Suspended Particulate Matter Research Articles

Inputs and transport of acid mine drainage-derived heavy metals in karst areas of Southwestern China

Heavy metal pollution caused by acid mine drainage (AMD) is a global environmental concern. The processes of migration and transformation of heavy metals carried by AMD are more complicated in karst areas where carbonate rocks are widely distributed. Water, suspended particulate matter (SPM), and sediments are the crucial media in which heavy metals migrate and it is important to elucidate the geochemical behavior of AMD heavy metals in these environments. This study tracked AMD heavy metals from release to migration and transformation in a natural river system in a karst mining area. AMD directly impacted the hydrochemical composition of the karst water environment, but the carbonate rock naturally neutralized the acidity of the AMD. AMD heavy metal concentrations decreased gradually after the tributaries from the mining area entered the main river, with the metals tending to accumulate in SPM and sediments. The forms in which heavy metals were present were influenced by pH and their relative concentrations. Raman spectroscopy and transmission electron microscopy of sediments from the mining area suggested that the presence of an iron phase plays an important role in the fate of AMD-derived heavy metals. It is, therefore, necessary to elucidate the mechanisms of iron phase precipitation from sediments in order to control AMD-derived heavy metals in karst mining areas. This study improves our understanding of the geochemical behavior of heavy metals in karst environments and provides direction for the prevention and control of AMD in affected areas.

Review on Zinc Isotopes in River Systems: Distribution and Application

Zinc (Zn) is an essential trace element widely present in rivers and plays a crucial role in ecosystems. Human activities have led to the extensive migration and dissemination of Zn in the environment. When the accumulation of Zn in rivers reaches excessive levels, it transforms into a potentially harmful contaminant. Consequently, tracing Zn’s origin by its isotope ratios (δ66Zn) from natural and anthropogenic sources is essential for the management of and safeguarding against river pollution and comprehending Zn behavior in rivers as well. This review presents the advancements in Zn isotope research in river environments, including a summary of Zn isotope measurement, the distribution and controlling factors (mineral adsorption, precipitation, and biological effects) of Zn isotopes, and the applications of Zn isotopes in rivers. The median δ66Zn values for uncontaminated river water and suspended particulate matter (SPM) were 0.37‰ and 0.22‰, respectively, close to the bulk silicate Earth (BSE) value of 0.28 ± 0.05‰. With respect to the contaminated river, δ66Zn falls within −0.73‰ to 1.77‰, with it being heavily influenced by anthropogenic sources, such as the electroplating and metal processing industries. Apart from contamination identification, this review summarizes the river material exchange process and the δ66Zn values of rainwater (−0.2‰~0.38‰), groundwater (−0.13‰~1.4‰), lake water (−0.66‰~0.21‰), and seawater (−1.1‰~0.9‰), which facilitates a holistic understanding of the Zn cycle and isotope fractionation in the river system. In conclusion, Zn isotopes are an effective tool for tracing pollution sources and Zn migration processes, with enormous unexplored potential. Therefore, this review finally summarizes some challenges and future directions in current research on Zn isotopes.

Molecular size variations of chromophoric dissolved organic matter (CDOM) along a salinity gradient in the Changjiang River estuary

Molecular size is a critical parameter for characterizing dissolved organic matter in aquatic systems. Four cruises were conducted in October 2018, March 2019, July 2019 (with a normal flood), and August 2020 (with an extreme flood), along a transect from the Changjiang (Yangtze) River freshwater to the shelf area with salinities near or > 30. During each cruise surface water samples at 5–6 stations were collected along the salinity gradient, and absorption spectra (to quantify and qualify chromophoric dissolved organic matter (CDOM)) were measured. In addition, ultrafiltration was conducted so that the size partitions including four factions of <1 kDa, 1–3 kDa, 3–10 kDa and 10 kDa–0.2 μm were obtained. In the different seasons, CDOM molecular sizes always showed decreasing trends from land to sea, which was consistent to most estuaries worldwide. In the freshwaters, those with sizes >1 kDa generally contributed 20%–40% of the bulk CDOM in different seasons, but these large colloidal molecules always disappeared at the offshore stations. The extreme flood in August 2020 brought more waters with lower salinity and higher CDOM concentration into the transects, and the extra CDOM materials were generally of larger molecular sizes. In addition to suspended particulate matter (SPM) resuspension, the flocculation of organic matter could also be another important reason for localised increased CDOM molecular size near the river mouth.

Suspended particulate matter affects the distribution and migration of heavy metals in the Yellow River

Suspended particulate matter (SPM) is an important heavy metal transporter in water. As a well-known high-SPM river, its impact on the distribution and migration of heavy metals in the Yellow River (YR) deserves special attention. In this study, the spatial distributions of heavy metals in surface water and SPM of the YR were investigated. The results indicate that the concentrations (dissolved and particulate phases) and bioavailability (particulate phase) of most heavy metals were higher during the rainy season than during the dry season. A considerable proportion of heavy metals (>70 %) was transported by SPM and fine particles (clay) controlled the pollution status of heavy metals in the YR. This could lead to higher heavy metal concentrations in the SPM midstream and downstream during the rainy season and higher heavy metal concentrations in upstream during the dry season. Heavy metal adsorption experiments showed that specific combination methods (such as binding with carbonate) between Cd and SPM may cause SPM to act as a source of Cd midstream and downstream. This study provides a new perspective on the effects of SPM on heavy metal distribution and migration in the YR.

Persistent Organic Pollutants and Suspended Particulate Matter in Snow of Eastern Siberia in 2009-2023: Temporal Trends and Effects of Meteorological Factors and Recultivation Activities at Former Industrial Area.

Suspended particulate matter (SPM), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCP) were studied in the snow cover at urban and suburban localities in the Irkutsk region, Eastern Siberia for their temporal variations in 2009-2023, daily deposition fluxes (DDFs), and effects of some meteorological factors, as well as the effects of different technogenic activities in the industrial area of the former organochlorine enterprises of Usol'ekhimprom. SPM loads at both stations were found to be at a low level of pollution. The levels of HCB, α + γ-HCH, and ∑p,p'-DDX were lower than Russian maximum permissible levels (MPLs) in drinking water, groundwater, and surface water for household drinking and cultural purposes. The sums of all organochlorine compounds studied in snow were higher than the MPL in freshwater water bodies for fishery purposes. The levels of the DDFs of HCHs, DDTs, and heptachlorinated PCB decreased, di- and trichlorinated PCB levels increased, and HCB levels changed at a polynomial line during 2009-2023. The change in the relative composition of PCBs was found as a result of recultivation activities at the industrial area of the former organochlorine enterprise of Usol'ekhimprom. The air humidity and temperature are the key meteorological factors affecting the DDFs of PCBs and OCPs.

Water Quality and Flooding Impact of the Record-Breaking Storm Gloria in the Ebro Delta (Western Mediterranean)

Extreme events are increasing in frequency and severity due to climate change, making the littoral zone even more vulnerable and requiring continuous monitoring for its optimized management. The low-lying Ebro Delta ecosystem, located in the NW Mediterranean, was subject to Storm Gloria in the winter of 2020, the most severe coastal storm registered in the area in decades and one of the most intense ever recorded in the Mediterranean. This event caused intense rainfall, severe flooding, the erosion of beaches, and the destruction of coastal infrastructures. In this study, the Landsat-8 and Sentinel-2 satellites were used to monitor the flooding impact and water quality status, including chlorophyll-a, suspended particulate matter, and turbidity, to evaluate the pre-, syn-, and post-storm scenarios. Image processing was carried out using the ACOLITE software and the on-the-cloud Google Earth Engine platform for the water quality and flood mapping, respectively, showing a consistent performance for both satellites. This cost-effective methodology allowed us to characterize the main water quality variation in the coastal environment during the storm and detect a higher flooding impact compared to the one registered three days later by the Copernicus Emergency Service for the same area. Moreover, the time series revealed how the detrimental impact on the water quality and turbidity conditions was restored two weeks after the extreme weather event. While transitional plumes of sediment discharge were formed, no phytoplankton blooms appeared during the study period in the delta. These results demonstrate that the workflow implemented is suitable for monitoring extreme coastal events using open satellite imagery at 10–30 m spatial resolution, thus providing valuable information for early warning to facilitate timely assistance and hazard impact evaluation. The integration of these tools into ecological disaster management can significantly improve current monitoring strategies, supporting decision-makers from the local to the national level in prevention, adaptation measures, and damage compensation.

What do we know about the natural sources, transport and sinks of antimony in the environment?

Limited attention has been given to antimony present in detrital form in the different environmental compartments except for highly polluted systems related in some way to ore deposits. In highly polluted systems, the ultimate sinks of Sb may be the minerals tripuhyite (FeSbO4) or perhaps schafarzikite (FeSb2O4) but how about Sb dynamics in the much more abundant, weakly polluted or ‘non-polluted’ systems? This deficiency in our knowledge is probably related to the perception that the element is mostly present ‘dissolved’ in waters and to a focus on the role of its binding to iron oxyhydroxides in solid phases. Here we evaluate the state of our knowledge in the Sb journey from geological matrices to detrital forms in soils and waters and identify key aspects that require further investigation. In high-temperature environments, Sb demonstrated its striking incompatibility by fractionation into aqueous fluids or sulfide/metallic melts, or by uptake in a few common minerals that accept this element (e.g., rutile or pyrite). In low-temperature environments, Sb enters the structures of minerals with different formation rates and solubilities, creating a confusing impression of being mobile and immobile at the same time. The estimates of Sb concentration in the upper continental crust are scattered and the Sb-bearing mineral(s) there have not yet been identified. Given that sedimentary rocks are consistently enriched in Sb, the carriers could be the clay minerals. In surface water bodies, Sb could be carried predominantly in the particulate fraction, despite the popular belief of the opposite. An important point to consider is the transport of Sb within the suspended particulate matter, not on its surface. In soils, many studies employed sequential extractions to show that Sb accumulates in the ‘residual’ fraction, without ever asking what the nature of this fraction is. Based on these facts (i.e., knowns), we have identified the unknowns regarding detrital Sb on our planet that should preferentially be addressed by future projects if our understanding is to improve.

Characteristics of Suspended Road Dust According to Vehicle Driving Patterns in an Urban Area and PM10 Content in Silt

Characterizing the influence factors of exhaust gas based on the suspended road dust on paved roads, according to the number of vehicles and their distance with regard to driving pattern, is important in order to provide a coefficient for driving patterns to find a model equation. This has been a limitation of previous studies, in which this was difficult to carry out in a large area reflecting various driving patterns because some sections were selected according to empirical measurement results, and only one vehicle measurement was used to find the level of road dust. This study measured the concentration of suspended road dust that could occur, depending on the vehicle’s driving patterns, on an experimental road in Yongin, South Korea, from May to July 2023. The study was conducted to determine the degree of the effect of exhaust gas, according to the concentration of suspended road dust generated, by determining the separation distance based on real-time measurements. This study attempted to determine the changes in suspended road dust based on driving patterns in urban areas and factor in the concentration of suspended road dust with regard to emission characteristics in terms of exhaust gas and particulate matter with a diameter of 10 microns or less (PM10). This was in accordance with conditions evaluated using mobile laboratories, based on suspended-PM10-concentration-measuring equipment. This study mainly focused on the following main topics: (1) increasing the level of suspended particulate matter at less than 10 m intervals produced by exhaust gas; (2) decreasing the level of suspended road dust with an increase in the number of vehicles, with the area measured at a distance of three cars in front showing the lowest level of suspended road dust in the air and a low level for the rear vehicle; (3) demonstrating that PM10 is effective in measuring the generation of suspended road dust; and (4) evaluating suspended road dust levels by road section. Based on the results, this research is necessary to more appropriately set the focus of analyses that aim to characterize suspended road dust according to exhaust gas and PM10 content in silt.

Indoor air quality improvement with filtration and UV-C on mitigation of particulate matter and airborne bacteria: Monitoring and modeling

Indoor air, especially with suspended particulate matter (PM), can be a carrier of airborne infectious pathogens. Without sufficient ventilation, airborne infectious diseases can be transmitted from one person to another. Indoor air quality (IAQ) significantly impacts people's daily lives as people spend 90% of their time indoors. An industrial-grade air cleaner prototype (filtration + ultraviolet light) was previously upgraded to clean indoor air to improve IAQ on two metrics: particulate matter (PM) and viable airborne bacteria. Previous experiments were conducted to test its removal efficiency on PM and airborne bacteria between the inlet and treated air. However, the longer-term improvement on IAQ would be more informative. Therefore, this research focused on quantifying longer-term improvement in a testing environment (poultry facility) loaded with high and variable PM and airborne bacteria concentrations. A 25-day experiment was conducted to treat indoor air using an air cleaner prototype with intermittent ON and OFF days in which PM and viable airborne bacteria were measured to quantify the treatment effect. The results showed an average of 55% reduction of total suspended particulate (TSP) concentration between OFF days (110 μg/m3) and ON days (49 μg/m3). An average of 47% reduction of total airborne viable bacteria concentrations was achieved between OFF days (∼3200 CFU/m3) and ON days (∼2000 CFU/m3). A cross-validation (CV) model was established to predict PM concentrations with five input variables, including the status of the air cleaner, time (h), ambient temperature, indoor relative humidity, and day of the week to help simulate the air-cleaning effect of this prototype. The model can approximately predict the air quality trend, and future improvements may be made to improve its accuracy.

Spatial variation of air pollutants by using GIS modelling

&lt;p&gt;Air pollution in Tamil Nadu has become a pressing issue, as various pollutants have surpassed the limits established by the pollution control board. The major air pollutants in the region, namely sulphur dioxide, nitrogen dioxide, and suspended particulate matter, have been identified. This study aims to monitor and analyse the levels of air pollution in Tamil Nadu, with a specific focus on key parameters such as SO2, NO2, PM2.5, PM10, and ozone. By examining the atmospheric levels of these pollutants and their correlation with temperature fluctuations, the impact on human health and respiratory problems can be evaluated. Moreover, the study will assess the contribution of traffic emissions and vehicular pollution to the concentration of PM10 in different areas. Additionally, GIS technology will be utilized to spatially and temporally investigate pollution concentrations and evaluate their effect on the air quality index. By comparing the pollution concentration from thermal power stations and vehicular pollution, the study will identify the sources of pollutants, with a particular emphasis on SO2 and NOx emissions from vehicles and higher levels of suspended particulate matter from thermal stations. The analysis of these pollutants and their sources will provide valuable insights for the implementation of effective pollution control measures and the management of environmental pollution in Tamil Nadu. Given the concerns regarding pollutants exceeding the prescribed limits set by the pollution control board, monitoring air pollution in Tamil Nadu is of utmost importance.&lt;/p&gt;&#x0D;

Studies on the airborne bacterial communities and antimicrobial resistance genes in duck houses based on metagenome and PCR analysis

The threat of antimicrobial resistance (AMR) is on the rise globally, especially with the development of animal husbandry and the increased demand for antibiotics. Livestock and poultry farms, as key sites for prevalence of antibiotic-resistant bacteria (ARB), can spread antimicrobial resistance genes (ARGs) through microbial aerosols and affect public health. In this study, total suspended particulate matter (TSP) and airborne culturable microorganisms were collected from duck houses in Tai'an, Shandong Province, and the bacterial communities and airborne ARGs were analyzed using metagenomics and PCR methods. The results showed that the bacterial communities in the air of duck houses were mainly Actinobacteria, Firmicutes, Proteobactria, Chlamydia, and Bcateroidetes at the phylum level. At the genus level, the air was dominated by Corynebacterium, Jeotgalicoccus, Staphylococcus, Brevibacterium, and Megacoccus, and contained some pathogenic bacteria such as Staphylococcus aureus, Corynebacterium diphtheriae, Klebsiella oxytoca, Acinetobacter baumannii, and Pseudomonas aeruginosa, which were also potential hosts for ARGs. The airborne ARGs were mainly macrolides (10.97%), penicillins (10.73%), cephalosporins (8.91%), streptozotocin (8.91%), and aminoglycosides (8.02%). PCR detected 27 ARGs in airborne culturable microorganisms, and comparative analysis between PCR and the metagenomic data revealed that a total of 9 ARGs were found to the same, including macrolides ErmA, ErmF, tetracyclines tetG, tetX, methicarbamazepines dfrA12, dfrA15, aminoglycosides APH3-VI, ANT2-Ⅰ, and sulfonamides sul2. Moreover, inhalation exposure modeling showed that the workers in duck houses inhaled higher concentrations of ARB, human pathogenic bacteria (HPB) and human pathogenic antibiotic-resistant bacteria (HPARB) than hospital workers. These results provide new insights into airborne microorganisms and ARGs in animal farms and lay the foundation for further study.

Nutrient dynamics in the Yellow River -a case study of different reservoir regulation operations

Global dam construction and reservoir artificial regulations change the biogeochemical processes of nutrients along river networks. Herein, nutrients and hydrologic parameters were analyzed to ascertain their spatiotemporal heterogeneity in the Yellow River and assess the retention effect of nutrients in the Xiaolangdi Reservoir (XLDR). Nutrients increased upstream of reservoirs (the Sanmenxia Reservoir and XLDR) due to the inflow of tributaries (Wei River and Fen River). The XLDR maintained a balanced effect on most nutrient levels from upstream of reservoirs to downstream by the disparities in biogeochemical processes during various periods, including biotic assimilation consumption in the upper layer and regeneration and release in the lower layer during the Drainage period; limited water residence time of the XLDR and constrained biotic assimilation processes in the Flood control period; vertical water mixing in the Impoundment period. The disparities of most nutrient levels upstream of reservoirs played a crucial role in nutrient characteristics in the Yellow River during various periods. The higher DSi levels derived from enhanced physical erosion and chemical weathering of rock/soil responded to the higher water discharge and suspended particulate matter levels upstream and in the Yellow River during the Flood control and Impoundment periods; however, the lower DIN (dissolved inorganic nitrogen) and TDP (total dissolved phosphorus) resulted from the point pollution source and amplified water dilution effect. We demonstrated that the XLDR acted as a nutrient source for DIN, DIP and DSi based on the mass balance model in a hydrological year (June 2017-May 2018), with retention efficiency (RETf) of −1.4 %, −11% and −7%, respectively. The decreased RETf of DIP primarily stemmed from the pronounced reservoir source effect in the Drainage period. Consequently, the XLDR could relieve the P limitation downstream and estuary by changing the nutrient stoichiometry ratios of outflow.

Manganese cycling and transport in boreal estuaries impacted by acidic Mn-rich drainage

As critical transition zones between the land and the sea, estuaries are not only hotspots of hydrogeochemical and microbial processes/reactions, but also play a vital role in processing and transferring terrestrial fluxes of metals and nutrients to the sea. This study focused on three estuaries in the Gulf of Bothnia. All of them experience frequent inputs of acidic and Mn/metal-rich creek waters due to flushing of acid sulfate soils that are widespread in the creekś catchments. Analyzing existing long-termwaterchemistrydata revealed a strong seasonal variation of Mn loads, with the highest values in spring (after snow melt) and autumn (after heavy rains). We sampled surface waters, suspended particulate matter (SPM), and sediments from the estuarine mixing zones and determined the loads and solid-phase speciation of Mn as well as the composition and metabolic potentials of microbial communities. The results showed that the removal, cycling, and lateral transport of Mn were governed by similar phases and processes in the three estuaries. Manganese X-ray absorption spectroscopy data of the SPM suggested that the removal of Mn was regulated by silicates (e.g., biotite), organically complexed Mn(II), and MnOx (dominated by groutite and phyllomanganates). While the fractional amounts of silicate-bound Mn(II) were overall low and constant throughout the estuaries, MnOx was strongly correlated with the Mn loadings of the SPM and thus the main vector for the removal of Mn in the central and outer parts of the estuaries, along with organically complexed Mn(II). Down estuary, both the fractional amounts and average Mn oxidation state of the MnOx phases increased with (i) the total Mn loads on the SPM samples and (ii) the relative abundances of several potential Mn-oxidizing bacteria (Flavobacterium, Caulobacter, Mycobacterium, and Pedobacter) in the surface waters. These features collectively suggested that the oxidation of Mn, probably mediated by the potential Mn-oxidizing microorganisms, became more extensive and complete towards the central and outer parts of the estuaries. At two sites in the central parts of one estuary, abundant phyllomanganates occurred in the surface sediments, but were converted to surface-sorbed Mn(II) phases at deeper layers (>3–4 cm). The occurrence of phyllomanganates may have suppressed the reduction of sulfate in the surface sediments, pushing down the methane sulfate transition zone that is typically shallow in estuarine sediments. At the outermost site in the estuary, deposited MnOx were reduced immediately at the water–sediment interface and converted most likely to Mn carbonate. The mobile Mn species produced by the Mn reduction processes (e.g., aqueous Mn(II) and ligand complexed Mn(III)) could partly diffuse into the overlying waters and, together with the estuarine Mn loads carried by the surface waters, transfer large amounts of reactive Mn into open coastal areas and subsequently contribute to Mn shuttling and inter-linked biogeochemical processes over the seafloor. Given the widespread occurrence of acid sulfate soils and other sulfidic geological materials on many coastal plains worldwide, the identified Mn attenuation and transport mechanisms are relevant for many estuaries globally.

Analysis of air temperature variation with atmospheric pollutants and meteorological parameters using SPSS

Temperature variation in the atmosphere is closely related to climatic change, environmental pollution and human health. It has become the prime concern of most countries due to the anthropogenic activities and adverse meteorological situations. This temperature variation depends on various factors like the meteorological parameters as well as the air pollutants. The analysis of temperature variation with these factors are done using Geographically Weighted Regression Modelling (GWR) in Statistical Package for Social Sciences (SPSS). This idea is used to study the chronographic change of relationship between a dependent attribute and one or more independent attribute from the output obtained from GWR equation from SPSS Software. In this study the variation of air temperature is analyzed with pollutants and meteorological parameters. The study areas chosen are Vytila, MG Road, Eloor, Methanam, Kalamasserry. The concentration of NO2, SO2, Respirable suspended particulate matter (RSPM) and the meteorological parameters like Relative Humidity (RH), precipitation and atmospheric temperature over 2010-2020 were collected. A numerical model is developed using the above data to study the variation of temperature in the selected areas.

Thermal Power Plant Pollution Monitoring and Control using Internet of Things

In our day-to-day life, environmental degradation and global warming are essential factors to consider. These problems were caused due to the contamination of water, air, and soil with the waste generated by industries. The pollutants level generated by the industries to be measured and controlled by central and state pollution control board. The air pollutants are the major cause for the deterioration. The existing pollutant monitoring system are complicated, inaccurate, unreliable, delayed intimation and less efficient. Hence in mettur thermal power plant, the internet of things-based pollutant gas monitoring system has been implemented. This system consists of numerous gas sensors, Arduino UNO controller, ESP8266 Wi-Fi module, ubidots server and alarm. The pollutants measured are carbon monoxide (CO), suspended particulate matters (SPM), sulphur oxides (Sox), nitrogen oxides (Nox) in air. When the pollutants level of industry is crossed the limit, the pollution control board has been intimated the exact location of the industry through internet. The pollution control board can automatically send alert SMS and email to the respective industry. This system is suitable for the recent technology industrial internet of things. The electrostatic precipitator has been installed for pollutant control. It is proved that the proposed system is a very good replacement for the conventional monitoring system done by the human. It is acted as user friendly interface for the operation of the system and is reliable. The system has attained improved pollutant control, increased stability, and consistency of the power plant and finally the safety of the employees working in the power plants and mine areas.

Organic Matter in the Ocean: Indicators of Biogeochemical Processes

The article presents informative organogeochemical indicators used in oceanology to characterize biogeochemical processes. A classification based on data on suspended particulate matter, plankton, benthos, bottom sediments, and sea, river, and pore water has been developed. Clusters have been identified that include the elemental and isotopic composition of organic matter (OM), the group composition of lipids, aliphatic and alicyclic hydrocarbons, higher alcohols, macromolecular acids and ketones, isoprenoids, lignin and its structural monomers, and PAHs. The most informative indices are considered, which make it possible to assess the genesis of the original OM, the degree of its transformation, sources, and the ratio of aquatic and terrigenous components. These indices reflect the influx of riverine and aeolian material and permafrost thawing and make it possible to reconstruct the temperature of river waters and coastal upwellings. They significantly complement biooceanological, lithological, and geochemical studies and expand the biogeochemical methodology for studying the carbon cycle.

Exhaled VOC Biomarkers from Rats Injected with PMs from Thirty-One Major Cities in China.

Particulate matter (PMs) of different origins can cause diverse health effects. Here, a homemade box was used to facilitate real-time measurements of breath-borne volatile organic compounds (VOCs) by gas chromatography-ion mobility spectrometry. We have tracked exhaled VOC changes in 228 Wistar rats that were injected with water-soluble PM suspension filtrates (after 0.45 μm) from 31 China cities for 1 h to up to 1-6 days during the experiments. Rats exposed to the filtrates exhibited significant changes in breath-borne VOCs within hours, featuring dynamic fluctuations in the levels of acetone, butan-2-one, heptan-2-one-M, acetic acid-M, and ethanol. Subsequently, on the fifth to sixth day after the injection, there was a notable increase in the proportion of aldehydes (including hexanal-M, hexanal-D, pentanal, heptanal-M, and (E)-2-hexenal). The 10 dynamic VOC fingerprint patterns mentioned earlier showcased the capability to indirectly differentiate urban PM toxicity and categorize the 31 cities into four distinct groups based on their health effects. This study provides valuable insights into the mechanisms of exhaled VOCs and underscores their critical role as biomarkers for differentiating the toxicity of different PMs and detecting the early signs of potential diseases. The results from this work also provide a scientific basis for city-specific air pollution control and policy development.

STUDIES OF THE AREA AROUND SINGRAULI COAL FIELD &amp; ENERGY BELT, DISTRICT SIGRAULI, MADHYA PRADESH INDIA

STUDIES OF THE AREA AROUND SINGRAULI COAL FIELD &amp; ENERGY BELT, DISTRICT SIGRAULI, MADHYA PRADESH INDIA

The Long-Term Detection of Suspended Particulate Matter Concentration and Water Colour in Gravel and Sand Pit Lakes through Landsat and Sentinel-2 Imagery

Over the past half century, the demand for sand and gravel has led to extensive quarrying activities, creating many pit lakes (PLs) which now dot floodplains and urbanized regions globally. Despite the potential importance of these environments, systematic data on their location, morphology and water quality remain limited. In this study, we present an extensive assessment of the physical and optical properties in a large sample of PLs located in the Po River basin (Italy) from 1990 to 2021, utilizing a combined approach of remote sensing (Landsat constellation and Sentinel-2) and traditional limnological techniques. Specifically, we focused on the concentration of Suspended Particulate Matter (SPM) and the dominant wavelength (λdom, i.e., water colour). This study aims to contribute to the analysis of PLs at a basin scale as an opportunity for environmental rehabilitation and river floodplain management. ACOLITE v.2022, a neural network particularly suitable for the analysis of turbid waters and small inland water bodies, was used to atmospherically correct satellite images and to obtain SPM concentration maps and the λdom. The results show a very strong correlation between SPM concentrations obtained in situ and those obtained from satellite images, both for data derived from Landsat (R2 = 0.85) and Sentinel-2 images (R2 = 0.82). A strong correlation also emerged from the comparison of spectral signatures obtained in situ via WISP-3 and those derived from ACOLITE, especially in the visible spectrum (443–705 nm, SA = 10.8°). In general, it appeared that PLs with the highest mean SPM concentrations and the highest mean λdom are located along the main Po River, and more generally near rivers. The results also show that active PLs exhibit a poor water quality status, especially those of small sizes (&lt;5 ha) and directly connected to a river. Seasonal comparison shows the same trend for both SPM concentration and λdom: higher values in winter gradually decreasing until spring–summer, then increasing again. Finally, it emerged that the end of quarrying activity led to a reduction in SPM concentration from a minimum of 43% to a maximum of 72%. In this context, the combined use of Landsat and Sentinel-2 imagery allowed for the evaluation of the temporal evolution of the physical and optical properties of the PLs in a vast area such as the Po River basin (74,000 km2). In particular, the Sentinel-2 images consistently proved to be a reliable resource for capturing episodic and recurring quarrying events and portraying the ever-changing dynamics of these ecosystems.

Assessment of water quality in a lake with limited tourist pressure due to the COVID-19 lockdown

This study provides a unique opportunity to realistically assess the impact of tourism pressure on the water quality of lakes. A quantitative analysis of the physicochemical and microbiological parameters of water during and after the COVID-19 lockdown period was made. The study covered Sztynorckie Lake located in the Great Masurian Lakes System (GMLS) (northeastern Poland), which is a holiday destination for hundreds of thousands of holidaymakers, and serves as a pillar of the local economy. Significant improvement in the microbiological water quality was observed only during the drastic reduction of human activity due to the pandemic-enforced lockdown. This was confirmed by the results of PCA (X-axis explains 88 % of the variability of the analyzed samples; statistical significance of p<0.05). The rapid increase in the number of coliforms and Escherichia coli (613.1 MPN/100 mL) in the first weekend after the lockdown (June 2020) indicates a point discharge of sewage (including fecal pollution). Illegal discharge of sewage and wastewater is a highly reprehensible offense, and radical legal steps should be taken to prevent it and to protect the water quality. No significant relationship was found between the lockdown and the lake water's physicochemical conditions. In the spring, increased primary production was evidenced by the high concentration of chlorophyll a (52.5 to 70.5 μg/L), suspended particulate matter (20.4 to 21.0 mg/L) and total organic carbon (20.7 to 22.7 mg/L). This is a warning that a nutrient-rich lacustrine ecosystem cannot be restored quickly.