Search Results (775)

Potentially toxic element (PTE) contamination of food systems has emerged as an important environmental and public health concern in many developing countries, including Uganda, owing to rapid urbanization, industrialization, mining activities, wastewater reuse, informal waste disposal, and expanding urban agriculture. This review synthesizes evidence from peer-reviewed and selected grey literature on the occurrence of cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), and arsenic (As) in cereals, vegetables, tubers, livestock products, fish, fruits, and processed foods consumed in Uganda. A structured literature synthesis and screening-level dietary risk assessment using estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), carcinogenic risk (CR), and total carcinogenic risk (TCR) were conducted to identify contamination hotspots, priority exposure pathways, and potential public health implications. The available evidence revealed substantial spatial variability, with contamination consistently concentrated in mining-influenced agricultural areas, wastewater-irrigated farms, municipal dumpsites, industrial corridors, and urban food markets. Vegetables, cereals, livestock products, fish, and street-vended foods exhibited the greatest contamination burdens, while Pb and Cd were the PTEs most frequently reported exceeding WHO/FAO, Codex Alimentarius, and Ugandan food safety limits. Screening-level risk estimates indicated that Pb, Cd, and Cr contributed most to cumulative dietary exposure, with children consistently exhibiting higher EDI, THQ, HI, and TCR values than adults because of greater food intake relative to body weight. Although cumulative HI and TCR values exceeded recommended screening thresholds in several hotspot regions, these estimates should be interpreted as conservative screening-level indicators derived from heterogeneous published datasets rather than nationally representative measures of dietary exposure. Overall, the evidence indicates that PTE contamination in Ugandan food systems is predominantly hotspot-driven and highlights the need for targeted surveillance, standardized monitoring and reporting, improved pollution control, and strengthened food safety management to reduce chronic dietary exposure and protect public health. Full article

With the continued advancement of industrialization and urbanization in northwestern China, heavy metal contamination of loess sites has become an increasingly serious environmental issue. Heavy metals such as copper (Cu) and lead (Pb) are toxic, persistent, and readily retained by the mineral-pore framework of loess, which makes remediation difficult and threatens regional ecological security and human health. This study investigated electrokinetic (EK) remediation of artificially prepared loess co-contaminated with Cu and Pb using tartaric acid (TA), citric acid (CA), and disodium ethylenediaminetetraacetate (EDTA) as catholytes. Cu was generally removed more effectively than Pb because Pb was less adsorbed and immobilized more strongly. All three chelators enhanced metal desorption and migration through complexation, particularly in the cathode-side section. EDTA produced the greatest enhancement because it formed stable, negatively charged complexes with Cu and Pb over a broad pH range. Relative to the deionized-water control, EDTA increased the overall removal efficiencies of Cu and Pb to 55.4% and 27.2%, respectively, and promoted their transfer from the soil to the anolyte. These findings demonstrate that chelator-assisted EK treatment, particularly with EDTA, can effectively improve Cu and Pb removal from loess, while field application requires control of energy use, residual chelator, and post-treatment metal mobility. Full article

Lead (Pb²⁺) pollution poses a severe threat to the ecological environment and human health due to its high toxicity, bioaccumulation, and refractory nature. Traditional treatment technologies for lead-contaminated wastewater, such as chemical precipitation, ion exchange, and membrane separation, often face limitations, including secondary pollution, high costs, and high energy consumption. In contrast, adsorption has emerged as a promising alternative technology with advantages such as a simple process, high efficiency at low concentrations, and renewability. Biomass-based hydrogels and their composite systems, as novel green adsorbent materials, combine the abundant functional groups of natural biomass with the structural stability, high porosity, and recoverability of hydrogels through a three-dimensional cross-linked network, offering unique advantages for lead ion adsorption. Depending on their composition, these systems range from fully biodegradable pure biopolymer networks to partly biodegradable or biomass-containing composites incorporating inorganic, carbon-based, or metal–organic framework (MOF) materials. This paper systematically reviews the latest research progress on cellulose, lignin, sodium alginate, chitosan, starch-based hydrogels, and their composite systems for lead (Pb²⁺) adsorption. First, the structural characteristics, cross-linking mechanisms, and functional modification strategies of various biomass hydrogels are introduced. Then, the adsorption mechanisms of Pb²⁺, including multiple modes of action such as coordination complexation, ion exchange, electrostatic interaction, and physical adsorption, are systematically analyzed. The adsorption performance of different material systems is compared in detail. The regeneration and recycling performance, as well as the potential practical applications, of the materials are evaluated. On this basis, the main challenges in current research are summarised: balancing adsorption capacity and mechanical strength, achieving selective adsorption in actual wastewater, improving regeneration efficiency, and optimizing costs. In addition, future development directions for biomass hydrogel adsorbent materials are discussed, including the design of multi-functional composite materials, the development of intelligent, responsive hydrogels, engineering-scale-up, and life-cycle assessment. This review aims to provide a theoretical framework and technical roadmap for the rational design of high-performance, sustainable hydrogel adsorbents and to promote their engineering application for the treatment of lead-contaminated wastewater. Full article

Background/Objectives: This study aimed to identify common target genes, molecular interaction networks, and signaling pathways shared across the investigated toxic metal(loid)s—lead (Pb), cadmium (Cd), methylmercury compounds (MMC), arsenic (As), nickel (Ni), and hexavalent chromium (Cr(VI))—and associated with lung cancer overall, non-small-cell lung cancer (NSCLC), and small-cell lung cancer (SCLC). Methods: The Comparative Toxicogenomics Database (CTD) was used to identify associated genes, GeneMANIA to characterize molecular interaction networks, and ToppFun for pathway enrichment analysis. Results: Two common genes (MTOR and TP53) were identified for SCLC, eight for NSCLC (CAT, CCNB1, MTOR, NQO1, SOD2, STAT3, TP53, and VEGFA), and eighteen for lung cancer overall. Gene network analysis revealed predominantly physical interactions in SCLC, pathway interactions in NSCLC, and co-expression in lung cancer overall. Several toxic metal(loid)s exhibited concordant effects on TP53, VEGFA, HMOX1, and IL6 expression. TP53 was the only gene common to all investigated toxic metal(loid)s and lung cancer categories. Pathway enrichment identified PI3K–AKT–mTOR signaling in both SCLC and NSCLC, VEGF signaling in NSCLC, and MAPK, interleukin, and macrophage-stimulating protein (MSP) signaling in lung cancer overall. Conclusions: The identified genes and pathways suggest molecular mechanisms potentially relevant to the association between exposure to the investigated toxic metal(loid)s and lung carcinogenesis, particularly those related to cell survival, inflammation, oxidative stress, and angiogenesis. TP53 may represent a common molecular link warranting further investigation. The identified pathways represent candidate biomarkers and mechanistic targets, highlighting the biological heterogeneity of lung cancer and the importance of subtype-specific analyses. Full article

Background: This up-to-date narrative review examines the associations of low environmental exposure to toxic trace elements—arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg)—on pregnancy. While high levels are known to be harmful, the impact of low levels has not been fully analyzed. The aim was to summarize global data on As, Cd, Pb, and Hg levels in maternal and cord blood of healthy pregnant women, compare their distribution, and assess associations with demographic factors, lifestyle, and pregnancy outcomes. Methods: A systematic literature search was conducted in PubMed, Cochrane Library, and Scopus for studies published between 1 January 1990 and 14 May 2025. The review was conducted in accordance with PRISMA 2020 guidelines. A total of 824 records were assessed for eligibility, and 656 were excluded based on predefined criteria. Exclusion criteria encompassed in vivo or in vitro studies, non-English written publications, treatment-based studies, and studies involving occupationally exposed pregnant women. Inclusion criteria included original full-length research papers with cross-sectional, prospective cohort, or case–control designs; studies measuring As, Cd, Pb, and/or Hg in maternal and/or cord blood; and studies examining associations with demographic, lifestyle, and pregnancy outcomes. The review was not registered, and no external funding was received. Given the narrative synthesis approach of the review, a formal risk-of-bias assessment was not undertaken. Results: A total of 168 studies were included: 32 reported findings on As, 55 on Cd, 78 on Pb, and 64 on Hg, with 26 addressing all four elements. No meta-analysis was performed; results were summarized narratively. Results show that As and Cd levels are higher in maternal blood, whereas Pb and Hg, including methylmercury, are higher in cord blood. Key factors include smoking, rural residence, and fish or seafood consumption, linked to higher Cd, Pb, and Hg levels, respectively. Interpretation: Low Pb levels show the strongest associations with adverse pregnancy outcomes, while As shows the weakest. Pb’s effects may relate to passive placental diffusion, unlike other elements. Further studies are needed. Full article

Heavy metal pollution has emerged as a major challenge in global environmental science in the 21st century because of its extensive distribution, long-term environmental persistence, and non-degradability. As indispensable pollinators in ecosystems, honey bees have undergone marked population declines, a trend closely associated with multiple environmental stressors, including heavy metal contamination. Notably, lead (Pb), a widespread legacy toxic metal pollutant, is released into the environment through industrial emissions, vehicle exhaust, and other anthropogenic sources, contributing to long-term environmental contamination. Moreover, Pb can be transferred to honey bees through contaminated pollen and nectar. This exposure route may pose a risk to honey bee health, particularly under chronic or repeated exposure. This review synthesizes current evidence on Pb exposure routes, bioaccumulation, sublethal toxicity, and physiological responses in honey bees, while highlighting major uncertainties in colony-level risk assessment. Pb-associated physiological effects may impair individual bee health, but their long-term implications for colony health require further study. Full article

Reprocessing historical lead–zinc (Pb–Zn) slag offers a circular-economy pathway for secondary metal recovery, yet it can remobilize legacy contaminants where containment is inadequate, transferring risk to the surrounding land. Sustainable management of such sites requires frameworks that link contamination assessment to actionable remediation. We integrated ICP-OES geochemistry, native-plant biomonitoring, and US EPA RAGS-based risk modeling at an active Pb–Zn slag reprocessing site in Shymkent, Southern Kazakhstan. Twenty-four soil samples along four cardinal transects, two reference samples, and four composite plant samples (Centaurea pseudosquarrosa + Plantago lanceolata) were analyzed for ten metals by ICP-OES. UCC-referenced indices classified six metals as geoaccumulation Class 6 at most points (enrichment factors up to 90,871, confirming an exclusively anthropogenic origin). Peak concentrations reached 9350 mg·kg⁻¹ Pb, 290 mg·kg⁻¹ Cd, and 10,900 mg·kg⁻¹ As—exceeding Kazakhstan MPC by 72×, 290×, and 5450×. Worst-case carcinogenic risk reached 4.3 × 10⁻³ (43× above the US EPA threshold), driven almost entirely by arsenic (93%); ecosystem risk (RCR_total = 223) was dominated by cadmium (43%), arsenic (27%), and mercury (16%)—a disconnect between mass-based and toxicity-based prioritization. On this basis we propose a three-tier remediation framework (engineered containment, phytostabilization, monitored attenuation) that couples resource recovery with contamination control, is transferable to analogous Pb–Zn legacy sites, and supports sustainable land use, urban resilience, and responsible secondary-resource use. Full article

Lead-bearing dusts from metallurgical processes are hazardous secondary resources due to their complex composition and toxicity. At the same time, their high lead content makes them a promising feedstock for resource recovery. This study proposes an energy-efficient electrosmelting approach based on the partial substitution of sodium carbonate with calcium-rich industrial waste (sugar-industry defecate). Thermodynamic analysis and equilibrium modeling of the Pb–Sb–Fe–Na–Ca–Si–S–Cl–As system were performed in the temperature range of 200–1200 °C using Outotec HSC Chemistry. The results indicate that under equilibrium conditions approximately 90–95% of lead is concentrated in the metallic phase (~56 kg from ~60 kg in the feed), while antimony is co-recovered (~1.9–2.0 kg). The slag is dominated by calcium silicates, primarily Ca₂SiO₄, confirming the important role of CaO in slag formation and impurity fixation. Chlorine is predominantly bound as NaCl and partially as CaCl₂, while sulfur is distributed between Na₂S and Na₂SO₄. A significant portion of arsenic is predicted to be retained in the slag as calcium and sodium arsenates (Ca₃(AsO₄)₂ and Na₃AsO₄), whereas its volatilization is thermodynamically negligible under equilibrium conditions. Preliminary experimental results are generally consistent with the thermodynamic predictions and confirm the feasibility of partially replacing Na₂CO₃ with sugar-industry defecate. The proposed approach contributes to reducing the consumption of conventional fluxes and promotes the utilization of industrial waste within a circular-economy framework. Full article

In this study, Prunus dulcis hull (PDH) has been used to develop a cost-effective and eco-friendly adsorbent material for the removal of Pb²⁺ ions from polluted waters. The PDH particles were characterized using various techniques, including ATR-FTIR spectroscopy, ion-selective electrode ISE-H⁺ potentiometric titrations, pH of point of zero charge (pH_pzc) analysis, thermogravimetric analysis (TGA), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). Single-batch adsorption experiments were conducted at different pH values, with pH 5.0 identified as the optimal initial pH in terms of Pb²⁺ adsorption performance of PDH. The study also evaluated the effects of temperature, ionic medium, and several organic ligands with different functional groups on the adsorption capacity of PDH. The results showed that PDH is an effective adsorbent for lead ions, with adsorption capacities (q_m) ranging from 43 to 101 mg g⁻¹ and an adsorption equilibrium time of approximately 750 min at room temperature. Additionally, column adsorption experiments demonstrated that PDH can be reused at least four times with minimal loss in performance. The adsorption behavior of PDH was comparable under both equilibrium (batch) and non-equilibrium (column) conditions, with the breakthrough time (BT_0.5) values significantly affected by the background salts present in the toxic metal ion solution. Full article

Freshwater ecosystems are increasingly exposed to metal contamination arising from natural and anthropogenic activities, potentially affecting fish physiology and ecosystem health. However, limited information is available regarding metal accumulation and associated biological responses in fish populations from Dukan Lake, northern Iraq. Therefore, this study investigated metal concentrations in water and tissues of common carp (Cyprinus carpio) and evaluated their relationships with selected fish health indicators. Water and fish samples were collected monthly from Dukan Lake, and a total of 60 fish were classified into three length groups (20–29 cm, 30–39 cm, and 40–49 cm). Metal concentrations in water, liver, and gonad tissues were analyzed using ICP-OES, while condition factor (CF), gonadosomatic index (GSI), and hepatosomatic index (HSI) were used to assess fish physiological condition. Sodium (Na), magnesium (Mg), potassium (K), iron (Fe), zinc (Zn), and barium (Ba) were detected in both water and fish tissues, with concentrations in water ranging from 50 to 7069 μg/L. In contrast, chromium (Cr), manganese (Mn), nickel (Ni), selenium (Se), silver (Ag), cadmium (Cd), antimony (Sb), lead (Pb), copper (Cu), and arsenic (As) were below detection limits. Biometric analysis revealed significant differences (p < 0.05) in the gonadosomatic index (GSI) among fish length groups, indicating size-dependent reproductive development. However, no significant relationship was observed between fish length and either the CF or HSI, suggesting relatively stable somatic condition or liver status across size classes. Correlation analysis showed no significant associations between water metal concentrations and CF or GSI. A significant positive correlation was identified between Zn concentration and HSI in the 30–39 cm length group, indicating a possible link between Zn exposure and hepatic physiological response. The findings indicate that essential elements dominate the metal profile in Dukan Lake, with limited evidence of toxic metal contamination. No major adverse effects on the general condition of the fish were observed. These results contribute to understanding metal bioaccumulation patterns and their implications for fish health in freshwater ecosystems. Full article

Lead (Pb) is a persistent aquatic pollutant that disrupts redox homeostasis in fish. This study investigated hepatic Pb accumulation, reactive oxygen species (ROS) production, antioxidant responses, lipid peroxidation, and transcriptomic alterations in juvenile pufferfish (Takifugu obscurus) exposed to waterborne Pb. Juvenile pufferfish were exposed to 5.98 mg/L waterborne Pb, corresponding to 10% of the 96 h LC₅₀, for 96 h. Liver, blood, and hepatocyte samples were collected at 0, 12, 24, 48, and 96 h, with four biological replicates at each sampling time point. Hepatic Pb accumulation increased over time and reached the highest level at 96 h. ROS levels in blood cells and hepatocytes increased rapidly and peaked at 12 h. Superoxide dismutase (SOD) and catalase (CAT) activities showed early activation followed by late suppression, whereas glutathione peroxidase (GSH-Px) displayed partial adaptive recovery. Malondialdehyde (MDA) content increased progressively and reached approximately 2.8-fold of the control level at 96 h, indicating persistent lipid peroxidation. RNA-seq analysis identified 167, 460, 1398, and 2580 differentially expressed genes at 12, 24, 48, and 96 h, respectively. Enrichment, temporal trend, and weighted gene co-expression analyses indicated that Pb exposure shifted hepatic responses from early redox regulation to later metabolic adaptation, protein processing in the endoplasmic reticulum, proteasome function, and oxidative phosphorylation. qRT-PCR validation of 12 hub genes supported the RNA-seq results. These findings provide integrated biochemical and transcriptomic evidence for oxidative-stress-mediated hepatic toxicity in pufferfish exposed to waterborne Pb. Full article

Lead (Pb) is a persistent and highly toxic heavy metal that poses significant ecological and human health risks due to its high bioaccumulation potential. In this study, nitrogen-doped biochar (NBC) was synthesized from straw-derived biochar via ball-milling and ammonium nitrate modification to remediate Pb-contaminated soil. Batch adsorption experiments demonstrated that the adsorption process was best described by the Langmuir isotherm model, indicating monolayer adsorption. X-ray photoelectron spectroscopy (XPS) revealed that Pb(II) immobilization by NBC occurred through multiple mechanisms, primarily precipitation and complexation with hydroxyl and pyrrolic-N functional groups. Subsequent pot experiments confirmed that NBC outperformed pristine biochar (BC) in reducing Pb bioavailability. This superior performance was attributed to the ability of NBC to increase soil pore water pH and significantly decrease soil redox potential (Eh). Moreover, compared to the control, a 5% NBC treatment (NBC2) significantly increased soil organic matter (SOM) by 136.24% while concurrently increasing soil available nitrogen (SAN), phosphorus (SAP), and potassium (SAK) by 46.91%, 75.72%, and 42.79%, respectively. Microbiological analyses indicated that NBC application enhanced soil alpha diversity (Chao1, ACE, and Shannon indices) and enriched beneficial bacterial phyla, such as Proteobacteria and Firmicutes. Random forest analysis identified the acid-soluble Pb fraction and SOM as the main drivers of bacterial operational taxonomic unit (OTU) composition. Specifically, NBC increased the relative abundance of the family Hungateiclostridiaceae, which may promote soil sulfide production and facilitate the precipitation of Pb into highly insoluble forms, further reducing its mobility and toxicity. Collectively, these findings demonstrate that NBC is a promising soil amendment that leverages both physicochemical and microbial pathways to immobilize Pb, mitigate environmental toxicity, and restore soil ecological health. Full article

The development of eco-friendly magnesium (Mg)-based materials that possess acceptable mechanical properties, good biodegradability, and non-toxicity in biomedical applications has become more attractive in recent years, particularly for engineering and biomedical applications. This work investigates the effects of nano-ZnO (2 wt.%) reinforcement and cryogenic treatment (CT) on the microstructural, mechanical, thermal, and corrosion behavior of a non-toxic Mg-1Zn-1Ca alloy. Disintegrated melt deposition (DMD) was the synthesis starting point, while refrigeration at −20 °C (RF20) and liquid-nitrogen exposure at −196 °C (LN) were employed as the CT methods. CT significantly refined the grain size of the alloy and composite materials by more than 31.3%, down to 4.4–4.5 μm in diameter, leading to enhanced mechanical performance through grain boundary strengthening. RF20-treated Mg-1Zn-1Ca alloy exhibited the best damping properties (attenuation coefficient and damping capacity improved by 52.1% and 48.7%, respectively). Compressive response was also improved due to the combined effect of refined grains and reinforcement, with LN-treated Mg-1Zn-1Ca-2ZnO exhibiting the best combination of compression properties, i.e., YS—165 MPa, UCS—634 MPa, ε—43.6%, and W_f—175 MJ/m³. Ignition resistance was also improved with the addition of ZnO reinforcement (3.8% increase in ignition temperature). A significant reduction in corrosion rate was achieved with RF20 treatment, leading to corrosion rate reductions of 62% and 40% in PBS (simulated human body fluid) and salt solution, respectively, primarily due to equiaxed grains and stable microstructure. These results demonstrate the efficacy of ZnO reinforcement and CT conducted at different temperatures in selectively enhancing and tailoring the properties of eco-friendly, biocompatible Mg-alloys and composites for biomedical and strength-based applications. Full article

Lead (Pb²⁺) and cadmium (Cd²⁺) are among the most hazardous heavy metal pollutants in wastewater owing to their high toxicity, environmental persistence, and detrimental impacts on human health and aquatic ecosystems. In this study, a novel ternary magnetic composite, SnFe₂O₄/activated carbon/polypyrrole (SnFe₂O₄/AC/PPy), was effectively synthesized and tested as an effective adsorbent in the removal of Pb²⁺ and Cd²⁺ from aqueous water. The composite was prepared by depositing spinel SnFe₂O₄ nanoparticles on activated carbon, followed by in situ polymerization of polypyrrole to enhance surface functionality and adsorption affinity. The successful fabrication of the porous SnFe₂O₄/AC/PPy hybrid composite was confirmed through FTIR, XRD, SEM–EDS, BET, XPS, and VSM characterization. The composite demonstrated a relatively high surface area (352.3 m²/g) and adequate magnetic responsiveness (12.33 emu/g), ensuring facile magnetic separation following wastewater treatment. Batch adsorption experiments showed great removal efficiency of 95.02 and 92.48% for Pb²⁺ and Cd²⁺ ions, respectively, at optimum conditions. The adsorption equilibrium data followed the Langmuir isotherm model with maximum adsorption capacities of 187.07 mg/g for Pb²⁺ and 96.45 mg/g for Cd²⁺ ions, which were attributed to monolayer adsorption on homogenous active sites. The kinetic and isothermal model indicated that the adsorption process was controlled by the combination of physical and chemical interactions. Thermodynamic parameters showed negative Gibbs free energy and enthalpy changes (ΔH° = −49.74 kJ/mol for Pb²⁺ and −38.82 kJ/mol for Cd²⁺ ions), confirming the spontaneous and exothermic nature of adsorption. Furthermore, the increasingly negative ΔG° values at lower temperatures indicated that the adsorption was thermodynamically more favorable under cooler conditions. According to the regeneration studies, the composite maintained a high removal efficiency after five consecutive cycles. In general, SnFe₂O₄/AC/PPy composite has good potential as a stable, reusable, and high-performance adsorbent to treat heavy metal wastewater. Full article

Slaughterhouse wastewater introduces potentially toxic elements into aquatic ecosystems, yet bioaccumulation patterns in commercial fish species and associated human health risks remain underexplored in West Africa. This study quantified zinc (Zn), lead (Pb), iron (Fe), magnesium (Mg), chromium (Cr), and cadmium (Cd) in three ecologically distinct fish species—Oreochromis niloticus (Nile tilapia), Clarias gariepinus (African sharptooth catfish), and Mugil cephalus (Flathead grey mullet)—from two slaughterhouse-impacted rivers (Transamadi and Mgbuosimini) and a control site (Iwofe) in Rivers State, Nigeria. Metal concentrations were measured using atomic absorption spectrophotometry. Two-way ANOVA assessed species and location effects. Principal component analysis (PCA) was performed, with Mg used as a potential geogenic tracer, as its loading pattern was independent of Pb and Cd and consistent with the natural background. A Water Quality Index (WQI) classified Mgboshimini and Iwofe as having poor water quality (WQI > 75), while Transamadi had medium quality. Health risks were evaluated using estimated daily intake (EDI), target hazard quotients (THQ), and hazard indices (HI) following USEPA guidelines. Metal levels varied significantly by species and location (p < 0.001). Flathead grey mullet from Mgbuosimini had the highest Pb (1.50 ± 0.05 mg/kg) and Cd (0.41 ± 0.02 mg/kg), exceeding EU maximum levels for fish muscle (Pb 0.30 mg/kg, Cd 0.05 mg/kg) by 500% and 800%, respectively. PCA explained 77.5% of the variance, with Pb and Cd clustering as anthropogenic sources, while Mg loaded independently. THQ for Pb approached unity in Flathead grey mullet (0.88), and THQ for Cd reached 0.97. HI exceeded 1.0 in all species from Mgbuosimini, peaking at 2.07 in Flathead grey mullet. Uncertainty analysis (using ±SD) gave a HI range of 1.89–2.25 for this species, all above the safety threshold. Carcinogenic risk for Flathead grey mullet (3.97 × 10⁻⁴) approached the upper acceptable limit. Slaughterhouse effluent appears to elevate Pb and Cd burdens in fish, with detritivorous Flathead grey mullet posing the highest health risk. Exceedance of safety thresholds and HI > 1.0 indicate potential non-carcinogenic and carcinogenic risks. We recommend improved wastewater treatment and species-specific consumption advisories. Full article