Elucidating the negatively influential and potentially toxic mechanism of single and combined micro-sized polyethylene and petroleum to Chlorella vulgaris at the cellular and molecular levels.

Although microplastics (MPs; <5 mm) may interact with co-contaminants (e.g., petroleum) in marine aquatic systems, little is known about their combined toxicity. Therefore, this study explored the toxicities and their mechanisms of micro-sized polyethylene (mPE) and their combination with petroleum to Chlorella vulgaris. The single MPs at various particle sizes, concentrations, and aging degree, single petroleum, and their combinations, were found to pose toxicities to C. vulgaris. This study also found the microcosm's microbial diversity changed. The microbial communities in the C. vulgaris biotopes were altered under exposure to mPE and petroleum, and were disturbed by external factors such as MPs particle size, concentration, aging time, and the combination with petroleum. Furthermore, as compared with the toxicity of petroleum on microalgal transcriptional function, mPE caused less toxic to C. vulgaris, and only impact the posttranslational modification, protein turnover, and signal transduction processes. Most importantly, mPE reduced petroleum toxicity in C. vulgaris via regulating the ABC transporter, eukaryotic ribosome synthesis, and the citrate cycle metabolic pathways. Overall, our findings could fundamentally provide insights into the joint ecotoxicological effects of MPs and petroleum, and highlight the potential risks of co-exsiting pollutants.

Insight into urban PM2.5 chemical composition and environmentally persistent free radicals attributed human lung epithelial cytotoxicity.

Fine particulate matter (PM2.5) is detrimental to the human respiratory system. However, the toxicity of PM2.5 and its associated potentially harmful species, notably novel pollutants like environmentally persistent free radicals (EPFRs), remains unclear. Therefore, one-year site monitoring and ambient air PM2.5 sampling in the Nanjing urban area was designed to investigate the relationships between chemical compositions (carbon fractions, metallic elements, and water-soluble ions) and EPFRs, and change in cytotoxicity with varying PM2.5 components. Oxidative stress (reactive oxygen species, ROS), inflammatory injury (IL-6 and TNF-α), and membrane injury (LDH) of human lung epithelial cells (A549) induced by PM2.5 were analyzed using in vitro cytotoxicity test. Both the composition and toxicity of PM2.5 from different seasons were compared. The average daily exposure of urban PM2.5 associated EPFRs load in Nanjing were 2.29 × 1011 spin m-3. Their exposure concentration and cytotoxic damage ability were stronger in the cold season than warm. The particle compositions of metals and carbon fractions were significantly positively correlated with EPFRs. The airborne EPFRs, organic carbon (OC), and heavy metal Cu, As, and Pb may pose principal cell damage ability, which is worthy of further study interlinking aerosol pollution and health risks.

Biochar application for remediation of organic toxic pollutants in contaminated soils; An update.

Bioremediation of organic contaminants has become a major environmental concern in the last few years, due to its bio-resistance and potential to accumulate in the environment. The use of diverse technologies, involving chemical and physical principles, and passive uptake utilizing sorption using ecofriendly substrates have drawn a lot of interest. Biochar has got attention mainly due to its simplicity of manufacturing, treatment, and disposal, as it is a less expensive and more efficient material, and has a lot of potential for the remediation of organic contaminants. This review highlighted the adverse impact of persistent organic pollutants on the environment and soil biota. The utilization of biochar to remediate soil and contaminated compounds i.e., pesticides, polycyclic aromatic hydrocarbons, antibiotics, and organic dyes has also been discussed. The soil application of biochar has a significant impact on the biodegradation, leaching, and sorption/desorption of organic contaminants. The sorption/desorption of organic contaminants is influenced by chemical composition and structure, porosity, surface area, pH, and elemental ratios, and surface functional groups of biochar. All the above biochar characteristics depend on the type of feedstock and pyrolysis conditions. However, the concentration and nature of organic pollutants significantly alters the sorption capability of biochar. Therefore, the physicochemical properties of biochar and soils/wastewater, and the nature of organic contaminants, should be evaluated before biochar application to soil and wastewater. Future initiatives, however, are needed to develop biochars with better adsorption capacity, and long-term sustainability for use in the xenobiotic/organic contaminant remediation strategy.

HPLC Method Validation for the Estimation of Lignocaine HCl, Ketoprofen and Hydrocortisone: Greenness Analysis Using AGREE Score.

In the current study, the reversed-phased high-pressure liquid chromatography (RP-HPLC) method was proposed for the estimation of lignocaine hydrochloride (LIG), hydrocortisone (HYD) and Ketoprofen (KET) according to International Conference for Harmonization (ICH) Q2 R1 guidelines, in a gel formulation. The chromatographic evaluation was executed using Shimadzu RP-HPLC, equipped with a C8 column and detected using UV at 254 nm wavelength, using acetonitrile and buffer (50:50) as a mobile phase and diluent, at flow rate 1 mL/min and n injection volume of 20 µL. The retention time for LIG, HYD, and KET were 1.54, 2.57, and 5.78 min, correspondingly. The resultant values of analytical recovery demonstrate accuracy and precision of the method and was found specific in identification of the drugs from dosage form and marketed products. The limit of detection (LOD) for LIG, HYD, and KET were calculated to be 0.563, 0.611, and 0.669 ppm, while the limit of quantification (LOQ) was estimated almost at 1.690, 1.833, and 0.223 ppm, respectively. The AGREE software was utilized to evaluate the greenness score of the proposed method, and it was found greener in score (0.76). This study concluded that the proposed method was simple, accurate, precise, robust, economical, reproducible, and suitable for the estimation of drugs in transdermal gels.

Transformation mechanism and fate of dissolved organic nitrogen (DON) in a full-scale drinking water treatment.

Dissolved organic nitrogen (DON) has attracted much attention in drinking water treatment due to its potential to produce nitrogenous disinfection by-products (N-DBPs). This work was designed to explore the transformation and fate of DON and dissolved inorganic nitrogen (DIN) in drinking water treatment. The changes of DON and formation of N-DBPs were evaluated along the water treatment route (i.e., pre-ozonation and biological-contact oxidation, delivery pipes' transportation, coagulation-sedimentation, sand filtration, post-ozonation, biological activated carbon, ultrafiltration and disinfection) of drinking water treatment plant (DWTP). The transformation mechanism of DON was comprehensively investigated by molecular weight fractionation, three-dimensional fluorescence, LC-OCD (Liquid Chromatography-Organic Carbon Detection), total free amino acids. A detailed comparison was made between concentrations and variations of DON and DIN affected by seasons in the drinking water treatment. Regardless of seasonal variation in raw water concentration, the DON removal trends between different treatment processes remain constant in the present study. Compared to other treatment processes, pre-ozonation and coagulation-sedimentation exhibited the dominant DON removal in different seasons, i.e., 11.13%-14.45% and 14.98%-22.49%, respectively. Contrary, biological-contact oxidation and biological activated carbon negatively impacted the DON removal, in which DON increased by 1.76%-6.49% in biological activated carbon. This may be due to the release of soluble microbial products (SMPs) from bacterial metabolism, which was further validated by the rise of biopolymers in LC-OCD.

Investigating the potential of locally sourced wastewater as a feedstock of microbial desalination cell (MDC) for bioenergy production.

Freshwater sources are limited and access to clean water is an acute challenge in recent decades. The sustainable water treatments methods are need of time and water desalination is one of the most interesting technology. Most desalination technologies are required high energy input while Microbial Desalination Cells (MDCs) represent a sustainable option that has added benefit of solving the ever-increasing wastewater treatment and management problem. MDCs are a customized type of Microbial Fuel Cells (MFCs) that depend on the electric potential generated by organic media to decrease salt concentration by electro-dialysis and give an unconventional way of clean water production. In this research, various experiments were conducted to examine the desalination ability of an indigenously designed experimental setup using domestic wastewater inoculated with sewage sludge under identical conditions. The electrochemical properties of the system, comprising the polarization curve and Electrochemical Impedance Spectroscopy (EIS), were examined along with the scope of chemical oxygen demand (COD) exclusion, to distinguish the cell behaviour. Furthermore, acidic water and Phosphate Buffer Solution (PBS) were tested as potential catholytes compared to the performance of the wastewater was gauged at various salt concentrations. The maximum salt removal efficiency was 31%, power density and current density were 32 mW-m-2 and 246 mA-m-2 respectively at a salt concentration of 35 g-L-1 that decreases with a decline in salt concentration. The maximum achieved power density and current density were 32 mW-m-2 and 246 mA-m-2 respectively. The applied method has huge potential to scaleup for large scale application in coastal regions.

Compost-mediated arsenic phytoremediation, health risk assessment and economic feasibility using Zea mays L. in contrasting textured soils.

Maize (Zea mays L.) is considered as a potential energy-yielding crop which may respond to compost application for arsenic (As) phytoremediation depending on soil type and compost application levels in soil. Here, we explored compost-mediated As phytoremediation potential of maize in the two different textured soils (sandy loam soil and clay loam soil) at varying As (0-120 mg kg-1) and compost (0-2.5%) levels under glasshouse conditions. Results revealed that in the absence of compost maize plants grown at different soil As levels (0-120 mg kg-1) accumulated 1.20-1.71 times more As from sandy loam soil than that of clay loam soil. The compost addition in soil at all levels, with 120 mg kg-1 As enhanced As accumulation in maize plants in the clay loam soil by 13%, while it reduced As phyto-uptake by 27% in sandy loam soil. This may be due to an increase in phosphate-extractable (bioavailable) soil As content from 2.7 to 3.8 mg kg-1 in clay loam soil. The estimated daily intake (EDI) of As (0.03-0.15 µg g-1 of body weight day-1) was above the US EPA's standard value. Arsenic phytoremediation potential of the maize plants was found to be economical for sandy loam soil with 1% compost level and for clay loam soil at 2.5% compost level, suggesting soil type specific dose dependence of compost for As phytoremediation programs. Novelty statement: To our knowledge, the role of compost in economic feasibility of energy crops at contaminated soils in general, and in the growing of maize at As-contaminated soil in particular, has not been addressed, so far. Moreover, it is the first time to evaluate environmental and health risk of compost-mediated As phytoremediation in different soil types.This study provided new insights of economic evaluation and risk assessment in the phytoremediation and mechanisms of compost in biomass production of energy crop at different As concentration. These aspects in phytoremediation studies are imperative to understand for developing safe, cost-effective and soil specific remediation strategies.

Microencapsulation: a pragmatic approach towards delivery of probiotics in gut.

Probiotics confer numerous health benefits and functional foods prepared with these microbes own largest markets. However, their viability during transit from gastrointestinal tract is a concerning issue. Microencapsulation of probiotics is a novel technique of major interest to increase their survivability in GIT and food matrices by providing a physical barrier to protect them under harsh conditions. This article contributes the knowledge regarding microencapsulation by discussing probiotic foods, different methods and approaches of microencapsulation, coating materials, their release mechanisms at the target site, and interaction with probiotics, efficiency of encapsulated probiotics, their viability assessment methods, applications in food industry, and their future perspective. In our opinion, encapsulation has significantly got importance in the field of innovative probiotic enriched functional foods development to preserve their viability and long-term survival rate until product expiration date and their passage through gastro-intestinal tract. Previous review work has targeted some aspects of microencapsulation, this article highlights different methods of probiotics encapsulation and coating materials in relation with food matrices as well as challenges faced during applications: Gut microbiota; Lactic acid bacteria; Micro-encapsulation; Stability enhancement; Cell's release, Health benefits.

Organics removal and microbial interaction attributes of zeolite and ceramsite assisted bioretention system in copper-contaminated stormwater treatment.

Bioretention has been increasingly used recently to treat heavy metals contaminated stormwater. However, less is known about how metal accumulation influences microbial performance and organics removal mechanisms in different layers of the bioretention system. Two lab-scale bioretention columns (i.e., control and Cu treatment) were designed and filled with soil and fillers (zeolite and ceramsite). The results obtained from the time-series experiment of 121 days showed that the removal of organics markedly affected by Cu accumulation and microbial activities, varied between soil and filler layers of bioretention system. The overall organics removal rate was higher in filler than soil. However, at the individual level, the chemical oxygen demand (COD) removal rate was higher than total organic carbon (TOC) in the soil, while the opposite trend was observed in fillers. Mixed media (soil + fillers) significantly reduced the bio-available and labile fractions of Cu from 33.5 to 8% and 67.5 to 33.4%, respectively. The bioretention column treated with Cu lost 14% more microbial biomass in soil than filler over the 121 days study period. Therefore mixed media in bioretention system can offset the substantial negative impacts of long-term metal accumulation on pollutant removal and microbial degradation function in the bioretention. The present study advanced our understanding to resolve the complex metals-impacted microbial pollutant biodegradation mechanisms and highlight importance of mixed media in the long-term maintenance of the bioretention system, which is imperative for developing effective and stormwater-specific remediation strategies.

A review on plant-microbial interactions, functions, mechanisms and emerging trends in bioretention system to improve multi-contaminated stormwater treatment.

Management and treatment of multi-polluted stormwater in bioretention system have gained significant attraction recently. Besides nutrients, recent source appointment studies found elevated levels of Potentially toxic metal(loid)s (PTMs) and contaminants of emerging concern (CECs) in stormwater that highlighted many limitations in conventional media adsorption-based pollutant removal bioretention strategies. The substantial new studies include biological treatment approaches to strengthen pollutants degradation and adsorption capacity of bioretention. The knowledge on characteristics of plants and their corresponding mechanisms in various functions, e.g., rainwater interception, retention, infiltration, media clogging prevention, evapotranspiration and phytoremediation, is scattered. The microorganisms' role in facilitating vegetation and media, plant-microorganism interactions and relative performance over different functions in bioretention is still unreviewed. To uncover the underneath, it was summarised plant and microbial studies and their functionality in hydrogeochemical cycles in the bioretention system in this review, contributing to finding their interconnections and developing a more efficient bioretention system. Additionally, source characteristics of stormwater and fate of associated pollutants in the environment, the potential of genetical engineered plants, algae and fungi in bioretention system as well as performance assessment of plants and microorganisms in non-bioretention studies to propose the possible solution of un-addressed problems in bioretention system have been put forward in this review. The present review can be used as an imperative reference to enlighten the advantages of adopting multidisciplinary approaches for the environment sustainability and pollution control.

Nitrous oxide emission from agricultural soils: Application of animal manure or biochar? A global meta-analysis.

Organic amendments (animal manure and biochar) to agricultural soils may enhance soil organic carbon (SOC) contents, improve soil fertility and crop productivity but also contribute to global warming through nitrous oxide (N2O) emission. However, the effects of organic amendments on N2O emissions from agricultural soils seem variable among numerous research studies and remains uncertain. Here, eighty-five publications (peer-reviewed) were selected to perform a meta-analysis study. The results of this meta-analysis study show that the application of animal manure enhanced N2O emissions by 17.7%, whereas, biochar amendment significantly mitigated N2O emissions by 19.7%. Moreover, coarse textured soils increased [lnRR‾ = 182.6%, 95% confidence interval (CI) = 151.4%, 217.7%] N2O emission after animal manure, in contrast, N2O emission mitigated by 7.0% from coarse textured soils after biochar amendment. In addition, this study found that 121-320 kg N ha-1 and ⩽ 30 T ha-1 application rates of animal manure and biochar mitigated N2O emissions by 72.3% and 22.5%, respectively. Soil pH also played a vital role in regulating the N2O emissions after organic amendments. Furthermore, > 10 soil C: N ratios increased N2O emissions by 121.4% and 27.6% after animal and biochar amendments, respectively. Overall, animal manure C: N ratios significantly enhanced N2O emissions, while, biochar C: N ratio had not shown any effect on N2O emissions. Overall, average N2O emission factors (EFs) for animal manure and biochar amendments were 0.46% and -0.08%, respectively. Thus, the results of this meta-analysis study provide scientific evidence about how organic amendments such as animal manure and biochar regulating the N2O emission from agricultural soils.

The potential of microbes and sulfate in reducing arsenic phytoaccumulation by maize (Zea mays L.) plants.

Arsenic (As) contamination in soil-plant system is an important environmental, agricultural and health issue globally. The microbe- and sulfate-mediated As cycling in soil-plant system may depend on soil sulfate levels, and it can be used as a potential strategy to reduce plant As uptake and improve plant growth. Here, we investigated the role of soil microbes (SMs) to examine As phytoaccumulation using maize as a test plant, under varying sulfate levels (S-0, S-5, S-25 mmol kg-1) and As stress. The addition of sulfate and SMs promoted maize plant growth and reduced As concentration in shoots compared to sulfate-treated plants without SMs. Results revealed that the SMs-S-5 treatment proved to be the most promising in reducing As uptake by 27% and 48% in root and shoot of the maize plants, respectively. The SMs-S treatments, primarily with S-5, enhanced plant growth, shoot dry biomass, Chl a, b and total Chl (a + b) contents, and gas exchange attributes of maize plants. Similarly, the antioxidant defense in maize plants was increased significantly in SMs-S-treated plants, notably with SMs-S-5 treatment. Overall, the SMs-S-5-treated plants possessed improved plant growth, dry biomass, physiology and antioxidant defense system and decrease in plant shoot As concentration. The outcomes of this study suggest that sulfate supplementation in soil along with SMs could assist in reducing As accumulation by maize plants, thus providing a sustainable and eco-friendly bioremediation strategy in limiting As exposure.

An unusual location and presentation of a usual pathology-Colloid cyst of fourth ventricle presenting as spontaneous rhinorrhea.

Colloid cysts are relatively rare benign intracranial lesions preferentially located within the third ventricle. There are only a few reports in which they have been found to be ectopic, such as in the fourth ventricle. A young female presented on with spontaneous non-traumatic cerebrospinal fluid (CSF) rhinorrhoea for three months which was positional in nature, relieved temporarily by neck flexion. Magnetic resonance imaging (MRI) scan showed a focal well-defined rounded cystic lesion along the fourth ventricle, showing subtle peripheral rim enhancement. Significant hydrocephalus was also noted. A suboccipital craniotomy and total excision of the lesion was done. Postoperatively, the patient recovered quickly with no neurological deficits. Her rhinorrhoea was completely cured. Histopathology was consistent with a colloid cyst. Colloid cyst is rarely found in infratentorial location. However, such a rare diagnosis has to be considered in the differential diagnosis in patients who present with an infratentorial cystic lesion associated with spontaneous CSF rhinorrhoea.

Super capacity of ligand-engineered biochar for sorption of malachite green dye: key role of functional moieties and mesoporous structure.

This study synthesized a new thiomalic acid-modified rice husk biochar (TMA-BC) as a versatile and eco-friendly sorbent. After undergoing chemical treatments, the mercerized rice husk biochar (NaOH-BC) and TMA-BC samples showed higher BET surface area values of 277.1 m2/g and 305.8 m2/g, respectively, compared to the pristine biochar (BC) sample, which had a surface area of 234.2 m2/g. In batch adsorption experiments, it was found that the highest removal efficiency for malachite green (MG) was achieved with TMA-BC, reaching 96.4%, while NaOH-BC and BC exhibited removal efficiencies of 38.6% and 27.9%, respectively, at pH 8. The engineered TMA-BC exhibited a super adsorption capacity of 104.17 mg/g for MG dye at pH 8.0 and 25 °C with a dosage of 2 g/L. The SEM, TEM, XPS, and FTIR spectroscopy analyses were performed to examine mesoporous features and successful TMA-BC carboxylic and thiol functional groups grafting on biochar. Electrostatic forces, such as π - π interactions, hydrogen bonding, and pore intrusion, were identified as key factors in the sorption of MG dye. As compared to single-solution adsorption experiments, the binary solution experiments performed at optimized dosages of undesired ions, such as humic acid, sodium dodecyl sulfate surfactant, NaCl, and NaSCN, reflected an increase in MG dye removal of 2.8%, 8.7%, 5.4%, and 12.7%, respectively, which was attributed to unique mesoporous features and grafted functional groups of TMA-BC. Furthermore, the TMA-BC showed promising reusability up to three cycles. Our study indicates that mediocre biochar modified with TMA can provide an eco-friendly and cost-effective alternative to commercially accessible adsorbents.

Managing antimony pollution: Insights into Soil-Plant system dynamics and remediation Strategies.

Researchers are increasingly concerned about antimony (Sb) in ecosystems and the environment. Sb primarily enters the environment through anthropogenic (urbanization, industries, coal mining, cars, and biosolid wastes) and geological (natural and chemical weathering of parent material, leaching, and wet deposition) processes. Sb is a hazardous metal that can potentially harm human health. However, no comprehensive information is available on its sources, how it behaves in soil, and its bioaccumulation. Thus, this study reviews more than 160 peer-reviewed studies examining Sb's origins, geochemical distribution and speciation in soil, biogeochemical mechanisms regulating Sb mobilization, bioavailability, and plant phytotoxicity. In addition, Sb exposure effects plant physio-morphological and biochemical attributes were investigated. The toxicity of Sb has a pronounced impact on various aspects of plant life, including a reduction in seed germination and impeding plant growth and development, resulting from restricted essential nutrient uptake, oxidative damages, disruption of photosynthetic system, and amino acid and protein synthesis. Various widely employed methods for Sb remediation, such as organic manure and compost, coal fly ash, biochar, phytoremediation, microbial-based bioremediation, micronutrients, clay minerals, and nanoremediation, are reviewed with a critical assessment of their effectiveness, cost-efficiency, and suitability for use in agricultural soils. This review shows how plants deal with Sb stress, providing insights into lowering Sb levels in the environment and lessening risks to ecosystems and human health along the food chain. Examining different methods like bioaccumulation, bio-sorption, electrostatic attraction, and complexation actively works to reduce toxicity in contaminated agricultural soil caused by Sb. In the end, the exploration of recent advancements in genetics and molecular biology techniques are highlighted, which offers valuable insights into combating Sb toxicity. In conclusion, the findings of this comprehensive review should help develop innovative and useful strategies for minimizing Sb absorption and contamination and thus successfully managing Sb-polluted soil and plants to reduce environmental and public health risks.

Trends and social aspects in the management and conversion of agricultural residues into valuable resources: A comprehensive approach to counter environmental degradation, food security, and climate change.

The circular economy is essential as it encourages the reuse and recycling of resources while reducing waste, which ultimately helps to reduce environmental pollution and boosts economic efficiency. The current review highlights the management of agricultural and livestock residues and their conversion into valuable resources to combat environmental degradation and improve social well-being. The current trends in converting agricultural residues into useful resources emphasize the social benefits of waste management and conversion. It also emphasizes how waste conversion can reduce environmental degradation and enhance food security. Using agricultural residues can increase soil health and agricultural output while reducing pollution, greenhouse gas emissions, and resource depletion. Promoting sustainable waste-to-resource conversion processes requires a combination of strategies that address technical, economic, social, and environmental aspects. These multiple strategies are highlighted along with prospects and considerations.

Comparative in vitro toxicological effects of water-soluble and insoluble components of atmospheric PM2.5 on human lung cells.

Fine particulates in city air significantly impact human health, but the hazardous compositional mechanisms are still unclear. Besides the toxicity of environmental PM2.5 to in vitro human lung epithelial cells (A549), the independent cytotoxicity of PM2.5-bound water-soluble (WS-PM2.5) and water-insoluble (WIS-PM2.5) fractions were also compared by cell viability, oxidative stress (reactive oxygen species, ROS), and inflammatory injury (IL-6 and TNF-α). The cytotoxicity of PM2.5 varied significantly by sampling season and place, with degrees greater in winter and spring than in summer and autumn, related to corresponding trend of air PM2.5 level, and also higher in industrial than urban site, although their PM2.5 pollution levels were comparable. The PM2.5 bound metals (Ni, Cr, Fe, and Mn) may contribute to cellular injury. Both WS-PM2.5 and WIS-PM2.5 posed significant cytotoxicity, that WS-PM2.5 was more harmful than WIS-PM2.5 in terms of decreasing cell viability and increasing inflammatory cytokines production. In particular, industrial samples were usually more toxic than urban samples, and those from summer were generally less toxic than other seasons. Hence, in order to mitigate the health risks of PM2.5 pollution, the crucial targets might be components of heavy metals and soluble fractions, and sources in industrial areas, especially during the cold seasons.

Effects of polypropylene microplastics on carbon dioxide dynamics in intertidal mangrove sediments.

Microplastics (MPs) in soil can influence CO2 dynamics by altering organic carbon (OC) and microbial composition. Nevertheless, the fluctuation of CO2 response attributed to MPs in mangrove sediments is unclear. This study explores the impact of micro-sized polypropylene (mPP) particles on the carbon dynamics of intertidal mangrove sediments. In the high-tide level sediment, after 28 days, the cumulative CO2 levels for varying mPP dosages were as follows: 496.86 ± 2.07, 430.38 ± 3.84 and 447.09 ± 1.72 mg kg-1 for 0.1%, 1% and 10% (w/w) mPP, respectively. The CO2 emissions were found to be increased with a 0.1% (w/w) mPP level and decreased with 1% and 10% (w/w) mPP at high-tide level sediment, suggesting a tide level-specific dose dependence of the CO2 emission pattern in mangrove sediments. Overall, results indicated that the presence of mPP in mangrove sediments would potentially affect intertidal total CO2 storage under given experimental conditions.

Assessment of meteorological and air quality drivers of elevated ambient ozone in Beijing via machine learning approach.

Over the past few years, surface ozone (O3) pollution has dominated China's air pollution as particulate matter has decreased. In Beijing, the annual average concentrations of ground-level O3 from 2015 to 2020 regularly increased from 57.32 to 62.72 µg/m3, showing a change of almost 9.4%, with a 1.6% per year increase. The meteorological factors are the primary influencer of elevated O3 levels; however, their importance and heterogeneity of variables remain rarely understood. In this study, we used 13 meteorological factors and 6 air quality (AQ) parameters to estimate their influencing score using the random forest (RF) algorithm to explain and predict ambient O3. Among the meteorological variables and overall, both land surface temperature and temperature at 2 m from the surface emerged as the most influential factors, while NO2 stood out as the highest influencing factor from the AQ parameters. Indeed, it is crucial and imperative to reduce the temperature caused by climate change in order to effectively control ambient O3 levels in Beijing. Overall, meteorological factors alone exhibited a higher coefficient of determination (R2) value of 0.80, compared with AQ variables of 0.58, for the post-lockdown period. In addition, we calculated the number of days O3 concentration levels exceeded the WHO standard and newly proposed peak-season maximum daily 8-h average (MDA8) O3 guideline for Beijing. The exceedance number of days from the WHO standard of MDA8 ambient O3 was observed to be the highest in June, and each studied year crossed peak season guidelines by almost 2 times margin. This study demonstrates the contributions of meteorological variables and AQ parameters in surging ambient O3 and highlights the importance of future research toward devising an optimum strategy to combat growing O3 pollution in urban areas.