Pollutants, Volume 6, Issue 1 (March 2026) – 19 articles

Air pollution is among the key topics in environmental policies and mitigation policies. Governments and institutions worldwide are working towards a better understanding of the phenomenon and means to reduce its impact on the environment and human health. In early 2020, the COVID-19 pandemic forced many countries to introduce strict regulations, effectively stopping non-essential anthropic activities. Italy had a pioneering role in this regard, anticipating other countries in Europe and across the world. These exceptional circumstances caused the concentrations of pollutants in the atmosphere to reach lower levels, thus allowing researchers to evaluate a number of hypotheses concerning the contribution of anthropogenic emissions. At the Lamezia Terme (code: LMT) World Meteorological Organization—Global Atmosphere Watch (WMO/GAW) regional station in Calabria, Italy, previous research highlighted the effects of governmental restrictions on the concentrations of gases (carbon monoxide, CO; carbon dioxide, CO₂; methane, CH₄, nitrogen oxides, NO_x) and aerosols (black carbon, BC). In this work, sulfur dioxide (SO₂) and ozone (O₃) are also evaluated and all parameters are subject to the analysis based on the O₃/NO_x ratio, the ONRPI (Ozone to Nitrogen Oxides Ratio Proximity Indicator), which has been widely used at LMT to verify the balance between local and remote sources of emission. The implementation of this method to the first 2020 COVID-19 lockdown in the country has allowed significant improvement in our understanding of the variability of all evaluated parameters at the site, assessing with greater detail weekly cycles and day–night contrasts, and the influence of local and remote sources of emission. Full article

Microplastics (MP) are transported through rivers, acting as major conduits to oceans, yet standard transport models often fail to capture polymer-specific dynamics like settling and removal. This study proposes two novel analytical frameworks to address this: a modified Advection–Dispersion Equation (ADE) incorporating first-order sinking and removal, and a multi-phase model accounting for hydrodynamic–particle coupling. We derived exact closed-form solutions for a finite pulse input and validated the baseline model against established results. Our results demonstrate that the conventional ADE significantly overestimates peak MP concentrations, while the modified ADE reveals a “stretching” effect that extends the duration of ecosystem exposure. Our analysis indicates that sinking is the primary driver of mass loss to sediments, with higher sinking rates reducing aqueous concentrations by approximately 50% compared to non-settling scenarios. However, removal employs negligible influence during the initial pulse phase but shows cumulative impact over long transport distances. The study highlights the critical need to incorporate sediment accumulation terms into risk assessments, as ignoring sinking leads to underestimating benthic pollution and overestimating marine flux. Additionally, the multi-phase formulation provides a theoretical basis for modeling dense plastic spills where particles alter flow momentum. Full article

Maize is highly vulnerable to aflatoxin contamination, constituting a serious food safety and public health concern. This study explored the relationship of extreme flood events in September 2020 (Storm Ianos) and September 2023 (Storm Daniel) in the Thessaly region, Greece, which occurred post-harvest, and aflatoxin contamination patterns in maize harvests of both the flood years and the following years (2021 and 2024). A total of 573 maize samples collected between 2019 and 2024 were analyzed using an enzyme-linked immunosorbent assay (ELISA). A 10 μg/kg cutoff was used (the ELISA upper limit of quantification); results > 10 ppb were classified as elevated concentrations. Overall, aflatoxins were detected in 47.8% of samples, with 14.0% having concentrations exceeding 10 μg/kg. The 2021 harvest year exhibited an exceedance rate of 28.75% (23/80), while the 2024 harvest showed a rate of 14.68%, 37/252. Exceedance rates during flood years were comparatively low; however, the maize harvested in the years following the flood events demonstrated a two-fold increase in the detection rate (60.2% vs. 30.7%) and a significant increase in exceedance percentages (18.07% vs. 8.30%) relative to non-flood years in the preceding period. While drought and heat remain the primary field risk factors for aflatoxin production, the correlational findings suggest that extreme floods may indirectly influence aflatoxin risk by increasing kernel damage, prolonging grain moisture, and disrupting post-harvest handling and storage, underscoring the need for continuous monitoring and robust mitigation strategies in flood-prone agricultural regions. Full article

The undegradable characteristics of heavy metals on environmental quality have become a serious human health concern. A study was conducted in a potato field to investigate the impact of soil amended with animal manure or biochar on the transport of toxic heavy metals and nitrates to runoff and seepage water. The soil in 18 field plots was separated, and each of 3 plots was mixed with biochar, chicken manure, vermicompost, sewage sludge, or cow manure, with 3 plots used as the control. Following a natural rainfall event, the impact of soil treatments on the runoff and infiltration water volume was monitored. Runoff water from the soil amended with biochar exhibited 10.6 L plot⁻¹, whereas cow manure exhibited 4.1 L plot⁻¹, indicating about 61% reduction in runoff water volume. The vermicompost-amended soil increased the seepage water volume from 1.6 L plot⁻¹ in the control treatment to 4.4 L plot⁻¹, indicating a 175% increase in percolating water, a desirable attribute to direct rainfall water towards the plant roots. The concentrations of Pb, Cd, Ni, Mn, Cr, Mg, Cu, and K in infiltration water were greater in runoff sediments, highlighting the need for runoff sediment remediation technology. Full article

Nano- and microplastics (NMPs), which are ubiquitous environmental pollutants, are commonly found in single-use plastic water bottles. They originate primarily from the bottle material itself with the amount increasing through mechanical wear. This review synthesizes current scientific knowledge on the occurrence, health risks, and regulatory considerations concerning NMPs in single-use plastic water bottles. The review revealed that concentrations vary widely, leading to potential human exposure risks. Ingested NMPs can induce oxidative stress, inflammation, disruption of gut microbiota and potential bioaccumulation. Current health risk assessments are challenged by inconsistent methods and lack of standardized reference materials. While regulatory frameworks addressing NMP contamination are developing globally, they lack consistency and legally enforceable limits. Standardized detection and monitoring are emerging priorities, but legally enforceable limits and comprehensive policies are underdeveloped. This review highlights an urgent need for consistent regulations, standardized analysis methods, and research that examines realistic human exposure and toxicological impacts. To safeguard consumer health amidst escalating plastic utilization, it is essential for policymakers, researchers, industry, and public health stakeholders to coordinate their efforts to mitigate NMP contamination in single-use plastic water bottles. Full article

Aging underground pipeline infrastructure across the United States, including systems used for potable water supply, wastewater collection, and stormwater conveyance, has exceeded its intended service life, emphasizing the need for replacement or rehabilitation to maintain reliable service to communities. Among available trenchless technologies, cured-in-place pipe (CIPP) is widely applied because it minimizes surface disruption and is well-suited for use in densely populated areas. Despite these advantages, environmental concerns remain regarding the release of total volatile organic compounds (VOCs) during CIPP installation and curing. This study evaluates total VOC emissions from CIPP liners under field conditions. Air samples were collected at six installation sites across the United States before, during, and after installation and curing to quantify key VOC species. Multiple sampling methods were employed, including photoionization detectors (PIDs), Summa canisters, and personal worker sampling. The measured compounds included styrene, cumene, acetophenone, hexane, toluene, and ethanol. Measured concentrations were compared with occupational exposure limits established by the U.S. Environmental Protection Agency (USEPA), the National Institute for Occupational Safety and Health (NIOSH), and the Occupational Safety and Health Administration (OSHA). The results indicate that styrene was the dominant compound within active CIPP work zones, with peak concentrations reaching 25.5 ppm during curing. In contrast, VOC concentrations decreased substantially within five feet downwind of the work zone. Overall, the findings suggest that potential public exposure risks are limited, while workers directly involved in CIPP operations may experience elevated short-term exposures during installation and curing activities. Full article

This study focused on the presence of heavy metals in the mining waste dump in the Certej area (Hunedoara County, Romania). The total content of metals (Cr, Cd, Cu, Mn, Pb, Ni, Zn, Fe) and the physical–chemical parameters (pH, redox potential, electrical conductivity, total dissolved solids, and salinity) were analyzed in the soil and sterile samples. The content of Cd, Cu, Zn, Pb, Mn in the samples collected nearby the mining waste dump was relatively low, being close to those considered normal levels in the national legislation. The samples from the mining waste dump indicated that Pb exceeded the alert levels, Zn almost reached the alert limit, and Cu exceeded the normal threshold. The content of Cd, Cu, Zn and Pb had an increasing trend from the top to the base of the dump, which may indicate a metal leakage due to water infiltration. Since agricultural activities take place in the proximity of the investigated area, special attention for plant uptake was taken into consideration. Full article

Ghost nets are the result of fishing nets ending up at sea by fishing vessels during operations, repairs, accidental loss, and from aquaculture activities. This is a major threat to the marine environment due to the entrapment of marine species, which often leads to the mortality of important species, the alteration of the marine benthic habitat, and the release of microplastics. In the current study, the authors conducted underwater clean-up activities in the marine protected area of Sounio in Greece (NATURA2000) to identify, evaluate whether they can be removed, and remove ghost nets. A total of 1200 Kg of ghost nets was removed within one year, with 68 different species reported to have colonized the nets. The reported groups were Mollusca, Porifera, Chordata, Arthropoda, Echinodermata, Bryozoa, Ochrophyta, Tracheophyta, Rhodophyta, Cnidaria, Chlorophyta, and Annelida. The species were not listed as threatened by the IUCN conservation status, while 86% were native, and 14% were invasive in the Mediterranean Sea. The current work presents the need to expand research efforts in the field of underwater plastic pollution, implement monitoring campaigns to a greater extent in the study area, and perform an assessment before the removal of ghost nets. Full article

The simplest definition of light pollution (LP) is the presence of artificial light at night (ALAN) at inappropriate times, intensity, and inappropriate amounts and colors. All these parameters of anthropogenic light clearly indicate that the presence of ALAN can disrupt the proper functioning of not only humans but all organisms on Earth that have evolved in conditions of alternating day and night, closing within a 24 h day. Cities are the primary source of LP, and the ever-increasing global urbanization makes LP one of the fastest-growing threats to our civilization. It is particularly dangerous because public awareness of its existence is exceptionally weak, as the presence of light is usually perceived as a good thing, generating safety and beauty, and it is difficult for people to understand that excess of light may turn against us. However, LP dysregulates the well-known circadian rhythms of humans and animals and disrupts normal plant physiology. Furthermore, in a light-polluted world, plant–pollinator relationships are also endangered, which can lead to disruptions in food chains. In this review, we will present various aspects of excessive lighting and propose solutions to mitigate the increasing LP, considering the threats it poses to all living organisms. Full article

Reduced mud in the Yoro tidal flat (inner part of Tokyo Bay, Japan) consists of black and highly viscous sediment containing high levels of polycyclic aromatic hydrocarbons (PAHs). The mud is formed through the decomposition of terrestrial plants washed up on the tidal flat; however, the origin of PAHs within the mud has remained unclear. To investigate the origin of PAHs in the mud, we analyzed PAHs in the mud and fragments of terrestrial plants using gas chromatography–mass spectrometry. The total PAH concentrations except for perylene were comparable between the mud (336 ± 58 μg kg-dry⁻¹) and the fragments of plants (247 ± 77–435 ± 235 μg kg-dry⁻¹), and their compositional patterns were also similar. These results indicate that the high levels of PAHs in the mud primarily originated from the fragments of plants that composed the mud. Furthermore, the perylene (Pery) concentrations in the fragments of plants were the same as or higher than those in the mud, suggesting that the formation of Pery begins in the plant tissues even before the mud was formed. These findings reveal a previously unrecognized pathway by which terrestrial plants introduce PAHs into tidal flat environments. Full article

Contamination of drinking water by potentially toxic elements (PTEs) remains a critical public-health concern in Uganda. This systematic review compiled and harmonized quantitative concentrations (mg/L) for key PTEs, lead (Pb), cadmium (Cd), arsenic (As), chromium (Cr), mercury (Hg), copper (Cu), zinc (Zn), nickel (Ni), cobalt (Co), manganese (Mn), and iron (Fe), across various potable and informal water sources used for drinking, including municipal tap water, boreholes, protected and unprotected springs, wells, rainwater, packaged drinking water, rivers, lakes, and wetlands. A comprehensive search of different databases and key institutional repositories yielded 715 records; after screening and eligibility assessment, 161 studies met the inclusion criteria, and were retained for final synthesis. Reported PTE concentrations frequently exceeded WHO and UNBS drinking water guidelines, with Pb up to 8.2 mg/L, Cd up to 1.4 mg/L, As up to 25.2 mg/L, Cr up to 148 mg/L, Fe up to 67.3 mg/L, and Mn up to 3.75 mg/L, particularly in high-risk zones such as Rwakaiha Wetland, Kasese mining affected catchments, and Kampala’s urban springs and drainage corridors. These hotspots are largely influenced by mining activities, industrial discharges, agricultural runoff, and corrosion of aging water distribution infrastructure, while natural geological conditions contribute to elevated background Fe and Mn in several regions. The review highlights associated health implications, including neurological damage, renal impairment, and cancer risks from chronic exposure, and identifies gaps in regulatory enforcement and routine monitoring. It concludes with practical recommendations, including stricter effluent control, expansion of low-cost adsorption and filtration options at household and community level, and targeted upgrades to water-treatment and distribution systems to promote safe-water access and support Uganda’s progress toward Sustainable Development Goal 6. Full article

Unsafe disposal of pesticide waste remains a critical environmental and public health issue in developing agricultural systems. This study examined cocoa farmers’ disposal behaviours and their determinants across Nigeria’s major cocoa-producing regions using an explanatory sequential mixed-methods design. Quantitative data were collected from 391 farmers, followed by 23 in-depth interviews to contextualise behavioural drivers. Results showed that knowledge of pesticide risks and availability of disposal facilities significantly predicted safer disposal practices (R² = 0.469, p < 0.05), whereas age had a negative influence. Qualitative findings revealed that negative attitudes, social norms, and limited infrastructure reinforced unsafe behaviours, while membership in farmers’ associations promoted safer practices through peer learning. A joint display demonstrated convergence between structural enablers (collection cages, extension support) and behavioural factors (knowledge, attitudes, norms). The study identifies a dual challenge of systemic shortcomings and behavioural inertia, suggesting that regulatory action alone is insufficient without farmer engagement and education. Policy and extension programmes should prioritise collection infrastructure, association-based training, and Integrated Pest Management to promote sustainable pesticide waste management. These insights advance understanding of pesticide disposal behaviour and offer actionable guidance for environmental governance in low- and middle-income agricultural contexts. Full article

Eutrophication is a major threat to freshwater ecosystems, leading to harmful algal blooms, biodiversity loss, and hypoxia. Excessive nutrient loading, primarily from nitrates and phosphates, is driven by fertilizer runoff, sewage discharge, and agricultural practices. Sediment microbial fuel cells (sMFCs) have emerged as a potential bioremediation strategy for nutrient removal while generating electricity. Although various studies have explored ways to enhance sMFC performance, limited research has examined the relationship between external resistance, electricity generation, and nutrient removal efficiency. This study demonstrated effective nutrient removal from overlying water, with 1200 Ω achieving the highest nitrate and phosphate removal efficiency at 59.0% and 32.2%, respectively. The impact of external resistances (510 Ω and 1200 Ω) on sMFC performance was evaluated, with the 1200 Ω configuration generating a maximum voltage of 466.7 mV and the 510 Ω configuration generating a maximum current of 0.56 mA. These findings show that external resistance plays a major role in both electrochemical performance and nutrient-removal efficiency. Higher external resistance consistently resulted in greater voltage output and improved removal of nitrate and phosphate. The findings also indicate that sMFCs can serve as a dual-purpose technology for nutrient removal and electricity generation. The power output may be sufficient to support small, eco-friendly biosensing devices in remote aquatic environments while mitigating eutrophication. Full article

Airborne micro- and nanoplastic particles (MNPs) are increasingly recognized as a potential occupational exposure hazard, yet substance-specific workplace data remain limited. This study quantified airborne MNP concentrations during polyester microfiber production using a correlative SEM–Raman approach that enabled chemical identification and size-resolved particle characterization. The aerosol mixture at the workplace was dominated by sub-micrometer particles, with PET—handled onsite—representing the main process-related MNP type, and black tire rubber (BTR) forming a substantial background contribution. Across both sampling periods, total MNP particle number concentrations ranged between 6.2 × 10⁵ and 1.2 × 10⁶ particles/m³, indicating consistently high particle counts. In contrast, estimated MNP-related mass concentrations were much lower, with PM₁₀ levels of 12–15 µg/m³ and PM_2.5 levels of 1.3–1.6 µg/m³, remaining well below applicable occupational exposure limits and near or below 8 h-equivalent WHO guideline values. Comparison with earlier workplace and indoor studies suggests that previously reported concentrations were likely underestimated due to sampling strategies with low efficiency for small particles. Moreover, real-time optical measurements substantially underestimated particle number and mass in this study, reflecting their limited suitability for aerosols dominated by small or dark particles. Overall, the data show that workplace MNP exposure at the investigated site is driven primarily by very small particles present in high numbers but low mass. The findings underscore the need for substance-specific, size-resolved analytical approaches to adequately assess airborne MNP exposure and to support future development of MNP-relevant occupational health guidelines. Full article

Plastic pollution is a growing environmental crisis, with millions of tons of plastic entering the ocean each year and breaking down into microplastics and nanoplastics. These tiny particles pose a serious threat to marine life, particularly to zooplankton, which are essential to aquatic ecosystems. This study investigated the distribution and toxicity of polystyrene nanoplastics in Artemia salina (brine shrimp), a key model organism in ecotoxicology. Using specialized imaging and spectroscopy techniques, we tracked the presence of nanoplastics in A. salina and examined their effects on survival, behavior, and body structure. The results showed that nanoplastics accumulated in the gut and, at higher concentrations, caused gut deformities. The toxicity assay revealed that after 48 h of exposure, lethal concentrations decreased by nearly half compared with 24 h, demonstrating a time-dependent toxic effect. The estimated concentration that caused 50% mortality was 30.21 ± 6.44 mg/L. Additionally, these findings suggest that nanoplastics may impair the salt gland, affecting osmoregulation and energy allocation, leading to reduced feeding and pigmentation. These results highlight the potential risks of nanoplastics to marine organisms and emphasize the need for further research to understand their broader ecological and health impacts. Full article

Harmful algal blooms (HABs) represent an escalating threat in marine and coastal ecosystems, posing increasing risks to ecological balance, public health, and blue economy industries including fisheries, aquaculture, and tourism. This review examines the impact of climate change and anthropogenic pressures on the escalation of HAB occurrences, focusing especially on vulnerable regions in Mexico, which are the primary case study for this investigation. The methodological framework integrates HAB risk assessment (RA) methods found in the literature. Progress in detection and monitoring technologies—such as sensing, in situ sensor networks, and prediction tools based on machine learning—are reviewed for their roles in enhancing early-warning systems and aiding decision support. The key findings emphasize four linked aspects: (i) patterns of HAB risk in coastal zones, (ii) deficiencies and prospects in HAB-related policy development, (iii) how governance structures facilitate or hinder effective actions, and (iv) the growing usefulness of online monitoring and evaluation tools for real-time environmental observation. The results emphasize the need for coupled technological and governance solutions to reduce HAB impacts, protect marine biodiversity, and enhance the resilience of coastal communities confronting increasingly frequent and severe bloom events. Full article

Microplastics (MPs)—synthetic polymer particles less than 5 mm in size—have emerged as ubiquitous contaminants in terrestrial and aquatic environments worldwide, raising concerns about their ecological and human health impacts. While research has predominantly focused on urban and marine settings, evidence shows that rural ecosystems are also affected, challenging assumptions of pristine conditions outside cities and coasts. This review synthesizes current knowledge on the presence, pathways, and impacts of MPs in rural environments, highlighting complex contamination dynamics driven by both local sources (agricultural plastics, domestic waste, rural wastewater, and road runoff) and regional processes (atmospheric deposition, hydrological transport, and sediment transfer). Key findings highlight that rural lakes, streams, soils, and groundwater systems are active sinks and secondary sources of diverse MPs, predominantly polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) in fibrous and fragmented forms. These particles vary in size, density, and color, influencing their transport, persistence, and bioavailability. Ecological effects include bioaccumulation in freshwater species, soil degradation, and potential food chain transfer, while human exposure risks stem from contaminated groundwater, air, and locally produced food. Despite these growing threats, rural systems remain underrepresented in monitoring and policy frameworks. The article calls for context-specific mitigation strategies, enhanced wastewater treatment, rural waste management reforms, and integrated microplastics surveillance across environmental compartments. Full article

This study examined the seasonal and spatial distribution of heavy metals (Cd, Pb, and Ni) in relation to environmental parameters in five regions of Greater Cairo, Egypt (Helwan, Al-Azhar, Al-Orman, Al-Orman Center, and Al-Moqattam) between 2023 and 2024 using Ficus nitida as a bioindicator. Leaf and soil samples were taken periodically and tested for heavy metal levels, growth factors, chlorophyll, NPK, and moisture content. Concentrations of Cd, Pb, and Ni were highest at Helwan, the industrial site, reaching 0.22 mg/kg, followed by Al-Azhar, a high-traffic urban area, with 0.12 mg/kg, particularly during the summer season. In contrast, the lowest concentrations (0.03 mg/kg) were recorded at Al-Orman Center and Al-Moqattam, both characterized as low-traffic residential zones. A positive correlation was observed between heavy metal concentrations in Ficus nitida leaves and those in the corresponding soils. Additionally, the minimum leaf area was recorded at Helwan during winter, followed by the Al-Azhar region, with values of 36.2 cm² and 41.7 cm², respectively. Reductions in chlorophyll content and nutritional composition were linked to heavy metal levels. Ficus nitida may function as a trustworthy bioindicator of the environmental heavy metal contamination and the health of urban ecosystems, and it accurately reflects soil and air pollution levels. Full article

Indoor Air Quality (IAQ) is a major public health concern, as prolonged exposure to indoor environments can significantly affect users’ well-being. In this context, the research proposes a sampling protocol, developed in compliance with ISO 16000 principles, for the assessment of key chemical and physical parameters influencing air quality in inpatient rooms. These spaces host fragile users, while also requiring adequate protection for healthcare staff. Referring to the scope of the paper, the study outlines a comprehensive methodology for monitoring selected volatile organic compounds (VOCs) and microclimatic factors—temperature and relative humidity—using passive samplers and/or active sensors. The protocol also integrates outdoor measurements to better understand the contribution of internal emission sources. Monitoring activities are scheduled over one year, with regular sampling campaigns (at least one week per month) to analyze seasonal variations and long-term trends. The flexible structure of the protocol allows it to be adapted to different research objectives and types of healthcare facilities. Overall, the proposed approach provides a replicable framework for assessing IAQ in healthcare settings and identifying the main factors affecting indoor environmental performance. This supports improvements in both environmental quality and health protection within healing spaces. Full article