditions of deep subsurface shale reservoirs to observe the chemical evolution of fluids during the shut-in phase of hydraulic fracturing (HF), a period when hydraulic fracturing fluids (HFFs) remain confined in the reservoir. The experiment was conducted by combining a synthetic hydraulic fracturing fluid and powdered shale core samples in high temperature/pressure static autoclave reactors for 14 days. Shale samples of varying maturity and mineralogy were used to assess the effect of these variations on the proliferation of inorganic ions and low molecular weight volatile organic compounds (VOCs), mainly benzene, toluene, ethylbenzene and xylenes (BTEX) and monosubstituted carboxylic acids. Ion chromatography results indicate that the relative abundance of ions present was similar to that of water produced from HF operations in the Marcellus Shale basin. There was an increase of SO42- and PO43- and a decrease in Ba2+ upon fluid-shale reaction. Major ionic shifts indicate calcite dissolution in two of the fluid-shale reactions and barite precipitation in all fluid-shale reactions. Toluene, xylene, and carboxylic acids were produced in the shale-free control experiment. The most substantial increase in BTEX analytes was observed in reactions with low maturity shale, while the high maturity shale reaction produced no measurable BTEX compounds. Total organic carbon decreased in all reactions including fracturing fluid and shale, suggesting adsorption onto the organic matter (OM) matrix. The results from this study highlight that both the nature of OM and mineralogy play a key role in determining the fate of inorganic and organic compounds during fluid-shale interactions in the subsurface shale reservoir. Overall this study aims to contribute to the growing understanding of complex chemical interactions that occur in the shale reservoirs during HF, which is vital for determining the potential environmental impacts of HF and designing more efficient HFF and produced water recycling techniques for environmentally conscious natural gas production.