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We show that the Landsat and Sentinel-2 satellites can detect NO2 plumes from large point sources at 10 to 60 m pixel resolution in their blue and ultrablue bands. We use the resulting NO2 plume imagery to quantify nitrogen oxides (NOx) emission rates for several power plants in Saudi Arabia and the United States, including a 13-y analysis of 132 Landsat plumes from Riyadh power plant 9 from 2009 through 2021. NO2 in the plumes initially increases with distance from the source, likely reflecting recovery from ozone titration. The fine pixel resolutions of Landsat and Sentinel-2 enable separation of individual point sources and stacks, including in urban background, and the long records enable examination of multidecadal emission trends. Our inferred NOx emission rates are consistent with previous estimates to within a precision of about 30%. Sources down to ~500 kg h-1 can be detected over bright, quasi-homogeneous surfaces. The 2009 to 2021 data for Riyadh power plant 9 show a strong summer peak in emissions, consistent with increased power demand for air conditioning, and a marginal slow decrease following the introduction of Saudi Arabia's Ambient Air Standard 2012. [ABSTRACT FROM AUTHOR]

China is likely the world's largest anthropogenic source of methane emissions, with coal mine methane (CMM) being the predominant contributor. Here, we deploy 2 years of satellite observations to survey facility‐level CMM emitters in Shanxi, the most prolific coal mining province in China. A total of 138 detected episodic events at 82 facilities are estimated to emit 1.20 (+0.24/−0.20, 95% CI) million tons of methane per year (Mt CH4/yr) during 2021–2023, roughly equivalent to 4.2 times the integrated flux from the Permian plumes and four times of the integrated flux from the Four Corners plumes, two of the world's largest hotspots for oil and gas methane emissions. This work reveals the heavy‐tailed distribution characteristic of CMM emission sources for the first time, with 20% of emitters contributing approximately 50% of total emissions. Comparison with the Global Energy Monitor (GEM) inventory reveals that the GEM estimate is about 4.1 times our estimate. Plain Language Summary: This study examines methane emissions from coal mines in Shanxi, China, identified as a significant source of global methane, a potent greenhouse gas. Using satellite data over 2 years, we found 138 detected episodic events at 82 facilities in Shanxi emitting an estimated 1.2 million tons of methane annually, far exceeding emissions from known global hotspots in the oil and gas sectors. Our analysis shows that a small percentage of these facilities contribute to the majority of emissions. The results, which challenge previous estimates from environmental monitoring organizations, underscore the need for direct, observational methods to accurately assess and address methane emissions. This work aims to guide efforts in mitigating climate change by identifying key areas for reducing methane release. Key Points: Satellite data identify 82 major methane emitters in Shanxi, China, with high annual emissions of up to 1.2 MtTop 20% of coal mines contribute to half of the region's total methane emissionsFindings highlight the importance of direct measurements for accurate emission estimates [ABSTRACT FROM AUTHOR]

Abstract China is likely the world's largest anthropogenic source of methane emissions, with coal mine methane (CMM) being the predominant contributor. Here, we deploy 2 years of satellite observations to survey facility‐level CMM emitters in Shanxi, the most prolific coal mining province in China. A total of 138 detected episodic events at 82 facilities are estimated to emit 1.20 (+0.24/−0.20, 95% CI) million tons of methane per year (Mt CH4/yr) during 2021–2023, roughly equivalent to 4.2 times the integrated flux from the Permian plumes and four times of the integrated flux from the Four Corners plumes, two of the world's largest hotspots for oil and gas methane emissions. This work reveals the heavy‐tailed distribution characteristic of CMM emission sources for the first time, with 20% of emitters contributing approximately 50% of total emissions. Comparison with the Global Energy Monitor (GEM) inventory reveals that the GEM estimate is about 4.1 times our estimate.

Formulation of the problem. The main danger of organic substances is the use of large amounts of oxygen for its oxidation. As a result, there are conditions of oxygen deficiency in polluted water sometimes to the formation of hypoxia. It leads to significant violations of biological groups and the death of certain species. The increase of nutrients leads to the uncontrolled development of higher aquatic plants and algae. It caused to undesirable imbalance of organisms in the water body and to decrease in water quality. So, control over the content of nutrients and organic substances in water is one of the important factors to ensure the proper functioning of aquatic ecosystems and maintain water quality. The Severskiy Donets river basin is a quite difficult water object with a variety of natural conditions. Water resources of the Severskyi Donets River serve to provide drinking and industrial water supply, agricultural needs and recreation function. Aim of the research is to determine the peculiarities of loading rivers of the Severskyi Donets basin with nutrients and organic substances. Methods. For the purpose of research, the state register 2TP-Vodhosp was used. It contains information about removal of pollutants from utilities and industrial enterprises. Statistical data about the number of population and settlements, distribution by the territory of the basin were borrowed from the database of the State Statistics Service of Ukraine and the Institute of Demography and Social Research. Scientific novelty of the work is that for the first time the loading of nutrients and organic substances for all first-order tributaries in the Severskyi Donets basin was calculated. Practical value. Analys of the main anthropogenic loads in the Severskyi Donets river basin and their impacts can be used for composition of the River Basin Management Plan as an important component. It may serve as a basis for the development of measures for surface water bodies and the river basin as a whole in order to achieve defined environmental goals. Results. The main load of nutrients and organic compounds is caused by cities with a population equivalent (PE) more than 100 thousand people. The rivers of the Uda sub-basin are the most polluted by these compounds (as a part of municipal sewage) mainly due to the influence of Kharkiv city. The amount of organic matter that enters with the industrial wastewater is also the largest for the Uda sub-basin. Among the industrial enterprises within the Severskyi Donets basin, the largest number of nutrients was diverted by PJSC NKMZ in Kramatorsk city to the rivers of the Kazenny Torets sub-basin and PJSC Severodonetsk Association "Azot" directly to the Severskyi Donets River. The main role in organic pollution from the rural population is played by 5 sub-basins: Velyka Kamyanka, Kazenny Torets, Severskyi Donets, Udy, Aidar. In general, they form 59% of the total organic substances load. The largest inflow of nitrogen and phosphorus compounds is observed to the sub-basins of the rivers Luhan, Kazennyi Torets, Udy, Aidar, Oskol and the Severskyi Donets.

The energy transfer process for acoustic propagation and scattering in inhomogeneous, lossy media is rigorously investigated. Two problems are considered: an arbitrarily composed cluster of lossy scatterers, excited by a single point source and a layered, lossy medium excited by an internal point-source distribution. Energy conservation laws and optical theorems are established. The connection of active intensity with the scattering cross section and the relation between reactive intensity and Lagrangian density are determined. Furthermore, the influence of the losses of the involved media to the kinetic energy is unveiled. Reductions to lossless media and near-zero frequency values are derived. [ABSTRACT FROM AUTHOR]

Background: Bacteria are ubiquitous in the marine environment. Increasing concern for human health has led to growing interest in contamination on public beaches. The presence of pathogenic microorganisms originating from anthropogenic activities such as defecation and disposal of sewage on beaches are of special concern. In this study, presence of pathogenic bacteria and bacterial load in beach zones and point sources were investigated. Methods: Sand core samples from the subtidal zone, intertidal zone, supratidal zone and point sources from 5 beaches in Accra, Ghana, were collected and analysed. Total aerobic, coliform and Escherichia (E. coli) counts were determined for each zone in the respective beaches. Bacteria isolates were presumptively identified using biochemical tests and confirmed with MALDI-TOF MS. Results: Mean total aerobic count and total coliform counts ranged from 2.10 to 3.01 log CFU/g and 0.29 to 2.18 log CFU/g respectively while E. coli counts ranged from 0.12 to 1.71 log CFU/g for the beaches. Total aerobic count from point sources was 2.4-folds higher than the subtidal zone while total coliform counts were 5-folds higher in the point sources compared to the supratidal zone. Point sources had 10 times (P =.0016) more E. coli counts as compared to the subtidal zone. Isolates recovered (n = 35) belonged to 10 bacteria genera. These were Bacillus spp. (25.7%), Acinetobacter spp. (14.3%), Aeromonas spp. (14.3%), Klebsiella pneumoniae (14.3%), Aerococcus viridans (8.6%), Staphylococcus spp. (8.6%), Shewanella profunda (5.7%), Rheinheimera soli (2.9%), Pseudomonas aeruginosa (2.9%), and Exiguobacterium aurantiacum (2.9%). Conclusion: Point sources are major contributors to contamination on beaches. The presence of potentially pathogenic bacteria in beach sand could be a public health risk. Sensitization on cleanliness in the marine environment including beaches in Ghana is needed to enhance public health and safety. [ABSTRACT FROM AUTHOR]

Current methods for detecting atmospheric plumes and inferring point source rates from high-resolution satellite imagery are labor intensive and not scalable to the growing satellite dataset available for methane point sources. Here we present a two-step algorithm called U-Plume for automated detection and quantification of point sources from satellite imagery. The first step delivers plume detection and delineation (masking) with a machine learning U-Net architecture for image segmentation. The second step quantifies point source rate from the masked plume using wind speed information and either a convolution neural network (CNN) or a physics-based Integrated Mass Enhancement (IME) method. The algorithm can process 62 128×128 images per second on a single core. We train the algorithm with large-eddy simulations of methane plumes superimposed on noisy and variable methane background scenes from the GHGSat-C1 satellite instrument. We introduce the concept of point source observability Ops = Q/(UW?B) as a single dimensionless number to predict plume detectability and source rate quantification error from an instrument as a function of source rate Q, wind speed U, instrument pixel size W, and instrument-dependent background noise κB. We show that Ops can powerfully diagnose the ability of an imaging instrument to observe point sources of a certain magnitude under given conditions. U-Plume successfully detects and masks plumes from sources as small as 100 kg h-1 over surfaces with low background noise and succeeds for larger point sources over surfaces with substantial background noise. We find that the IME method for source quantification is unbiased over the full range of source rates while the CNN method is biased toward the mean of its training range. The total error in source rate quantification is dominated by wind speed at low wind speeds and by the masking algorithm at high wind speeds. A wind speed of 2-4 m s-1 is optimal for detection and quantification of point sources from satellite data. [ABSTRACT FROM AUTHOR]

Formulation of the problem. The main danger of organic substances is the use of large amounts of oxygen for its oxidation. As a result, there are conditions of oxygen deficiency in polluted water sometimes to the formation of hypoxia. It leads to significant violations of biological groups and the death of certain species. The increase of nutrients leads to the uncontrolled development of higher aquatic plants and algae. It caused to undesirable imbalance of organisms in the water body and to decrease in water quality. So, control over the content of nutrients and organic substances in water is one of the important factors to ensure the proper functioning of aquatic ecosystems and maintain water quality. The Severskiy Donets river basin is a quite difficult water object with a variety of natural conditions. Water resources of the Severskyi Donets River serve to provide drinking and industrial water supply, agricultural needs and recreation function. Aim of the research is to determine the peculiarities of loading rivers of the Severskyi Donets basin with nutrients and organic substances. Methods. For the purpose of research, the state register 2TP-Vodhosp was used. It contains information about removal of pollutants from utilities and industrial enterprises. Statistical data about the number of population and settlements, distribution by the territory of the basin were borrowed from the database of the State Statistics Service of Ukraine and the Institute of Demography and Social Research. Scientific novelty of the work is that for the first time the loading of nutrients and organic substances for all first-order tributaries in the Severskyi Donets basin was calculated. Practical value. Analys of the main anthropogenic loads in the Severskyi Donets river basin and their impacts can be used for composition of the River Basin Management Plan as an important component. It may serve as a basis for the development of measures for surface water bodies and the river basin as a whole in order to achieve defined environmental goals. Results. The main load of nutrients and organic compounds is caused by cities with a population equivalent (PE) more than 100 thousand people. The rivers of the Uda sub-basin are the most polluted by these compounds (as a part of municipal sewage) mainly due to the influence of Kharkiv city. The amount of organic matter that enters with the industrial wastewater is also the largest for the Uda sub-basin. Among the industrial enterprises within the Severskyi Donets basin, the largest number of nutrients was diverted by PJSC NKMZ in Kramatorsk city to the rivers of the Kazenny Torets sub-basin and PJSC Severodonetsk Association "Azot" directly to the Severskyi Donets River. The main role in organic pollution from the rural population is played by 5 sub-basins: Velyka Kamyanka, Kazenny Torets, Severskyi Donets, Udy, Aidar. In general, they form 59% of the total organic substances load. The largest inflow of nitrogen and phosphorus compounds is observed to the sub-basins of the rivers Luhan, Kazennyi Torets, Udy, Aidar, Oskol and the Severskyi Donets. [ABSTRACT FROM AUTHOR]

Many Galactic sources of gamma rays, such as supernova remnants, are expected to produce neutrinos with a typical energy cutoff well below 100 TeV. For the IceCube Neutrino Observatory located at the South Pole, the southern sky, containing the inner part of the Galactic plane and the Galactic Center, is a particularly challenging region at these energies, because of the large background of atmospheric muons. In this paper, we present recent advancements in data selection strategies for track-like muon neutrino events with energies below 100 TeV from the southern sky. The strategies utilize the outer detector regions as veto and features of the signal pattern to reduce the background of atmospheric muons to a level which, for the first time, allows IceCube searching for point-like sources of neutrinos in the southern sky at energies between 100 GeV and several TeV in the muon neutrino charged current channel. No significant clustering of neutrinos above background expectation was observed in four years of data recorded with the completed IceCube detector. Upper limits on the neutrino flux for a number of spectral hypotheses are reported for a list of astrophysical objects in the southern hemisphere.

Acoustic excitation of a layered sphere by N external and internal point sources is considered. The direct problem is solved by developing a T-Matrix method leading to the analytical determination of all the involved acoustic fields. Low-frequency far-field approximations are derived for different source distributions and scatterer's characteristics. The behaviour of the scattering cross sections is investigated. Several inverse problems are formulated and solved analytically; thus the respective unknown quantities are recovered explicitly. These problems include localization of the sources, determination of their number, identification of the core's type and extraction of the parameters of the scatterer's layers. [ABSTRACT FROM AUTHOR]

This study investigated the microplastic pollution of surface waters in and around the most populated and urbanized city in Sri Lanka from 2019 to 2022. The sampling regime was designed to cover the rainfall-driven hydrology and varying levels of urbanization approximated by the built area fraction. Mass and particle concentrations of microplastics ranged from undetected to 0.01 g/L (average ± standard deviation: 0.00464 ± 0.00528 g/L) and from 2 to 36 particles/L (5.3 ± 6.9), respectively. The highest microplastic pollution was observed in the lake; however, in many cases it was without a statistically significant (P < 0.05) difference with canals. Concentrations in the dry state (i.e., at least 30 days after no rainfall) were about 1.5 times more than the wet state (i.e., at least 50 mm/day rainfall for 10 days) in the lake and in the semi-urban canal, but again, the differences were not significant; however, in urban canals, the concentrations were similar in both states. Over 80% of the microplastics were fibre and fragments. Mass concentrations of microplastics showed moderately positive (Pearson's r > 0.6) correlations with the built area fraction of the contributing catchment in both states but was significant (P < 0.1) only in the dry state. In the case of particle concentrations, none showed even a weak correlation. The independence of microplastic content against built area fraction and rainfall, as well as twice the concentrations found in point source inputs against the surface waters, gave the following insights. Microplastic content in our study area was governed mostly by the modified catchment hydrology spearheaded by stormwater drainages (some cases trans-catchment) and diffusion factors such as non-residential population. [ABSTRACT FROM AUTHOR]

The use of radiation is mandatory in modern life, but the harms of radiation cannot be avoided. To minimize the effect of radiation, protection is required for the safety of the environment and human life. Hence, inventing a better shield than a conventional shielding material is the priority of researchers. Due to this reason, this current research deals with an innovative shielding material named EKZ samples having a composition of (epoxy resin (90–40) wt %-kaolin clay (10–25) wt %-ZnO-nano particles (0–35) wt %). The numerous compositional variations of (epoxy resin, kaolin clay, and ZnO-nano particles on the prepared EKZ samples varied the density of the samples from 1.24 to 1.95 g/cm3. The radiation shielding parameter of linear attenuation coefficient (LAC), half value layer (HVL), tenth value layer (TVL), and radiation protection efficiency (RPE) were measured to evaluate the radiation diffusion efficiency of newly made EKZ samples. These radiation shielding parameters were measured with the help of the HPGe detector utilizing the three-point sources (Am-241, Cs-137, and Co-60). The obtained results exposed that the value of linear attenuation coefficient (LAC) and radiation protection efficiency (RPE) was maximum, yet the value of half value layer (HVL), and tenth value layer (TVL), were minimum due to the greater amount of kaolin clay and ZnO-nanoparticles, whereas the amount of epoxy resin was lesser. In addition, it has been clear that as-prepared EKZ samples are suitable for low-dose shielding applications as well as EKZ-35 showed a better shielding ability. [ABSTRACT FROM AUTHOR]

The mixing ratios of methane (CH4) were recorded with high temporal and spatial resolution in Münster, Germany, to identify urban CH4 sources and to quantify the overall inner city CH4 emissions. Both mobile and stationary measurement techniques were employed. The background mixing ratios showed a diurnal cycle with higher values at night under stable stratification conditions. In the industrial park, periodic peaks were detected. Ten mappings of the urban CH4 mixing ratio were made with an instrumented cargo bicycle. Repeated local increases in mixing ratios were found at 13 individual locations. The emission rate was estimated to be 22.0 g h−1 km−1. A total of five leaks from the underground gas distribution network were identified. From the increase in background mixing ratio, the overall source strength of the study area was estimated to be 24.6 g m−2 a−1, which is approximately three times the total CH4 emissions from the city's most recent emissions report. The contribution of point sources was 0.64 g m−2 a−1, suggesting that significant additional CH4 sources exist within the study area. In the interest of climate protection, there is an urgent need for further research on the urban CH4 sources and emission fluxes in detail. [ABSTRACT FROM AUTHOR]

A Bayesian Belief Network was developed to simulate phosphorus (P) loss in an Irish agricultural catchment. Septic tanks and farmyards were included to represent all P sources and assess their effect on model performance. Bayesian priors were defined using daily discharge and turbidity, high-resolution soil P data, expert opinion, and literature. Calibration was done against seven years of daily Total Reactive P concentrations. Model performance was assessed using percentage bias, summary statistics, and visually comparing distributions. Bias was within acceptable ranges, the model predicted mean and median P concentrations within the data error, with simulated distributions more variable than the observations. Considering the risk of exceeding regulatory standards, predictions showed lower P losses than observations, likely due to simulated distributions being left-skewed. We discuss model advantages and limitations, the benefits of explicitly representing uncertainty, and priorities for data collection to fill knowledge gaps present even in a highly monitored catchment. • First study evaluating Bayesian Network of P pollution against high-resolution data. • Bayesian model allowed knowledge gap identification in a highly monitored catchment. • Model shows strong predictive performance against the observed interquartile ranges. • Model structural, data and parametric uncertainties are represented. • Wide posterior distributions are an inherent property of the modelling approach. [ABSTRACT FROM AUTHOR]

Water is the founding fundamental of life and hence is a basic need of life. However, due to the ever-rising population, industrialization has emerged as a global issue. This problem has notably escalated in developing countries. Their citizens face problems such as floods, drought, and poor water quality. Due to poor water quality and sanitation problems, most health issues are caused by water-borne infections. In developing countries, untreated wastewater is released into water bodies or the ground, thereby polluting natural resources. This is due to the lack of sufficient infrastructure, planning, funding, and technologies to overcome these problems. Additionally, the urbanization of megacities in developing countries is highly accelerated, but it is disproportionate to the required resources for treating wastewater. Due to this biological oxygen demand (BOD): chemical oxygen demand (COD) ratio is increasing exponentially in developing countries compared to developed ones. Spreading awareness, education and supporting relevant research, and making stringent rules for industries can alone solve the water problem in developing countries. [ABSTRACT FROM AUTHOR]

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We show that the Landsat and Sentinel-2 satellites can detect NO 2 plumes from large point sources at 10 to 60 m pixel resolution in their blue and ultrablue bands. We use the resulting NO 2 plume imagery to quantify nitrogen oxides (NO x ) emission rates for several power plants in Saudi Arabia and the United States, including a 13-y analysis of 132 Landsat plumes from Riyadh power plant 9 from 2009 through 2021. NO 2 in the plumes initially increases with distance from the source, likely reflecting recovery from ozone titration. The fine pixel resolutions of Landsat and Sentinel-2 enable separation of individual point sources and stacks, including in urban background, and the long records enable examination of multidecadal emission trends. Our inferred NO x emission rates are consistent with previous estimates to within a precision of about 30%. Sources down to ~500 kg h -1 can be detected over bright, quasi-homogeneous surfaces. The 2009 to 2021 data for Riyadh power plant 9 show a strong summer peak in emissions, consistent with increased power demand for air conditioning, and a marginal slow decrease following the introduction of Saudi Arabia's Ambient Air Standard 2012., Competing Interests: Competing interests statement:The authors declare no competing interest.

Human population growth has led to increased energy and food production, fertilizer usage and wastewater flows. Increased nitrogen availability is a worldwide cause of eutrophication of rivers, lakes and estuaries, however, quantitative evaluation the impacts of nitrogen loads has been insufficient in developing countries because of poor data availability. The Nam Ngum River basin, Laos, which supplies quality water for domestic use in the Vientiane Metropolis, was selected as the target area for this study. The Nam Ngum River basin is 415 km long with a 17,000 km² catchment area, and the main land uses in 2000 were paddy (15.6%), forest (32.3%), shrub (40.3%) and urban (0.2%). By UN estimation, population in Laos is expected to increase 2.1 times from 2000 to 2050, and fertilizer use also will increase to produce sufficient food. Therefore, future water quality is a main concern in this river basin. Meteorological and hydrological data from 1995 to 2004, and spatial data such as topography, land use, and soil properties were collected for model simulation. A conceptual nitrogen balance model with three nitrogen pools was developed and combined with a rainfall runoff model. Simulated river discharge and nitrogen loads agreed with the observed data. Then, we investigated future nitrogen load variations in the basin under different population growth and agricultural modernization scenarios. As a result, even when population in the basin increased 2.1 times, nitrogen load did not change significantly (11,676 tons/year in 2000 and 11,822 tons/year in 2050). However, the fertilizer increase scenario, from 25 kg/ha/season to 50 kg/ha/season, showed significant increase in nitrogen loading, from 11,676 ton/year to 17,010 ton/year. Our results provide initial insight into the magnitude and spatial distribution of nitrogen loading in Nam Ngum River Basin, showing that this type of model may be useful for future impact assessments. [ABSTRACT FROM AUTHOR]

Water resources are under the threat of pollution from anthropogenic activities. The aim of this study is to present an integrated approach for analysis of pressures and impacts on the water quality. The application site is a small Mediterranean watershed, Acisu Stream, that is located in Antalya City of Turkey. This stream drains into the Mediterranean Sea and it has a high local impact on the sea water quality. An intense water quality monitoring program was conducted at twelve monitoring stations along the stream network with monthly intervals for a period of 1 y. The monitoring study involved onsite measurements and analyses of many physicochemical, bacteriological parameters and pesticides. The discharges of three wastewater treatments were the main sources of point pollution. The diffuse pollution of total nitrogen (TN) and total phosphorus (TP) were estimated on daily basis using MapShed watershed model and GIS. Cropland, septic systems and farm animals are the main sources of diffuse pollution. The areal loading rates of diffuse TN and TP were estimated at nearly 20 and 4 kg/ha/y. The contribution of cropland to TN and TP pollution loads was the highest among all sources and they were estimated at 58% and 67%, respectively. The pollution loads of TN (24.33%) and TP (21.99%) were also high for point sources. These pollution sources have an adverse impact on the water quality and there is a need for integrated management to improve water status both for the stream and the coastal water. [ABSTRACT FROM AUTHOR]

The water quality of lakes is highly dependent on external phosphorus (P) loading. The vast external loadings from sewage and other wastewater discharge that European lakes have historically received have been dramatically reduced today by improved wastewater treatment. Gaining knowledge of the catchment characteristics that influence external P-loading should enable predictions of the achievable water quality of lakes. In this study, we tested this proposition. Data from 90 new Danish lakes show no apparent relationship between the mean summer P-concentration and the size or land use of the catchments. The external P-loading and resulting annual P-concentration were further investigated on a representative subset of 12 of the new lakes, using six methods. Three of the methods used empirical estimates of P-transport from catchments, based on the national average P-transport, runoff-dependent P-transport, and crop-dependent P-transport, and the other three methods used different empirical models tested on the lakes. External P-loading was reliably predicted by several of the methods. The predictions of the annual P-concentration were highly dependent on the inclusion of annual runoff. However, the predicted P-concentrations were generally overestimated, most pronounced for the nutrient-poor and most recently established lakes. In these lakes, internal P-loading was found to be the most important factor in predicting achievable water quality. [ABSTRACT FROM AUTHOR]

Estuaries function as temporary storage sites for plastic debris, influencing the distribution of microplastics (MPs) across ecosystems. This research delves into the presence of MPs in the water, sediment, fish, and shellfish of Ashtamudi Lake, a Ramsar wetland with brackish water located on the southwest coast of India. Given the lake's significance in supporting the livelihoods of numerous fishers and acting as a vital source of fishery resources for both local consumption and export, examining the contamination of the system by MPs becomes particularly pertinent. The highest percentage composition of MPs was found in macrofauna at 60.6% (with fish at 19.6% and shellfish at 40.9%), followed by sediment (22.8%) and water (16.7%). The primary types of MPs identified in all samples were fibers (35.6%), fragments (33.3%), and films (28%), with beads being the least represented at 3.03%. ATR-FTIR and Raman spectra analysis identified five polymers from shellfish (polypropylene, polyethylene, polystyrene, nylon, and polyvinyl chloride), five from fish guts (nylon, polypropylene, polyethylene, polyurethane, and polysiloxane), four in sediment (polypropylene, polyethylene, nylon, rayon), and four in water samples (polypropylene, polyethylene, nylon, and polystyrene). SEM-EDAX analysis of MPs obtained from the samples revealed degradation and the presence of inorganic elements such as Na, Mg, Al, Si, S, K, Cl, P, and Ca, as well as heavy metals like Pb, Mo, Rh, Pd, Ti, and Fe. The existence of these plastic polymers and heavy metals in microplastic samples poses a threat to vulnerable biota; people consume contaminated fish and shellfish, underscoring the importance of monitoring MPs in lake water. This investigation of MPs in Ashtamudi Lake highlights the system's susceptibility to plastic pollution and the bioavailability of smaller MPs to aquatic organisms. Identified sources of MPs in the lake include fishing and aquaculture activities, sewage pollution, improper solid waste management in lake watersheds, and unsustainable tourism. Upstream and downstream management interventions are recommended to address MP pollution in Ashtamudi Lake. [Display omitted] • Abundance of MPs in Ashtamudi Lake was: Fauna > sediment > water. • MP types detected are Fibers, fragments, films. • Polymers identified were PP, PE, NY, PVC, PU, Psi, PS, RY & PBT. • Pb, Mo, Rh, Pd, Ti, and Fe were the heavy metals in MPs. [ABSTRACT FROM AUTHOR]

Anthropogenic methane (CH _4 ) emissions contribute significantly to the current radiative forcing driving climate change. Localized CH _4 sources such as occurring in the fossil fuel industry contribute a substantial share to the anthropogenic emission total. The temporal dynamics of such emissions is largely unresolved and unaccounted for when using atmospheric measurements by satellites, aircraft, and ground-based instruments to monitor emission rates and verify reported numbers. Here, we demonstrate the usage of a ground-based imaging spectrometer for quantifying the CH _4 emission dynamics of a ventilation facility of a coal mine in the Upper Silesian Coal Basin, Poland. To this end, we deployed the imaging spectrometer at roughly 1 km distance from the facility and collected plume images of CH _4 column enhancements during the sunlit hours of four consecutive days in June 2022. Together with wind information from a co-deployed wind-lidar, we inferred CH _4 emission rates with roughly 1 min resolution. Daily average emission rates ranged between 1.39 ± 0.19 and 4.44 ± 0.76 tCH _4 h ^−1 , 10 min averages ranged between (min) 0.82 and (max) 5.83 tCH _4 h ^−1 , and puff-like events caused large variability on time scales below 15 min. Thus, to monitor CH _4 emissions from such sources, it requires measurement techniques such as the imaging spectrometer evaluated here that can capture emission dynamics on short time scales.

A large quantity of CH4 is emitted to the atmosphere via ventilation shafts of underground coal mines. According to the European Pollutant Release and Transfer Register (E-PRTR), hard coal mines in the Upper Silesia Coal Basin (USCB) are a strong contributor (447 kt CH4 in 2017) to the annual European CH4 emissions. However, atmospheric emissions of CH4 from coal mines are poorly characterized, as they are dispersed over large areas. As part of the Carbon Dioxide and CH4 Mission (CoMet) pre-campaign, a study of the USCB's regional CH4 emissions took place in August 2017. We flew a recently developed active AirCore system aboard an unmanned aerial vehicle (UAV) to obtain CH4 mole fractions downwind of a single coal mining ventilation shaft. Besides CH4, we also measured CO2, CO, atmospheric temperature, pressure, and relative humidity. Wind-speed and wind-direction measurements were made using a lightweight balloon-borne radiosonde. Fifteen UAV flights were performed flying perpendicular to the wind direction at several altitude levels, to effectively build a ‘curtain’ of CH4 mole fractions in a two-dimensional plane at a distance between 150 and 350 m downwind of a single ventilation shaft. Furthermore, we have developed an inverse Gaussian approach for quantifying CH4 emissions from a point source using the UAV-based observations, and have applied it as well as the mass balance approach to both simulated data and actual flight data to quantify CH4 emissions. The simulated data experiments revealed the importance of having multiple transects at different altitudes, appropriate vertical spacing between the individual transects, and proper distance between the center height of the plume and the center flight transect. They also showed that the inverse Gaussian approach performed better than the mass balance approach. Our estimate of the CH4 emission rates from the sampled shaft ranges from 0.5 to 14.5 kt/year using a mass balance approach, and between 1.1 and 9.0 kt/year using an inverse Gaussian method. The average difference between the mass balance and the inverse Gaussian approach was 2.3 kt/year. Based on the observed correlation between CO2 and CH4 (R-squared > 0.69), the CO2 emissions from the shaft were estimated to be between 0.3 and 9.8 kt/year. This study demonstrates that the UAV-based active AirCore system provides an effective way of quantifying coal mining shaft emissions of CH4 and CO2.

The use of radiation is mandatory in modern life, but the harms of radiation cannot be avoided. To minimize the effect of radiation, protection is required for the safety of the environment and human life. Hence, inventing a better shield than a conventional shielding material is the priority of researchers. Due to this reason, this current research deals with an innovative shielding material named EKZ samples having a composition of (epoxy resin (90–40) wt %-kaolin clay (10–25) wt %-ZnO-nano particles (0–35) wt %). The numerous compositional variations of (epoxy resin, kaolin clay, and ZnO-nano particles on the prepared EKZ samples varied the density of the samples from 1.24 to 1.95 g/cm3. The radiation shielding parameter of linear attenuation coefficient (LAC), half value layer (HVL), tenth value layer (TVL), and radiation protection efficiency (RPE) were measured to evaluate the radiation diffusion efficiency of newly made EKZ samples. These radiation shielding parameters were measured with the help of the HPGe detector utilizing the three-point sources (Am-241, Cs-137, and Co-60). The obtained results exposed that the value of linear attenuation coefficient (LAC) and radiation protection efficiency (RPE) was maximum, yet the value of half value layer (HVL), and tenth value layer (TVL), were minimum due to the greater amount of kaolin clay and ZnO-nanoparticles, whereas the amount of epoxy resin was lesser. In addition, it has been clear that as-prepared EKZ samples are suitable for low-dose shielding applications as well as EKZ-35 showed a better shielding ability.

Recently, IceCube found evidence for a diffuse signal of astrophysical neutrinos in an energy range of ∼60TeV to the PeV-scale [1]. The origin of those events, being a key to understanding the origin of cosmic rays, is still an unsolved question. So far, analyses have not succeeded to resolve the diffuse signal into point-like sources. Searches including a maximum-likelihood-ratio test, based on the reconstructed directions and energies of the detected down- and up-going neutrino candidates, were also performed on IceCube data leading to the exclusion of bright point sources. In this paper, we present two methods to search for faint neutrino point sources in three years of IceCube data, taken between 2008 and 2011. The first method is an autocorrelation test, applied separately to the northern and southern sky. The second method is a multipole analysis, which expands the measured data in the northern hemisphere into spherical harmonics and uses the resulting expansion coefficients to separate signal from background. With both methods, the results are consistent with the background expectation with a slightly more sparse spatial distribution, corresponding to an underfluctuation. Depending on the assumed number of sources, the resulting upper limit on the flux per source in the northern hemisphere for an E-2 energy spectrum ranges from ∼1.5·10-8 GeV/cm2 s−1, in the case of one assumed source, to ∼4·10-10 GeV/cm2 s−1, in the case of 3500 assumed sources.

The mixing ratios of methane (CH4) were recorded with high temporal and spatial resolution in Münster, Germany, to identify urban CH4 sources and to quantify the overall inner city CH4 emissions. Both mobile and stationary measurement techniques were employed. The background mixing ratios showed a diurnal cycle with higher values at night under stable stratification conditions. In the industrial park, periodic peaks were detected. Ten mappings of the urban CH4 mixing ratio were made with an instrumented cargo bicycle. Repeated local increases in mixing ratios were found at 13 individual locations. The emission rate was estimated to be 22.0 g h−1 km−1. A total of five leaks from the underground gas distribution network were identified. From the increase in background mixing ratio, the overall source strength of the study area was estimated to be 24.6 g m−2 a−1, which is approximately three times the total CH4 emissions from the city’s most recent emissions report. The contribution of point sources was 0.64 g m−2 a−1, suggesting that significant additional CH4 sources exist within the study area. In the interest of climate protection, there is an urgent need for further research on the urban CH4 sources and emission fluxes in detail.

Water is the founding fundamental of life and hence is a basic need of life. However, due to the ever-rising population, industrialization has emerged as a global issue. This problem has notably escalated in developing countries. Their citizens face problems such as floods, drought, and poor water quality. Due to poor water quality and sanitation problems, most health issues are caused by water-borne infections. In developing countries, untreated wastewater is released into water bodies or the ground, thereby polluting natural resources. This is due to the lack of sufficient infrastructure, planning, funding, and technologies to overcome these problems. Additionally, the urbanization of megacities in developing countries is highly accelerated, but it is disproportionate to the required resources for treating wastewater. Due to this biological oxygen demand (BOD): chemical oxygen demand (COD) ratio is increasing exponentially in developing countries compared to developed ones. Spreading awareness, education and supporting relevant research, and making stringent rules for industries can alone solve the water problem in developing countries.

A layered medium is excited by N external or internal point sources. Boundary-value problems for the generated acoustic waves are formulated. General scattering and optical theorems are established relating the involved fields and far-field patterns due to groups of sources. Interaction scattering cross sections are defined and associated physical bounds are derived. The large-N behavior of these cross sections is also investigated. Numerical results are presented demonstrating the variations of the interaction cross sections and their physical bounds. [ABSTRACT FROM AUTHOR]

Featured Application: The prototype developed in this work can rapidly detoxify agrochemical solutions directly at farms, allowing for their safe disposal in the environment or water reuse. The worldwide increase in the number and use of agrochemicals impacts nearby soil and freshwater ecosystems. Beyond the excess in applications and dosages, the inadequate management of remnants and the rinsing water of containers and application equipment worsen this problem, creating point sources of pollution. Advanced oxidation processes (AOPs) such as photocatalytic and photo-oxidation processes have been successfully applied in degrading organic pollutants. We developed a simple prototype to be used at farms for quickly degrading pesticides in water solutions by exploiting a UV–H2O2-mediated AOP. As representative compounds, we selected the insecticide imidacloprid, the herbicide terbuthylazine, and the fungicide azoxystrobin, all in their commercial formulation. The device efficiency was investigated through the disappearance of the parent molecule and the degree of mineralization. The toxicity of the pesticide solutions, before and during the treatment, was assessed by Vibrio fischeri and Pseudokirchneriella subcapitata inhibition assays. The results obtained have demonstrated a cost-effective, viable alternative for detoxifying the pesticide solutions before their disposal into the environment, even though the compounds, or their photoproducts, showed different sensitivities to physicochemical degradation. The bioassays revealed changes in the inhibitory effects on the organisms in agreement with the analytical data. [ABSTRACT FROM AUTHOR]

Published reports suggest efforts designed to prevent the occurrence of harmful algal blooms and hypoxia by reducing non‐point and point source phosphorus (P) pollution are not delivering water quality improvements in many areas. Part of the uncertainty in evaluating watershed responses to management practices is the lack of standardized estimates of phosphorus inputs and outputs. To assess P trends across the conterminous United States, we compiled an inventory using publicly available datasets of agricultural P fluxes, atmospheric P deposition, human P demand and waste, and point source discharges for 2002, 2007, and 2012 at the scale of the 8‐digit Hydrologic Unit Code subbasin (∼1,800 km2). Estimates of agricultural legacy P surplus accumulated from 1945 to 2001 were also developed. Fertilizer and manure inputs were found to exceed crop removal rates by up to 50% in many agricultural regions. This excess in inputs has led to the continued accumulation of legacy P in agricultural lands. Atmospheric P deposition increased throughout the Rockies, potentially contributing to reported increases in surface water P concentrations in undisturbed watersheds. In some urban areas, P fluxes associated with human waste and non‐farm fertilizer use has declined despite population growth, likely due, in part, to various sales bans on P‐containing detergents and fertilizers. Although regions and individual subbasins have different contemporary and legacy P sources, a standardized method of accounting for large and small fluxes and ready to use inventory numbers provide essential infromation to coordinate targeted interventions to reduce P concentrations in the nation's waters. Plain Language Summary: Excessive phosphorus (P) concentrations in surface water endanger public health and welfare by contributing to harmful algal blooms and hypoxic zones. Many efforts to decrease P pollution to the nation's waters have not achieved desired outcomes. To help decision‐makers develop strategies to decrease P loads, we developed an inventory of inputs and outputs of P across the United States. This inventory reveals the source and magnitude of P in a local area and how it changes through time. We found that agricultural P inputs were the largest source of P nationwide and inefficiencies in use contribute to the continued accumulation of phosphorus across the landscape. This excess phosphorus may make it more difficult to achieve water quality goals. However, many agricultural regions in the eastern and western United States demonstrated more efficient use of phosphorus fertilizer in 2012. On another positive note, urban areas in certain regions have likely decreased their fertilizer application rates, the amount of P being released by detergents, and point source loads. These efforts may have contributed to recent reports of improved water quality in more urbanized watersheds. Decision makers should consider the role of current fluxes and legacy P when designing strategies to reduce P pollution. Key Points: Agricultural surplus declined by 8% for the entire US and declines are seen in many subbasins of the eastern and western United StatesAtmospheric phosphorus (P) deposition increased by 9% from 2002 to 2012, coincident with increases in stream P concentrations in undisturbed watershedsSummed legacy P surplus accumulation is more than 50 times contemporary P surplus and may perpetuate eutrophication in the nation's waters [ABSTRACT FROM AUTHOR]

Changes in river water quality often follow typical trajectories characterized by sequential phases of degradation and recovery induced by management measures, typically achieved with combinations of legislative and technological interventions. However, the key question about the effectiveness of the different types of legal interventions – source control, use-related, and end-of-pipe – remains poorly understood. With the case of phosphorus (P), which is a valuable indicator of surface water quality and a widespread target of legislation at various governance levels in order to control eutrophication of water bodies, we quantified the relation between point source loading of P and resulting river water quality for a multidecadal trajectory of the river Ruhr (Germany). In particular, we analysed P-related legislation targeting point source pollution enforced at EU, national, state, and local level and linked their development with measured total phosphorus (TP) concentrations in the river Ruhr (Germany). To this end, we combined archival data with information in the literature and conducted interviews with contemporary witnesses to describe and quantify the efficacy of each legislative approach. Although not specifically targeted at P reduction, end-of-pipe measures (sewer systems and wastewater treatment plants (WWTP)) reduced TP inputs to surface waters already in the 1960s and 1970s, curbing TP inputs to the Ruhr by 38% in 1980. The first targeted source control legislation – the banning of phosphates in textile detergents in 1981 – effectively reduced TP concentrations in WWTP influents by 36% since 1990. In combination with stronger end-of-pipe legislation focusing on P elimination in WWTP since the 1990s, TP concentrations in WWTP effluents were reduced by 86% at the end of the 1990s and by 92% in 2021. Complete and successful source control for textile detergents made use-related legislation redundant. Our study demonstrates that source control measures should be prioritized, because they are the fastest way to curb emissions. These findings provide insights that can inform efficient decision-making regarding water quality in a trajectory perspective of hierarchical governance and technological needs, as well as effective policy-making and management for other pollutants requiring control from point sources. [Display omitted] • We synthesize legislation, its implementation, and effects on river water quality. • Efficacies of source control, use-related, and end-of-pipe measures are quantified. • Source control led to a 36% reduction in phosphorus inputs to the Ruhr river. • End-of-pipe measures are crucial complementary interventions for phosphorus reduction. • Implementation capacities, motivation, and monitoring impact legislative efficacy. [ABSTRACT FROM AUTHOR]

Motivated by practical applications in satellite formations and directional antenna arrays, the problem of targeting a planar array of point sources at one common object of interest is proposed and then solved using novel distributed coordination strategies. These point sources are arbitrarily located on the x – y plane and the boundary point sources, whose either x or y coordinate is extremal, already orient to the non-coplanar target point. The only global information shared among the remaining point sources is the positive directions of the global coordinate axes x and y , and hence, they have to rely on sensing the changes of the orientation angles of their nearest neighbors to adjust their own orientation. We prove that under our control law, the orientation lines will asymptotically intersect at the same point of concurrency as the boundary point sources. The main idea behind the designed control law is the intuitive argument from Euclidean geometry that reducing the differences between the distances to the x – y plane of the pairwise intersection points of the orientation lines leads to realizing concurrent targeting. We further show the boundedness and exponential convergence speed of the orientation angles. [ABSTRACT FROM AUTHOR]