Arsenic (As) accumulation is a critical environmental concern in many developing countries due to its high toxicity and wide distribution. In the current investigation, As contents were estimated in soil, forage and cow's milk samples collected from rain-fed and groundwater-irrigated areas of Chakwal, Pakistan. The samples were subjected to wet digestion and examined for As contents using an atomic absorption spectrophotometer. As concentrations ranged from 2.28 to 10.57 mg kg in soil, 0.663 to 2.40 mg kg in forages, and 0.012 to 0.017 mg kg in milk. Among the forages Chenopodium album demonstrated the highest As contents at the groundwater-irrigated site, while Tribulus terresteris had the lowest As contents at the rain-fed site. All samples exhibited As levels below the permissible limits set by WHO. This study also found a significant positive correlation between As levels in soil and forages at both sites, while the correlation between forages and milk was negative and non-significant. All estimated pollution indices were below the threshold limit, indicating insignificant As contamination across study sites. However, Chenopodium album exhibited significantly higher pollution indices than other forage species (p < 0.05), signaling its enhanced bioconcentration potential.

Nitrogen dioxide (NO₂) in the air at concentrations exceeding permissible levels impacts environmental quality and human health. In addition, NO₂ is also a precursor to ozone and an agent that creates acid rain that affects the habitat of organisms. NO₂ emission inventories are the first and most important step, especially in urban or industrial production areas. This study assesses NO₂ emissions in Ho Chi Minh City (HCMC), Vietnam-a large city with high traffic and industrial activity but limited published emission data. Using the Lifetime-Modified Accumulation Method (LMAM), we analyze tropospheric NO₂ column data from the OMI/Aura satellite (2019-2024) to estimate spatial and temporal emission trends. The results showed an average emission rate of 6.56 × 10 molecules cm⁻ h⁻ in 2019, decreasing to 5.79 × 10 molecules cm⁻ h⁻ in 2020 due to the COVID-19 lockdown. Emissions were highest in urban and industrial areas and lowest in suburban areas. The LMAM model demonstrated a strong correlation with TROPESS Chemical Reanalysis (TCR) NO data (Spearman's r = 0.71 in 2019; r = 0.70 in 2020), confirming its reliability for trend analysis. Long-term trends reflect the socioeconomic impact: a sharp decline during the pandemic (2020-2021) followed by a recovery to 1.3 × 10⁶ molecules cm⁻ h⁻ in 2023-2024 when economic activities resume. This result can provide information on NO₂ emissions as a reference for future city emission control policies and inventory plans.

Benzene is a highly volatile monoaromatic hydrocarbon and genotoxic carcinogen. In Brazil, it is considered a priority for the National Health System. However, although this compound is targeted by health surveillance in Brazil, scarce data are available on occupational or environmental exposure. This review contributes to an overview regarding benzene levels in the second-largest metropolis in Southeastern Brazil, Rio de Janeiro, and associated risks. A decreasing trend has been noted in the city of Rio de Janeiro, in the last decades, due to more stringent vehicular emission legislations and advances in vehicular technology, although adulterated gasoline is still a concern. Future actions regarding reductions of benzene emissions in the city include regulatory and surveillance programs concerning adulterated gasoline, substitution of raw materials to reduce benzene input to production processes, implementing changes in operating conditions to minimize benzene formation or volatilization and equipment modification to avoid benzene escaping into the environment. Finally, the increasing use and further construction of alternative transportation can significantly contribute to lowering benzene emissions in Rio de Janeiro and other metropolis worldwide and should be implemented as soon as possible.

Microplastics can serve as sites for microbial attachment, however their role in facilitating biotoxin entry into marine food webs remains poorly understood. This study quantified the adsorption and desorption kinetics of brevetoxin 3 (PbTx-3), a neurotoxin produced by the dinoflagellate Karenia brevis, on polyethylene (PE) surfaces in relation to the presence of biofilms using radiolabeled H-PbTx-3. It was hypothesized that the presence of biofilms would enhance toxin retention on PE. Contrary to this hypothesis, results revealed significantly reduced adsorption of brevetoxin on biofilm-coated PE (0.035 ± 0.007 nmol mg, p < 0.001) compared to virgin PE (0.59 ± 0.076 nmol mg). Furthermore, toxin desorption from biofilm-coated PE occurred rapidly, with less than 20% activity remaining after 24 h, whereas virgin PE retained over 80% activity over the same period. Complete toxin depuration was not observed within one week under either condition. These findings demonstrate that biofilms not only reduce brevetoxin adsorption on PE but also accelerate desorption. Further research is needed to elucidate the broader ecological and health implications of microplastic-mediated biotoxin transport, albeit the results of this study suggest that biofilm-coated PE likely plays a minor role as vector for biotoxins in marine food webs, at least compared to its virgin counterpart.

Heavy metal pollution in aquatic environment is a rising concern and for its assessment, aquatic organisms are often used as biomonitors. The present study investigates the distribution of heavy metals (Fe, Cr, Pb, Cu, Zn, and Cd) in the surface water, surface sediment, and selected tissues of edible fish Mugil cephalus Linnaeus, collected from Kadinamkulam estuary, South India. The hierarchy of heavy metals in the estuary water is found in the order Fe > Zn > Cd > Pb > Cu > Cr, and in the surface sediments, Fe > Zn > Cd > Cu > Cr > Pb. The study shows that Pb and Cr contents in the surface water are above the permissible limits prescribed by BIS 1982 and USEPA. This study reveals that heavy metals accumulated in fish tissue is in the order of liver > gill > muscle. The metal concentrations followed the sequence Fe > Zn > Pb > Cu > Cd > Cr. The heavy metals Zn, Cd, and Pb show concentrations above the limit prescribed by the USFDA. The nearby agricultural activities and domestic waste may be the sources of high levels of heavy metals in the study area. Based on the potential human health risk indices, Mugil cephalus Linnaeus can be categorised as non-carcinogenic. The study underlines the significance of monitoring of the health status of aquatic organisms in Kadinamkulam estuary, and that of humans who may consume the estuarine fish. It is suggested that the use of pesticides and fertilizer in agricultural fields in the nearby areas be limited.

We investigated the effects of settleable atmospheric particulate matter (SePM, 1 g L, 96 h) on metal bioaccumulation and blood biomarkers of the estuarine fish Centropomus parallelus. After exposure, V, Cr, Ni, Cu, Mo, Ag, W, and Pb accumulated in erythrocytes, while V, Cr, Fe, Nb, Mo, and Pb were found in plasma. SePM increased erythrocyte nuclear abnormalities (89.9%) and micronuclei frequency (117.6%), while decreasing neutrophils (51.6%). The erythrocyte antioxidant system responded with higher CAT and SOD activity (18.4% and 54%) to mitigate biomolecular damage, yet lipoperoxidation (162%) and protein carbonylation (97.1%) persisted in erythrocytes, along with lipoperoxidation (91.3%) in plasma. Our findings demonstrate that SePM exposure alters antioxidant defenses and hematological responses. Observed mutagenic alterations indicate damage with potential ecological implications. Blood biomarkers thus represent sensitive, non-invasive tools for biomonitoring and early detection of stress in aquatic organisms exposed to SePM.

China faces escalating ozone pollution challenges, with O becoming the primary pollutant in summer since 2013 and exhibiting deteriorating compliance rates (Grade I attainment plummeted from 6.9 to 0.3% during 2015-2023). Critical hotspots include the Beijing-Tianjin-Hebei region (exceeding standards by 20 µg/m), driven by inadequate coordinated control of VOC and NO. Analysis of the ABaCAS-EI v2.0 dataset (2005-2021) reveals divergent precursor trends: VOC emissions shifted from residential to industrial dominance, with industrial solvents (PRSO) surging 389% during 2005-2013 and comprising 61% of national totals by 2021. Spatially, eastern provinces (e.g., Guangdong) showed transport-industrial emission profiles (TRON: 28%; PRSO: 32%), while northern regions achieved significant NO reductions through industrial restructuring, with Hebei's emissions falling 46% from peak levels. Conversely, NO emissions peaked earlier (2011), but transportation's share grew to 42% by 2021 (TRON: 31%). Regional disparities persist-coastal areas leveraged advanced controls, whereas western provinces struggled with expanding pollution bases. These findings underscore the imperative for spatially-explicit strategies addressing sector-region heterogeneities to mitigate ozone's health/ecological impacts.

This study investigated the bioaccumulation of Zn, Pb, and Cd in the sternal feathers of house sparrows (Passer domesticus) collected from five sites in Meknes, Morocco, representing urban, industrial, and rural environments. Metal concentrations were quantified using inductively coupled plasma optical emission spectrometry (ICP-OES). The analysis revealed significant spatial differences for Pb and Cd, whereas Zn showed no marked variation among sites. Post-hoc comparisons confirmed that urban and industrial stations had considerably higher Pb and Cd levels compared to the rural reference site. No significant sex-related differences were found. Principal Component Analysis (PCA) was used as a descriptive tool to visualize correlations among metals and sampling sites, confirming spatial clustering linked to anthropogenic influence. These findings highlight P. domesticus as a reliable and non-invasive bioindicator of urban and industrial metal pollution, particularly for Pb and Cd, emphasizing its ecological relevance in monitoring environmental contamination.

Sarus crane, Antigone antigone, is the tallest flying resident crane in India. As these birds use agricultural fields as foraging and nesting grounds, they are exposed to environmental contaminants from agricultural runoff. This study documents the presence of the residue of selected agrochemicals in the tissues of birds from electrocution. Vital tissues, including liver, muscle, kidney, brain, and gut content from 14 individuals, were analyzed to determine the presence of 67 pesticide residues using Gas Chromatography-Mass Spectrometry and Liquid Chromatography-Mass Spectrometry. Sixty-four percent of the birds that were tested had at least one pesticide residue. Out of 67 chemicals tested, residues of only 4 chemicals, namely Chlorpyrifos, Dichlorodiphenyltrichloroethane, Hexachlorocyclohexane, and Endosulfan, were at detectable levels. This study presents the first report on pesticide levels in A. antigone in Uttar Pradesh, India. Although the levels of pesticide detected were below the previously reported levels, the mortality due to pesticide poisoning and power lines across the entire distribution range of Sarus cranes in India remains a cause for concern.

This study evaluates a novel mixed bacterial culture, comprising Acinetobacter baumannii IITG19, Klebsiella michiganensis RK, Providencia vermicola IITG20, and Pseudomonas aeruginosa IITG21, for its effectiveness in remediating diesel-contaminated soil and water. Through in-Lab degradation efficiency tests, simulated field studies, phytotoxicity tests, and degradation kinetics analysis, the potential of this culture was explored. During in-Lab study, the mixed culture showed 90% degradation of 4% v/v diesel over 15 days, at 35 °C temperature, pH 7, and 1% v/v inoculum concentration. Subsequent field studies showed diesel degradation of 96 and 99% in soil and water, respectively. The mixed culture showed 97% degradation of n-alkanes and branched alkanes and 96% degradation of naphthenes and aromatics in soil. In water, it showed over 99% degradation for all components. Phytotoxicity assessments with Brassica nigra seeds, ascertained successful growth in mixed culture-treated soil and water due to remediation. Degradation kinetics analysis confirmed first-order degradation, with a rate constant (k) of 0.144 day for in-Lab study. Field studies yielded values of 0.196 day for soil and 0.288 day for water. These findings showed that the mixed bacterial culture in this study was not only able to remove diesel contamination from soil and water but also restored soil health for plant growth. Its efficient performance under field-like conditions established its real potential for use in large-scale environmental clean-up efforts.

Atmospheric transport and deposition of microplastics (MPs) represent an emerging pathway whereby plastic pollution reaches even the most remote ecosystems. To investigate how elevation influences this process, we collected rainfall and snowfall samples across eight sites in the Central Himalaya, India, at elevations from 445 m to 3,378 m. After multi-stage sieving (5 mm to 100 μm), oxidative digestion, and vacuum filtration onto 0.8 μm cellulose membranes, samples were analyzed for concentration, size distribution, and polymer composition. We observed an inverse relationship between altitude and MPs concentration, with urban low-elevation sites yielding up to 137 MPs L⁻¹ at 445 m, compared to only 5.5 MPs L⁻¹ at 3,378 m. Fibers dominated all samples (74.1%), reflecting textile sources, while films, fragments, cluster and foam composed the remainder. Particle size distributions shifted with height, larger MPs (1-5 mm) prevailed in low-lying areas, whereas fine particles (< 100 μm; 100 μm-1 mm) accounted for high-altitude and mid-altitude deposits, highlighting the role of small MPs in long-range atmospheric transport. Polymer composition also varied with elevation lightweight polymers like polyethylene (PE) and polypropylene (PP) became more common at higher sites, while heavier polymers such as polyvinyl chloride (PVC) & polytetrafluoroethylene (PTFE) remained concentrated at lower elevations. These findings suggest that altitude is a key control on atmospheric MP deposition low-altitude regions near dense urban sources exhibit higher concentrations, while remote high-altitude zones receive fewer but finer particles may be transported from urban area.

The acute toxicities of para-phenylenediamine quinones (PPDQs) to salmonids at the whole-organism level remain unclear. Therefore, in this study, we investigated the acute toxicities of three PPDQs, 6PPDQ, 7PPDQ, and 8PPDQ in coho salmon (Oncorhynchus kisutch) juveniles and embryonic cells (CSE-119) using 24-h acute toxicity tests and cytotoxicity assays. The 24-h 50% effect concentration values of 6PPDQ and 7PPDQ for the juveniles were 41.5 ng/L (95% confidence interval: 21.6-61.4) and 5.39 μg/L (2.26-8.53), respectively, while 8PPDQ did not affect mortality at the tested concentration (60.6 μg/L). Further, the 24-h 50% effect concentration value of 6PPDQ for CSE-119 was 14.9 μg/L (13.0-16.7), but 7PPDQ and 8PPDQ did not sufficiently reduce CSE-119 cell viability even at concentration up to 500 μg/L, indicating marked differences in toxicity among the compounds. These findings indicate that, at both the whole-organism and cellular levels, 6PPDQ exhibited the highest toxicity among the three PPDQs, likely due to differences in chemical structure.

Research on emerging micro-pollutants (EMPs) in Indonesia is scarce. Studies indicate that even at relatively low concentrations (µg/L), these substances pose health risks to aquatic biota. This study aimed to identify EMPs in septic tanks and the Surabaya River and assess the influence of social factors such as habits and sanitation levels. Solid-phase extraction (SPE) and High-Performance Liquid Chromatography (HPLC) were used to determine EMPs concentrations in samples. SPE and HPLC were selected for their high sensitivity, selectivity, and efficiency, with SPE enabling sample pre-concentration and purification, while HPLC ensured precise separation and quantification of trace contaminants. The results showed high paracetamol levels (15.54 mg/L) in septic tanks and significant caffeine concentrations (10.31 mg/L) in the Surabaya River. This trend was linked to residents' habit of urinating on bathroom floor drains instead of using toilets, allowing contaminants to flow into drainage systems and the river. Societal consumption habits influenced the types of EMPs in urine, with high caffeine concentrations attributed to the widespread consumption of over-the-counter medications and beverages such as tea and coffee. The lack of regulations on pollutant concentrations in Indonesian rivers increases the risk of contaminants entering clean water treatment systems. Given these findings, stricter monitoring and comprehensive regulations are urgently needed to mitigate potential public health risks and environmental impacts.

Environmental pollution, particularly in aquatic ecosystems, poses a major global threat. The Ganga River, vital to millions, suffers from severe contamination despite multiple remediation efforts. Bioremediation, especially enzyme-mediated approaches, offers an eco-friendly and efficient alternative to conventional methods. This study utilizes metagenomic reads to identify bioremediating enzymes, their host microorganisms, target pollutants, and enzyme abundance at two Ganga sites: Nawabganj, Kanpur (highly polluted), and Below Farakka Bridge, West Bengal (less polluted). In-silico analysis was conducted using RemeDB for enzyme identification and MG-RAST for microbial abundance. Enzyme abundance was determined by integrating microbial profiles with the RemeDB enzyme database. Key enzymes identified include Phenylacetaldehyde dehydrogenase (plastic), Biphenyl dioxygenase (hydrocarbons), and Catechol 1,2-dioxygenase (dyes). Results indicate higher bioremediating enzyme diversity in the more polluted Nawabganj site. The findings highlight the potential of native enzymes for pollutant degradation and support further exploration for environmental cleanup strategies.

The water in the coastal lagoons of the Tramandaí River Basin (TRB) in southern Brazil is affected by domestic, industrial, and agricultural effluents. The towns within the TRB experience significant population surges during peak vacation periods, which may further impact water quality. The micronucleus (MN) test is a useful tool for detecting genotoxic effects induced by pollutant mixtures and can serve as an indicator of water quality. This study aimed to evaluate the temporal variation in genotoxic potential and fecal contamination of water samples from four coastal lagoons within the TRB. Water sampling was conducted across four periods in the Cidreira, Fortaleza, Gentil, and Tramandaí lagoons. Specimens of Astyanax jacuhiensis were exposed to water samples and a negative control for 96 h in laboratory conditions. The frequencies of MN and other nuclear abnormalities (NA) were analyzed in the erythrocytes of the fish. Thermotolerant coliforms were assessed as an indicator of fecal contamination. Significant differences were noted during the summer season, with higher MN frequencies observed in the Gentil lagoon and increased NA frequencies in both the Gentil and Cidreira lagoons compared to the control group. During warmer periods, thermotolerant coliform counts exceeded the limits established by Brazilian legislation for recreational use in the Tramandaí, Gentil, and Cidreira lagoons. These results indicate temporal variations in fecal contamination and water genotoxicity in the TRB lagoons, with the highest values recorded in summer likely linked to increased tourism in the region.

The Amazon hosts the world's richest biodiversity but faces increasing anthropogenic pressures that threaten ecosystem health. To evaluate aquatic pollution impacts at molecular and biochemical levels, we analyzed DNA methylation, gene expression and oxidative stress biomarkers in gill, liver, and muscle tissues of the fish Geophagus surinamensis collected from Breves (reference), Abaetetuba, and Barcarena (industrial area). Individuals from Abaetetuba exhibited the strongest responses, with global hypermethylation in liver and muscle, decreased expression of dnmt1, dnmt3b, and tet2, and altered GST and LPO levels. Barcarena samples also showed increased methylation but milder transcriptional and biochemical changes, likely due to contaminant dispersion by Pará River hydrodynamics. The liver was the most responsive organ, reflecting its detoxification role. Overall, these findings demonstrate that pollution in Barcarena significantly affects nearby aquatic environments, highlighting the value of epigenetic and oxidative stress biomarkers as sensitive tools for environmental monitoring.

Mussels have been widely used in ecotoxicological studies due to their filter-feeding activity and sessile lifestyle, which makes them a suitable bioindicator organism. Thus, freshwater mussels (Unio delicatus) were exposed to different concentrations (0, 0.5, 2.5, 12.5 mg/L) of ZnO nanoparticles (18 nm) for 14 days to investigate responses of biomarkers belonging to the antioxidant, osmoregulation and energy systems. Laboratory-cultured algae (Chlorella vulgaris) were served to mussels (approximately 250,000 algae/ml) during the experiments. Significant (p < 0.05) accumulation of Zn occurred only in the gills. Enzymes belonging to the gill osmoregulation system did not respond to ZnO NP exposures (p > 0.05). However, activities of antioxidant system enzymes were altered significantly (p < 0.05) in the digestive glands. Levels of glucose and lipid significantly (p < 0.05) decreased, resulting in a decrease in immediate energy reserves of mussels. Although ZnO nanoparticles exhibited low tissue accumulation, they affected the metabolic systems of U. delicatus, emphasising the potential effects of nanoparticles.

The chemical fractions of heavy metals in sediments provides important information on their mobility, bioavailability, and toxicity. This study identified the chemical fractions of six heavy metals (Pb, Zn, Cu, Cd, Cr, and Ni) in the sediments of Yeongsan River Basin, South Korea. The heavy metals were bound to sediments in the order of Pb ≈ Cd > Zn > Cu > Ni > Cr in the labile fraction, and Pb, Cd, Zn, and Cu exhibited high mobility and bioavailability. The risk assessment code (RAC), individual contamination factor (ICF), and global contamination factor (GCF) assessment results confirmed that the mobility and bioavailability of the heavy metals were relatively higher in the mid-upstream compared to downstream. The sediments in the mid-upstream had a high proportion of heavy metals bound in the labile fraction, indicating a close relationship with pollutants discharged from densely populated regions and industrial complexes.

Pesticides pose a significant threat to soil ecosystems worldwide due to their widespread use in agricultural practices. Bioremediation offers a sustainable solution by leveraging the natural capabilities of microorganisms. This study explores the efficacy of Chlorella vulgaris in remediating dimethoate and atrazine contamination in soil environments. Culturing C. vulgaris in a pesticide-contaminated soil slurry revealed a dose-dependent increase in removal efficiency, peaking at a 1.0 mgL concentration for both pesticides. Moreover, contact time significantly influenced removal rates, with 40% dimethoate and 45.5% atrazine removal achieved after 14 days. Optimal microalgal dosage (10 mL) yielded the highest removal efficiencies, indicating a saturation effect beyond this threshold. High-performance liquid chromatography analysis confirmed notable reductions in pesticide concentrations post-bioremediation. Response Surface Methodology analyses further validated the model's significance and suitability for predicting removal efficiencies, highlighting the robustness of the bioremediation process. Findings underscore the potential of C. vulgaris as a cost-effective and environmentally friendly approach for mitigating pesticide contamination in agricultural soils. Future research should focus on elucidating the underlying mechanisms driving observed trends to further optimize bioremediation strategies.