Air Resources Research Articles

Human Dimensions of Air Quality: Introduction to the Special Issue

Poor ambient air quality is one of today’s greatest environmental health risks. However, unlike water, wildland fire, or wildlife, comparatively less human dimensions scholarship has focused on air resources. The papers in this special issue highlight how people across varying cultures, geographies, and identities create and relate to varying air quality conditions. In doing so, the issue challenges dominant perspectives of air pollution as a purely material entity and argues for the need to attend to the socio-cultural and political dimensions that define, create, or mitigate poor air quality.

California’s cap-and-trade program: is it effective in advancing social, economic, and environmental equity?

PurposeCompanies affected by California’s cap-and-trade legislation are allotted certain credits for production that can be used or sold and can purchase additional credits from the state, which become a revenue source to be used for activities that reduce carbon emissions. The purpose of this paper is to investigate who ultimately pays for this program, its effectiveness in reducing carbon emissions in accordance with established goals, and the related effectiveness to advance social, economic, and environmental equity.Design/methodology/approachThe methodology used for this research is secondary data analysis, triangulating three sources: California’s Climate Change Investment Reports, 2019-2021; repositories maintained by the California High-Speed Rail Authority and the California Air Resources Board; and a review of the literature and websites from other professional sources which addressed, directly and indirectly, the topics and questions explored in the study.FindingsKey findings include evidence of enhancing social and environmental equity but ineffectiveness in reducing carbon emissions in accordance with state goals. Furthermore, the program displays evidence of economic inequity as it demonstrates characteristics of regressive taxation and an inability of low-income persons to acquire electric vehicles due to high costs.Originality/valueThe research effort is unique in that no other academic efforts were located which attempt to examine the cap-and-trade program’s effectiveness in attaining its goals.

Preparation of dual-use GPTES@ZnO photocatalyst from waste warm filter cake and evaluation of its synergic photocatalytic degradation for air-water purification

Organic pollutants are the most critical threats to the health of air and water resources. On this basis, fabricating a photocatalytic acrylic film with dual-use (i.e. removing benzene from air and MB/MO dyes from water) was aimed in this research. For this purpose, waste warm filter cake (WWFC) was used to extract zinc from it. Zinc element was separated from WWFC by a basic leaching method and acidified to prepare zinc oxide nanoparticles. In the following, a simple hydrothermal method was used to increase the surface functionality of the extracted ZnO nanoparticles in order to establish active reaction sites for reaction to silane coupling agent and increase in the holes that were prepared during photo-excitation. Thereafter, the nanoparticles were modified with 3-glycidoxypropyltriethoxysilane (GPTES) at different concentrations. The band gap of the modified nanoparticles decreased from 3.25 to 3.1 eV by surface modification. The photocatalytic performance of ZnO nanoparticles was assessed by degradation of MB and MO aqueous solution (50 ppm) under simulated UV/Visible irradiations. MB and MO were degraded 91 and 60% under UV light and 65 and 50% under visible light after 150 min of irradiation. The photo degradation rate increased after adding carboxy methyl cellulose (CMC) surfactant to methylene blue and adding cocamide-dea (CDE-G) surfactant to methyl orange. The results confirmed that the green surfactants improve the dispersion and surface interaction of the modified nanoparticles in the dyes solution and cause more electron charge transfer which creates effective photocatalytic sites. The prepared nanocomposite films were placed in a photo-reactor to remove gaseous benzene from air under UV/visible irradiation. Gas chromatography (GC) results showed that the modified nanoparticles removed up to 35.25 and 20.34% of benzene from air. Colorimetric analysis (ΔE*) showed that the acrylic film contained modified nanoparticles degraded 91 and 82% of MB, and 85 and 76% of MO under UV/visible lights, respectively. In the end, it can be said that these photocatalytic films are able to remove environmental pollution in air and water.

Assessing the Impact of Transport Modality on Prehospital Times for Victims of Motorcycle Road Traffic Collisions in the Scottish Highlands

ObjectiveDispersed population, mountainous topography, and extreme weather present logistical challenges for the emergency services providing care to the resident population and tourists visiting the Scottish Highlands. Debate over the value of air ambulances has left uncertainty over when they benefit patients and when their use may inadvertently prolong transfer times in rural settings. The primary objective of this study was to find a provisional threshold at which air ambulances are likely to improve time from injury to arrival at the emergency department for this rural patient cohort using motorcycle road traffic collisions as a single trauma etiology. MethodsA retrospective search of Scottish Trauma Audit Group data was undertaken within the time frame of January 1, 2019, to September 30, 2020, inclusive to identify adult motorcyclists who had sustained traumatic injuries on highland roads resulting in a transfer to the single trauma unit located within the territorial health board of NHS Highland. For inclusion to the Scottish Trauma Audit Group audit, injuries sustained had resulted in a hospital stay of 3 or more days or death with an Injury Severity Score calculated post–computed tomography/operating room diagnosis. The method of arrival to the hospital was categorized as 1 of the following: road ambulance only, road ambulance (+ prehospital doctor), any involvement of air resources, or self-presentation to hospital. ResultsForty-two cases were identified. The mean on-scene times were longer for patients who were transported by air by 43 minutes. Within an isochrone of 77 minutes (road transfer time) around Raigmore Hospital in Inverness, transfer by land ambulance was faster than air. The majority of patients received definitive care at Raigmore Hospital and did not require further onward transfer. ConclusionFor adult motorcyclists with traumatic injuries in the Highlands, helicopter transfer appears to reduce transport times when the estimated journey to the trauma unit by land is greater than 77 minutes or approximately 49 miles. Patients injured closer to the hospital should be transferred by land to achieve an earlier arrival time. On-scene times were shorter for patients conveyed by land rather than helicopter, and the presence of a physician during the prehospital phase did not prolong on-scene time.

Environmental Preservation and Water Pollution from the Islamic Perspective

Islam is a religion of peace, security, and prosperity for all beings in our surroundings. This paper aims to discuss environmental and water pollution according to Islamic views. The study of environmental protection, environmental control, preservation, and balance of nature is something that is urgent from an Islamic point of view. This research is qualitative research that obtains data from primary and secondary sources, namely books, articles, journals, and papers. Data were analyzed inductively, deductively, and comparatively regarding Islamic sources and environmental science. After that, all data was collected and recorded descriptively. This study concludes that Islamic law strictly prohibits all actions that can damage and destroy the environment. The environment must be maintained and monitored as best as possible from the occurrence of something that can damage it. The term damage is often repeated by Allah SWT in the Qur'an to show that it is something that is important to understand and must be fully paid attention to in order to ensure environmental sustainability. Environmental damage comes from human actions that clearly damage this earth and human beings themselves. Human behavior is usually influenced by desire regardless of the consequences for the environment. The research also argues that Islamic law is very concerned about protecting the environment and prohibits strict environmental encroachment and if there are parties who pollute air resources, they can be prosecuted. This paper contributes to environmental preservation according to the Islamic perspective.

California will phase out hexavalent chromium

The California Air Resources Board (CARB) has voted to amend its rules on airborne toxics and phase out the use of hexavalent chromium by the state’s 117 chrome-plating facilities. The May 25 amendment targets both decorative and functional chrome-plating operations and requires the facilities to stop using the compound by 2030 and 2039, respectively. Chrome plating is the act of electrically applying a layer of chromium to the surface of an object. Although it is often associated with shiny automotive and motorcycle parts, chrome plating is also used to improve the durability of aviation components such as landing gears. But the process of applying the chromium coating creates toxic fumes that pose a cancer risk to people living nearby . According to CARB, over 70% of California’s chrome-plating facilities are located in low-income communities . Under the amended rule, CARB is requiring chrome-plating facilities to install building enclosures to reduce

Analysis of Environmental Sustainability through a Weighting Matrix in the Oil and Gas Industry

In the oil sector, various strategies are applied to mitigate harmful effects on the environment. These strategies include, among others, compensation plans, the measurement and control of the carbon footprint and/or water footprint, the recovery of waste from activities and processes, and Environmental Management Systems (EMS). An EMS provides a formal framework that enables more efficient work on environmental issues, thereby improving performance. It aims to raise awareness of the environmental impacts associated with the oil industry in different areas through the use of weighting matrices. Additionally, it seeks to conduct sustainable studies and optimize the direct activities involved in the exploitation of hydrocarbons as a natural resource. Factors considered in decision making include ensuring that the strategy does not compromise the well-being of future generations, has economic viability, and does not hinder any oil sector activities such as exploration, drilling, production, or processing of derivatives. The purpose of this is that it allows for the creation of decision matrices based on weighting methodologies that outline possible correlations between specific activities of the oil sector such as water use, effects on soils and landscapes, greenhouse gas emissions, solid waste, liquid effluents, hazardous waste, and toxic waste, among others. The decision matrices can also help elucidate the relationship of these activities with mitigation strategies to provide a decision-making tool for environmental management plans so that activities are implemented in a way that can mitigate impacts on water, soil, and air resources. The results of this study were classified using a traffic light matrix, based on the level of technical congruence, using an optimal (green), regular (yellow), medium (orange), and at-risk (red) scale. The environmental impact of “alteration of the geoform of the land” was positioned in the at-risk category due to its assessment by experts in relation to the activity of “land adaptation”. In the medium category, a total of 23 impacts were identified, while 10 impacts fell into the regular category. These results were evaluated in the context of the environmental, social, and economic sustainability of the oil industry.

Influence of COVID-19 lockdown on river water quality and assessment of environmental health in an industrialized belt of southern Western Ghats, India.

The COVID-19 pandemic and sudden lockdown have severely hampered the country's economic growth and socio-cultural activities while imparting a positive effect on the overall fitness of the environment especially air and water resources. Increased urbanization and rapid industrialization have led to rising pollution and deterioration of rivers and associated sectors such as agriculture, domestic and commercial needs. However, various available studies in different parts of the country indicate that the COVID-19 pandemic has changed the entire ecosystem. But it is noted that studies are lacking in the southern Western Ghats region of India. Therefore, the present study attempts to investigate how the continuous lockdowns affect the River Water Quality (RWQ) during lockdown (October 2020) and post-lockdown (January 2021) periods in the lower catchments (Eloor-Edayar industrialized belt) of Periyar river, Kerala state, South India. A total of thirty samples (15 samples each) were analyzed based on drinking water quality, irrigational suitability, and multivariate statistical methods to evaluate the physical and chemical status of RWQ. The results of theWater Quality Index (WQI) for assessing the drinking water suitability showed a total of 93% of samples in the excellent and good category during the lockdown, while only 47% of samples were found fit for drinking during the post-lockdown period. Irrigational suitability indices like Mg hazard, KR, PI, SAR, and Wilcox diagram revealed lockdown period samples as more suitable for irrigational activities compared to post-lockdown samples with site-specific changes. Spearman rank correlation analysis indicated EC and TDS with a strong positive correlation to Ca2+, Mg2+, Na+, K+, TH, SO42-, and Cl- during both periods as well as strong positive correlations within the alkaline earth elements (Ca2+ and Mg 2+) and alkalis (Na+ and K+). Three significant components were extracted from principal component analysis (PCA), explaining 88.89% and 96.03% of the total variance for lockdown and post-lockdown periods, respectively. Variables like DO, BOD, Ca2+, NO3-, and Cl- remained in the same component loading during both periods elucidating their natural origin in the basin. The results of health risk assessment based on US EPA represented hazard quotient and hazard index values below the acceptable limit signifying no potential noncarcinogenic risk via oral exposure except As, suggesting children as more vulnerable to the negative effects than adults. Furthermore, this study also shows rejuvenation of river health during lockdown offers ample scope to policymakers, administrators and environmentalists for deriving appropriate plans for the restoration of river health from anthropogenic stress.

Identifying Toxic Consumer Products: A Novel Data Set Reveals Air Emissions of Potent Carcinogens, Reproductive Toxicants, and Developmental Toxicants.

Consumer products are important sources of exposure to harmful chemicals. Product composition is often a mystery to users, however, due to gaps in the laws governing ingredient disclosure. A unique data set that the California Air Resources Board (CARB) uses to determine how volatile organic chemicals (VOCs) from consumer products affect smog formation holds a partial solution. By analyzing CARB data on VOCs in consumer products, we identified and quantified emissions of volatile chemicals regulated under the California Safe Drinking Water and Toxic Enforcement Act ("Prop 65"). We here highlight individual chemicals as well as consumer product categories that people are likely to be exposed to as individual consumers, in the workplace, and at the population level. Of the 33 Prop 65-listed chemicals that appear in the CARB emissions inventory, we classified 18 as "top tier priorities for elimination". Among these, methylene chloride and N-methyl-2-pyrrolidone were most prevalent in products across all three population groups. Of 172 consumer product categories, 105 contained Prop 65-listed chemicals. Although these chemicals are known carcinogens and reproductive/developmental toxicants, they remain in widespread use. Manufacturers and regulators should prioritize product categories containing Prop 65-listed chemicals for reformulation or redesign to reduce human exposures and associated health risks.

California's ambitious greenhouse gas policies: Are they ambitious enough?

California's landmark AB 32 legislation, enacted in 2006, tasked the California Air Resources Board (CARB) with (1) ensuring that statewide greenhouse gas emissions in 2020 would not exceed the 1990 level, and (2) achieving the “maximum technologically feasible and cost-effective reductions in greenhouse gas emissions”. CARB adopted a caps-and-standards framework for regulating emissions in energy sectors (electricity generation, industrial combustion, and transportation fuels). The regulations interpreted the statutory emissions limit in 2020 as a predetermined “target”, thus rendering the maximum-reduction mandate ineffectual. CARB's November 2022 Scoping Plan extends the same framework to implement California's new legislative directive (AB 1279) requiring achievement of “net zero greenhouse gas emissions as soon as possible, but no later than 2045”. The plan continues CARB's reliance on Cap-and-Trade, which establishes the minimum statutory requirement as a “target” and disincentivizes overcompliance by nullifying the environmental benefits of supplemental climate actions (the “waterbed effect”). To put California on track toward decarbonization at the scale and pace required for global climate stabilization, the legislature should institute a regulatory policy paradigm that accommodates and supports local and individual climate action, and which gives meaning and effect to the mandate requiring maximum technologically feasible and cost-effective emissions reductions.

Impact of Hydrothermal and Chemical Aging on SCR Storage Characteristics and NO <italic><sub>x</sub></italic> Reduction Performance in an Ultra-Low NO <italic><sub>x</sub></italic> System

<div class="section abstract"><div class="htmlview paragraph">This work is a part of medium-duty Low NO<i><sub>x</sub></i> technology development project with a focus on evaluating a combination of engine and advanced aftertreatment for 0.02 g/bhp-hr NO<i><sub>x</sub></i> regulation proposed by CARB (California air resource board). In this project, a control oriented chemical kinetics model of SCR (Selective catalytic reduction) was used in the aftertreatment controller that is susceptible to performance degradation due to hydrothermal and chemical aging. This paper focuses on modeling the NO<i><sub>x</sub></i> conversion and NH3 storage characteristics using a controls oriented SCR plant model which is further used for a model-based urea dosing scheme. A set of steady state reactor tests were used to calibrate the SCR performance at degreened, hydrothermal only and hydrothermal + chemical aging conditions and also to determine inhibition factors related to aging. The resultant model is capable of simulating SCR performance deterioration such as a reduction in NO<i><sub>x</sub></i> conversion and NH3 storage. A non-linear aging profile was observed for Lo-SCR and downstream SCR showing a change in the NO<i><sub>x</sub></i> conversion in the aged system when compared to a degreened system. Upon chemical aging further deterioration of low temperature performance was observed. This aging phenomenon impacts the dosing control strategy of the system. The results on controller performance for a set of Heavy Duty Federal Test Protocol(FTP), Ramp Modal Cycle (RMC), and Low Load Cycle (LLC) are presented.</div></div>

Considering Waste Generation in the Energy Sector during the Transition to a Circular Economy

The need to reduce the negative environmental impact of energetics with the growing energy demand in the world is the core objective of the industry for the upcoming decades. The global agenda in the field of environmental protection increases the requirements for evaluation of the energy investment projects, in particular for their environmental efficiency. Currently, much attention is paid to assessing the impact of the project on atmospheric air, water bodies and land resources, including the formation of industrial waste during the operational stage. The formation of production and consumption waste at other stages of the project life cycle is not considered either when generating cash flows or when conducting the assessment pf environmental efficiency. It might significantly reduce the reliability of assessment results. The purpose of this study is to develop a system of integrated accounting for all types of waste generated and the environmental costs incurred for handling them during the environmental and economic assessment of energy projects. The paper discusses modern waste management practices at energy enterprises, waste generation at various stages of investment projects implementation, and provides recommendations on waste accounting when assessing their environmental and economic efficiency.

The oscillatory effect of chemical constituents, dynamics, barometric, and thermodynamics on weather over Accra, and Bissau

A sharp contrast in atmospheric weather conditions prevailed over Accra and Bissau and that led to the oscillatory nature of weather conditions between the two cities. During the latter part of July 2022, Bissau experienced persistent and continuous rains whilst Accra remained fair and dry. It was realized that when an air parcel rises, low-pressure system is created at the surface but when the air parcel sinks, high pressure forms. Pressures were predominantly high over Accra and low over Bissau during that time. Models from CAMS were used to study chemical compositions to determine the concentration and effect of Sulphur Dioxide (SO2) over the two cities. Wind behavior over various levels in the atmosphere was considered using model products from ECMWF, satellite imagery from EUMETSAT, and t-phi gram from the Air Resources Laboratory of NOAA to study the thermodynamics of the skies. METAR, hourly observations made by the National Meteorological Offices from the two cities were retrieved from the AADS and Ogimet to study the barometric nature during the period. Results show that the atmosphere over Bissau had been less polluted as compared to that of Accra which makes Bissau to be persistently cloudy. Atmospheric chemical constituents would have to compete for moisture if the concentration is high and does not support the sustenance of massive clouds capable of producing rain. It has been realized that the development of anticyclone, an anticlockwise circulation at the 200 hPa level contributed to the cloud sustenance over Bissau during that time.

Estimating enhancement ratios of nitrogen dioxide, carbon monoxide and carbon dioxide using satellite observations

Abstract. Using co-located space-based measurements of carbon dioxide (CO2) from the Orbiting Carbon Observatory-2 and Orbiting Carbon Observatory-3 (OCO-2/3) and carbon monoxide (CO) and nitrogen dioxide (NO2) from the TROPOspheric Monitoring Instrument (TROPOMI), we calculate total column enhancements for observations influenced by anthropogenic emissions from urban regions relative to clean background values. We apply this method to observations taken over or downwind of 27 large (population of >1 million) urban areas from around the world. Enhancement ratios between species are calculated and compared to emissions ratios derived from four globally gridded anthropogenic emissions inventories. We find that these global inventories underestimate CO emissions in many North American and European cities relative to our observed enhancement ratios, while smaller differences were found for NO2 emissions. We further demonstrate that the calculation and intercomparison of enhancement ratios of multiple tracers can help to identify the underlying biases leading to disagreement between observations and inventories. Additionally, we use high-resolution CO2 inventories for two cities (Los Angeles and Indianapolis) to estimate emissions of CO and NO2 using our calculated enhancement ratios and find good agreement with both a previous modelling study for the megacity of Los Angeles and California Air Resources Board (CARB) inventory estimates.

Sustainable and responsible mining through sound mine closure

This paper provides an overview of planning requirements, including regulatory, and implementation approaches for achieving ecologically sound reclamation and restoration of mines upon closure in the USA. Mine closure includes mined-out areas, decommissioning of plants and structures, and appropriate monitoring of post-mining land, water, and air resources. Although the discussion provides general guidelines, each mine closure site presents unique challenges. The overall chemical composition of coal and associated strata with mineable coal seams, structural characteristics of the deposit, weather patterns, environmental conditions, processing and scale of mining of the deposit, and public and private infrastructure must be considered. Future land use and water resource requirements are also important considerations. The planning and closure activities must ensure that the resultant site has the appropriate post-mining land and water resources use, and the site does not pose any future environmental and health and safety risks. These requirements suggest that closure activities should be integrated with the mining activity planning process from the start. This paper discusses mine closure issues and describes several practices for a surface coal mine in the Western USA.

Application of Model-Based Controller on a Heavy-Duty Dual Selective Catalytic Reduction Aftertreatment

<div>Commercial vehicles require advanced engine and aftertreatment (AT) systems to meet upcoming nitrogen oxides (NO<sub>x</sub>) and carbon dioxide (CO<sub>2</sub>) regulations. This article focuses on the development and calibration of a model-based controller (MBC) for an advanced diesel AT system. The MBC was first applied to a standard AT system including a diesel particulate filter (DPF) and selective catalytic reduction (SCR) catalyst. Next, a light-off SCR (LO-SCR) was added upstream of the standard AT system. The MBC was optimized for both catalysts for a production engine where the diesel exhaust fluid (DEF) was unheated for both SCRs. This research shows that the tailpipe (TP) NO<sub>x</sub> could be reduced by using MBC on both catalysts. The net result was increased NO<sub>x</sub> conversion efficiency by one percentage point on both the LO-SCR and the primary SCR. The CO<sub>2</sub> emissions were slightly reduced, but this effect was not significant. Finally, the MBC was used with a final setup representative of future AT systems which included standard insulation on the catalysts and optimal DEF dosing controls. This final configuration resulted in an improved NO<sub>x</sub> and CO<sub>2</sub> such that the composite Federal Test Procedure (FTP) NO<sub>x</sub> was 0.060 g/hp-hr and the composite FTP CO<sub>2</sub> was 508.5 g/hp-hr. The article details this cycle along with the low-load cycle (LLC) and beverage cycle. More technologies are required to meet the future California Air Resources Board (CARB) 2027 standard, which will be shown in future work.</div>

A Border Gateway Protocol LRA-BGP for Integrated Satellite-terrestrial Networks

With the rapid development of information technology, the demand for multi-dimensional integrated information resources of air, sky, and ground in the future information service industry is increasing day by day. The integrated satellite-terrestrial networks will become an important development trend in my country’s communication network in the future. However, the movement of satellites will cause frequent topology changes, which will seriously affect the overall performance of the terrestrial network. Aiming at this problem, this paper proposes a lightweight route advertisement border gateway protocol LRA-BGP. LRA-BGP protects terrestrial networks from the high dynamics of satellites by reducing the number of advertised routes. In addition, a real network environment is also built for actual testing. The results show that LRA-BGP can reduce the bandwidth resource occupation of the ground network by 26.9%~68.8% and CPU usage by 6.17%~7.31%.

Improved assessment of baseline and additionality for forest carbon crediting.

In the California compliance cap-and-trade carbon market, improved forest management (IFM) projects generate carbon credits in the initial reporting period if their initial carbon stocks are greater than a baseline. This baseline is informed by a "common practice" stocking value, which represents the average carbon stocks of surveyed privately owned forests that are classified into the same general forest type by the California Air Resources Board. Recent work has called attention to the need for more ecologically informed common practice carbon stocking values for IFM projects, particularly those in areas with sharp ecological gradients. Current methods for estimating common practice produce biases in baseline carbon values that lead to a clustering of IFM projects in geographical areas and ecosystem types that in fact support much greater forest carbon stocks than reflected in the common practice. This phenomenon compromises additionality, or the increases in carbon sequestration or decreases in carbon emissions that would not have occurred in the absence of carbon crediting. This study seeks to expand upon recent work on this topic and establish unbiased common practice estimates along sharp ecological gradients using methods that do not rely upon discrete forest classification. We generated common practice values for credited IFM projects in the Southern Cascades using a principal components analysis on species composition over an extensive forest inventory to determine the ecological similarity between inventoried forests and IFM project sites. Our findings strengthen the results of recent research suggesting common practice bias and adverse selection. At several sites, even after controlling for private ownership, 100% of the initial carbon stocks could be explained by ecological variables. This result means that improved management did not preserve or increase carbon stocks above what was typical, suggesting that no carbon offsets should have been issued for these sites. This result reveals greater bias than that been found at project sites in this region by research that has used discrete forest categorization.

Critical review on biogeochemical dynamics of mercury (Hg) and its abatement strategies

Mercury (Hg) is among the naturally occurring heavy metal with elemental, organic, and inorganic distributions in the environment. Being considered a global pollutant, high pools of Hg-emissions ranging from >6000 to 8000 Mg Hg/year get accumulated by the natural and anthropogenic activities in the atmosphere. These toxicants have high persistence, toxicity, and widespread contamination in the soil, water, and air resources. Hg accumulation inside the plant parts amplifies the traces of toxic elements in the linking food chains, leads to Hg exposure to humans, and acts as a potential genotoxic, neurotoxic and carcinogenic entity. However, excessive Hg levels are equally toxic to the plant system and severely disrupt the physiological and metabolic processes in plants. Thus, a plausible link between Hg-concentration and its biogeochemical behavior is highly imperative to analyze the plant-soil interactions. Therefore, it is requisite to bring these toxic contaminants in between the acceptable limits to safeguard the environment. Plants efficiently incorporate or absorb the bioavailable Hg from the soil thus a constructive understanding of Hg uptake, translocation/sequestration involving specific heavy metal transporters, and detoxification mechanisms are drawn. Whereas recent investigations in biological remediation of Hg provide insights into the potential associations between the plants and microbes. Furthermore, intense research on Hg-induced antioxidants, protein networks, metabolic mechanisms, and signaling pathways is required to understand these bioremediations techniques. This review sheds light on the mercury (Hg) sources, pollution, biogeochemical cycles, its uptake, translocation, and detoxification methods with respect to its molecular approaches in plants.

Molecularly imprinted MOFs-driven carbon nanofiber for sensitive electrochemical detection and targeted electro-Fenton degradation of perfluorooctanoic acid

The polyfuoroalkyl substances, especially perfluorooctanoic acid (PFOA), are emerging as harmful environmental micropollutants that are known to globally contaminate water, air, and soil resources. Herein considering the urgent demand for the sensitive detection and effective degradation of PFOA present in water environment, a novel molecular imprinting polymer (MIP) MOFs (Co/Fe)-driven carbon nanofiber (Co/Fe@CNF) electrode has been developed for electrochemical detection and electro-Fenton (EF) degradation of PFOA. MIP was formed by one-pot step by electro-polymerization of the pyrrole in the presence of PFOA template on the Co/Fe@CNF. The MIP has a strong adsorption force on PFOA for the special O–H-π hydrogen bond between PFOA and the imprinting site, helped PFOA to access the surface of electrode. Therefore, the resulting MIP Co/Fe@CNF was able to detect PFOA with a good linear response in the range of 1 × 10-8–9 × 10-5 M, and the limit of detection (LOD) was reached 1.073 × 10-9 M. Moreover, the imprinted cavity on MIP can precisely adsorb PFOA and its intermediates to shorten the transmission distance between free radicals and targets, which enhanced the degradation ability in the EF process, and the targeted degradation efficiency reached 93% with 180 min.