Health risk assessments of arsenic and toxic heavy metal exposure in drinking water in northeast Iran

Risk assessment of potentially toxic elements and mapping of groundwater pollution indices using soft computer models in an agricultural area, Northeast Algeria

Groundwater (GW) quality and contamination by potentially toxic elements (PTEs) are major concerns for environmental sustainability, particularly in arid regions. The aim of this study was to assess the human health risks associated with GW contamination by PTEs in the Terminal Complex (TC) aquifer of the Tolga oasis, located in northeastern Algeria. Seventeen GW samples were analyzed using standard methods to determine contamination levels and associated health risks. Results showed that GW was generally contaminated with lead (Pb), which exceeded the WHO permissible limit of 0.01 mg/L in 76.47 % of the samples. Although some samples were rich in Cr and Mn, their levels were below WHO guidelines. Pollution indices, including Contamination Factor (CF), Heavy Metal Pollution Index (HMI), and Nemerow Pollution Index (NPI), indicated that over 50 % of the samples had medium to high pollution levels. These indices were further estimated using artificial neural network (ANN) and Multiple Linear Regression (MLR) machine learning models, whose performances were validated by Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and Nash-Sutcliffe Efficiency Coefficient (NSE). The Taylor diagram analysis showed that MLR models were more accurate than ANN models in estimating GW pollution indices. Mapping these indices using support vector machine (SVM) algorithms and applying chemometric statistical techniques, including principal component analysis (PCA), revealed that alteration of geological formations and anthropogenic activities significantly affected GW contamination by PTEs in the study area. The assessment of health risks associated with heavy metals revealed a significant non-carcinogenic risk, particularly for children, with 41.17 % of samples exceeding the hazard index threshold of 1 due to Pb exposure, while carcinogenic risks were low. This study establishes predictive models based on heavy metal pollution indices, providing crucial information on the spatial distribution of GW contamination. The results support the development of targeted mitigation strategies and intervention plans to safeguard GW resources and public health in the region.

Heavy Metals and Carbapenem-Resistant Klebsiella pneumoniae in a River System of Odisha, India: Correlation and Integrated Risk Assessment

The unregulated release of heavy metals and antibiotics into rivers has the potential to significantly impact human health. Infections caused by healthcare-associated pathogen, carbapenem-resistant Klebsiella pneumoniae (CRKP), present a critical challenge to clinical practitioners due to its resistance to last-line antibiotics. In this study, we investigated co-contamination of heavy metals (As, Cd, Cr, Mn, and Pb) and CRKP isolates in water samples from multiple sites along the river receiving wastewater discharge from urban areas of twin-city, Odisha. We used a composite risk scoring framework integrating chemical risks (based on hazard indices (HI) of heavy metals) and biological risks (based on the proportion of CRKP isolates exhibiting multidrug-resistant phenotypes and their multiple antibiotic resistance (MAR) index. Furthermore, Spearman's correlations and redundancy analysis (RDA) were employed to assess the association between heavy metals and antibiotic resistance genes (ARGs). From the total CRKP isolates identified (n = 91), 90.1% and 9.89% exhibited multidrug resistant (MDR) and extensively drug-resistant (XDR) phenotypes, respectively. Sites D2 and C2 were flagged as high-risk sites based on their composite risk scores of 0.735 and 0.699, respectively. Positive correlations were observed between heavy metals and ARGs (blaOXA-48, blaTEM, and blaSHV). The findings raise concern regarding the potential threat of CRKP and heavy metal pollution in river water while also emphasizing the need for integrated assessment to control their release into the environment.

Evaluation of the exposure to perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) through drinking water and human risk assessment

In the present study, two most commonly used Perfluoroalkyl substances (PFASs), namely perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS), were determined in 45 tap water samples from the city of Isfahan (Iran) by dispersive liquid-liquid extraction (DLLME) and liquid chromatography-mass spectrophotometry (LC-MS) analysis. Risk assessment was also performed to determine the risk to human health. The mean concentration of PFOA was 38.1 ± 26.4ng/L (min = 5.1 and max = 1056ng/L). The mean concentration of PFOS was 33.7 ± 25.09ng/L (min = 4.3 and max = 99.2ng/L). The combined concentrations of PFOA and PFOS were above the US-EPA advisory levels (70ng/L) in 48.8% of the samples. The distance between the sampling locations and the water treatment plant showed no significant correlation (p > 0.05). The results of the risk assessment showed that all calculated hazard quotients (HQ) and hazard indices (HI) are below 1, indicating that the risk to human health from exposure to PFOA and PFOS via drinking water in the city of Isfahan was not high for adults and children. These results indicate a significant contamination of Isfahan tap water by PFOA and PFOS of unknown origin. Further studies are needed on the Zayande-Roud River water as a supplier of Isfahan tap water and the efficiency of the water treatment plant and the role of the water distribution network in PFASs contamination of tap water.

A framework for evaluating less-than-lifetime exposures: advancing toxicological risk assessment for drinking water quality

The increasing production and use of chemicals leads to a higher number of contaminants in (drinking) water sources, which poses significant challenges to those responsible for water quality. An important task for water companies and regulators is to ensure that (drinking) water quality does not compromise public health and confidence in water safety. A key component of this effort is toxicological risk assessment, which evaluates the safety of chemicals that may be present in water systems. Although there has been considerable progress in risk assessment methods, there is currently a lack of a clear approach to the risk assessment of chemicals in (drinking) water for which concentrations vary over time. In the current study, methods for the assessment of less than lifetime exposure (LTL) are presented that are particularly applicable for substances with time-varying concentrations in (drinking) water. The presented framework is a decision tree that helps experts to decide whether a measured or predicted LTL exposure to a chemical can lead to adverse health effects. To develop these methods, we used existing knowledge and incorporated new developments in toxicological risk assessment. A case study illustrates the application of the proposed approaches in a realistic scenario. The method can be used by risk assessors as a tool to improve the understanding of human exposure to contaminants in (drinking) water and to inform risk-based monitoring. In addition, it enables customised investigations and responses that lead to a more nuanced view of water quality and its impact on public health.

Development of sulfonated polystyrene resin-supported tungsten oxide for Pb2+ ion sequestration

A sulfonated polystyrene resin-supported tungsten oxide (SO3-PSWO) was synthesized and evaluated for its efficiency in removing lead (Pb2+) from aqueous solutions. Morphology, phase purity, structural properties, thermal stability, and elemental composition of SO3-PSWO, are evaluated using SEM, XRD, FTIR, TGA, and CHNS analyzers. The ICP-OES technique was utilized for quantitative measurements of the Pb2+ ions. The influence of key parameters such as pH, adsorbent dose, contact time, metal ion concentration, temperature, and interference of competing ions on Pb2+ removal is systematically investigated. Under optimum conditions (pH 3.5-5.5), SO3-PSWO achieved a maximum Pb2+ removal efficiency of 99.7% within one hour and demonstrated an exceptional adsorption capacity of 386 mg g-1, as described by the Langmuir isotherm model. Kinetic analysis revealed a pseudo-second-order mechanism, highlighting chemisorption as the predominant process. Thermodynamic studies indicated an exothermic and spontaneous adsorption behavior. With its easy synthesis, cost-effectiveness, rapid kinetics, high adsorption capacity, and superior efficiency, SO3-PSWO emerges as a promising material for the remediation of Pb2+ contamination in water treatment applications.

Lead, cadmium and arsenic species in spices from markets in Hanoi, Vietnam

Spices are essential to cooking and include health benefits. Nevertheless, information regarding the prevalence of heavy metals (Pb, Cd and As) and As species in spices is limited. Consequently, 254 samples from 6 varieties of commercially available branded and non-branded spices were examined for heavy metal and As species content. The analytical results were ranked as Pb > As > Cd (p < 0.05), with red chilli and garlic exhibiting the highest and lowest levels, respectively. A significant difference in heavy metal levels was observed between branded and non-branded samples (p < 0.05), suggesting that processing and trade influence the initial metal levels. Arsenite was the predominant form in spices, but dimethylarsinic acid and monomethylarsonic acid primarily accumulated in spices from the Zingiberaceae (p < 0.05). No carcinogenic risk to human health from heavy metals in spices was identified (HIs < 1).

Study of the Trace Element Composition of Drinking Water in Almaty City and Human Health Risk Assessment

This research investigates the elemental composition of 78 drinking water samples collected during the summer, autumn, and winter of 2023 in different districts of Almaty city. Seasonal average concentrations and standard deviations were calculated for a range of chemical elements, including arsenic (As), beryllium (Be), cobalt (Co), cadmium (Cd), copper (Cu), lithium (Li), molybdenum (Mo), nickel (Ni), lead (Pb), selenium (Se), uranium (U), mercury (Hg), aluminum (Al), barium (Ba), chromium (Cr), iron (Fe), manganese (Mn), strontium (Sr), vanadium (V), zinc (Zn), calcium (Ca), potassium (K), magnesium (Mg), and sodium (Na), across three distinct datasets. The sites of sampling represent various categories of drinking water sources. The quality of drinking water was assessed by comparing the obtained data with current national, international, and World Health Organization (WHO) standards. Drinking water contaminant indices for the heavy metal groups were calculated and the water quality compliance with the hygienic criteria adopted in the Republic of Kazakhstan was determined. With the exception of two sampling points, the levels of non-carcinogenic risk remained below the acceptable threshold. The predominant pathway for exposure for both adults and children was identified as the oral ingestion of hazardous elements. Carcinogenic risks linked to Ni, Pb, and Cr presence in the drinking water of Almaty were identified, with risk values at the majority of sampling sites categorically classified within the "high risk" designation. No substantial differences in carcinogenic risk levels were detected between adults and children. These results underscore the necessity for enhanced water purification methodologies and ongoing surveillance to protect public health.

Health Risk Assessment of Exposure to Heavy Metals in Wheat Flour from Iran Markets: Application of Monte Carlo Simulation Approach

The significance of flour in the Iranian diet underscores the need to ensure its safety from chemical pollutants. This study aimed to evaluate the potential health risks posed by certain heavy metals, such as Fe, Zn, Cu, Al, Co, Hg, Cr, Ni, Pb, and Cd, in wheat flour available in the Iranian market. A total of 248 flour samples were collected from 11 provinces in Iran during the winter of 2021. The health risks associated with heavy metals in children and adults were evaluated using USEPA health risk assessment guidance for superfund part A and Monte Carlo Simulation. The average concentration of Fe, Zn, Cu, Al, Co, Hg, Cr, Ni, Pb, and Cd, was equal to 30.62 ± 59.24, 4.94 ± 13.64, 1.24 ± 3.08, 2.85 ± 4.98, 0.03 ± 0.01, 0.12 ± 0.03, 1.42 ± 1, 0.23 ± 0.05, 1.71 ± 0.65, and 0.02 ± 0.004 mg/kg dry weight, respectively. Analysis of Fe, Cr, Al, Hg and Cr in all flour samples showed that the average concentration of these metals were greater than the standards levels set by the WHO/FAO. The results of the non-carcinogenic risks (HI) showed that the hazard index values (children: 0.969 ± 1.04, adult: 0.837 ± 0.905) of heavy metals through the consumption of flour to both study population were acceptable. The results of the carcinogenic risks (CR) based on Cd, and Pb concentration showed that the CR values from ingestion of flour to the children and adults population were 1.45 × 10-5 ± 5.08 × 10-5 and 1.26 × 10-5 ± 4.40 × 10-5, respectively. The results of Monte Carlo simulation showed that conventional deterministic health risk evaluation could overestimate risk outcomes. Likewise, Cr has 68.8% and 69.1% probability of non-carcinogenic risk to children and adult, respectively, and 80% and 79.8% probability of CR for adults and children respectively for Pb, suggesting that Cr and Pb is a priority control heavy metals. Therefore, it is recommended to continuously monitor the levels of heavy metals in wheat and its derived food products to ensure food safety.

Correlation Between Urinary Heavy Metals and Early Childhood Caries in a Typical Industrial and Mining Area

In order to assess the association between urinary heavy metals and early childhood caries (ECC), a survey of deciduous tooth decay and urinary heavy metal concentrations of 408 children was conducted in a typical industrial and mining area. The results indicated that urinary heavy metal concentrations were ranked as Zn > Fe > Cu > Pb > Ni > Cd > As > Cr > Mn > Hg. The zero-inflated negative binomial model identified Hg as a significant risk factor for ECC (P25 ~ P75, OR = 3.499; > P75, OR = 3.184). Bayesian kernel machine regression further revealed that Pb, Cd, and Hg were positively correlated with ECC. Additional analysis using the Wilcoxon rank sum test and restricted cubic splines confirmed a positive correlation between the urinary concentrations of Pb, Cd, As, and Hg and the number of ECC (p < 0.05). Moreover, Bayesian kernel function regression and weighted quantile sum regression indicated that combined exposure to heavy metals was positively associated with ECC, with Hg (0.420) being the most dominant contributor, followed by As, Pb, and Cd. In conclusion, this study demonstrated a significant positive correlation between urinary heavy metals and both the occurrence and severity of ECC, with Hg identified as the most influential factor. It was recommended to minimize children's exposure to heavy metals to protect their dental health.

Exposure to a mixture of arsenic species and growth indicators in 6-12-year-old children from the cycles 2007-2020 NHANES

BACKGROUND

Exposure to arsenic (As) and its metabolites can affect normal growth in children, but the combine effects at simultaneous low-level exposures, remain uncertain. Hence, this study aims to analyze how the combined effects of As and its metabolites can impact growth indicators in 1,792 US children aged 6-12 years, from the NHANES.

METHODS

Levels of arsenic species in urine were measured using HPLC coupled with ICP-DRC-MS during the 2007-2020 NHANES cycles. The sum of iAs ([AsIII + AsV]), MMA, and DMA was used as a biomarker of internal iAs exposure (∑As), and methylation efficiency was assessed using the primary and secondary methylation indices (PMI, SMI). Linear regression and BKMR models were applied to identify adverse effects, nonlinear associations, interactions, and combined effects.

RESULTS

Median concentrations of MMA, DMA, iAs, and ∑As were 0.56 μg/L, 4.07 μg/L, 1.33 μg/L, and 6.40 μg/L, respectively. In the linear regression analyses, higher urinary concentrations of MMA were associated with reductions in several growth indicators. Specifically, each interquartile range (IQR) increase in MMA concentration was linked to decreases of -0.18 (95 % CI: -0.29, -0.06) in Body Mass Index (BMI) Z-score, -0.18 (95 % CI: -0.29, -0.06) in Weight Z-score, and -0.01 (95 % CI: -0.02, -0.01) in Waist circumference/Height ratio. Additionally, higher DMA concentrations were negatively associated with Height Z-score, with a reduction of -0.08 (95 % CI: -0.15, -0.01). In the BKMR analysis, DMA consistently emerged as the dominant contributor across multiple outcomes, showing the highest Posterior Inclusion Probabilities (PIPs) for indicators such as BMI Z-score and Waist circumference/Height ratio. While MMA exhibited notable PIPs in certain models, its influence was generally weaker than that of DMA.

CONCLUSION

Childhood exposure to a mixture of arsenic species, even at low levels, appears to influence growth indicators and adversely affect physical development in children enrolled in NHANES.

Biomonitoring and Health Risk Assessment of Arsenic Contamination in Drinking Water among Rural Residents in Western Tehran

Arsenic is a widespread environmental contaminant that poses a significant threat to global health due to its toxicity and carcinogenicity. Given the high levels of arsenic found in the drinking water of western areas of Tehran, the objective of this study was to analyze levels of arsenic in multiple biological samples (blood, hair, and nails) collected from residents living in these areas. This cross-sectional study was conducted over three weeks in November 2022 in five villages. A total of 67 residents from these villages were included in the exposure group. Analysis of arsenic was carried out by using the Perkin Elmer Optima 8000 ICP-OES instrument coupled with the FIAS 100 flow injection module after sample digestion. The average concentration of arsenic in people's blood was 4.19 μg/l, which exceeds the standard limit of ATSDR (1 μg/l) by about 4 times. Additionally, 47.8% of blood samples exceeded the standard, while for nail and hair samples, the percentages were 22.4% and 13.4%, respectively. Water samples showed the highest percentage above the standard, with 67.2%. There is no significant relationship between arsenic levels in drinking water, hair and blood. However, a significant positive correlation was observed between the concentration of arsenic in drinking water and nail samples. The mean of hazard quotient (HQ) and carcinogenic risk (CR) indices of arsenic in drinking water suggest that the daily intake levels of the examined arsenic in the study area exceeded the acceptable thresholds ((HQ < 1) and (CR < 1 × 10-4)). Although this study demonstrated elevated arsenic exposure among the population in western Tehran, our findings showed no significant correlation between arsenic concentrations in drinking water and biological samples. Therefore, further research is required to identify other potential exposure pathways and develop targeted intervention strategies. Additionally, remediation measures to improve water quality remain essential in this rural area.

Multi-indicator assessment of heavy metal pollution in Qinzhou Harbour sediments: Unraveling ecological and human health risks

The study of heavy metal content in the sediments of the coastal zone of Qinzhou Harbour was used to analyse the level, distribution and sources of heavy metal pollution in the region and its hazards to the ecological environment and human health. The results showed that the average concentrations of Mn, Ni, Cr, Cu, and Pb exceeded background values along the shores of Qinzhou Harbour, Guangxi. Comprehensive assessments using Igeo, RI, and PLI identified Cu, Ni, and Pb as primary contaminants in the area, presenting slight to moderate ecological risks and biological toxic effects. Source analysis suggested that these metals primarily originated from anthropogenic activities including shipbuilding, chemical plant discharges, oil refining, and industrial smelting. Integrating SQGs with human health risk models revealed carcinogenic risks associated with Ni exposure, particularly for children. However, noncarcinogenic risks were not significant, and the risk to children was higher than to adults.

Efficient lead ion removal from aqueous solutions for wastewater treatment using a novel cross-linked alginate-rice husk ash-graphene oxide-chitosan nanocomposite

This research introduces an innovative composite, the cross-linked alginate-rice husk ash-graphene oxide-chitosan nanoparticles (CL-ARCG-CNP), designed for the effective adsorption of lead ions (Pb2+) in water treatment applications. Comprehensive characterization was performed using techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), High-Resolution Transmission Electron Microscopy (HR TEM), Selected Area Electron Diffraction (SAED), Atomic Force Microscopy (AFM), Thermogravimetric Analysis (TGA), and Brunauer-Emmett-Teller (BET) analysis. These analyses revealed notable structural and morphological features. The CL-ARCG-CNP composite demonstrated a significant surface area of approximately 148.44 m2/g, achieving an impressive adsorption capacity of 242.5 mg/g and a removal efficiency of 95.2 % after 240 min of contact duration. The adsorption process conformed to the Freundlich isotherm model (R2: 0.998) and the pseudo-second-order kinetic model (R2: 0.9992). Thermodynamic studies confirmed the spontaneity and endothermic nature of the adsorption process. Reusability tests showed that the composite could be reused for up to five cycles with minimal loss in adsorption capacity. These findings indicate that the CL-ARCG-CNP composite is highly effective for the removal of Pb2+ ions from aqueous solutions, making it a promising material for wastewater treatment.

Comparative analysis of heavy metals toxicity in drinking water of selected industrial zones in Gujranwala, Pakistan

Heavy metal contamination of drinking water, primarily driven by industrial activities, represents a critical challenge, with implications for human health and environmental safety. Gujranwala is an industrial and thickly populated city. The current study aimed to assess and compare heavy metal contamination levels in drinking water from five industrial areas and evaluate their potential impacts on human health. Total 100 water samples were collected and analysed for physicochemical parameters and heavy metals. Zonal variations in heavy metal concentrations revealed that Zone 2 had the highest mean levels of cadmium (0.331 mg/L), lead (0.573 mg/L), chromium (0.164 mg/L), arsenic (0.042 mg/L), and aluminium (0.484 mg/L), while Zone 4 showed elevated mean levels of iron (1.88 mg/L) and mercury (0.259 mg/L). Spearman correlation analysis among heavy metals revealed positive relationships among several heavy metals with As notably showing a strong correlation with Hg (0.701**). Kruskal-Wallis test revealed significant spatial variation (p < 0.05) in parameters like pH, EC, TDS, and heavy metals (Cd, Pb, Fe, Cu, Mn, Al), indicating spatial heterogeneity across zones. Spatial distribution maps also depicted heavy metal elevated concentrations of Cd, Pb, Fe, Cr, As, and Hg exceeding in Zone 2 (Engineering industries zone) and 4 (Iron and steel industries zone). The findings revealed a strong link between elevated heavy metal levels and health risks, including dermatological, respiratory, gastrointestinal, and neurological disorders. This study highlights the need for stricter wastewater management, regular monitoring of drinking water, and policies to address water toxicity in industrial premises and to protect public health.

Assessment of heavy metal contamination in groundwater of rural areas of Kurdistan Province Iran: A comprehensive study

This study focuses on the contamination of groundwater by heavy metals (HMs) in the Kurdistan Province of Iran, an area heavily reliant on these water resources, especially in rural regions. This research aimed to quantify the concentrations of 20 HMs in groundwater sources and assess the associated health risks, including both carcinogenic and non-carcinogenic effects, for different age groups. The study was conducted in 2024. We collected 155 groundwater samples from water resources of the villages in Kurdistan Province, west of Iran. The study encompassed comprehensive sampling of groundwater from various wells and springs throughout the province, which was subsequently subjected to thorough laboratory analysis utilizing Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) for the quantification of heavy metal (HM) concentrations. The highest concentrations of As, Co, Cu, and Mo were 7.90, 0.22, 2.48, and 1.68 μg/l, respectively. It was related to the cities of Qorveh, Sanandaj, Baneh, and Qorveh respectively. A Health Risk Assessment (HRA) was performed, indicating that, while the concentrations of most HMs were within the thresholds established by national and international standards, certain metals, such as arsenic and lithium, presented notable non-carcinogenic risks, especially to children. These metals were responsible for over 48 % of the cumulative hazard index (HI) across all ten cities evaluated. Furthermore, the HI for the adult demographic exceeded 1.0 (specifically 1.23) exclusively in Qorwe city. The study also identified a high carcinogenic risk associated with lead across the province, which has a carcinogenic risk of 7.3 × 10-03 in 10 studied cities, which is more than the guideline value of 10-04. The findings underscore the urgent need for continuous monitoring and the implementation of preventive measures to safeguard public health. The results provide crucial insights for policymakers and health authorities, facilitating informed decisions to mitigate the health risks posed by HM contamination in the region's groundwater.

Quantitative Assessment of Human Health Risks Associated with Heavy Metal and Bacterial Pollution in Groundwater from Mankweng in Limpopo Province, South Africa

Heavy metal and microbial pollution in groundwater raises health concerns due to its adverse effects. This study aimed to assess the health risks associated with heavy metal and bacterial pollution in groundwater in Mankweng. Heavy metals and Escherichia coli were detected using inductively coupled plasma mass spectrophotometry and a Colilert system, respectively. The heavy metal pollution index (HPI) and non-carcinogenic and carcinogenic risks were computed. The β-Poisson dose-response model was employed to predict the probability of E. coli infection. The metals' concentrations were all within the permissible limits of the South African National Standard (SANS). However, Pb levels at sites E and G exceeded the World Health Organization (WHO) guideline (≤0.01 mg/L). HPI values were all less than 100, indicative of low contamination. The hazard quotient values were all less than 1, except for vanadium. The cumulative cancer risk ranged between 3.06 × 10-5 and 1.81 × 10-4 and between 3.55 × 10-5 and 2.20 × 10-4 for adults and children, respectively. E. coli was only detected at site L. The annual risk of E. coli infection exceeded the WHO risk limit of 10-4. The results underscore the need for the regular monitoring of groundwater.

New insights on the hydrochemistry, geothermometry, and isotopic characteristics of the hydrothermal groundwater of the SASS basin: case study of the Jérid geothermal field, Southern Tunisia

Chemical and isotopic indicators were used to recognize the origin of hydrothermal groundwater, to assess the mineralization processes and groundwater quality, to identify the source of solutes and the likely mixing with cold, and elucidate the fluid geothermometry in the Jérid field of Southern Tunisia. The results show that the geothermal groundwater is neutral to slightly alkaline. They are characterized by SO4-Cl-Na-Ca water type. The dissolution of evaporates and pyrite-bearing rocks is the dominant mineralization process. The groundwater quality index indicates that the majority of samples are very hard and belong to poor to unsuitable for drinking classes. Applications and calculations of hydrogeochemical parameters, including SAR, %Na, PI, Kr, and MAR, showed that the majority of samples are unsuitable for agricultural practices. The human health risk was assessed based on hazard quotient and total hazard index through ingestion and dermal contact with iron-rich groundwater. The consumption of CI groundwaters does not present non-carcinogenic risk to adults and children. The δ18 O and δ2H signatures indicate that the geothermal groundwater was recharged by ocean precipitation during cold and wet paleoclimatic periods. The slight enrichment of oxygen-18 and deuterium contents suggests a limited mixing effect between geothermal water and cold groundwater within the same aquifer. This mixing effect is confirmed by the Na-K-Mg and the chloride-enthalpy diagrams. The K-Mg and SiO2 geothermometers provided fairly reliable reservoir temperature values, ranging between 69.6 and 99 °C. Calculated geothermal potential values, varying between 469 and 16987 kWth, which allow several applications such as domestic and agricultural heating.

Ecological and human health risk associated with heavy metals (HMs) contaminant sourced from petroleum refinery oily sludge

The environmental and human health risk of heavy metals (HMs) in petroleum based oily sludge (OS) varies depending upon the source of origin of the crude oil and treatment processes practiced at the refineries. Consequently, the present study explores the potential risk associated with HMs of OS obtained from different refinery sites to the environment and human health. The results showed that HMs (Cu, Ni, Zn, Mn) present in OS surpasses the permissible limit of WHO guidelines except for Cr. Additionally, the Igeo value (grade 3-6), Ef (2.48-121.4), PLI (5.12-22.65), Cd (32.48-204.76) and PERI (grade 1-5) confirmed the high level of HMs contamination into the OS and its risk to the environment. Besides, the hazard index (HI) and the total carcinogenic risk (TCR) for HMs show substantial risk to both adult and children health. Likewise, the G-mean enzyme index and potential soil enzyme risk index (PSERI) of the OS showed a high risk to soil biological properties. Furthermore, statistical analysis confirmed the heterogeneity in properties of the OS and its potential impact on the soil ecosystem arising from different sites. Finally, the study unveils a novel perspective on the environmental and human health consequences associated with the OS.

High lead contamination in Mother's breastmilk in Bihar (India): Health risk assessment of the feeding children

Lead poisoning in the recent times has caused serious health threats in the exposed human population. It is estimated that about 815 million people are exposed to lead poisoning worldwide and in India total 275 million children are exposed to blood lead contamination. The present study was carried outed in 6 districts of Bihar to know the extent of lead exposure in the children through their mother's breastmilk. The biological samples such as breastmilk, mother's urine, child's urine, and mother's blood samples were collected for quantitative lead estimation. Moreover, the selected household water sources (handpump) and the food consumed by the individuals-wheat, rice and potato samples were also collected for lead quantification. The study reveals that the breastmilk had high lead content in 92% of the samples (highest value 1309 μg/L), in blood presence of lead was observed in 87% studied samples (highest value 677.2 μg/L). In mother's urine the highest lead value was 4168 μg/L (62%) and in child's urine the highest value was 875.4 μg/L (62%) respectively of the studied samples. Moreover, in the studied food samples, wheat had lead content in 45% the studied samples (highest value 7910 μg/kg). In rice in 40% of the studied samples (highest value 6972 μg/kg) and in potato 90% of the studied samples (highest value = 13786 μg/kg) were found with elevated lead content respectively. The hazard quotient (HQ) and the cancer risk (CR) for lead contamination was very much higher in mothers followed by their children. The entire study indicated that lead exposure through food (wheat, rice and potato) has reached the mother's breastmilk and from their it has reached their child's body. This could cause serious hazards in the exposed children causing serious neurological damages, low IQ, low memory, and low mental growth in them. Therefore, a strategic action is required to control the present problem.

Assessing heavy metal contamination and health risks in playground dust near cement factory: exposure levels in children

Heavy metals pose significant threats to human health, particularly children. This study aimed to assess heavy metal pollution in children's playgrounds using surface dust as an indicator and to ascertain the associated exposure levels and health risks. A total of one hundred twenty dust samples were collected from the surface of playground toys in areas surrounding the cement factory in Bursa, Türkiye, on precipitation-free days. The heavy metal content of the samples was analyzed using ICP-MS. The average total concentration of heavy metals ranged from 2401 to 6832 mg/kg across the sampling sites, with the highest values observed at PG4, PG3, PG2, and PG1, respectively. The most commonly detected heavy metals in the samples included Cr, Mn, Fe, Co, Cu, Zn, Pb, Cd, As, and Ni. Statistical analysis revealed significant positive correlations (p < 0.01) among Cr, Mn, Fe, Co, Cu, Pb, As, and Ni, with Cu and Pb also showing correlation (p < 0.05). PCA analysis identified three principal components explaining 79.905% of the total variance. The Hazard Quotient (HQ) and Hazard Index values for heavy metals were found to be below the safe threshold (HQ < 1). Quantitative techniques such as the geoaccumulation index and enrichment factor are used to determine pollution levels at the sampling sites. Overall, the results indicate that cement factories significantly contribute to heavy metal pollution, with observed values varying based on proximity to the emission source.

Geospatial analysis of toxic metal contamination in groundwater and associated health risks in the lower Himalayan industrial region

Once known for its clean and natural environment, the lower Himalayan region is now no exception to human-induced disturbances. Rapid industrial growth in Baddi-Barotiwala (BB) industrial region has led to degradation of groundwater resources in the area. Groundwater samples were collected from 37 locations to study the groundwater chemistry, geospatial variation of 15 toxic metals in groundwater, source apportionment, metals of concern and associated health risks in the region. The results showed rock dominated hydrogeology with decreasing order of anion and cation abundance as HCO3- > Cl- > SO42- > NO3- > Br- > F- and Ca+ > Na+ > Mg2+ > K+ > Li+ respectively. Concentrations of Iron (BDL-3.6 mg/l), Nickel (BDL-0.023 mg/l), Barium (0.22-0.89 mg/l), Lead (0.0001-0.085 mg/l) and Zinc (0.006-21.4 mg/l) were found above the permissible limits at few locations. Principal component analysis (PCA) and coefficient of variance (CV) showed both geogenic and anthropogenic origin of metals in groundwater of the BB industrial region. A consistent concentration of Uranium was detected at all the sampling locations with an average value of 0.0039 mg/l and poor spatial variation indicating its natural presence. Overall, non-carcinogenic (N-CR) risk in the study area via oral pathway was high for adults and children (Hazard Index > 1) with geogenic Uranium as the major contributor (Hazard Quotient > 1) followed by Zinc, Lead and Cobalt. Carcinogenic (CR) risk in the region was high for adults having mean value above the threshold (1E-04) with Nickel and Chromium as the metals of major concern. Spatial variation of health risks was overlayed on village boundaries of the region to identify the potential industrial sources of the metals of major concern. The results highlight the need for immediate remediation of groundwater resources in order to achieve a harmonious coexistence between industrialization and human well-being.

Can metals and radionuclides in Shiveluch (Kamchatka) volcanic ash affect human health?

Volcanic eruption is associated with the release of large volumes of pollutants in the environment, which can pose a risk to humans and other living organisms. The elemental and radioisotope composition of ash released during the Shiveluch Volcano eruption in 2023 was analyzed using ICP-MS and low-background gamma spectrometry. The ash consisted of 59% SiO2, 16.7% Al2O3, 5.3% CaO, 4.6 % Na2O, 4.5% Fe2O3, 1.4% K2O, 0.48% TiO2, 0.17% P2O5, 0.15% S, 0.078% MnO and 44 trace elements. Hazard Quotient and Hazard Index were calculated in order to evaluate the potential health risks to children and adults due to exposure to contaminants via inhalation, ingestion, and dermal contact. All values were below the unit, indicating a low probability of non-carcinogenic and cancerogenic risk occurrence in target groups. The average activity concentrations of the natural radionuclides were 350, 12.4 and 4.84 Bq/kg for 40K, 226Ra and 232Th. Radiological indices, including external and internal risk assessment, radium equivalent activity, annual effective dose, gamma index, and excess lifetime cancer risk were calculated to estimate the radiological hazard for the population. The values of all indices were below the recommended safety limits, indicating a low level of hazard for the exposed population.

Examining carcinogenic and noncarcinogenic health risks related to arsenic exposure in Ethiopia: A longitudinal study

Background

The carcinogenic properties of arsenic make it one of the most hazardous chemicals globally. Nevertheless, the exact level of human exposure to arsenic and the associated risks of cancer and non-cancer effects through different pathways in Ethiopia are still uncertain.

Objective

The primary aim of this study was to evaluate the risk of both cancer and non-cancer outcomes among children and adults who have been exposed to arsenic through drinking water in the Adami Tulu Jido Kombolcha district of Ethiopia.

Methods

For this study, a longitudinal study design was employed. A total of 45 groundwater sources were sampled using the census sampling method. The concentrations of total arsenic were measured using Agilent 7900 series inductively coupled plasma mass spectrometry. Carcinogenic and noncarcinogenic risk assessments were conducted by calculating lifetime cancer risk and hazard quotients. Microsoft Office Excel was utilized to calculate human health risk indices, and descriptive statistical analysis were performed using SPSS software.

Results

Our findings revealed that during the dry season, the mean arsenic concentration in the groundwater samples was 11.15 ± 9.38 µg/L, while during the rainy season, it was 10.67 ± 8.16 µg/L. The total cancer risk for children, resulting from oral ingestion and skin contact, was 1.15 × 10-2 and 1.07 × 10-2 during the dry and rainy seasons, respectively. For adults, the total cancer risk from oral ingestion and skin contact during the dry and rainy seasons was 4.95 × 10-3 and 4.59 × 10-3, respectively. Furthermore, the total hazard quotients for children via oral ingestion and skin absorption were 25.9 and 24.0 during the dry and rainy seasons, respectively. For adults, the total hazard quotients from ingestion and dermal contact during the dry and rainy seasons were 11 and 10, respectively.

Conclusions

The findings indicate that the risks of cancer and non-cancer effects resulting from arsenic exposure through ingestion and dermal exposure were found to exceed the acceptable thresholds in both seasons. These results emphasize the urgent need for focused attention on the study population in the study area due to the high likelihood of experiencing adverse health outcomes.

Health risks of metals in soils and staple foods of the subsistence food gardens in the floodplains of Watut River, Papua New Guinea

The health risks associated with the consumption of staples cultivated in the subsistence food gardens along the Watut River were investigated in Papua New Guinea. Twenty soil samples and twenty-nine samples of staple foods (including banana, taro, sweet potato, and Singapore taro) were collected from the food gardens following a three-day dietary recall survey. The concentration of metals (Cr, Cu, Pb, and Ni) was analyzed in the soil and food samples using Inductively Coupled Plasma Optical Emission Spectrophotometer. The descending order of mean metal concentration in the food garden soils is as follows: Cr > Cu > Ni > Pb. The concentration of Pb in all samples and Cr in 97% of staple foods exceeded the FAO/WHO permissible limits. Approximately 87% of adult consumers of bananas (Musa sp) were found to have estimated Cr and Pb ingestion levels exceeding the permissible daily tolerable intake of metals (0.2 and 0.21 mg day-1, respectively). Hazard index values from the staples analysis indicate that the consumption of bananas (9.40) poses the highest risk of non-carcinogenic effects on adults, followed by taro (7.32), sweet potato (6.13), and Singapore taro (4.30). The consumption of taro is dangerous due to cancer risk associated with the intake of excessive Ni (2.88E-02) and Cr (8.82E-03) in adults and children compared to banana, sweet potato, and Singapore taro. Non-carcinogenic hazards of metal ingestion were found to be pronounced in the younger population, while carcinogenic effects were more serious in adults. Urgent measures must be implemented to protect communities, especially children, from the dangerous effects of heavy metal ingestion through staples in the lower Watut region.

Molecular identification of Proteus mirabilis, Vibrio species leading to CRISPR-Cas9 modification of tcpA and UreC genes causing cholera and UTI

Heavy metal accumulation increases rapidly in the environment due to anthropogenic activities and industrialization. The leather and surgical industry produces many contaminants containing heavy metals. Cadmium, a prominent contaminant, is linked to severe health risks, notably kidney and liver damage, especially among individuals exposed to contaminated wastewater. This study aims to leverage the natural cadmium resistance mechanisms in bacteria for bioaccumulation purposes. The industrial wastewater samples, characterized by an alarming cadmium concentration of 29.6 ppm, 52 ppm, and 76.4 ppm-far exceeding the recommended limit of 0.003 ppm-were subjected to screening for cadmium-resistant bacteria using cadmium-supplemented media with CdCl2. 16S rRNA characterization identified Vibrio cholerae and Proteus mirabilis as cadmium-resistant bacteria in the collected samples. Subsequently, the cadmium resistance-associated cadA gene was successfully amplified in Vibrio species and Proteus mirabilis, revealing a product size of 623 bp. Further analysis of the identified bacteria included the examination of virulent genes, specifically the tcpA gene (472 bp) associated with cholera and the UreC gene (317 bp) linked to urinary tract infections. To enhance the bioaccumulation of cadmium, the study proposes the potential suppression of virulent gene expression through in-silico gene-editing tools such as CRISPR-Cas9. A total of 27 gRNAs were generated for UreC, with five selected for expression. Similarly, 42 gRNA sequences were generated for tcpA, with eight chosen for expression analysis. The selected gRNAs were integrated into the lentiCRISPR v2 expression vector. This strategic approach aims to facilitate precise gene editing of disease-causing genes (tcpA and UreC) within the bacterial genome. In conclusion, this study underscores the potential utility of Vibrio species and Proteus mirabilis as effective candidates for the removal of cadmium from industrial wastewater, offering insights for future environmental remediation strategies.

Systematic review and meta-analysis of arsenic concentration in drinking water sources of Iran

Recent studies have found arsenic contamination of drinking water in some parts of Iran, as in many other countries. Thus, a comprehensive systematic review is necessary to assess the distribution and concentration of arsenic in drinking water sources. For this purpose, articles published from the first identification until December 2023, were retrieved from various national and international databases. Of all the studies examined (11,726), 137 articles were selected for review based on their conceptual relationship to this survey. A review of the extracted studies presented that ICP methods (ICP-MS, ICP-OES, 56%) and atomic absorption spectrophotometry (AAS, 34.1%) were the two most commonly used techniques for the analysis of arsenic in water samples. The order of arsenic content in the defined study areas is descending, as follows: northwest ˃ southeast ˃ southwest ˃ northeast. A review of studies performed in Iran depicted that provinces such as Kurdistan, Azerbaijan, and Kerman have the highest arsenic concentrations in water resources. Accordingly, the maximum concentration of arsenic was reported in Rayen, Kerman, and ranged from < 0.5-25,000 µg/L. The primary cause of elevated arsenic levels in water resources appears to be geologic structure, including volcanic activity, biogeochemical processes, sulfur-bearing volcanic rocks, Jurassic shale, the spatial coincidence of arsenic anomalies in tube wells and springs, and, to some extent, mining activities. The findings of the presented survey indicate that it is essential to take serious measures at the national level to minimize the health risks of arsenic contamination from drinking water consumption.

Hazard-mapping and health risk analysis of iron and arsenic contamination in the groundwater of Sylhet district

This study investigates groundwater contamination by arsenic and iron and its health implications within the Sylhet district in Bangladesh. Utilizing geographic information system (GIS) and inverse distance weighting (IDW) methods, hazard maps have been developed to evaluate contamination risk across various upazilas. The findings show significant arsenic and iron pollution, particularly in the northwestern part of the district. In about 50% of the area, especially in Jaintiapur, Zakiganj, Companiganj, and Kanaighat where arsenic levels surpass 0.05 mg/L which is the standard limit of Bangladesh. Iron levels peak at 13.83 mg/L, severely impacting 45% of the region, especially in Gowainghat, northeastern Jaintiapur, Zakigonj, and Golabganj. The study employs USEPA health risk assessment methods to calculate the hazard quotient (HQ) and hazard index (HI) for both elements via oral and dermal exposure. Results indicate that children face greater noncarcinogenic and carcinogenic risks than adults, with oral HI showing significant risk in Balagonj and Bishwanath. Dermal adsorption pathways exhibit comparatively lower risks. Cancer risk assessments demonstrate high carcinogenic risks from oral arsenic intake in all areas. This comprehensive analysis highlights the urgent need for effective groundwater management and policy interventions in the Sylhet district to mitigate these health risks and ensure safe drinking water.

Health risk assessments of heavy metals and trace elements exposure in the breast milk of lactating mothers in the Northeastern Iran

Mother's breast milk is a natural and complete food for infants but can be a main source of exposure to toxic pollutants. These pollutants can negatively affect the health of the infant. Therefore, conducting biomonitoring surveys is essential to evaluate such health effects in toxicological research. This study aimed to estimate the probable health risks for infants exposed to essential and non-essential trace elements through breast milk ingestion. This descriptive-analytical, cross-sectional study was performed on 90 breastfeeding mothers referred to the health centers in Mashhad, Iran in January 2021. The health risk assessments (carcinogenic and non-carcinogenic risk) were estimated using chronic daily intake (CDI), hazard quotient (HQ), hazard index (HI), and lifetime carcinogenic risk (CR), which were recommended by the US Environmental Protection Agency (US EPA). The results of the HQ values of trace elements through ingestion exposure for arsenic (90%), copper (90%), zinc (40%), and iron (10%) exceeded the threshold of HQ, and arsenic (66.59%), copper (16.91%), and zinc (9.68%) and iron (4.57%) had the highest contribution to increasing the HI index. The average value of CR was 5. 08 × 10-3. Chromium and iron showed significant relationships (P<0.05) with education level and disease background in this study, and the concentration of chromium, iron, and zinc in the breast milk samples significantly changed during lactation stages (P<0.05). Overall, the risk of carcinogenicity through exposure to breast milk for infants was higher than the safety level of US EPA risk. Therefore, there could be a potential health risk of trace elements, particularly arsenic, copper, and zinc for infants in Mashhad, Iran through the consumption of mothers' breast milk. More efforts are required to control and reduce routes of receiving trace elements in breastfeeding mothers by the competent authorities.

Carcinogenic and non-carcinogenic human health risk assessments of heavy metals contamination in drinking water supplies in Iran: a systematic review

The contamination of water due to heavy metals (HMs) is a big concern for humankind; particularly in developing countries. This research is a systematic review, conducted by searching google scholar, Web of Science, Science Direct, PubMed, Springer, and Scopus databases for related published papers from 2010 to July 2021, resulting in including 40 articles. Among the analyzed HMs in the presented review, the average content of Cr, Pb, Ba, Al, As, Zn, and Cd exceeded the permissible limits suggested by the World Health Organization (WHO) and 1,053 Iranian standards. Also, the rank order of Hazard Quotient (HQ) of HMs was defined as Cd>As>Cr>Pb>Li for children which means Cd has the highest non-carcinogenic risk and Li has the least. This verifies to the current order As>Cr>Pb>Fe=Zn=Cu>Cd for adults. The corresponded values of HQ and Hazard Index (HI) in most cities and villages were investigated and the results indicated a lower than 1 value, which means consumers are not at non-carcinogenic risk (HQ). Carcinogenic risk (CR) of As in the adult and children consumers in most of the samples (58.82% of samples for both groups) were investigated too, and it was more than>1.00E-04 value, which determines that consumers are at significant CR.

Potentially toxic elements contamination in the water resources: an integrated risk assessment approach in the upper Citarum watershed area

The Citarum watershed is West Java Province's most important water resource; hence, harmful compounds should be monitored regularly. This study assessed pollution levels along with ecological and health risks from Cd, Pb, Mn, Fe, Cu, Cr, and Hg contamination in river water, sediment, groundwater, and soil in Citarum's upper watershed. In river water, the average amounts of Cd, Pb, Mn, Fe, Cu, Cr, and Hg were 0.002, 0.05, 0.092, 0.649, 0.022, 0.001, and 0.421 mg/L. In sediment, they were 7.4, 1175.1, 32,289.9, 37.3, 3.9, and 0.015 mg/kg. The mean concentrations of Cd, Pb, Mn, Fe, Cu, Cr, and Hg in groundwater were 0.004, 0.046, 0.567, 0.366, 0.019, 0.001, and 0.177 mg/L, and in soil, BDL, 10.2, 744.6, 50,094.1, 45.6, 5.9, and 0.015 mg/kg. The river water and groundwater were highly polluted by PTEs, with HPI values of 14,733 and 933, respectively. While PTEs pollution levels and risk in sediment and soil were low based on I-geo, CF, PLI, and M-ERM-Q values, PTEs contamination in river water may cause adverse impacts on aquatic living organisms (HQ > 1). The population doing recreational activities in river ecosystems was still safe from non-carcinogenic and carcinogenic impacts due to PTEs exposure from river water and sediment (THI < 1 and TCR value < 1E-04), while the population in the upper Citarum River was not safe from the carcinogenic risk due to PTE exposure from groundwater and soil (TCR > 1E-04). The sensitivity analysis showed that Cd concentration in groundwater is the most influential factor in cancer risk, with a total contribution of 99.9%. Therefore, a reduction in Cd concentration in groundwater is important to reduce cancer risk in the population.

Safeguarding drinking water: A brief insight on characteristics, treatments and risk assessment of contamination

Water pollution stands as a critical worldwide concern, bearing extensive repercussions that extend to human health and the natural ecosystem. The sources of water pollution can be diverse, arising from natural processes and human activities and the pollutants may range from chemical and biological agents to physical and radiological contaminants. The contamination of water disrupts the natural functioning of the system, leading to both immediate and prolonged health problems. Various technologies and procedures, ranging from conventional to advanced, have been developed to eliminate water impurities, with the choice depending on the type and level of contamination. Assessing risks is a crucial element in guaranteeing the safety of drinking water. Till now, research is continuing the removal of contaminates for the sake of supplying safe drinking water. The study examined physical, inorganic, organic, biological and radiological contaminants in drinking water. It looked at where these contaminants come from, their characteristics, the impact they have and successful methods used in real-world situations to clean the contaminated water. Risk assessment methodologies associated with the use of unsafe drinking water as future directives are also taken into consideration in the present study for the benefit of public concern. The manuscript introduces a comprehensive study on water pollution, focusing on assessing and mitigating risks associated with physical, inorganic, organic, biological and radiological contaminants in drinking water, with a novel emphasis on future directives and sustainable solutions for public safety.

The Role of microRNAs in Arsenic-Induced Human Diseases: A Review

MicroRNAs (miRNAs) are noncoding RNAs with 20-22 nucleotides, which are encoded by endogenous genes and are capable of targeting the majority of human mRNAs. Arsenic is regarded as a human carcinogen, which can lead to many adverse health effects including diabetes, skin lesions, kidney disease, neurological impairment, male reproductive injury, and cardiovascular disease (CVD) such as cardiac arrhythmias, ischemic heart failure, and endothelial dysfunction. miRNAs can act as tumor suppressors and oncogenes via directly targeting oncogenes or tumor suppressors. Recently, miRNA dysregulation was considered to be an important mechanism of arsenic-induced human diseases and a potential biomarker to predict the diseases caused by arsenic exposure. Endogenic miRNAs such as miR-21, the miR-200 family, miR-155, and the let-7 family are involved in arsenic-induced human disease by inducing translational repression or RNA degradation and influencing multiple pathways, including mTOR/Arg 1, HIF-1α/VEGF, AKT, c-Myc, MAPK, Wnt, and PI3K pathways. Additionally, exogenous miRNAs derived from plants, such as miR-34a, miR-159, miR-2911, miR-159a, miR-156c, miR-168, etc., among others, can be transported from blood to specific tissue/organ systems in vivo. These exogenous miRNAs might be critical players in the treatment of human diseases by regulating host gene expression. This review summarizes the regulatory mechanisms of miRNAs in arsenic-induced human diseases, including cancers, CVD, and other human diseases. These special miRNAs could serve as potential biomarkers in the management and treatment of human diseases linked to arsenic exposure. Finally, the protective action of exogenous miRNAs, including antitumor, anti-inflammatory, anti-CVD, antioxidant stress, and antivirus are described.

Health Risks from Intake and Contact with Toxic Metal-Contaminated Water from Pager River, Uganda

Pollution of water resources is one of the major impediments to the realization of Sustainable Development Goals, especially in developing countries. The aim of this study was to investigate the physicochemical quality and potentially toxic element (lead and cadmium) concentrations in surface water sampled from Pager River, a tributary of the Nile River in Northern Uganda. Water samples (n = 18) were taken from six different points upstream (A, B, and C) and downstream (D, E, and F) of the river and analyzed following standard methods for their physiochemical properties. Atomic absorption spectroscopy was used to quantify lead and cadmium concentrations. Human health risks from ingestion and dermal contact with potentially toxic metal-contaminated water were calculated. The results obtained indicated that the mean temperature (27.7 ± 0.5-29.5 ± 0.8 °C), turbidity (40.7 ± 2.1-50.1 ± 1.1 NTU), lead (0.296 ± 0.030-0.576 ± 0.163 mg/L) and cadmium (0.278 ± 0.040-0.524 ± 0.040 mg/L) occurred at levels that surpassed their permissible limits as per World Health Organization guidelines for drinking water. Human health risk assessment showed that there are potential non-cancer risks from the ingestion of water from Pager River by adults, as the total hazard quotients were greater than one. These results emphasize the urgency to restrict the dumping of wastes into the river to minimize chances of impacting the Nile River, which flows northwards to the Mediterranean Sea. Further studies should perform routine monitoring of the river during both dry and wet seasons to establish the spatiotemporal variations of physicochemical, microbial, and trace metal profiles of the river and the associated health risks.

Water quality and health risk assessment of heavy metals in groundwater of Ranbir Singh Pura tehsil of Jammu and Kashmir, India

Groundwater is one of the important sources available for drinking, agricultural, domestic, and various other purposes in the study area. Study area is having agricultural importance and is famous for Basmati rice production in the world. In order to assess water suitability for irrigation and drinking purposes, 25 sampling sites were selected and water samples were collected from handpumps, borewells and motors from May 2022 to June 2022. Fifteen physico-chemical parameters and water quality index (WQI) was calculated to assess the drinking water suitability. The results obtained then compared with the BIS (2012) and WHO drinking water guidelines. For irrigation water suitability, irrigation water quality index (IWQI) and other indices were calculated. Heavy metal health risk assessment was also evaluated using target hazard quotient (THQ), carcinogenic risks (CR), non-carcinogenic risks, heavy metal pollution index (HPI), etc. Study found 60% of water samples under poor category of WQI. All water samples were found suitable for irrigation purposes according to different indices except for permeability index for which only 32% samples were found suitable. IWQI classifies 52%, 32%, and 12% of water samples under moderate, low, and no restriction category respectively. Groundwater of the study area found to be contaminated with copper (Cu), iron (Fe), lead (Pb), and chromium (Cr) while low contamination of zinc (Zn) and arsenic (As) was found according to heavy metal evaluation index (HEI). High contamination of chromium (HPI= 9740.8) and lead (HPI=188) was recorded as per HPI. HQ value for men, women, and children in case of zinc were found safe while HQ values for copper and lead in all population groups were found at risk. Overall, the study area was found highly contaminated with the lead, copper, and chromium concentrations. Thus, study recommends regular monitoring of the groundwater of study area as well as treatment before using this water for drinking purposes.

Groundwater pollution and risk assessment using indexed-based models: a case study of Igbo-Etiti area, eastern Nigeria

Water is one of the most abundant resources on earth not evenly distributed. Due to the high shortage of water sources in Igbo-Etiti and intensive agricultural practices in the area, assessment of groundwater pollution and its potential risk to contamination is imperative, as its remediation when contaminated is extremely challenging. Vertical electrical sounding (VES) and physicochemical analysis were carried out in twenty (20) locations and five groundwater samples, respectively, with the aim to evaluate the groundwater pollution indices and the ecological and human health risk associated with its pollution. The VES results delineated five geologic layers and ten characteristic curve types. The fourth layer with the aid of the VES results constrained by the borehole lithologic information on the water bearing geologic unit was delineated as the major exploitable aquifer layer. Results of groundwater vulnerability to pollution classified the area into low (15%), moderate (60%), and high (20%) vulnerability. Physicochemical analysis results on the studied groundwater revealed acidic (pH 4.6) to alkaline (pH 7.2) groundwater conditions. Pollution index of groundwater results delineated a moderate to very high pollution index, with cadmium and arsenic consistently identified as the heavy metals contaminating the groundwater. Ecological risk assessment revealed a moderate to very high integrated potential ecological risk, while human health risk results delineated a target hazard index greater than one in all the studied groundwater samples. This study will serve as a guide to the residents and society in sustainable development decision-making that will preserve the quality of the study area groundwater.

Bioaccumulation Pattern and Health Risk Assessment of Heavy Metals in Cirrhinus mrigala at Panjnad Headworks, Bahawalpur, Pakistan

Heavy metal accumulation in freshwater ecosystem has become one of the major aquatic environmental concerns for freshwater flora and fauna due to their higher stability and bioaccumulation as well as bio-magnification properties. Furthermore, passing through the food web, these heavy metals affect human populations ultimately. This study assessed the heavy metal accumulation in Cirrhinus mrigala in spring, autumn, and winter at different locations (I, II, and III) of Panjnad headwork. Furthermore, the human health risk assessment for the consumption of C. mrigala from the sampling locations was also carried out. Fish were collected from upper (I), middle (II), and lower (III) stream of Panjnad on a monthly basis. The current study evaluated the accumulation of Aluminum (Al), Arsenic (As), Barium (Ba), and Lead (Pb) in various fish organs (liver, kidney, gills, fins, skin, muscles and bones) and assessed their potential hazard to human health through health risk assessment indicators. The results demonstrated a significant difference (p < 0.05) in heavy metal accumulation in different fish organs, seasons, and locations. The accumulation of Al, As, Ba, and Pb were considerably higher in liver and kidney as compared to the other body organs and followed a trend of liver > kidney > gills > fins > skin > bones > muscle and the overall mean concentrations of metals in different body tissues of C. mrigala were in the order of Al > As > Ba > Pb. The results also concluded that C. mrigala caught from the Panjnad headwork is not safe for human consumption due to higher values of TTHQ_Ing (3.76), THQ_Ing for Ba (3.27) and CR_Ing for As (6.4742).

The Protective Effects of Trametes Versicolor on Arsenic-Induced Male Reproductive Toxicity through Regulation of Oxidative Stress: A Biochemical and Histopathological Survey

Exposure to arsenic is linked to a wide range of diseases, in particular male reproductive toxicities. Trametes versicolor is a traditional medicinal fungus with a remarkable potential for antioxidant activity. The purpose of this study was to examine the ameliorating effects of water and methanol extracts of T. versicolor on arsenic-induced male reproductive toxicities via the abrogation of oxidative stress. The mice were divided as follows: control: normal saline, As: arsenic (15 mg/kg), WE: water extract (400 mg/kg), ME: methanol extract (400 mg/kg), As + WE: arsenic (15 mg/kg) + water extract (100, 200, 400 mg/kg), As + ME: arsenic (15 mg/kg) + methanol extract (100, 200, 400 mg/kg), and positive control: arsenic (15 mg/kg) + vitamin C (500 mg/kg). Animals were treated via the intraperitoneal route. About 24 hr later, the mice were euthanized, and oxidative stress parameters (reactive oxygen species [ROS], lipid peroxidation, glutathione concentration, protein carbonylation, glutathione peroxidase, and superoxide dismutase activity), histopathological changes and sperm parameters (count, motility, and morphology) were examined in the testicular tissue. Arsenic caused significant pathological changes in the testicular tissue and sperm morphology and significantly reduced sperm count and motility. Moreover, arsenic mediated oxidative stress via significant increases in ROS generation, lipid peroxidation, and protein carbonyl content, as well as significant depletion in glutathione concentration and superoxide dismutase and glutathione peroxidase activities. Although, coadministration of water and methanol extracts of T. versicolor at 200 and 400 mg/kg counteracted arsenic-induced oxidative and histopathological damages and improved sperm parameters. Our study indicated that T. versicolor ameliorated arsenic-induced testis toxicity and sperm dysfunction via attenuation of oxidative damage.

Arsenic level in drinking water, its correlation with water quality parameters, and associated health risks

This study aimed to evaluate the occurrence and likelihood of health risks related to arsenic in drinking water of all counties of the Hamadan province in the northwest of Iran. In this work, 370 samples were collected from all of the water resources of urban and rural regions, during 5 years (2017 to 2021). Oracle Crystal Ball software was used to perform the Monte Carlo simulation and investigate the potential health risks. According to the results, the average values of arsenic in the nine counties were in the order Kabudarahang (40.1 ppb), Malayer (13.1 ppb), Nahavand (6.1 ppb), Bahar (2.05 ppb), Famenin (0.41 ppb), Asadabad (0.36 ppb), Tuyserkan (0.28 ppb), Razan (0.14 ppb), and Hamadan (< 0.1 ppb). The highest concentration of arsenic occurred in Kabudarahang with a maximum value of 185 ppb. In the spring season, the average concentration of the cations, including calcium, magnesium, sodium, lead, cadmium, and chromium, obtained 109.51 mg/l, 44.67 mg/l, 20.50 mg/l, 88.76 ppb, 0.31 ppb, and 0.02 ppb, respectively. Based on the Delphi classification, the P 90% of oral lifetime cancer risk, in Hamadan province, were within level II (low risk) to VII (extremely high risk). The risk analysis revealed there was a possible carcinogenic risk to humans from oral exposure to As-contaminated groundwater, especially in Kabudarahang county. Therefore, there is an urgent need for management and precise measures in contaminated areas to reduce and prevent the adverse health effects of arsenic.

Carcinogenic and non-carcinogenic risk assessment of consuming metal-laden wild mushrooms in Nigeria: Analyses from field based and systematic review studies

This study investigated the potential health risk associated with the consumption of metal-laden mushrooms in Nigeria. Concentrations of Pb, Cd, Cr, Cu, Ni, Zn and Al in wild mushrooms collected from the Nigerian environment were measured using atomic absorption spectrometer. Also, systematic analysis of articles on metal accumulation in mushrooms from Nigeria were obtained from scientific databases. Using hazard model indices, the metal concentration in mushrooms were evaluated for their potential carcinogenic and non-carcinogenic health risk when consumed by adults and children. Zn and Cd, respectively, had the highest and lowest mean concentrations (mg kg-1) in the analysed mushrooms from the field study, while Fe and Co, respectively, had the highest and lowest mean concentrations (mg kg-1) in the systematically reviewed articles. In the field study, the percentage distribution of THQ of the heavy metals greater than 1 was 0% and 42.85% for adults and children respectively. While for the systematic study, 30% and 50% of the heavy metals for adults and children respectively exceeded the limit of 1. The hazard indices obtained from both the systematic and field studies for both age groups were all >1, indicating significant health risk. The findings from both the systematic and field studies revealed that consuming metal-laden mushrooms by adults and children increases the carcinogenic risk to Cd, Cr, and Ni since they exceeded the acceptable limit of 1E-04 stated by USEPA guideline. Based on the findings from the systematic and field studies, it suggests that consuming mushrooms collected from metal polluted substrates increases carcinogenic and non-carcinogenic health risk among Nigerians.

Arsenic and heavy metals at Japanese abandoned chemical weapons site in China: distribution characterization, source identification and contamination risk assessment

As-containing chemical weapons (CWs) and their degraded products pose a great threat to the environment and to human health. In this study, concentration and distribution characteristics, source identification, and health risk assessments were determined for As, Cr, Ni, Cu, Zn, Cd and Pb in environmental samples from Lianhuapao (LHP), a typical site of Japanese abandoned chemical weapons (JACWs) in China. The results show that the concentration levels of As, Cr and Ni in the LHP soils are abnormally high, with 69.57%, 83.33% and 91.67%, respectively, of the total sample exceeding the risk screening values for soil contamination of agricultural land. As levels in water samples were generally within safety limits, with the exception of perched water in the core contamination area. In the study area, none of the dominant plant species were enriched with As, except for the Pteris vittata L. Pentavalent arsenic was found to be the predominant arsenic species in the topsoil and water samples. Source identification using statistical approaches indicated that the concentrations of As, Pb, Cu, Cd and Zn are likely influenced by JACWs, while Cr and Ni levels may be related to the natural weathering process. The total concentrations of As, Cr and Ni showed a significant degree of contamination, but only As displayed high potential ecological risk. The calculated indexes of health risk evaluation strongly indicate an unacceptable carcinogenic risk (1E-04) to children, and higher non-carcinogenic risk, relative to that of adults. Our data indicate that the health risk from the resulting As contamination is still a cause for concern, although the JACWs were excavated decades ago from these soils.

Carcinogenic and non-carcinogenic risk assessment of exposure to trace elements in groundwater resources of Sari city, Iran

The daily intake of trace elements through water resources and their adverse health effects is a critical issue. The purpose of this research was to assess the carcinogenic and non-carcinogenic risks of exposure to iron (Fe), copper (Cu), manganese (Mn), zinc (Zn), chromium (Cr), lead (Pb), and arsenic (As) in groundwater resources of Sari city, Iran. The concentrations of the trace elements in a total number of 66 samples from the groundwater sources were measured using inductively coupled plasma mass spectrometry (ICP-MS). The hazard index (HI) levels of exposure to the trace elements from the groundwater sources for adults, teenagers, and children were 0.65, 0.83, and 1.08, respectively. The carcinogenic risk values of Cr and As in the groundwater sources for children, teenagers, and adults were 0.0001, 0.00009, 0.00007, 0.0003, 0.0002, and 0.0001, respectively, causing a total carcinogenic risk value higher than the acceptable range, and removing Cr and As from the groundwater resources is recommended for safe community water supply.

Accumulation and human health risk assessment of trace elements in two fish species, Cirrhinus mrigala and Oreochromis niloticus, at Tarukri Drain, District Rahimyar Khan, Punjab, Pakistan

The toxic discharge of heavy metals into the water affects the aquatic ecosystem as well as the human population interacting with it because of their toxicity, bioaccumulation, long persistence, and transfer through the food chain. Thus, it is very important to conduct studies to determine the level of heavy metal pollution in order to better control, manage, and preserve the pollution of aquatic ecosystems. This study assessed heavy metal contamination in fish and its associated health risk to the population around the Tarukri Drain, Punjab, Pakistan. Two fish species (Oreochromis niloticus and Cirrhinus mrigala) were collected from three different sites in two different seasons. Collected fish were analyzed for cadmium (Cd), iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) accumulation using atomic absorption spectrometer (AAS). Furthermore, the human health risks associated with the consumption of affected fish were also assessed. Target hazardous quotient for seasonal consumers was between 0.12, - 1.58 × 10^-4, and 0.54 - 3.28 × 10^-4 (mg/kg) in O. niloticus and C. mrigala, respectively. While for regular consumers it was between 0.28-3.71 × 10^-4 and 1.27-7.68 × 10^-4 (mg/kg) in O. niloticus and C. mrigala respectively for the studied heavy metals. Fish sampled from Sadiqabad contained the highest concentration of heavy metals. The analysis of fish organs (kidney, liver, and muscles) showed heavy metal accumulation in the order of kidney > liver > muscles (p < 0.00). The obtained results showed that heavy metal contaminations in both fish species were within the permissible limits recommended by the World Health Organization (WHO). Both sampling seasons (i.e., summer and winter) showed a non-significant difference in heavy metal concentration. The calculated total target hazardous quotient across all heavy metals remained < 1 with only one exception. The carcinogenic risk assessment of heavy metals showed a non-significant effect in both fish species.

Seasonal Variations in the Trace Elements and Mineral Profiles of the Bivalve Species, Mytilus galloprovincialis, Chamelea gallina and Donax trunculus, and Human Health Risk Assessment

This study aimed to provide data on selected toxic (Cd, Pb and Ni), essential (Cr, Cu, Fe, Mn and Zn) and microelement (Na, K, Ca and Mg) concentrations in edible tissues of the Mediterranean mussel (Mytilus galloprovincialis), striped venus clam (Chamelea gallina) and the wedge clam (Donax trunculus). Samples were collected from the Black Sea (Bulgaria) four times over, a period of one year (2022). In comparison with the maximum permissible levels set by the EU and USFDA, all elemental concentration found in the bivalve species were lower than the prescribed limits. An estimation of the dietary metal intake through calculation of the target hazard quotients (THQ), hazard index (HI) and target risk (TR) was performed. The target hazard quotient (THQ) for individual metal and HI for combined metals were lower than 1, indicating no health risk for consumers due to the intake of either individual element or combined ones. The target risk value for toxic inorganic Pb and Cr was below 10^-6, indicating no carcinogenic risk. According to these results, the consumption of these bivalve species is completely safe for human health.

Ecological and health risk assessment of heavy metals: a case study of residential waste sites in Umuahia, South-East Nigeria

This study assessed the human health hazards and ecological risks of heavy metals from waste sites in residential vicinity. The heavy metals analyzed were Cr, Pb, Cd, Ni, Cu, and Zn. A total of 40 soil samples were collected from waste sites in two residential estates located in the urban and suburb areas of Umuahia, Abia state. Results revealed a trend in concentrations of the heavy metals for both sites in the following order: Cu > Ni > Zn > Cr > Cd > Pb. The concentrations of heavy metals were higher in rural soils than in urban soil. The contamination factor (CF) indices for Pb, Cr, Cu, Ni, and Zn were less than 1 for both sites, signifying a low contamination scenario. The contamination factor for Cd (6 > CF) for both sites indicated a very high contamination status. The estimated degree of contamination (Cdeg) was less than the lower threshold of 8.0, denoting a low degree of contamination. Cd was the highest contributor to ecological risk with Er index value of 184.2 among measured heavy metals. The overall potential ecological risk index for urban and rural sites are 187.1 and 196.1 respectively, classifying the sites as moderate risk. The overall non-carcinogenic hazard index values (HI) for adults and children in urban and rural soils are 0.00248, 0.0198 and 0.0028, 0.0223 respectively, which are below the acceptable limit (HI < 1), indicating that the exposed residents are unlikely to experience any apparent adverse health hazards. However, children are more susceptible to non-carcinogenic hazards than adults in the study areas.

The concentration of potentially toxic elements (PTEs) in drinking water from Shiraz, Iran: a health risk assessment of samples

The existence of potentially toxic elements (PTEs) in water bodies has posed a menace to human health. Thus, water resources should be protected from PTEs, and their effect on the exposed population should be investigated. In the present investigation, the concentrations of PTEs such as lead (Pb), mercury (Hg), manganese (Mn), and iron(Fe) in the drinking water of Shiraz, Iran, were determined for the first time. In addition, hazard quotient, hazard index, cancer risk, and sensitivity analysis were applied to estimate the noncarcinogenic and carcinogenic impacts of Pb, Hg, Mn, and Fe on exposed children and adults through ingestion. The mean concentrations (µg/L) of Pb, Hg, Mn, and Fe were 0.36, 0.32, 2.28, and 8.72, respectively, in winter and 0.50, 0.20, 0.55, and 10.36, respectively, in summer. The results displayed that Fe concentration was more than the other PTEs. PTE concentrations were lower than the standard values of the Environment Protection Agency and World Health Organization. Values of the degree of contamination and heavy metal pollution index for lead, mercury, manganese, and iron were significantly low (< 1) and excellent (< 50), respectively. Based on the Spearman rank correlation analysis, positive and negative relationships were observed in the present study. The observations of the health risk assessment demonstrated that mercury, lead, iron, and manganese had an acceptable level of noncarcinogenic harmful health risk in exposed children and adults (hazard quotients < 1 and hazard index < 1). The carcinogenic risk of lead was low (< E - 06), which can be neglected. Monte Carlo simulation showed that water intake rate and mercury concentration were the most critical parameters in the hazard index for children and adults. Lead concentration was also the most crucial factor in the cancer risk analysis. The results of the present study proved that the drinking water of Shiraz is safe and healthy and can be confidently consumed by people.

Deterministic and Probabilistic Health Risk Assessment of Toxic Metals in the Daily Diets of Residents in Industrial Regions of Northern Ningxia, China

This study was designed to investigate the toxic metal (aluminum (Al), arsenic (As), chromium (Cr), cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn)) concentrations in drinking water and different foodstuffs meat (pork, beef, and mutton), cereals (rice, flour, corn, millet), beans (cowpeas, tofu), potatoes (potato, sweet potato), solanaceous fruits (pepper, eggplant, bitter gourd, cucumber), vegetables (cabbage, cauliflower, spinach), and fruits (apples, watermelons, pears, grapes)) and then estimate the potential health risks of toxic metal consumption to local residents in industrial regions of northern Ningxia, China. As in drinking water, Cr in meat, Pb in cereals, Pb in beans, As and Pb in potatoes, Pb in solanaceous fruits, Cr and Ni in vegetables, and Ni and Pb in fruits were the most contaminated heavy metals in the corresponding food with over-standard rates of 16.7%, 12.5%, 5.1%, 60%, 50%, 50%, 38.2%, 44.4%, 44.4%, 31.8%, and 31.8%, respectively.The results of the deterministic assessment of health risks showed that the total noncarcinogenic risk value of dietary intake of toxic metals by the local population was 5.6106, indicating that toxic metals pose a high noncarcinogenic risk. The order of the non-carcinogenic risk is HI_cereal (1.2104) > HI_{solanaceous fruit} (0.9134) > HI_Vegetables (0.8726) > HI_Fruit (0.8170) > HI_Meat (0.7269) > HI_{Drinking water} (0.6139) > HI_Beans (0.2991) > HI_Potatoes (0.1573). The total carcinogenic health risk from exposure to toxic metals through dietary intake was 9.98 × 10^-4, indicating that the total cancer risk value of residents is beyond the acceptable range (10^-4) under the current daily dietary exposure and implies a high risk of cancer. The order of the carcinogenic risk is R_{Drinking water} (2.34 × 10^-4) > R_Meat (2.11 × 10^-4) > R_{solanaceous fruit} (1.89 × 10^-4) > R_Fruit (1.88 × 10^-4) > R_cereal (1.36 × 10^-4) > R_Potatoes (2.44 × 10^-5) > R_Vegetables (1.51 × 10^-5) > R_Beans (0). The probabilistic assessment results showed that 98.83% of the population is exposed to severe noncarcinogenic risk and 87.02% is exposed to unacceptable carcinogenic risk. The sensitivity analysis showed that drinking water, local cereals, vegetables, and fruits were the major contributors to health risks. Our results indicated that the daily dietary exposure of residents in industrial regions of northern Ningxia poses a serious threat to human health, and it is suggested that relevant departments should strengthen monitoring and control of the current situation of toxic metal pollution in the environment and continue to pay attention and take measures to reduce the exposure of toxic metals in the diets of residents in this area.

Status, social norms, or safety? understanding intended and reported bottled water use in Urban Mashhad, Iran

Personal plastic-bottled water use is highly commodified, raising an array of cost and environmental concerns, and continues to grow globally. Studies in lower-income nations suggest safety as a primary motivation for such water purchases, but studies in high-income nations with greater relative affordability suggest it is more tied to socially situated consumer decisions like status and aesthetics. Here, we consider what motivates bottled water use in an urban city (Mashhad) in a middle-income predominantly Muslim country (Iran), where there is a likely intersection of safety (due to contamination), social norms, and status concerns. Surveys were collected with a random population-representative sample of resident adults from discrete households (n = 970). Structured equation modeling testing the relative effects on reported bottled water intentions and use shows that all these factors are shaping people's decisions. Both higher- and lower-income residents' responses suggest that status and social norms considerably influence intentions to use. Overall, even despite real safety issues with tap water, social norms and status concerns seem to weigh more heavily on residents' decisions to drink bottled water.

Contamination and Human Health Risk Assessment of Toxic Trace Elements in Drinking Water of Gilgit-Baltistan, Pakistan

This study investigated the contamination level and risk associated with toxic trace elements in springs’ water from Gilgit-Baltistan, Pakistan. Toxic trace elements, including Hg, As, and Zn, were analyzed by metalyzer, HM 2000 serial no. MY-011-006, while elements such as Cr, Al, B, Ni, Cu, Mn, and Fe were analyzed using Metalometer HM 2000 serial no. MM005-007, the United Kingdom. The mean concentrations of TTEs in water samples from Skardu were ordered as, Mn < Cu < Fe < Zn < Al < Cr < As < Ni < Hg, in Gilgit, Mn < Cu < Zn < Ni < B < Cr < Fe < As < Hg, in Ghizer Cu < Mn < Zn < Ni < Cr < Fe < As < Hg, while in Nagar the concentration of TTEs in water samples were ordered as Cu < Mn < Fe < Ni < Al < Cr < Zn < As < Hg. Results obtained from this study showed that the concentrations of As, Hg, Ni, Cr, Al, and Mn in some water samples were higher than the limits recommended by WHO and Pak-NDWQS. However, the chronic daily intake indices (CDIs) and health risk index (HRI) in all samples were found below the US-EPA standards. The correlation analysis revealed a positive association among different elements, which revealed that the sources of TTES in water samples were mainly geological strata and anthropogenic activities.