Shieldsfuentes6266

A rough extrapolation suggested that Antarctic tundra may degrade about 2.4 metric tons of atmospheric CCl4 each year. Combining soil CCl4 fluxes from this study and other literature reports, CCl4 partial lifetime with respect to the soil sink was evaluated to be 354 (235-474) years, which supported the recent viewpoint that the soil sink of CCl4 is smaller than previously thought.There is a need for destructive technologies for per- and polyfluoroalkyl substances (PFAS) in soil. While planetary ball mill have been shown successful degradation of PFAS, there are issues surrounding scale up (maximum size is typically 0.5 L cylinders). While having lower energy outputs, horizontal ball mills, for which scale up is not a limiting factor, already exist at commercial/industrial sizes from the mining, metallurgic and agricultural industries, which could be re-purposed. This study evaluated the effectiveness of horizontal ball mills in degrading perfluorooctanesulfonate (PFOS), 62 fluorotelomer sulfonate (62 FTSA), and aqueous film forming foam (AFFF) spiked on nepheline syenite sand. Horizontal ball milling was also applied to two different soil types (sand dominant and clay dominant) collected from a firefighting training area (FFTA). Liquid chromatography tandem mass spectrometry was used to track 21 target PFAS throughout the milling process. High-resolution accurate mass spectrometry was also used to identify the presence and degradation of 19 non-target fluorotelomer substances, including 62 fluorotelomer sulfonamido betaine (FtSaB), 73 fluorotelomer betaine (FtB), and 62 fluorotelomer thioether amido sulfonate (FtTAoS). In the presence of potassium hydroxide (KOH), used as a co-milling reagent, PFOS, 62 FTSA, and the non-target fluorotelomer substances in the AFFF were found to undergo upwards of 81%, 97%, and 100% degradation, respectively. Despite the inherent added complexity associated with field soils, better PFAS degradation was observed on the FFTA soils over the spiked NSS, and more specifically, on the FFTA clay over the FFTA sand. These results held through scale-up, going from the 1 L to the 25 L cylinders. The results of this study support further scale-up in preparation for on-site pilot tests.A sensitive analytical method has been developed and validated for the determination of 16 polyfluorinated alkyl substances (PFAS) in fine airborne particulate matter (PM2.5) using on-line solid phase extraction (SPE) coupled with liquid chromatography (LC) - negative electrospray ionisation high resolution mass spectrometry (-) ESI-HRMS. On-line SPE allows simultaneous sample clean-up from interfering matrices and lower limits of detection (LODs) by injecting a large volume of sample into the LC system without compromising chromatographic efficiency and resolution. The method provides LODs in the range 0.08-0.5 pg/mL of sample extract allowing detection of selected PFAS in aerosol particles at low fg/m3 level and showed good tolerance to the considered PM matrix. The validated method was applied for analysis of PFAS in ambient PM2.5 samples collected at two urban locations in Ireland, i.e., Enniscorthy and Dublin. Several PFAS were observed above the detection limit, including perfluorobutyrate (PFBA), perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorobutanesulfonic acid (L-PFBS) and perfluorononanoic acid (PFNA), as well as fluorotelomer sulfonates 42 FTS, 62 FTS and 82 FTS. The results indicate that some toxic PFAS, such as PFOS and PFOA, are still detected in the environment despite being phased out from production and subject to restricted use in the EU and USA for more than two decades. Observation of fluorotelomer sulfonates (42 FTS, 62 FTS and 82 FTS, which are used as alternatives for legacy PFOA and PFOS) in ambient PM2.5 samples raises a concern about their persistence in the atmosphere and impact on human health considering emerging evidence that they could have similar health endpoints as PFOA and PFOS. To our knowledge, this is the first study to identify PFAS in ambient PM2.5 at urban locations in Ireland and also the first study to detect 42 and 82 fluorotelomer sulfonates in atmospheric aerosol particles.Ecosystem vulnerability is the degree to which an ecosystem is susceptible to adverse effects of external disturbances. Exploring the pattern of ecosystem vulnerability and its driving mechanism is important for regional ecological protection and management. A little study has conducted the ecosystem vulnerability assessment from the perspective of multiple ecosystems characteristics, and the spatial heterogeneity impacts of climate change and human activities on ecosystem vulnerability variation need to be further explored. In this study, a habitat-structure-function framework was proposed to evaluate ecosystem vulnerability pattern of the Yangtze River Basin (YRB) in China from 1990 to 2018. Then, the spatial heterogeneity impacts of various factors on ecosystem vulnerability changes were examined utilizing the Geographically Weighted Regression model. Results show that the ecosystem vulnerability index (EVI) pattern in the YRB decreased from upstream to downstream. There was 63.85% of the basin area experiencing a decline in EVI from 1990 to 2018, which was primarily found in the source, southwest and north regions, while the southeast and east regions have suffered an increase in EVI. The impact of climate change on EVI changes increased as time scales increase, while, human activities were still the dominant factor leading EVI changes. Overall, areas with great impact of climate change on EVI variation were concentrated in the source region and upper reaches, while the remarkable impact of human activities occurred in the whole basin. The enhancement of climate warming and humid trend and the strengthen of ecological protection were benefit to the decline of EVI. The proposed framework can be extended to assess vulnerability in other areas or specific ecosystem types, and the findings are expected to provide policy recommendations for ecosystem conservation and management in the YRB.Climate water stress internationally challenges the goal of achieving food, energy, and water security. This challenge is elevated by population and income growth. Increased climate water stress levels reduce water supplies in many river basins and elevate competition for water among sectors. Organized information is needed to guide river basin managers and stakeholders who must plan for a changing climate through innovative water allocation policies, trade-off analysis, vulnerability assessment, capacity adaptation, and infrastructure planning. Several hydroeconomic models have been developed and applied assessing water use in different sectors, counties, cultures, and time periods. However, none to date has presented an optimization framework by which historical water use and economic benefit patterns can be replicated while presenting capacity to adapt to future climate water stresses to inform the design of policies not yet been implemented. This paper's unique contribution is to address this gap by desig use adaptation patterns under various levels of climate water stress. That basin's issues and challenges can be of relevance to other river basins internationally.Hydrogen oxidizing bacteria (HOB), a type of chemoautotroph, are a group of bacteria from different genera that share the ability to oxidize H2 and fix CO2 to provide energy and synthesize cellular material. Recently, HOB have received growing attention due to their potential for CO2 capture and waste recovery. This review provides a comprehensive overview of the biological characteristics of HOB and their application in resource recovery and pollutant removal. Selleckchem Hesperadin Firstly, the enzymes, genes and corresponding regulation systems responsible for the key metabolic processes of HOB are discussed in detail. Then, the enrichment and cultivation methods including the coupled water splitting-biosynthetic system cultivation, mixed cultivation and two-stage cultivation strategies for HOB are summarized, which is the critical prerequisite for their application. On the basis, recent advances of HOB application in the recovery of high-value products and the removal of pollutants are presented. Finally, the key points for future investigation are proposed that more attention should be paid to the main limitations in the large-scale industrial application of HOB, including the mass transfer rate of the gases, the safety of the production processes and products, and the commercial value of the products.Through the synergistic effect of photocatalysis and biodegradation, intimately coupling photocatalysis and biological (ICPB) technology could improve the removal rate and mineralization rate of refractory pollutants and reduce the toxicity of intermediate products. ICPB system was characterized with the advantages of simple operation, low energy consumption and high treatment efficiency. As a new sewage treatment technology, ICPB system has shown great potential in the treatment of refractory pollutants, and has been widely concerned. In this study, the research progress of photocatalyst, carrier and biofilm in ICPB system were discussed, and the degradation mechanism was introduced. The shortcomings of the current ICPB system were pointed out, and the possible research directions of ICPB in the future were proposed. This review aimed to deepen the understanding of ICPB technology and promoted the further development of ICPB technology in the treatment of refractory pollutants.Antibiotics are priority contaminants of emerging concern due to their pseudo-persistence in the environment and contribution to the development of antimicrobial resistance. In solution, antibiotics undergo (de)protonation reactions that affect their UV absorbance and, therefore, photolytic fate in natural and engineered systems. This study employed enhanced spectrophotometric methods to determine the acid dissociation constants (as pKa values) and molar absorption coefficients for 12 fluoroquinolone, 9 sulfonamide, and 7 tetracycline antibiotics of environmental relevance. Molar absorption coefficient heatmaps were generated for all 28 antibiotics at 200-500 nm and pH 1.8-12.2. The data in the heatmaps were deconvoluted to calculate pKa values and specific molar absorption coefficients at each wavelength. All antibiotics had at least one pKa value in the environmentally relevant range of 5.5-8.5, and pKa values were reported for methacycline, moxifloxacin, nadifloxacin, rolitetracycline, sulfadoxine, and sulfapyridine for the first time. Deprotonation of the carboxylic acid associated with pKa,1 (5.5-6.7) exerted the strongest effects on the UV absorbance of fluoroquinolones. For tetracyclines, deprotonation of the tertiary amine at pKa,3 (7.8-10.2) was responsible for major shifts in UV absorbance. Although sulfonamides have conserved pKa sites, no general trends were observed for the molar absorption coefficients. The structural similarity of fluoroquinolones and tetracyclines supported the potential for a class-based approach to identifying molar absorbance as a function of pH. Overall, the reported pKa values and specific molar absorption coefficients will serve as important resources for future studies on antibiotic fate in natural and engineered systems.