Accumulation Of Pollutants Research Articles

Plastic pollution on remote islands: A baseline study of Príncipe, Gulf of Guinea

Plastic is the most abundant marine anthropogenic debris in the ocean and is of serious global environmental concern. Projects aimed at monitoring plastic pollution quantities are key in evaluating the success of reduction. This study provides baseline information on the quantities of marine debris found on the island of Príncipe in the Gulf of Guinea in the Atlantic coast of Central Africa. A total of 13,196 items were collected with 64.5% of these items being plastic. Plastic pieces the size of 2.5–50 cm made up 20.8% of all plastic items, followed by plastic bags (13.3%) and fishing material (11.39%). The density of mesoplastic items (<25 and >5mm) ranged between 0 and 6.78 items m−2. Beach location, community presence, and beach level (for turtle-nesting beaches) were important factors in explaining differences in plastic abundance and density around the island. Our results highlight the significance of high plastic pollution accumulation on remote islands.

A CNN-SVR model for NO2 profile prediction based on MAX-DOAS observations: The influence of Chinese New Year overlapping the 2020 COVID-19 lockdown on vertical distributions of tropospheric NO2 in Nanjing, China

In this study, a hybrid model, the convolutional neural network-support vector regression model, was adopted to achieve prediction of the NO2 profile in Nanjing from January 2019 to March 2021. Given the sudden decline in NO2 in February 2020, the contribution of the Coronavirus Disease-19 (COVID-19) lockdown, Chinese New Year (CNY), and meteorological conditions to the reduction of NO2 was evaluated. NO2 vertical column densities (VCDs) from January to March 2020 decreased by 59.05% and 32.81%, relative to the same period in 2019 and 2021, respectively. During the period of 2020 COVID-19, the average NO2 VCDs were 50.50% and 29.96% lower than those during the pre-lockdown and post-lockdown periods, respectively. The NO2 volume mixing ratios (VMRs) during the 2020 COVID-19 lockdown significantly decreased below 400 m. The NO2 VMRs under the different wind fields were significantly lower during the lockdown period than during the pre-lockdown period. This phenomenon could be attributed to the 2020 COVID-19 lockdown. The NO2 VMRs before and after the CNY were significantly lower in 2020 than in 2019 and 2021 in the same period, which further proves that the decrease in NO2 in February 2020 was attributed to the COVID-19 lockdown. Pollution source analysis of an NO2 pollution episode during the lockdown period showed that the polluted air mass in the Beijing-Tianjin-Hebei was transported southwards under the action of the north wind, and the subsequent unfavorable meteorological conditions (local wind speed of < 2.0 m/sec) resulted in the accumulation of pollutants.

Effect of mixed physical barrier on seawater intrusion and nitrate accumulation in coastal unconfined aquifers.

Physical barrier has been proven to be one of the most effective measures to prevent and control seawater intrusion (SWI) in coastal areas. Mixed physical barrier (MPB), a new type of physical barrier, has been shown to have higher efficiency in SWI control. As with conventional subsurface dam and cutoff wall, the construction of MPB may lead to the accumulation of nitrate contaminants in coastal aquifers. We investigated the SWI control capacity and nitrate accumulation in the MPB using a numerical model of variable density flow coupling with reactive transport, and performed sensitivity analysis on the subsurface dam height, cutoff wall depth and opening spacing in the MPB. The differences in SWI control and nitrate accumulation between MPB and conventional subsurface dam and cutoff wall were compared to assess the applicability of different physical barrier. The numerical results show that the construction of MPB will increase the nitrate concentration and contaminated area in the aquifer. The prevention and control efficiency of MPB against SWI is positively correlated with the depth of the cutoff wall, reaching the highest efficiency at the minimum effective dam height, and the retreat distance of the saltwater wedge is positively correlated with the opening spacing. We found a non-monotonic relationship between the change in subsurface dam height and the extent of nitrate accumulation, with total nitrate mass and contaminated area increasing and then decreasing as the height of the subsurface dam increased. The degree of nitrate accumulation increased linearly with increasing the height of the cutoff wall and the opening spacing. Under certain conditions, MPB is 46-53% and 16-57% more efficient in preventing and controlling SWI than conventional subsurface dam and cutoff wall, respectively. However, MPB caused 14-27% and 2-12% more nitrate accumulation than subsurface dam and cutoff wall, respectively. The findings of this study are of great value for the protection of coastal groundwater resources and will help decision makers to select appropriate engineering measures and designs to reduce the accumulation of nitrate pollutants while improving the efficiency of SWI control.

Insights into ecotoxicity effects of PAHs and ecosystem responses of remediation strategies under cold stress: From PAHs degradation to ecological restoration regulated by signal molecular

Polycyclic aromatic hydrocarbons (PAHs) known as persistent contaminants have been detected in soils worldwide, especially in cryogenic environment. Although researchers have conducted lots of researches on PAHs, the ecological toxicity of PAHs and the remediation mechanism of PAHs polluted soils under low temperature are still unclear. Herein, we attempted to characterize remediation of PAHs polluted environment by coupling the PAH degradation with ecological restoration. PAHs could not degrade completely in natural and multiple metabolites accumulate in soil under low temperature. Long-term accumulation of pollutants could cause severe oxidative stress, inhibit the growth of plants and normal process and transformation of substances of microorganisms, while increased the relative abundance of PAHs degrading bacteria (Sphingobacterium, Pseudomonas, Rhodococcus and Massilia etc) and degradation genes (nidA nidB, nahAa, nahAb, nahAc, nidD, phdJ and phdG). As soil amendents, biochar, microbial agent, biochar together with microbial agent could remove 75%, 83%, and 93% of PAHs from soil, and 47%, 50%, and 58% of PAHs from plants, respectively. Under the bioaugmentation of soil amendments, soil microorganisms played an important role in PAHs degradation and ecological restoration. Meanwhile, we identified three signal molecules related to ecological restoration which play a crucial role in regulating pollution removal and ecological restoration by indigenous microorganisms. OOHL and C10-HSL are involved in environmental resistance, degradation of PAHs and transformation of nutrients. 3-oxo-C14-HSL promoted the degradation of PAHs and cold adaption of microorganism. Our study provided an innovative strategy for controlling PAHs degradation and ecological restoration from the perspective of microbial transboundary informatics.

Spatial distribution, source identification and flux estimation of polycyclic aromatic hydrocarbons and organochlorine pesticides in basins of the Eastern Indian Ocean

Although polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) have been recorded worldwide, information on their presence in the Eastern Indian Ocean (EIO), especially south of 10°S, remains limited. We investigated the distribution and depositional fluxes of PAHs and OCPs, and the major sources and ecological risks of PAHs in EIO surface sediments from the Central Indian Ocean (CIOB) and Wharton Basin (WB). The concentration of Σ18 PAHs and ∑10 OCPs had an average value (± SD) of 138.4 ± 52.34 and 0.8 ± 0.20 ng g−1, respectively. PAHs may mainly affected by traffic emission and biomass and wood combustion. Persistent organic pollutant accumulation rate (PAR) and depositional flux (DF) values showed that abundant PAHs might lost during top-down transport. The low trans- chordane (CHL)/cis-CHL ratio and PAR of OCPs may indicated few OCPs were inputted into the EIO recently. The results of binary isotope mixing modeling indicate the predominance of marine organic matter (MOM) in total organic carbon (TOC) of sediments. Fluoranthene (Flour) and pyrene (Py) might have potential biological effects in the EIO. The study provided background values for PAHs and OCPs in the Indian Ocean, and preliminarily revealed the fate of POPs in the open oceans.

Analysis of hydrodynamic characteristics during the occurrence of red tide in the Qinhuangdao sea area

The Qinhuangdao coastal area in northern China is a significant site for aquaculture and coastal tourism. However, frequent red tides have adversely affected water quality and fishery resources in recent years. This research investigates the hydrodynamic characteristics of the area by conducting continuous seabed observations during the summer of 2019 and analyzing historical data. The goal is to identify potential impacts on bath water quality and red tide disasters. The findings indicate that Qinhuangdao falls under the diurnal tide sea area category with a small tidal range. The northern and southern regions experience regular and irregular diurnal tides, respectively, with tropic and equinoctial tides occurring every half a month. The prevailing tidal current type is an irregular semidiurnal tidal current, with M2 tidal current prevailing along the coast, exhibiting weak power and slightly higher offshore velocity. During the summer, the residual current velocity is relatively small, mainly flowing northeastward along the isobaths, while the surface residual current in the southeast of Beidaihe flows toward the shore. The area has several rivers with high summer runoff, resulting in pollutants from Tanghe, Daihe, and Yanghe river estuaries being easily transported to the beach, adversely affecting water quality and the environment. Pollutant accumulation on the north side of the bath, near the harbor area, is likely due to weak water exchange and offshore residual current inflow, which may trigger red tide outbreaks.

ANALYSIS OF THE CURRENT STATE OF WARNING OF EMERGENCY SITUATIONS IN THE TERRITORIES OF UKRAINE WHICH WERE SUFFERED BY ROCKET AND ARTILLERY IMPACTS

The author created an array of soil disturbances as a result of military operations. Physical and chemical exposure lead to a drastic increase in dangerous factors. Dangerous factors to local (in the worst case scenario to background) changes in indicators of physical and chemical properties (condition) of soils, they have a long-term nature of danger to the soil environment and pose a danger to the population and territories. The author established that there is a primary accumulation of pollutants in the soil with subsequent redistribution both in the soil itself and in other environments - surface and underground waters. The process of modeling the spread of pollutants is a complex task due to the need to take into account many variables in time and space, physical and chemical parameters of the soil, as well as environmental conditions and the form of pollutants. Scientific developments in the field of monitoring and ecological-geochemical assessment of soil conditions are fragmentary in nature. To date, no universal methodologies have been created for assessing the safety of soils in territories affected by war and approaches regarding the permissible level of their pollution for the prevention of emergency situations. Research should be conducted using a complex of field, remote and laboratory methods. The author determined that the development of new organizational and technical methods of emergency prevention in territories that have suffered missile and artillery damage, based on comprehensive forecasting, monitoring and modeling of soil hazards, should be based on unified methodological positions regarding the place and role of the processes of prevention, prevention, localization and liquidation in the structure of the general process of combating emergency situations. The methodologies were previously tested in a number of works on the development and implementation of organizational, operational engineering and information methods for the prevention of emergency situations of various types of occurrence and spread. Keywords: military-technogenic load, soil pollution, solid metals, emergency happening, prevention of emergency situations.

Connections Between Air Pollution, Climate Change, and Cardiovascular Health.

Globally, more people die from cardiovascular disease than any other cause. Climate change, through amplified environmental exposures, will promote and contribute to many noncommunicable diseases, including cardiovascular disease. Air pollution, too, is responsible for millions of deaths from cardiovascular disease each year. Although they may appear to be independent, interchangeable relationships and bidirectional cause-and-effect arrows between climate change and air pollution can eventually lead to poor cardiovascular health. In this topical review, we show that climate change and air pollution worsen each other, leading to several ecosystem-mediated effects. We highlight how increases in hot climates as a result of climate change have increased the risk of major air pollution events such as severe wildfires and dust storms. In addition, we show how altered atmospheric chemistry and changing patterns of weather conditions can promote the formation and accumulation of air pollutants: a phenomenon known as the climate penalty. We demonstrate these amplified environmental exposures and their associations to adverse cardiovascular health outcomes. The community of health professionals-and cardiologists, in particular-cannot afford to overlook the risks that climate change and air pollution bring to the public's health.

Constrained stochastic differential games with Markovian switchings and additive structure: The total expected payoff

The main objective of this work is to give conditions for the existence of Nash equilibria for a nonzero-sum constrained stochastic differential game with additive structure and Markovian switchings. In this type of game, each player is interested only in maximizing their finite-horizon total payoff when an additional cost function of the same type is required to be dominated above by another function (in particular, by a constant). The dynamic system for this game is controlled by two players and evolves according to a Markov-modulated diffusion (also known as switching diffusions or piecewise diffusion or diffusion with Markovian switchings). Given that, each player has to solve an optimization problem with constraints. The existence of a Nash equilibrium is thus proved using the Lagrange multipliers approach combined with standard dynamic programming arguments. The Lagrange approach allows the transformation of a constrained game into an unconstrained game. Therefore, this work gives conditions under which a Nash equilibrium for the unconstrained stochastic differential game is also a Nash equilibrium for the corresponding nonzero-sum constrained stochastic differential game. The theory developed here is illustrated by a pollution accumulation problem with two players. Therein, the evolution is governed by a linear stochastic differential equation with Markovian switching, and the decay pollution rate depends on a Markov chain.

"Nonlinear" pursuit of understanding pollutant accumulation and chemistry at environmental and biological interfaces.

Over the past few decades, the public recognition of the prevalence of certain classes of pollutants, such as perfluoroalkyl substances and nanoplastics, within the environment, has sparked growing concerns over their potential impact on environmental and human health. Within both environmental and biological systems, the adsorption and structural organization of pollutants at aqueous interfaces can greatly impact the chemical reactivity and transformation. Experimentally probing chemical behavior at interfaces can often pose a problem due to bulk solvated molecules convoluting molecular signatures from interfacial molecules. To solve this problem, there exist interface-specific nonlinear spectroscopy techniques that can directly probe both macroscopic planar interfaces and nanoplastic interfaces in aqueous environments. These techniques can provide essential information such as chemical adsorption, structure, and reactivity at interfaces. In this perspective, these techniques are presented with obvious advantages for studying the chemical properties of pollutants adsorbed to environmental and biological interfaces.

Remotely visible impacts on air quality after a year-round full-scale Russian invasion of Ukraine

A full-scale Russian invasion of Ukraine caused large devastation, including significant pressure on the environment. Numerous missile strikes on industrial facilities, wildfires near the front-line, use of military equipment, and other accidents and various processes resulting from the war have impacted air quality. In this paper, we aim to assess changes in air pollution following a year-long period of the war based on the nitrogen dioxide (NO2) and carbon monoxide (CO) content derived from the TROPOspheric Monitoring Instrument (TROPOMI) data. The general air quality changes were often uncertain for much of the territory due to meteorological influence on favorable conditions for air pollution accumulation or dispersion. The most crucial changes were observed during the first months of the war, showing a decrease in NO2 levels in major cities, NO2 increase close to the borders, including eastern and northeastern Ukraine, and elevated CO content over wildfires near the front-line. The impact of the war on cities varied depending on their distance from the front-line, the availability of critical infrastructure, and “occupied – non-occupied” status. The essential role of remote sensing is discussed as for assessing over a long period as well as for detecting short-term releases of air pollutants, which can be important for identifying accidental events.

Study of polycyclic aromatic hydrocarbons accumulation in bioretention facilities and its influence on microbial community structure.

Bioretention facilities are one of the most widely used measures for urban stormwater control and utilization. In this study, the accumulation characteristics of polycyclic aromatic hydrocarbons (PAHs) in bioretention facilities and the effects of PAHs on the structure of microbial communities were explored by combining on-site monitoring and water distribution simulation experiments. The correlation between pollutant accumulation and dominant microorganisms in the bioretention systems was also clarified. The results showed that all 16 priority PAHs were detected in the bioretention facilities in the sponge city pilot area. The PAH concentrations in the soil during the non-rainy season were higher than those in the rainy season and medium- and high-ring PAHs dominated. PAHs in the study area were mainly derived from coal and biomass combustion. The potential carcinogenic risk of PAHs accumulated in the bioretention facilities in the study area was low. The microbial diversity during the non-rainy season was greater than that during the rainy season. Firmicutes, Bacteroidetes, Bacteroides, and Massilia were strongly correlated with naphthalene (NAP), pyrene (PYR), fluoranthene (FLT), and benzo[a]pyrene (BaP). According to the results of the small-scale water distribution test, the addition of PAHs had little effect on the decline in water quantity, and there was no significant regularity in the reduction of water quality including TP, NH4+-N, NO3-N, and TN. The addition of PAHs had a significant effect on the microbial community structure and an inhibitory effect on enzyme activity.

Emission of volatile organic compounds from residential biomass burning and their rapid chemical transformations

Biomass combustion releases a complex array of Volatile Organic Compounds (VOCs) that pose significant challenges to air quality and human health. Although biomass burning has been extensively studied at ecosystem levels, understanding the atmospheric transformation and impact on air quality of emissions in urban environments remains challenging due to complex sources and burning materials. In this study, we investigate the VOC emission rates and atmospheric chemical processing of predominantly wood burning emissions in a small urban centre in Greece. Ioannina is situated in a valley within the Dinaric Alps and experiences intense atmospheric pollution accumulation during winter due to its topography and high wood burning activity. During pollution event days, the ambient mixing ratios of key VOC species were found to be similar to those reported for major urban centres worldwide. Positive matrix factorisation (PMF) analysis revealed that biomass burning was the dominant emission source (>50 %), representing two thirds of OH reactivity, which indicates a highly reactive atmospheric mixture. Calculated OH reactivity ranges from 5 s−1 to an unprecedented 278 s−1, and averages at 93 ± 66 s−1 at 9 PM, indicating the presence of exceptionally reactive VOCs. The highly pronounced photochemical formation of organic acids coincided with the formation of ozone, highlighting the significance of secondary formation of pollutants in poorly ventilated urban areas. Our findings underscore the pressing need to transition from wood burning to environmentally friendly sources of energy in poorly ventilated urban areas, in order to improve air quality and safeguard public health.

Toxic metals from atmospheric particulate matter in food species of tomato (Solanum lycopersicum) and strawberry (Fragaria x ananassa) used in urban gardening. A closed chamber study

In this work, two plant foods, strawberry and tomato, were subjected to exposure to metals from synthetic airborne particles in a closed chamber experiment. The synthetic particles were obtained in the laboratory. Within the closed chamber, particles were added and recirculated for 4 days in a turbulent air stream, causing deposition on the different parts of the plants. They were evaluated because of their increasingly frequent cultivation in urban gardens of cities. The main objectives were to determine whether the species accumulate metals significantly, which species accumulate the most, and in which parts of the plant. Finally, an attempt was made to differentiate the accumulation of pollutants by surface deposition on leaves and fruits from the adsorbed metals into the leaf or the fruit by their stomata or cuticles. The concentration of heavy metals was quantified in fruits, leaves and the soil after exposure. Metals were evaluated as a whole and individually, both in dry and fresh weight basis. The decrease of particulate matter and metals in the air inside the chamber was also studied in order to evaluate the use of both food species as air purifier by vertical gardens. The concentration of metals in plants (mg kg−1) and airborne particles (mg m−3) was measured by microwave plasma optical emission spectroscopy (MP-AES). For the sake comparison of total amount of metals in the samples concentrations were normalized. Strawberries was the food species that accumulated the largest amount of metals. In a dry weight basis, tomato leaves and strawberry fruits were the parts of the plants with higher accumulation capacity of particles and metals. The potential toxic elements Cd, Ni and Cr in tomato leaves and in strawberry fruits had a higher presence in the interior of the plant system. In a fresh weight basis, the strawberry fruit had the most accumulation capacity for metals.

Mechanochemically synthesized Mn3O4@β-cyclodextrin mediates efficient electron transfer process for peroxymonosulfate activation

The rational surface engineering of heterogeneous catalysts is of great significance in advanced oxidation processes (AOPs) for eliminating refractory contaminants but remains challenging. In this study, β-cyclodextrin modified Mn3O4 (Mn3O4@β-CD) was prepared through a mechanochemical approach for peroxymonosulfate (PMS) activation, which achieved efficient bisphenol A (BPA) removal via electron transfer process (ETP). The reactive PMS* complex with elevated potential was identified to dominate the ETP by withdrawing electrons from BPA with Mn3O4@β-CD working as electron shuttle, as evidenced by spectroscopy and electrochemical techniques. Experimental results and density functional theory (DFT) calculations showed that the β-CD modification enhanced the interfacial accumulation of pollutants and shortened the migration distance between pollutants (electron donor) and catalysts (electron shuttle) to mediate electron transfer more effectively. Benefitting from the improved ETP, the Mn3O4@β-CD/PMS system showed efficient PMS utilization and practical adaptability in actual waterbodies. This study provides a rational approach for modulating the surface structure of heterogeneous catalysts in PMS-based AOPs for environmental remediation.

Heavy Metal Induced Oxidative Stress Mitigation and ROS Scavenging in Plants.

Although trace elements are essential for life, environmental contamination due to metal accumulation and overuse in various sectors, such as healthcare, agriculture, industry, and cosmetics, poses significant health concerns. Exposure of plants to heavy metals leads to the overproduction of reactive oxygen species (ROS) due to their ability to change mitochondrial membrane permeability and restrict the action of ROS clearance enzymes in the cellular antioxidant system. The interaction of ROS with cellular membranes, heavy-metal-induced interactions directly or indirectly with different macromolecules, and signaling pathways leads to the accumulation of environmental pollutants and oxidative stress in exposed organisms. The heavy metal-ROS-cell signaling axis affects various pathological processes such as ATP depletion, excess ROS production, mitochondrial respiratory chain damage, decoupling of oxidative phosphorylation, and mitochondrial death. This review focuses on discussing the toxic effects of different heavy metals on plants, with particular emphasis on oxidative stress, its consequences, and mitigation strategies.

Micro problems with macro consequences: accumulation of persistent organic pollutants and microplastics in human breast milk and in human milk substitutes.

Industrial activities provide a modern human lifestyle with advances and comforts in every field. However, such scenario has brought several negative issues. Persistent organic pollutants (POPs) and a growing plastic usage together with the degradation byproducts, namely microplastics (MPs), are current environmental problems present in every ecosystem, disturbing all forms of life. POPs and MPs are also found in human consumption products including animal and vegetal derivatives, human milk substitutes, and in human breast milk. To date, it is currently unknown what are the effects of MPs and POPs when ingested during the first and most important stage for health programming of the offspring, the first 1000days of life. Here, we add epidemiological and clinical evidence supporting major sources of POPs and MPs in the ecosystem; and we will precisely describe the effect of POP and MP accumulation in animal- or plant-based infant formulas and human breast milk, modulating health outcomes in the newborn. This review provides a rational to incentive the POP and MP identification in human breast milk and human milk substitutes for avoiding susceptibility to negative health outcomes for the newborn.

Assessing the Impacts of COVID-19 on SO2, NO2, and CO Trends in Durban Using TROPOMI, AIRS, OMI, and MERRA-2 Data

This research report investigated the impacts of the COVID-19 lockdown restrictions on CO, SO2, and NO2 trends in Durban from 2019 to 2021. The COVID-19 lockdown restrictions proved to decrease greenhouse gas (GHG) emissions globally; however, the decrease in GHG emissions was for a short period only. Space-borne technology has been used by researchers to understand the spatial and temporal trends of GHGs. This study used Sentinel-5P to map the spatial distribution of CO, SO2, and NO2. Use was also made of the Atmospheric Infrared Sounder (AIRS), Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2), and the Ozone Monitoring Instrument (OMI) to understand the temporal trends of CO, SO2, and NO2, respectively. To validate the results of this study, we used the Sequential Mann–Kendall (SQMK) test. This study indicated that there were no significant changes in all the investigated gases. Therefore, this study failed to reject the null hypothesis of the SQMK test that there was no significant trend for all investigated gasses. Increasing trends were observed for CO, SO2, and NO2 trends during winter months throughout the study period, whereas a decreasing trend was observed in all investigated gases during the spring months. This shows that meteorological factors play a significant role in the accumulation of air pollutants in the atmosphere. Most importantly, this study has noted that there was an inverse relationship between the trends of all investigated gases and the COVID-19 lockdown restrictions.

Discovering a catholyte free design for gas phase electrocatalytic NO gas reduction to NH3 at room temperature

Nitric oxide (NOx) is one of the most contributors to the health risks associated with breathing in flue gases and it is crucial to eliminate this pollutant from the air when solid waste is burned. Electrochemical gas phase reduction of NO to NH3 is the promising method to mitigating the accumulation of NO gas pollutants and producing a valuable NH3 as a product at room temperature. In this investigation, for the first time, we designed a catholyte-free cell for gas phase electrochemical NO to NH3 conversion using K2[Ni(CN)4] coated carbon felt (CF) electrode as a electrocatalyst at room temperature. Herein, K2[Ni(CN)4] heterogeneous mediator transfers the electron between the NO gas molecule and electrode. The NO removal efficiency and NH3 formation were simultaneously monitored by using online gas phase FTIR spectroscopy. In the catholyte-free gas phase NORR process, the K2[Ni(CN)4]/CF electrode exhibits excellent NORR performance, with a high NH3 yield rate of 1128.9 µmol h−1 cm−2, an excellent 89.5 % NH3 faradaic efficiency at − 1 V vs quasi reference Ag and enhanced long term NORR durability. It is noteworthy that, this is the highest yield rate and faradaic efficiency of NH3 during gas phase NORR at room temperature. In addition, K2[Ni(CN)4]/CF electrocatalyst exhibits 99 % of NO removal efficiency with the formation of value-added product (NH3). Moreover, the proposed electrocatalyst shows excellent chemical, and morphological stability after long durability NORR operations. Furthermore, the detailed electrode-electrolyte free cell, NORR reduction mechanism was proposed. Present discovery provides great insights for sustainable NORR operations in real-site applications.

Can water dating trace the transport history of HCHs in the ocean?

Long-range atmospheric and oceanic transport play a crucial role in the accumulation of persistent organic pollutants (POPs), including hexachlorocyclohexanes (HCHs), in the Arctic Ocean. Herein, transient tracers, specifically chlorofluorocarbon-12 and sulfur hexafluoride, were used to determine the ventilation time of HCHs. Results revealed that dissolved HCHs can penetrate to a depth of ~500 m in the western Arctic Ocean, corresponding to water masses with a mean age of 45 ± 14 years. The average long-range transport time for α-HCH from initial atmospheric release to entering the western Arctic Ocean was estimated to be >30 ± 5 years, indicating continued moderate to high ecological risks from HCHs in the Arctic. This study demonstrates that transient tracers serve as effective water dating tools to elucidate the transport history of stable POPs in the ocean, contributing to a better understanding of their environmental characteristics and fate.