Pollutants, Volume 5, Issue 3 (September 2025) – 15 articles

The aim of this study was to devise a methodology for the on-site evaluation of the potential presence of persistent organic pollutants (POPs) in incoming waste materials. A novel approach to POP screening was developed, integrating an excitation–emission matrix method, which facilitates facile and comprehensive measurement, with machine learning of the resulting spectral images. With this approach, it is possible to determine the presence or absence of POPs with very high accuracy for screening, with a correct response rate of ≥75% and a specificity ≥80%. Assuming that this method is applied to actual delivery, we estimate that it is possible to obtain a discrimination result in about 10 min after sample removal. Full article

Plastics have been widely used in agriculture, particularly as mulching materials, due to their ability to improve soil conditions and enhance productivity. However, their degradation into microplastics (MPs) raises significant environmental and agronomic concerns, as these particles may change soil properties, affect microbial communities, and pose risks to surrounding ecosystems. While methodologies for MP detection in aquatic environments are well established, the analysis of MPs in soils remains challenging due to the complexity and heterogeneity of soil matrices. Currently, there is no standardized protocol for the determination of MPs in soils. This study critically evaluated and compared three different pre-treatment methods for removing organic matter from soil prior to MP analysis in an agricultural soil, and proposes a comprehensive methodology comprising two main phases: (i) organic matter removal, a crucial step of MP particles, and (ii) density separation of MP particles. Three distinct removal chemical methods were tested using samples from an agricultural soil in Southern Portugal. The most effective method was then applied to assess MP particles in an experimental field, using soil samples collected before mulching and 14 months later beneath a polyethylene-based soil cover. This was one of the first studies contributing to the establishment of a routine methodology for monitoring MPs in soils, particularly the agricultural soils, ensuring compliance with the future “Directive for Soil Monitoring”. Full article

Milk and dairy products play a key role in the human diet but may also be vehicles for toxic contaminants, particularly heavy metals and metalloids (HMs), such as lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As). This integrative review examines peer-reviewed studies published between 2015 and 2025 to examine sources, occurrence, and health risks associated with HM contamination in milk and dairy products. Key sources include industrial emissions, agricultural runoff, contaminated feed and water, and inadequate packaging. This review highlights regulatory inconsistencies, limited surveillance, and underuse of metal speciation analysis, which hinder accurate toxicity assessment. Advances in trace-level HM detection systems are discussed in terms of sensitivity, accessibility, and feasibility. Studies from diverse geographic regions frequently report high levels of Pb and Cd in samples originating from industrialized areas in low- and middle-income countries. Health risk indicators, such as target hazard quotients (THQs) and margins of exposure (MOEs), often exceed safety thresholds, particularly in children, indicating significant public health risks, especially with prolonged exposure. These findings underscore the urgent need for systematic contaminant monitoring, harmonized regulations, source-focused mitigation policies, and investment in rapid, cost-effective testing technologies to safeguard milk and dairy product safety worldwide. Full article

Lead (Pb) is a naturally occurring metal that is environmentally ubiquitous due to industrial activities, such as mining, smelting, and fossil fuel combustion. Exposure to Pb adversely affects the central nervous system, gastrointestinal tract, lungs, liver, bones, and cardiovascular system, leading to a multitude of negative health impacts, such as anemia and neurological disorders. While significant research has focused on the effects of Pb on the nervous and immune systems, Pb’s impact as a reproductive endocrine disruptor remains largely understudied. The first objective of this review was to collate the current literature regarding the effects of Pb on the reproductive system of aquatic species (primarily fish) and agricultural livestock to highlight the ecological significance and impacts on animal health. Literature supports the hypothesis that exposure to Pb can impede reproductive processes by affecting hormone levels, reproductive organ development, and fertility. A second objective of this review was to elucidate putative mechanisms underlying Pb as a reproductive endocrine disruptor using molecular data and computational approaches. Based on transcriptomics data, Pb is hypothesized to perturb key pathways important for hypothalamic–pituitary–gonadal axis functions, such as circadian regulation and estrogen receptor signaling. Given the widespread environmental presence of Pb, understanding these mechanisms is essential for improving risk assessments and protecting animal reproductive health. Full article

This study investigated the extent to which the North Atlantic Oscillation (NAO) modulated daily surface-level concentrations of ozone (O₃), nitrogen dioxide (NO₂), and sulfur dioxide (SO₂) on São Miguel Island, Azores, between 2017 and 2021. Using validated data from two air quality monitoring stations, São Gonçalo (SG) (urban background) and Ribeira Grande (RG) (semi-urban), we applied descriptive statistics, seasonal Pearson correlations, and robust linear regression models to assess pollutant responses to NAO variability. The results reveal a significant and positive association between NAO phases and O₃ concentrations, particularly in spring and summer. NO₂ levels exhibited a strong negative correlation with NAO during summer in urban settings, indicating enhanced atmospheric dispersion. In contrast, SO₂ concentrations showed weak and inconsistent relationships with the NAO index, likely reflecting the influence of local and episodic sources. These findings demonstrate that large-scale synoptic drivers such as the NAO can significantly modulate pollutant dynamics in island environments and should be integrated into air quality forecasting and environmental health planning strategies in small island territories. Full article

Exposure to potentially toxic elements (PTEs) in commonly used substances remains a serious public health concern, especially in low-regulation environments. This study assessed and compared the concentrations of five PTEs, cadmium (Cd), lead (Pb), zinc (Zn), iron (Fe), and copper (Cu), in marijuana and Aspen-brand cigarettes consumed in Bauchi, Nigeria. Using atomic absorption spectrophotometry (AAS), we analyzed PTE content in both substances after acid digestion and proper calibration. Cigarettes showed higher levels of all tested metals. Cd (3.12 μg/g) and Pb (0.88 μg/g) in cigarettes exceeded WHO limits, while marijuana contained lower levels of Cd (0.645 μg/g) and Pb (0.11 μg/g), with only Cd approaching the level that poses environmental and public health concern. Zn (71.2 μg/g), Cu (64.0 μg/g), and Fe (19.2 μg/g) were also significantly higher in cigarettes (p < 0.01). The high levels of Cd and Pb in cigarettes indicate that smokers are more exposed to harmful PTEs through inhalation than marijuana users, which points to a greater health risk from cigarette use. These findings call for stronger policies and regulations that ensure cleaner agricultural practices and industrial accountability to minimize exposure to harmful PTEs and protect community health in Bauchi. Full article

(1) Background: Dioxins and dioxin-like polychlorinated biphenyls (dl-PCBs) are persistent organic pollutants (POPs), characterized by high toxicity and strong lipophilicity, which promote their bioaccumulation in human tissues. Their detection in breast milk raises concerns about early-life exposure during lactation. Although dietary intake is the primary route of maternal exposure, environmental pathways—including inhalation, dermal absorption, and residential proximity to contaminated sites—may also significantly contribute to the maternal body burden. (2) Methods: This narrative review examined peer-reviewed studies investigating maternal and environmental determinants of dioxin and dl-PCB concentrations in human breast milk. A comprehensive literature search was conducted in PubMed, Scopus, and Web of Science (2000–2024), identifying a total of 325 records. Following eligibility screening and full-text assessment, 20 studies met the inclusion criteria. (3) Results: The included studies consistently identified key exposure determinants, such as high consumption of animal-based foods (e.g., meat, fish, dairy), living near industrial facilities or waste sites, and maternal characteristics including age, parity, and body mass index (BMI). Substantial geographic variability was observed, with higher concentrations reported in regions affected by industrial activity, military pollution, or inadequate waste management. One longitudinal study from Japan demonstrated a declining trend in dioxin levels in breast milk, suggesting the potential effectiveness of regulatory interventions. (4) Conclusions: These findings highlight that maternal exposure to dioxins is influenced by identifiable environmental and behavioral factors, which can be mitigated through public health policies, targeted dietary guidance, and environmental remediation. Breast milk remains a critical bioindicator of human exposure. Harmonized, long-term research is needed to clarify health implications and minimize contaminant transfer to infants, particularly among vulnerable populations. Full article

Environmental risk assessment (ERA) for pesticide approval in the context of predatory insects remains inadequate as it often overlooks the influence of agricultural practices. An increasing number of studies have shown that prolonged and synergistic pesticide exposure can elevate insect mortality. However, such effects remain largely unstudied in non-target predatory carabid beetles. The carabid beetle Platynus assimilis was subjected to repeated oral and continuous contact exposure to low doses of prothioconazole (20 g·ha⁻¹), lambda-cyhalothrin (0.4 g·ha⁻¹), or their combination over a 64-day period. The food consumption rate, body mass, locomotor activity, and mortality were monitored throughout the experiment. All pesticide-treated groups showed significantly increased final mortality, with median lethal times (LT₅₀) of 51.6 days for prothioconazole, 60.3 days for lambda-cyhalothrin, and 12.2 days for their combination. A significant synergistic effect on mortality was observed in the combined treatment group, with the highest synergistic ratio detected 20 days after the first exposure. Pesticide-treated beetles exhibited significant abnormalities in locomotor activity and body mass compared to the untreated group. These findings demonstrate that both time-cumulative mortality and potential synergistic interactions, reflecting field-realistic conditions, must be considered in ERA. Failure to do so may lead to an underestimation of pesticide toxicity to predatory carabids. Full article

Seafood contamination by heavy metals is a growing public health concern, particularly in regions like Tunisia where seafood is a major dietary component. This study assessed concentrations of cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) in the muscle tissue of the red shrimp Parapenaeus longirostris, collected in 2023 from four coastal regions: Bizerte, Monastir, Kerkennah, and Gabes. Metal analysis was conducted using flame atomic absorption spectroscopy. This species was chosen due to its ecological and economic importance. The study sites were chosen based on their differing levels of industrial, urban, and agricultural influence, providing a representative overview of regional contamination patterns. Mean concentrations were 1.04 µg/g for Zn, 0.59 µg/g for Cu, 1.56 µg/g for Pb, and 0.21 µg/g for Cd (dry weight). Pb was the most prevalent metal across sites. Statistically significant variation was observed only for Cu (p = 0.0334). All metal concentrations were below international safety limits set by FAO/WHO and the European Union. Compared to similar studies, the levels reported were similar or slightly lower. Human health risk was evaluated using target hazard quotient (THQ), hazard index (HI), and cancer risk (CR) values. For adults, THQ ranged from 5.44 × 10⁻⁶ to 8.43 × 10⁻⁴, while for children it ranged from 2.40 × 10⁻⁵ to 3.72 × 10⁻³. HI values were also well below 1, indicating negligible non-carcinogenic risk. CR values for Cd and Pb in both adults and children fell within the acceptable risk range (10⁻⁶ to <10⁻⁴), suggesting no significant carcinogenic concern. This study provides the first field-based dataset on metal contamination in P. longirostris from Tunisia, contributing valuable insights for seafood safety monitoring and public health protection. Full article

The application of animal manure and organic soil amendments as an alternative to expensive inorganic fertilizers is becoming more prevalent in the USA and worldwide. A field experiment was conducted on Bluegrass–Maury silty loam soil at the Kentucky State University Research Farm using the Kennebec variety of white potato (Solanum tuberosum) under Kentucky climatic conditions. The study involved 12 soil treatments in a randomized complete block design. The treatments included four types of animal manures (cow manure, chicken manure, vermicompost, and sewage sludge), biochar at three application rates (5%, 10%, and 20%), and native soil as control plots. Additionally, animal manures were supplemented with 10% biochar to assess the influence of combining biochar with animal manure on the accumulation of heavy metals in potato tubers. The study aimed to (1) determine the concentration of seven heavy metals (Cd, Cr, Ni, Pb, Mn, Zn, Cu) and two essential nutrients (K and Mg) in soils treated with biochar and animal manure, and (2) assess metal mobility from soil to potato tubers at harvest by determining the bioaccumulation factor (BAF). The results revealed that Cd, Pb, Ni, Cr, and Mn concentrations in potato tubers exceeded the FAO/WHO allowable limits. Whereas the BAF values varied among the soil treatments, with Cd, Cu, and Zn having high BAF values (>1), and Pb, Ni, Cr, and Mn having low BAF values (<1). This observation demonstrates that potato tubers can remediate Cd, Cu, and Zn when grown under the soil amended with biochar and animal manure. Full article

Agriculture relies on the widespread application of nitrogen fertilisers to improve crop yields and meet the demands of a growing population. However, the excessive use of these fertilisers has led to significant water quality challenges, posing risks to aquatic life, ecosystems, and human health. This study examines the relationship between synthetic nitrogen fertiliser usage and water pollution while identifying gaps in existing research to guide future studies. A systematic search across databases (Scopus, Web of Science, and Greenfile) identified 18 studies with quantitative data, synthesised using a single-group meta-analysis of means. As the data were continuous, the mean was used as the effect measure, and a random-effects model was applied due to varied study populations, with missing data estimated through statistical assumptions. The meta-analysis found an average nitrate concentration of 34.283 mg/L (95% confidence interval: 29.290–39.276), demonstrating the significant impact of nitrogen fertilisers on water quality. While this average remains marginally below the thresholds set by the World Health Organization (50 mg/L NO₃⁻) and EU Nitrate Directive, it exceeds the United States Environmental Protection Agency limit (44.3 mg/L NO₃⁻), signalling potential health risks, especially in vulnerable or unregulated regions. The high observed heterogeneity (I² = 100%) suggests that factors such as soil type, agricultural practices, application rate, and environmental conditions influence nitrate levels. While agriculture is a key contributor, other anthropogenic activities may also affect nitrate concentrations. Future research should comprehensively assess all influencing factors to determine the precise impact of nitrogen fertilisers on water quality. Full article

4-Aminodiphenylamine (4-ADPA) is a common additive in rubber tires, known for its antioxidant properties. It plays a crucial role in enhancing tire durability by preventing issues such as drying, cracking, and degradation from prolonged exposure to environmental factors like heat, oxygen, and ozone. However, despite its advantages in extending tire lifespan, the use of 4-ADPA raises significant environmental concerns. As tires wear down, microscopic tire wear particles (TWPs) containing 4-ADPA are released into the environment with substantial leaching, contaminating the waterways. The 4-ADPA leachates pollute and pose a threat to aquatic ecosystems, affecting various forms of marine life. The current study investigates the ecotoxicological effects of 4-ADPA on the aquatic plant Lemna minor (L. minor), focusing on its impact on relative growth and physiological biomarkers. Several parameters were assessed to evaluate ecotoxicity, including frond morphology, fresh biomass, total frond number, chlorophyll content, and starch accumulation. L. minor was grown for 7 and 14 days under controlled laboratory conditions using Hoagland media with varying concentrations of 4-ADPA (10–100 μg/L), while a control group was maintained in media without 4-ADPA. The results indicate that exposure to 4-ADPA led to a dose-dependent reduction in fresh biomass, total frond number, and chlorophyll levels. Lugol’s staining revealed increased starch accumulation in the fronds after exposure to 4-ADPA. The biological effects observed in L. minor following exposure to 4-ADPA, even at environmentally relevant concentrations, demonstrate a significant ecotoxicological impact on aquatic ecosystems. Further research involving additional species and investigating the mechanisms behind 4-ADPA toxicity is recommended to better understand its long-term consequences. Full article

Karst aquifer systems are highly vulnerable due to their unique underground water flow characteristics, making them prone to contamination and abandonment. This study compares an active karst water source (Ljubija) with a previously abandoned one (Rečica) to assess freshwater quality and water protection risks, especially as water scarcity becomes a concern during dry summer periods. The Ljubija and Rečica catchments, designated as water protection areas (WPAs), were monitored over a year (January–December 2020). Groundwater (GW) and surface water (SW) were analyzed twice a month during both dry and wet periods, adhering to European and national guidelines. An interdisciplinary approach integrated natural and human impact indicators, linking water quality to precipitation, hydrogeography, and landscape characteristics. After Slovene regulation standards (50 mg/L), the Ljubija source demonstrated stable water quality, with low nitrate levels (average 2.6 mg/L) and minimal human impact. In contrast, the Rečica catchment was more vulnerable, with its GW excluded from drinking use since the 1990s due to organic contamination, worsened by the area’s karst hydrogeology. In 2020, its nitrate concentration averaged 6.0 mg/L. These findings highlight the need for improved monitoring regulations, particularly for vulnerable karst water sources, to safeguard water quality and ensure sustainable use. Full article

The metalloid arsenic (As) and the metals lead (Pb) and mercury (Hg), which together we call the “Toxic Triad”, are among the pollutants of greatest global concern, harming the health of millions of people and contributing to biodiversity loss. The widespread distribution of As, Pb and Hg facilitates the exposure of humans and other species to these elements simultaneously, potentially amplifying their individual toxic effects. While As, Pb and Hg are well established as toxic elements, the mechanisms by which they interact with genetic material and impact the health of various species remain incompletely understood. This is particularly true regarding the combined effects of these three elements. In this context, the objective of this work was to perform a toxicogenomic analysis of As, Pb and Hg to highlight multiple aspects of element-gene interactions, in addition to revisiting information on the genotoxicity and carcinogenicity of the Toxic Triad. By using The Comparative Toxicogenomics Database, it was possible to identify that As interacts with 7666 genes across various species, while Pb influences 3525 genes, and Hg affects 692 genes. Removing duplicate gene names, the three elements interact with 9763 genes across multiple species. Considering the top-20 As/Pb/Hg-interacting genes, catalase (CAT), NFE2 like bZIP transcription factor 2 (NFE2L2), caspase 3 (CASP3), heme oxygenase (HMOX1), tumor necrosis factor (TNF), NAD(P)H quinone dehydrogenase 1 (NQO1) and interleukin 6 (IL6) were the most frequently observed. In total, 172 genes have the potential to interact with the three elements. Gene ontology analysis based on those genes evidenced that the Toxic Triad affects several cellular compartments and molecular functions, highlighting its effect on stimulation of toxic stress mechanisms. These 172 genes are also associated with various diseases, especially those of the urogenital tract, as well as being related to biological pathways involved in infectious diseases caused by viruses, bacteria and parasites. Arsenic was the element with the best-substantiated genotoxic and carcinogenic activity. This article details, through a toxicogenomic approach, the genetic bases that underlie the toxic effects of As, Pb and Hg. Full article

Air quality management concerns the assessment, analysis and mitigation strategies associated with ensuring that air is breathable and non-toxic. Successful management is a cognitively intensive task, knowledge-focused and converges multiple sources of information to develop a shared understanding of a problem. To operate effectively in this space, managers and operational teams share common points of reference in discussing problems and solutions, strategies, tactical briefings, etc., and communication and technical language use are key to the discipline. However, few studies have homed in on the language communities of air quality management discourse, and fewer still have exploited this to gain insight into the cognitive processes underpinning salient operational knowledge production. This paper draws upon a discussion from a multi-stakeholder workshop on bioaerosols and the built environment and draws upon Cognitive Linguistics to systematically examine the cognitive structuring of those different stakeholder representations. This approach is then explored as a contribution to good practice in air quality knowledge management and communication that is consistent with studies on cognitive and learning science and has potential for policy formulation. Full article