Search Results (1,976)

Boron is a chemically distinctive bioelement whose electron-deficient structure enables reversible coordination with oxygen-rich functional groups such as diols and hydroxyls. This property allows boron to modulate molecular stability, conformation, and biological reactivity, giving rise to both beneficial pharmacological effects and toxicological outcomes. This review examines the dual biological role of boron through the framework of bioactive boron-containing natural products and natural compounds capable of forming reversible boron complexes. Particular attention is given to naturally occurring boron-containing antibiotics, including the polyketide macrodiolides boromycin, aplasmomycin, tartrolons, and hyaboron, where boron plays a direct structural and functional role in antimicrobial activity. These compounds demonstrate how boron coordination can influence ion transport, membrane interactions, and molecular assembly, contributing to potent antibacterial properties. Beyond intrinsically boron-containing metabolites, many natural antibiotics and toxins possess oxygen-rich architectures capable of forming transient borate complexes through vicinal 1,2-diol motifs. Examples include polyene macrolide antibiotics such as amphotericin B, fungichromin, and nystatin, as well as tetracyclines, rifamycins, and macrolides such as sorangicin A, where boron coordination may affect solubility, aggregation, ionophoric behavior, and biological selectivity. Similar chemistry is observed in marine neurotoxins and polyether toxins—including tetrodotoxin, saxitoxin derivatives, azaspiracids, pectenotoxins, ciguatoxins, and gambierones—whose hydroxyl-rich frameworks enable reversible interactions with boron species present in seawater. Such complexation may enhance aqueous stability and contribute to trophic transfer and bioaccumulation within marine ecosystems. By framing boron as a molecular “double edge,” this review integrates chemical, biological, and environmental perspectives to highlight how boron coordination can simultaneously enhance antimicrobial activity while influencing toxicity and ecological persistence. Recognizing the role of boron in shaping the activity of natural products provides new insight into antibiotic function, toxin behavior, and the broader impact of boron chemistry in biological systems. Full article

Organochlorine pesticides (OCPs), a broad class of highly stable and lipophilic chemicals, have been widely used to control pests and disease vectors in agriculture, households, and the public health sector. Due to their lipophilic nature and resistance to degradation, OCPs accumulate in the fatty tissues of fish and shellfish, positioning these foods as critical vectors for human exposure. This review synthesizes current global research on the presence of OCPs in fish and shellfish, with an emphasis on geographical variation, species-specific accumulation patterns, and temporal trends. This study discusses the sources and pathways which bring OCPs to the aquatic environment to highlight regional disparities in pollutant levels, influenced by industrial activities, agricultural practices, and waste management systems. It also explores the mechanisms of bioaccumulation and biomagnification that contribute to the elevated levels of OCPs in fish and shellfish, underscoring the complexities of food chain dynamics in contaminant transfer. This paper also highlights the diverse adverse effects of OCPs on consumer health, including chronic and carcinogenic diseases such as endocrine and respiratory malfunctions, neurotoxicity, kidney and liver damage, reproductive disorders, and skin or eye injuries, while suggesting mitigation strategies to promote an OCP-free and healthy aquatic environment. Full article

We compared fish assemblage structure and total mercury (THg) bioaccumulation between a natural floodplain lake and a constructed irrigation canal in central Brazil. A total of 473 individuals representing 34 species were recorded, and dorsal muscle samples from 62 specimens representing shared species or species occupying comparable trophic positions were analyzed for THg (Curimatella immaculata, Hemiodus microlepis, Astyanax aff. bimaculatus, Triportheus albus, Geophagus sveni, Pimelodus blochii, Pygocentrus nattereri, Lycengraulis batesii, and Cichla kelberi). The floodplain lake exhibited higher species richness, diversity, and evenness, whereas the irrigation canal supported a simplified assemblage dominated by fewer species. Total Hg concentrations were significantly higher in the lake than in the irrigation canal; however, this pattern was observed only for the carnivorous guild (t = 5.384, p < 0.0001) and the detritivorous guild (t = 4.183, p = 0.0001). THg increased significantly with trophic level in both systems, from detritivores to carnivores (F₂,₄ = 15.127, p = 0.009), yielding comparable trophic magnification slopes (lake: 1.46, 95% CI: 1.11–1.81; canal: 1.36, 95% CI: 0.94–1.77). Despite lower diversity and THg concentrations in the irrigation canal, Hg transfer efficiency across trophic levels was conserved between systems. Full article

Per- and polyfluoroalkyl substances (PFAS) continue to be one of the most persistent global contaminants and are increasingly recognized as leading metabolic- and hepatic-dysfunction mediators. Despite extensive investigation of PFAS toxicity, a critical gap in the identification and integration of toxicokinetic drivers of hepatic bioaccumulation with mechanistic pathways driving mitochondrial and nuclear receptor-related injury, more specifically, with respect to alternative PFAS strategies, still remains. Legacy PFAS, including PFOA and PFOS, accumulate in the liver and disturb mitochondrial homeostasis as they disrupt β-oxidation, induce oxidative stress, and alter lipid and bile acid metabolism. Meanwhile, the next-generation PFAS variants (including short-chain and polymeric substitutes) are rapidly increasing in environmental concentrations, but remain insufficiently characterized and poorly regulated, raising concerns that substitution-based strategies may maintain their toxicological risk. We summarize the evidence of the association between PFAS bioaccumulation and mitochondrial dysfunction, metabolic reprogramming, and inflammatory signaling, and illustrate mechanistic convergence across legacy and emerging PFAS. We also review insights from recent experimental models, such as 3D hepatocyte systems and human-relevant receptor platforms that more closely mimic chronic exposure states. This review emphasizes mechanistic convergence across legacy and emerging PFAS, highlighting shared pathways that may persist despite chemical substitution. Thus, we discuss key gaps in monitoring, toxicity assessment, and policy, including the requirement of regulatory paradigms that treat PFAS as a class rather than individual compounds. Full article

This study provides a comprehensive assessment of 12 metal(loid)s in the muscle tissue of the commercially vital shrimp, Penaeus semisulcatus, from four stations (Bozyazi, Silifke, Karatas, and Iskenderun) along the Northeastern Mediterranean. Metal concentrations were evaluated separately for males and females, utilizing Estimated Weekly Intake (EWI), Target Hazard Quotient (THQ), Carcinogenic Risk (CR), and Selenium Health Benefit Value (HBV_Se) indices. While the species is generally safe for consumption across the region, a striking, localized bioaccumulation of Chromium (Cr) was identified specifically in Iskenderun Bay, where male shrimps exhibited concentrations (1.209 mg/kg wet weight) approximately 10-fold higher than females, highlighting a sex-specific sensitivity likely linked to metabolic and physiological differences. By adopting a precautionary risk assessment framework—considering the region’s intense industrial profile—this localized spike resulted in a Total Carcinogenic Risk (∑CR = 5.15 × 10⁻⁴) for this group, exceeding the priority threshold. Furthermore, widespread Lead (Pb) contamination was detected across all stations, with several samples surpassing EU maximum levels (0.50 mg/kg). Regarding Arsenic (As), while high total concentrations led to THQ values > 1 across the regional gradient, this was characterized as a conservative modeling artifact rather than a physiological threat, as Arsenic in crustaceans is predominantly in the non-toxic organic form. Conversely, any potential risk from Mercury (Hg) was conclusively mitigated by an overwhelming molar excess of Selenium (Se) at all locations, confirmed by consistently positive HBV_Se values (0.312–0.658). In conclusion, our findings demonstrate that seafood safety is conditional and region-specific. The study underscores that localized contamination “hotspots” can be easily masked by non-sex-specific sampling and emphasizes the necessity of moving beyond simplistic risk models by incorporating selenium-mercury antagonism and precautionary risk assumptions for industrial pollutants. Full article

Urban and peri-urban river systems subjected to intensive agriculture are vulnerable to diffuse metal(loid) inputs, yet the integration of hydrological compartments, bioindicators, and human health risk remains poorly explored. This study investigated the seasonal dynamics, bioaccumulation patterns, and potential human health risks associated with metal(loid)s in the Santa Virgem River (Brazil–Paraguay border), using water from backwater zones and three plant groups (Apiaceae angiosperms, mosses, and the liverwort Dumortiera sp.). Water and plant samples were collected during five seasonal campaigns (2019–2020) and analyzed by ICP OES. Multivariate analysis (PCA) was applied, and biological accumulation coefficients (BAC) and chronic daily intake (CDI) were estimated for adults and children under different ingestion scenarios. Results showed that Mg, Fe, K, S, and P dominated water chemistry, while As, Cd, Cr, Cu, Pb, and Se were mostly below detection limits. PCA explained 77.6% of total variance, distinguishing agricultural and hydrological phases. Bryophytes exhibited markedly higher BAC values, particularly for Mn (up to 2.3 × 10⁵) and Fe, compared with Apiaceae. CDI and hazard assessment indicated negligible non-carcinogenic risk for most elements (HQ < 1), except phosphorus, which dominated the Hazard Index due to its low reference dose. Overall, the results demonstrate that hydrodynamic conditions and plant functional traits jointly control metal(loid) dynamics, highlighting the value of multispecies biomonitoring in peri-urban river systems. Full article

Human activities inevitably affect natural ecosystems, the impact of which most often refers to negative factors resulting in the accumulation of toxic elements in environmental components. This study quantified the presence of 12 toxic elements (Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, Zn, As, and Se) in water, soil, and six melliferous plant species across the Republic of Croatia. Sampling sites were classified into four groups according to the dominant anthropogenic impact: agricultural areas, urban and traffic-affected zones, industrial vicinities, and forested hill regions. The results demonstrate the transfer of toxic elements from abiotic matrices into plants, indicating their potential as bioaccumulators. Soil contamination with toxic metals was identified as a relevant ecological risk factor, while contamination of melliferous plants highlights potential implications for human health through the production of honeybee-derived products. Element concentrations in water and soil were determined using three atomic absorption spectrometry techniques (FAAS, GFAAS, and CVAAS), whereas concentrations in floral samples of melliferous plants were measured using inductively coupled plasma mass spectrometry (ICP MS). The obtained results were interpreted in relation to natural background levels and the current national legislation. Anthropogenic impacts were further evaluated using environmental quality indices and bioaccumulation factors, revealing site-specific contamination patterns of both natural and anthropogenic origin. Full article

While mining is a highly important economic activity, it generates considerable environmental impact, especially during the grinding and extraction stages of metallic minerals, leading to the formation of waste known as mine tailings. These mine tailings, often abandoned in various regions of Mexico due to a lack of prior environmental regulations, contain heavy metals that pose a risk to both the environment and human health. In Huautla, Morelos, where metals such as silver (Ag), gold (Au), copper (Cu), lead (Pb), and zinc (Zn) were extracted from the 16th century until 1988, it is estimated that there are approximately 780,000 tons of mine tailings. These mine tailings are contaminated with heavy metals such as cadmium (Cd), Cu, chromium (Cr), manganese (Mn), Pb, and Zn, and the bioaccumulation and biomagnification of these metals have been documented in various plant and animal species in the region, indicating their bioavailability. The study conducted in this area consisted of determining the concentration of Cd, Cu, Cr, Mn, Pb, and Zn, as well as the sequential extraction of mine tailings 1 and 2 to identify metal bioavailability. The results showed for both mine tailings, that the metals with the highest concentrations were Pb (mine tailing 1: 1666 ± 317.7 mg/kg, mine tailing 2: 1329 ± 30.8 mg/kg) and Zn (mine tailing 1: 1327 ± 314.9 mg/kg, mine tailing 2: 1099 ± 34.3 mg/kg), found in fractions IV and VI, respectively. In mine tailings 1, the main bioavailable metals were Cd (75.3%), Mn (53%), Pb (39.8%), and Cu (36.4%), while in mine tailings 2, the bioavailable metals were Cd (56.8%), Pb (37.9%), and Cu (29.3%). In general, Cd and Pb exhibited the highest bioavailability in both mine tailings. According to the calculated risk indices, bioavailable Cd and Pb pose the highest pollution, ecological, and non-carcinogenic risk in both mine tailings, while bioavailable Cr showed the highest determined carcinogenic risk. This study demonstrated that the mining waste from Huautla contains high levels of bioavailable heavy metals, posing ecological and public health risks, and provides valuable information for the development of effective environmental remediation strategies. Full article

Chlorinated polyfluoroalkyl ether sulfonate (F-53B), a common substitute for perfluorooctane sulfonate (PFOS), exhibits similar environmental persistence and bioaccumulation potential, raising concerns about its ecological and health impacts. However, comprehensive toxicological data remain limited for adequate environmental risk assessment. In this study, we evaluated the developmental toxicity of F-53B using embryos/larvae of a commercially important benthic fish, blotched snakehead (Channa maculata). Embryos (<1 h post-fertilization, hpf) were exposed to various concentrations of F-53B (0.002, 0.02, 0.2, and 2 mg/L) for 120 h. Exposure resulted in concentration-dependent adverse effects, including reduced hatching success, increased mortality, and morphological malformations (yolk sac edema, spinal curvature). Histopathological analysis revealed substantial hepatic injury (vacuolization, nuclear pyknosis) and intestinal damage (villi atrophy) at higher concentrations (0.2 and 2 mg/L). Mechanistically, F-53B induced oxidative stress through inhibition of superoxide dismutase (SOD) and catalase (CAT), depletion of glutathione (GSH), and elevated malondialdehyde (MDA). Additionally, the observed immune dysregulation was characterized by the up-regulation of pro-inflammatory cytokines, including interleukin 1β (IL-1β), interleukin 8 (IL-8), and tumor necrosis factor-α (TNF-α), consistent with activation of the TLR-MAPK signaling pathway, and coincided with a shift from metabolic adaptation to pronounced inflammation. These integrated findings indicate that F-53B impairs early development in C. maculata through pathways involving oxidative damage, tissue injury, and immune disruption. This underscores the ecological risk F-53B poses to aquatic organisms and highlights the need for more comprehensive environmental risk assessment. Full article

The influence of three different types of microplastics (PE, PET, and PS) on soil physicochemical properties is the main scope of the present investigation. To this end, a pot experiment has been conducted, incorporating each kind of microplastic (MP) in two different soil samples in equal portions. The soils were typical of Mediterranean areas, moderately contaminated with Pb and Zn. Furthermore, two different plants, Nicotiana tabacum L. (Burley cv.) and Cannabis sativa L. (Fedora cv.), were planted to study the influence of a multi-contaminated soil environment on plant growth, along with their ability to absorb metals in their tissues. The addition of microplastics caused stronger reactions in slightly acidic soil, where the bioavailability of zinc and lead increased by 5–20% compared to alkaline soil rich in CaCO₃. Plant-to-soil indices have been calculated to monitor the plant’s capacity to transfer metals from the soil environment to plant tissues. PE induced the strongest and most consistent responses, increasing Zn and Pb bioavailability and systematically enhancing total concentration factors (TC), bioaccumulation factors (BAF), and translocation factors (TF) by up to 20%, particularly in acid soil, while PET reduced the mobility of metals on the surface while enhancing vertical transport, and PS caused moderate but stable changes. Plant responses were cultivar-dependent. Plant biomass increased by approximately 7–15% in Cannabis sativa L. (cv. Fedora 17), while Nicotiana tabacum L. (cv. Burley) showed greater sensitivity to the presence of microplastics. Even low MP inputs can subtly but persistently modify soil structure, metal dynamics, and soil–plant transfer processes without increasing total metal loads, highlighting the importance of soil chemistry and polymer type in assessing the environmental risk of microplastics for sustainable agroecosystems. Full article

Chronic exposure to heavy metals poses significant health risks. This study analyzed the concentrations of toxic (Cr, Pb, Cd, Ni) and essential (Cu, Zn, Se, Mn) elements in autopsy samples (the frontal pole area of the brain, the 6th intercostal space of the liver, and lungs (average of left and right lung samples) from 45 residents of South-Eastern Poland using ICP-MS. The aim was to determine the average body burden and organ-specific accumulation in a moderately industrialized region. HDBSCAN clustering revealed highly homogeneous elemental profiles, suggesting a unifying influence of local environmental factors. The liver acted as a metabolic hub, showing preferential sequestration (p < 0.0001) of essential elements (Zn, Se, Mn, Cu) regulated by homeostatic mechanisms. Toxic metals exhibited ‘metabolic trap’ patterns, particularly Cd and Pb in the liver and Cr in the lungs, due to their long biological half-lives. Strong positive correlations (Se–Zn, Se–Cu) indicated integrated antioxidant responses, while toxic pairs (Cr–Ni, Pb–Cd) suggested shared exposure pathways and molecular mimicry via transporters such as DMT1. Results confirmed long-term bioaccumulation, with toxic elements in the brain remaining below 0.25 µg/g. In the lungs, the accumulation hierarchy (Pb > Mn > Cd > Cr) reflected inhalation exposure. These findings emphasize the role of organ-specific sequestration in assessing long-term environmental exposure. Full article

Polyester microfibers (MF) are widespread in aquatic environments and increasingly recognized as an emerging factor affecting fish physiology. This study aimed to investigate the effects of intestinal accumulation of MF on gut tissue and cellular alterations, as well as on the HPG axis and oocyte maturation in adult female zebrafish. Adult female zebrafish were exposed to environmentally relevant concentrations of MF (1000 and 3000 particles/L) for 14 days to examine endocrine-regulated physiological and reproductive responses. For comparative reference, a bisphenol A (BPA) exposure group was included to contextualize endocrine-related responses. MF exposure resulted in intestinal accumulation. Gene expression analyses showed increased expression of vtg1 and esr2a, along with decreased expression of gnrh3, fshβ, lhβ, cyp17, and cyp19a1, indicating altered regulation of the HPG axis and steroidogenic pathways. Ovarian histology revealed alterations in oocyte development, especially at the higher MF concentration, indicating that MF can affect endocrine-regulated physiology and reproduction in fish. Together, these findings provide new evidence that intestinal accumulation of microfibers, along with associated histological and transcriptional alterations, elicits estrogen-responsive physiological patterns that influence HPG axis regulation and oocyte maturation in fish. Full article

Oxybenzone (BP-3) and polystyrene microplastics (PS MPs) are pervasive aquatic contaminants whose combined biological effects remain insufficiently characterized. This study investigated co-exposure to BP-3 and PS MPs in zebrafish embryos (Danio rerio), focusing on developmental endpoints, tissue bioaccumulation, and time-dependent sorption behavior. Embryos were exposed to 0.10–1.50 mg/L BP-3 for 96 h in the presence of PS MPs. Mortality, developmental abnormalities, and tissue BP-3 concentrations were measured, and chemical analysis was performed by HPLC-DAD. Although mortality was not significantly affected, embryos exhibited developmental abnormalities, particularly in swim bladder formation. Tissue BP-3 accumulation increased with exposure concentration. The influence of PS MPs on BP-3 uptake was concentration-dependent: at lower BP-3 exposures, PS MPs reduced tissue accumulation, whereas at higher exposures this reduction became negligible or was no longer observed. This suggests a dual role for PS MPs: mitigating direct aqueous exposure by sequestering BP-3 yet simultaneously acting as potential vectors for its environmental persistence and trophic transfer through alternative pathways. Independent time-resolved experiments showed rapid BP-3 removal from the aqueous phase in the presence of PS MPs, with early stabilization consistent with rapid partitioning behavior. These findings highlight the complex interactions between emerging contaminants and MPs, underscoring the need for further research into their ecological implications. Full article

Mercury (Hg) contamination in deep-sea ecosystems is of increasing concern due to its strong bioaccumulation potential and implications for seafood safety. However, depth-resolved information on Hg speciation and tissue-specific accumulation in deep-sea fish remains limited, particularly in semi-enclosed marginal seas such as the East Sea of Korea. In this study, total mercury (THg) and methylmercury (MeHg) concentrations were quantified in multiple tissues (muscle, liver, gill, bone, and skin) of deep-sea fish collected across a pronounced depth gradient (100–1300 m). Hg concentrations increased significantly with sampling depth (p < 0.05), indicating depth-driven enrichment processes. MeHg accounted for 61.8–87.4% of THg and predominated in muscle and liver, highlighting its toxicological relevance. Human health risk assessment based on Estimated Daily Intake (EDI) and Target Hazard Quotient (THQ) suggested that average exposure levels remained below international safety thresholds. Nevertheless, several deep-sea taxa (e.g., Lycodes tanakae and Malacocottus gibber) approached cautionary levels under high-consumption scenarios. These findings demonstrate that habitat depth is a key ecological driver of Hg accumulation in deep-sea fish and underscore the importance of depth-resolved, species-specific monitoring for effective seafood safety management as deep-sea fisheries expand. Full article

Fish consumption provides nutritional benefits but can also contribute to exposures to bioaccumulative contaminants, requiring guidance that integrates both dimensions. We conducted a deterministic pilot risk–benefit assessment of Latvian inland lake fish using pooled samples stratified by lakes and species. Risks were characterized for methylmercury, estimated from total mercury, and for Σ4 PFAS (PFOS, PFOA, PFNA, PFHxS) by calculating weekly intakes under three consumption scenarios (150, 300, and 450 g/week) for a 70 kg adult and comparing them to health-based guidance values. Benefits were quantified as weekly contributions of EPA + DHA, iodine, and protein relative to reference intakes, combined into a nutritional index and integrated with risk using a benefit–risk quotient (BRQ). The primary decision outputs were safe weekly consumption amounts (g/week) and the contaminant limiting factor. Across lake-species groups, mercury was the dominant constraint on safe consumption for most predatory fish, while PFAS limited selected groups with lower mercury burdens. EPA + DHA provided the strongest differentiating benefit signal between groups, whereas iodine contribution was limited because measurements were left-censored and constant after limit of quantification (LOQ) handling. This pilot demonstrates an interpretable framework for generating lake- and species-specific consumption guidance that can be updated as monitoring coverage expands. Full article