Search Results (282)

To cope with severe seasonal changes in climate and food availability, colonies of Apis mellifera L. generate two distinct worker phenotypes during winter and summer. The aim of this research was to evaluate the effect of oral exposure to insecticides on the toxic susceptibility of winter and summer honeybee workers (Apis mellifera L.) under laboratory conditions. In this work, under all tested conditions and seasons, emamectin benzoate was the most toxic compound and used as the standard (Toxicity Index = 100) for comparison with other compounds. It had the lowest LC₅₀ (Lethal Concentration required to kill 50% of the tested honeybees) values, which decreased to 0.004 mg/L in winter bees after 48 h following oral exposure. Sulfoxaflor had moderate toxicity, and indoxacarb was the least toxic to honeybees. The results also revealed that the toxic effect was time-dependent, with lethal concentrations at 48 h significantly lower than those at 24 h. In addition, seasonal effects play a role; winter honeybees were, overall, more sensitive to the treatments than summer honeybees. Under the conditions of this study, it can be concluded that emamectin benzoate was the most toxic substance and indoxacarb the least toxic. Toxicity increased with exposure time. Winter honeybees showed greater sensitivity than summer honeybees. A field-relevant Hazard Quotient (HQ) analysis further indicated that indoxacarb, despite its lower acute toxicity, exhibited the narrowest margin relative to field-recommended spray concentrations, highlighting the value of incorporating field-relevant exposure metrics alongside LC₅₀-based rankings in pollinator risk assessment. It is worth clarifying that this narrower margin reflects indoxacarb’s higher field-recommended application rate relative to its LC₅₀, rather than a greater intrinsic toxicity than emamectin benzoate, and the two aspects of risk (intrinsic toxicity vs. use-rate-based field risk) should be interpreted separately. Full article

Groundwater nitrate contamination is delayed, spatially heterogeneous and difficult to screen with sparse monitoring, especially when exceedance probability and exposure concern must be considered together. We analysed 157 shallow groundwater samples from Handan City, China, collected in 2023, and 14 environmental predictors to map NO₃⁻ exceedance above 50 mg/L. Random forest, support vector machine (SVM) and XGBoost classifiers were evaluated by repeated stratified testing and spatial block cross-validation, with SHAP used to interpret model responses. Ordinary kriging and the USEPA non-carcinogenic risk framework estimated adult and child hazard quotients (HQs), and exceedance probability was cross-classified with child HQ in a probability–HQ matrix. Thirty-one samples (19.7%) exceeded the threshold. Although SVM achieved the highest ROC-AUC, XGBoost was retained for early-warning mapping because it better controlled missed exceedances. High-probability zones were concentrated in central-western and urban-fringe Handan. SHAP responses indicated that hydroclimatic, hydrogeological, land-use, terrain and soil factors jointly shaped model discrimination, without implying source attribution. Children had higher HQs than adults. At P = 0.5, general protection, exceedance-warning, concentration-verification and priority-intervention zones occupied 81.26%, 18.40%, 0.01% and 0.33% of the area, respectively. The framework supports targeted monitoring and drinking-water verification rather than fixed contamination boundaries. Full article

Workers are exposed to pollutants generated by hair salon activities, which may pose potential health risks. This study measured volatile organic compound (VOC) concentrations in five hair salons using a high-sensitivity photoionization detector (PID) during daily work shifts. The highest VOC concentration was observed in Hair Salon III (0.87 ± 0.57 ppm), likely due to its high customer volume and the use of organic solvents during cleaning procedures. VOC concentrations were higher on weekends than on weekdays. Workers’ exposure to VOCs was elevated during the morning and evening periods, possibly due to inadequate ventilation and cleaning activities conducted at the beginning and end of business hours. The variance structure indicated that indoor VOC concentrations were primarily influenced by emission sources within the salons. Therefore, representative monitoring should prioritize a range of salon types to adequately characterize the variability in VOC exposure. Hair Salon III exhibited the highest exposure concentration (EC), hazard quotient (HQ), and hazard index (HI), with values of 0.055, 0.018, and 0.047, respectively. The health risk assessment indicated that workers in all five hair salons were not at significant risk of non-carcinogenic health effects, as all HQ values were below the acceptable threshold of 1.0. Full article

Mycotoxins are toxic fungal secondary metabolites that can contaminate the feed of dairy animals and can be transferred into milk and dairy products. This study aims to assess the occurrence of major mycotoxins in 190 samples of milk-based infant foods commercially available in São Paulo, Brazil, and characterize the associated risks. Aflatoxins (AFs) M₁ (AFM₁), B₁ (AFB₁), B₂ (AFB₂), G₁ (AFG₁) and G₂ (AFG₂), fumonisins (FBs) B₁ (FB₁) and B₂ (FB₂), ochratoxin A (OTA), zearalenone (ZEN), deoxynivalenol (DON), and T-2 toxin were analyzed using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC–MS/MS). Ninety-eight samples (51.6%) were contaminated with at least one mycotoxin, while the co-occurrence of two to four mycotoxins was observed in 32 samples (16.8%). ZEN was the most prevalent mycotoxin (60 samples; 32%), followed by FBs (FB₁ and FB₂) (42 samples; 22%), OTA (11 samples; 5.8%), DON (8 samples; 4.2%), and T-2 toxin (2 samples; 1.1%). AFs were quantified in only two samples (1.1%), one milk-based product containing 0.630 μg/kg of AFM₁ and one flavored milk powder with AFB₁ at 5.850 μg/kg. The analyzed flavored milk powder samples showed the highest maximum concentrations of DON, FBs, and OTA (165.5, 93.79, and 86.77 μg/kg, respectively), while unflavored milk powder contained the highest concentration of ZEN (17.40 μg/kg). Infant formula provided the highest estimated daily intake (EDI) value of DON (1.226 μg/kg bw/day) for infants aged ≤one year. Hazard quotient (HQ) values > 1 revealed a potential health concern for DON in only one sample of infant formula intended for infants up to six months of age. Margin of exposure (MoE) values for AFs and OTA were <10,000, emphasizing the need for continuous monitoring due to their potential toxic effects. These findings emphasize the need for stringent preventive measures and regulatory compliance to prevent mycotoxin contamination in milk-based infant foods in Brazil. Full article

This study investigates the geochemical distribution, integrated contamination status, and human health risks of potentially toxic elements (PTEs) in 31 agricultural topsoil samples collected from Najran, southwestern Saudi Arabia. As, Co, Cr, Cu, Ni, Pb, and Zn were measured and interpreted using spatial distribution maps, the pollution load index (PLI), Nemerow integrated pollution index (PN), chronic daily intake (CDI), hazard quotient (HQ), hazard index (HI), cancer risk (CR), and lifetime cancer risk (LCR) for both children and adults. The measured concentrations (mg/kg) varied from 2–8 for As, 2–14 for Co, 11–50 for Cr, 5–50 for Cu, 9–50 for Ni, 2–28 for Pb, and 10–249 for Zn. Based on mean values (mg/kg), the PTEs followed the descending sequence Zn (52.94) > Cr (26.68) > Ni (24.55) > Cu (16.68) > Co (6.81) > Pb (6.65) > As (4.45). PLI values ranged between 0.117 and 0.642, with an average of 0.355, suggesting generally low combined pollution by multiple elements across all sampling locations. However, PN values extended from 0.137 to 1.930, classifying 27 locations as safe, 2 as warning-level sites, and 2 as slightly polluted, mainly due to elevated Zn and Pb levels. The assessment of non-carcinogenic risk indicated no exceedance of the level of concern, as total HI values ranged from 0.156 to 0.678 for children and from 0.017 to 0.075 for adults. On average, children had HI values about 9.1 times higher than adults, with soil ingestion representing the principal exposure route. The element-specific mean HI results indicated that As and Cr were the dominant contributors to non-carcinogenic risk. Carcinogenic risk was assessed for As, Cr, and Pb. Total LCR values ranged from 1.005 × 10⁻⁵ to 4.387 × 10⁻⁵ for children and from 4.460 × 10⁻⁶ to 1.950 × 10⁻⁵ for adults, remaining within the widely accepted or tolerable risk range. Among the carcinogenic elements, Cr accounted for the highest proportion of total LCR, contributing 68.67%–69.66%, followed by As with 30.09%–31.07%, while Pb made a very small contribution of only 0.25%–0.26%. In spatial terms, the greatest HI and LCR values were concentrated mainly in the western to central-western agricultural areas, where several elements relevant to health risk were present together. Full article

This study evaluated the reliability and application of relative potency factors (RPFs) for assessing hepatic mixture risks of per- and polyfluoroalkyl substances (PFASs) in Korean finished drinking water. A total of 1254 finished water samples collected from 70 drinking water treatment plants between 2018 and 2024 were analyzed for eight PFAS compounds. Hepatic RPFs proposed by the National Institute for Public Health and the Environment (RIVM) were assessed using a structured scoring system and applied to estimate PFOA-equivalent mixture risks. Hazard quotients (HQs) based on hepatic toxicity reference doses were also calculated for comparison. PFAS concentrations generally declined over time, including PFOA from 0.0032 to 0.0014 μg/L, PFOS from 0.0008 to 0.0003 μg/L, and PFHxS from 0.0072 to 0.0004 μg/L between 2018 and 2024. The RPF-based method produced higher cumulative risk estimates than the individual toxicity-based approach, suggesting that single-compound HQs may underestimate risks from co-occurring PFASs. Although total risks were generally below the non-carcinogenic threshold of 1.0, the 95th percentile PFOA-equivalent risk for PFNA exceeded the individual threshold of 0.1. These findings support endpoint-specific RPF-based assessment for PFAS mixtures in drinking water. Full article

Honey bee (Apis mellifera) colonies are exposed to multiple environmental stressors, including pesticide contamination and landscape changes, which may affect colony dynamics and colony condition. This study evaluated pesticide residue occurrence, landscape quality through the Agroecosystem Apibotanical Interest Index (AABI), and colony demographic structure across five contrasting agricultural systems in Uruguay using a comparative case-study approach. Pesticide residues were analyzed in multiple hive matrices, and residue occurrence was assessed using cumulative hazard quotients (HQ). Colony dynamics were characterized using population variables and the adult-to-brood ratio, associations were evaluated with generalized linear models. Pesticide diversity and cumulative HQ values were higher in intensively managed landscapes, particularly in horticultural and soybean systems, whereas forestry systems showed consistently low values. Residues were detected in all matrices, with greater diversity in wax and bee bread. Colony dynamics varied among landscapes, with more stable patterns in native forest systems. Demographic states based on the adult-to-brood ratio were consistently associated with colony demographic structure. We identified a significant negative statistical association between AABI and the demographic state defined by the adult-to-brood ratio, whereas cumulative HQ showed only marginal effects. Given the observational nature of the study and the multifactorial determinants of colony dynamics, this relationship should be interpreted as an observed pattern within the studied dataset rather than evidence of a direct biological effect of landscape quality on colony adult-to-brood ratio. Overall, the results suggest associations between environmental conditions and colony adult-to-brood ratio. Full article

The Wadi Al-Ahsaba watershed is an arid to semi-arid catchment situated in southwestern Saudi Arabia, characterized by intermittent surface flow, high evaporation and low rainfall, and a dam reservoir built for flood control. The work aims to assess hydrological and anthropogenic controls on surface and groundwater quality, pollution status, and human health risks using an integrated approach of hydrogeochemical analysis, multivariable statistics, and water quality and contamination indices. A total of 21 water samples (15 surface water, 6 groundwater) were analyzed for general chemistry, major ions, and trace elements. Hydrogeochemical analysis and principal component analysis (PCA) were implemented to differentiate the geogenic from anthropogenic control on water quality. The pollution status and associated risk were evaluated using water quality index (WQI), contamination degree (Cd), Hazard Quotient (HQ), and Hazard Index (HI). Results suggest limited surface–groundwater interaction, with surface water dominated by Ca–Mg–HCO₃ facies, indicating recent recharge and limited water–rock interaction, whereas groundwater exhibits mixed Ca–Mg–Cl and Ca–Na–Cl–SO₄ types, revealing longer residence time and water–rock interaction. Nitrate (9.5–109 mg/L) and TDS (522–1003 mg/L) exceeded drinking water standards in 90% and 95% of tested samples, respectively, and WQI ranged from 43 to 134, reflecting excellent to poor water. High non-carcinogenic risk from nitrate was observed, especially for infants. The study concluded that the geogenic processes (water–rock interaction, evaporation, and mineral dissolution) control the general chemistry of tested water, while anthropogenic input from wastewater and agriculture input are likely contributors to nitrate contamination. The study contributes to the understanding of arid wadi-dam systems by revealing how limited recharge, hydrological connectivity, and episodic flow control contaminant transport and persistence, underscoring the critical role of integrated hydrological analysis and land use management in safeguarding freshwater resources in arid environments. Full article

Background: Access to safe drinking water remains a critical public health concern in rural Ghana, particularly in climatically vulnerable and underserved settings. This study assessed the microbiological and chemical quality of drinking water and evaluated nitrate-related health risks in the North Gonja and North-East Gonja Districts of the Savannah Region. Methods: A cross-sectional study was conducted between January and March 2025. A total of 460 water samples were collected from groundwater sources and household storage containers. Microbial analyses targeted total coliforms and Escherichia coli. Physicochemical and chemical parameters included nitrate-nitrogen, pH, residual chlorine, major ions, and trace metals. Data was analyzed using descriptive statistics, chi-square tests, spatial interpolation, and non-carcinogenic health risk assessment based on the hazard quotient (HQ) approach. Results: Widespread microbial contamination was observed, with 91.5% of household water samples positive for total coliforms and 46.6% for E. coli. Contamination of source water was significantly higher in North Gonja than in North-East Gonja. Overall, 49.1% (n = 55) of groundwater sources exceeded the World Health Organization guideline value for nitrate-nitrogen, with exceedances predominantly occurring in North Gonja. Additionally, 67.0% (n = 75) of samples were outside the acceptable pH range (6.5–8.5), including 74 samples below 6.5 and one above 8.5. Residual chlorine was not detected in any of the samples. Health risk assessment indicated potential non-carcinogenic risks associated with nitrate exposure, particularly among infants and children. Conclusions: The study demonstrates significant microbial contamination and nitrate-related health risks in the study area, particularly in North Gonja. Interventions such as improved source protection, routine water quality monitoring, chlorination, household water treatment, and implementation of Water Safety Plans are recommended to enhance drinking water safety and reduce associated public health risks. Full article

Excessive fluoride intake from drinking water remains a public health concern in geogenic high-fluoride regions, yet direct evidence linking environmental fluoride levels to internal exposure in remote high-altitude areas is limited. This study integrated environmental monitoring with human biomonitoring to assess fluoride exposure and health risks in the Taruo Lake region of the Tibetan Plateau. Surface water (n = 45 for Taruo Lake; n = 8 for its tributaries) and groundwater samples (n = 4) were collected and analyzed for fluoride concentrations, and blood ionic fluoride (BIF) levels were measured in 122 local residents (47 adults, 75 children). The results showed that fluoride concentrations in most surface water tributaries of Taruo Lake and groundwater sources were below China’s drinking water standard, whereas those in Taruo Lake exceeded this limit (routine monitoring mean 2.54 mg/L; multi-site mean 2.79 mg/L). BIF levels were significantly higher in adults (0.126 ± 0.041 mg/L) than in children (0.075 ± 0.032 mg/L) and showed a positive correlation with age (r = 0.533, p < 0.001). Notably, 23.4% of adults and 1.3% of children exceeded 0.15 mg/L, an empirical threshold typical for healthy populations in non-endemic areas. Based on the hazard quotient (HQ) model recommended by the US EPA, most drinking water sources posed acceptable non-carcinogenic risks (HQ < 1). In contrast, Taruo Lake water presented an elevated risk (HQ > 1) in 2024 primarily due to the regional geological background, and although not used for daily drinking, this finding offers an indicative reference for local water management and risk prevention. This preliminary monitoring and biomonitoring assessment provides baseline data for future studies and underscores the necessity of continuous surveillance and evaluation of total dietary fluoride intake to protect the health of this vulnerable high-altitude population. Full article

Background: Foods containing essential elements are important to human health. There is concern regarding micronutrient deficiency in the African population, and there is a need to identify foods that can address this public health issue. This study focuses on the determination of essential elements (EEs) in four African food categories: plant-based agricultural products (PBAPs), spices (SPs), fishery products (FPs), and non-food items/additives (NFAs) on sale in the UK market. Methods: Inductively coupled plasma mass spectrometry (ICP-MS) was used for measuring trace essential elements (TEEs—Mn, Fe, Cu, Zn, Se) and major essential elements (MEEs—Na, Mg, K, Ca) in the four categories of the African foods. Results: Mean concentrations (µg/g) for the TEEs were Cu 5.3, 7.3, 23.5, and 7.4; Fe 79.0, 263, 107.7, and 1311.3; Mn 23.4, 28.5, 15.9, and 47.4; Se 0.3, 0.1, 1.6, and 0.6; Zn 8.9, 11.4, 26.8, and 6.2 (PBAPs, SPs, FPs, NFAs, respectively). Mean concentrations of the MEEs (mg/g) were Na 0.6, 11.2, 13.3, and 32.9; Mg 1.6, 1.9, 2.4, and 5.5; K 9.2, 14.6, 9.6, and 8.3; Ca 4.1, 3.3, 27.5, and 127.8. All elements were below the upper intake limits (ULs) established by WHO/EFSA. When expressed as a percentage of the recommended daily allowance (%RDA) for adult males/females, 100% or more of the requirement was achieved for Cu (107.1%) and Ca (112.8%) in FPs. Excess index (EI), hazard quotient (HQ) and hazard index (HI) values for all TEEs were <1, indicating there is no non-cancerogenic health concern across all food categories. Conclusions: These findings demonstrate that African foods available in the UK are substantial sources of essential micronutrients. The fishery products contain high levels of nutrients that are often deficient in African diets. However, before recommending these foods for nutritional interventions, a comprehensive risk–benefit assessment, considering potential toxic metal contamination and microbial hazards must be undertaken. Future studies should expand the sample pool to include a broader range of African foodstuffs and national representation, coupled with integrated risk-benefit analyses. Full article

In situ leaching is increasingly used for rare earth element (REE) extraction because of its operational efficiency; however, acidic and chemically reactive leaching solutions may generate substantial environmental risks in riverine systems. This study evaluated water contamination and screening-level ecological risk following a cyanide leakage incident associated with a pilot REE mining operation in Houaphanh Province, northern Lao PDR. Surface water samples were collected from 12 downstream monitoring locations between February and April 2024. Physicochemical parameters, free cyanide (CN⁻), and dissolved metals, including arsenic (As), lead (Pb), copper (Cu), manganese (Mn), aluminum (Al), zinc (Zn), and iron (Fe), were analyzed using portable multiparameter probes, colorimetric cyanide determination, and ICP-OES. Contamination severity was interpreted using Pollution Index (PI) and Hazard Quotient (HQ) indicators based on Lao national standards and international guideline values. Results showed severe downstream contamination, with free cyanide and several dissolved metals substantially exceeding permissible thresholds. Observed elevated concentrations of As (30.29 mg/L), Pb (10.38 mg/L), Cu (14.97 mg/L), and CN⁻ (0.51 mg/L) indicated elevated ecological risk conditions, while acidic pH conditions may have enhanced metal mobilization and downstream transport. Descriptive spatial observations indicated apparent downstream contaminant dispersion within affected downstream river communities reliant on river water for domestic use, irrigation, and fisheries. Field observations additionally documented fish mortality, reduced irrigation usability, and deterioration of river water quality conditions in affected downstream communities. The findings suggest the potential vulnerability of Mekong-connected river systems to chemically intensive REE extraction activities and highlight the importance of preventive environmental governance, continuous monitoring, and operational risk management in emerging rare earth mining regions. Full article

Crops can accumulate heavy metals (HMs) from soil, leading to human exposure through dietary intake. However, the influence of interregional food trade on dietary HMs exposure remains underexplored. In this study, using data derived from existing literature, the occurrence and distribution patterns of six HMs, namely arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), and zinc (Zn), in soil and crops across China were investigated. Furthermore, the influence of food trade on human exposure to soil-derived HMs was assessed. The average total concentration of the six HMs in soil was 234.01 ± 29.54 mg/kg, while concentrations in rice and wheat were 16.06 ± 2.91 mg/kg and 22.48 ± 4.22 mg/kg, respectively. The hazard quotients (HQs) for As in rice exceeded 1 in the Central, Central Coast, South Coast, Southwest, and Northeast regions, indicating potential health risks. Interregional food trade significantly redistributed these risks. Through rice consumption, the Central and Northeast regions accounted for up to 36.78% and 45.08% of the daily intakes of As and Cd in other regions, respectively. Similarly, through wheat consumption, the Central and Southwest regions accounted for up to 51.33% and 25.97% of the daily intakes of As and Cd, respectively. This redistribution is largely attributed to the concentration of major crop production in the Central, Northeast, and Southwest regions. Overall, this study highlights the critical role of interregional food trade in modulating population health risks associated with contaminants, providing a more accurate and comprehensive assessment of dietary HMs exposure. Full article

(1) Background: Highway toll plazas are environments impacted by atmospheric pollutants that may affect workers’ health. However, there are still few studies on these environments. This study evaluated particulate matter (PM) concentrations by size fraction (PM_10–9.0 to PM_0.43) and associated arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and vanadium (V) at two toll plazas in Brazil. (2) Methods: PM and trace element concentrations were compared between dry and rainy seasons, and a health risk assessment was conducted for toll collectors based on inhalation exposure. (3) Results: PM_10–2.5 concentrations ranged from 31.8 to 360 µg m⁻³ in the dry season and from non-detectable to 287 µg m⁻³ in the rainy season. PM_2.5 levels varied between 14.9 and 150 µg m⁻³ (dry) and 3.46–174 µg m⁻³ (rainy). Although trace element concentrations were within Occupational Safety and Health Administration (OSHA) limits, the hazard quotient (HQ) for manganese and arsenic exceeded unity (HQ > 1), indicating potential health risks. (4) Conclusions: These findings suggest that toll plaza workers may experience increased inhalation-related risk under the exposure assumptions used. Improved ventilation and protective measures, including the use of protective screens, are recommended to reduce occupational exposure. Full article

River water quality assessments are commonly conducted under conventional anthropogenic pressures; however, the long-term environmental impacts of armed conflicts remain insufficiently understood. This study addresses this gap by evaluating the persistence of war-related heavy metal contamination and its associated human health risks in the Tigris River, Mosul, a post-conflict urban system. The results revealed that Cd, Pb, Cr, and Ni concentrations exceeded WHO guideline values across most sites, while Zn remained within acceptable limits. The highest contamination levels were observed in the central urban zone (Zone 3), which was directly affected by military activities. Hazard quotient (HQ) values for Cd and Pb exceeded the safe threshold (HQ > 1) at all sites, identifying them as dominant contributors to toxicity. The cumulative hazard index (HI) reached extremely high levels (>300 in 2022 and >200 in 2023), indicating severe non-carcinogenic health risks despite a slight temporal improvement. Spatially, contamination increased from upstream to downstream, with midstream and downstream areas acting as critical hotspots. Temporally, although pollutant levels declined in 2023, they remained significantly above safe limits, demonstrating limited natural recovery. Overall, the findings provide clear evidence of the long-term persistence of conflict-related contamination and its sustained risks to human health. This study highlights the need for targeted remediation strategies and offers a transferable framework for assessing water quality in conflict-affected river systems.: Full article