HUMAN HEALTH RISK ASSESSMENT OF HEAVY METALS IN DRINKING WATER SOURCES IN THREE SENATORIAL DISTRICTS OF ANAMBRA STATE, NIGERIA

Spatial variations and health risk assessment of heavy metal levels in groundwater of Qatar

The present work's objective is to give a comprehensive overview of the quality of groundwater in Qatar in terms of heavy metals content as well as investigating the cause and effect of the elevation in their levels above the WHO/US-EPA standards. The scope of the study included (1) physical and chemical analysis of 82 groundwater samples collected from various locations around Qatar, (2) development of ArcGIS maps depicting the variations in the levels, (3) assessment of the human health risks associated with the existing levels using three of the most used models which are: Hazard index (HI), Nemerow comprehensive pollution index (NCPI) and Incremental Lifetime Cancer Risk (ILCR). There is no extensive study ever reported to assess the health risks linked with the consumption of groundwater characterized with such heavy metals levels in Qatar. The chronic daily intake (CDI) of the investigated heavy metals (Ag, Mn, Cr, V, Mo and Sr) through ingestion and dermal pathways had a range of 1.4 × 10-5-6.7 × 10-1 mg/kg/day while the NCPI's range was reported at 0-4.39. Moreover, the HI and ILCR were found to have a range of 0-3.2 and 5.6 × 10-4-5.5 × 10-2, respectively. The assessment of health risks, conducted in the present work, could be beneficial in building the baseline of heavy metals levels in groundwater in Qatar. This will also help in the determination of any future contamination of groundwater.

Renoprotective effect of hyperin against CdCl2 prompted renal damage by activation of Nrf-2/Keap-1 ARE pathway in male mice

OBJECTIVES

This study explored the mitigating properties of hyperin (HYP) on renotoxicity induced by cadmium chloride (CdCl2).

METHODS

Four groups of seven male albino mice each were used in this experiment. Group 1 served as the control, receiving no treatment. Group 2 received daily oral gavage of CdCl2 at 0.3 mg/kg body weight for 28 d. Group 3 received both CdCl2 (0.3 mg/kg) and HYP (100 mg/kg) daily using the same administration method. Finally, Group 4 received only HYP (100 mg/kg) daily.

RESULTS

Cd exposure significantly increased kidney dysfunction markers (blood urea nitrogen and creatinine) and oxidative stress (reactive oxygen species [ROS] and malondialdehyde [MDA]). Conversely, it decreased antioxidant enzyme activities (glutathione peroxidase (GPx] and catalase [CAT]) and glutathione (GSH) levels. Nuclear factor erythroid 2-related factor 2 (Nrf-2) and antioxidant gene expression decreased, while Kelch-like ECH-associated protein 1 expression increased. Additionally, Cd exposure increased inflammatory mediators (nuclear factor kappa B, tumor necrosis factor alpha [TNF-α], interleukin-1β [IL-1β], and cyclooxygenase-2) and apoptotic markers (Bax and caspase-3), alongside decreased Bcl-2 expression and renal tissue abnormalities. Mitochondrial dysfunction manifested with diminished activities of Krebs cycle and respiratory chain enzymes, and reduced mitochondrial membrane potential. Co-treatment with HYP significantly attenuated these detrimental effects through its anti-apoptotic, antioxidant, and anti-inflammatory properties.

CONCLUSION

HYP co-treatment significantly attenuated CdCl2-induced renal damage in mice, suggesting its potential as a protective agent against Cd-induced kidney toxicity.

Evaluating the human health risks of heavy metal contamination in copper and steel factory effluents in Nnewi, Anambra State, Nigeria

Heavy metal (HM) contamination above permissible limits poses a risk to human health. The study evaluated the health risk (cancer and non-cancer) of exposure to copper (Cu) and steel factory wastes on water samples near the factory based on the hazard quotient (HQ) derived from the HM concentrations. Triplicate water samples were collected by purposive sampling and their concentrations of selected HMs [Pb, Zn, Cu, Mn, Mg, Fe, Cd] were analyzed by Atomic Absorption Spectrometry. The health risks were determined from the concentrations of HMs in water samples ingested orally. The range concentrations were [Fe, 0.074-0.178], [Pb, 0.011-0.013], [Cd, 0.005-0.02], and [Mn, 0.023-0.045] which were above the reference values set by World Health Organization. The contribution of the individual metal to the chronic daily intake (CDI) in the three samples are Mg>Fe>Mn>Zn>Cd>Pb>Cu. In the three different samples, the CDI for Mg was highest in the factory borehole [0.15523]. Comparing the CDI values from the three different collection points, Cu, Pb, Zn and Fe were highest from the factory effluent. Mg contributed the highest HQ [5.46307] in all the water samples, followed by Pb [3.87618] and then Cd[2.64009], which reflect their significantly high hazard indices observed. The incremental life cancer risk [ILCR] via ingestion showed that the cancer risk resulting from Cd in the different sources demands attention. The factory effluent recorded the highest mean levels of the metals analyzed, which were higher than the permissible limits. Magnesium contributed the highest non-cancer risk, while Cd had the highest cancer risk.

Exposure to Nickel-Cadmium Contamination of Drinking Water Culminates in Liver Cirrhosis, Renal Azotemia, and Metabolic Stress in Rats

Drinking water polluted by heavy metals has the potential to expose delicate biological systems to a range of health issues. This study embraced the health risks that may arise from subchronic exposure of thirty-four male Wistar rats to nickel (Ni)-cadmium (Cd)-contaminated water. It was done by using the Box-Behnken design (BBD) with three treatment factors (Ni and Cd doses at 50-150 mg/L and exposure at 14-21-28 days) at a single alpha level, resulting in seventeen experimental combinations. Responses such as serum creatinine (CREA) level, blood urea nitrogen (BUN) level, BUN/CREA ratio (BCR), aspartate and alanine aminotransferases (AST and ALT) activities, and the De Ritis ratio (DRR), as well as malondialdehyde (MDA) level, catalase (CAT), and superoxide dismutase (SOD) activities, were evaluated. The results revealed that these pollutants jointly caused hepatocellular damage by raising AST and ALT activities and renal dysfunction by increasing CREA and BUN levels in Wistar rats' sera (p < 0.05). These outcomes were further supported by BCR and DRR values beyond 1. In rats' hepatocytes and renal tissues, synergistic interactions of these metals resulted in higher MDA levels and significant impairments of CAT and SOD activities (p < 0.05). In order to accurately forecast the effects on the responses, the study generated seven acceptable regression models (p < 0.05) with r-squared values of > 80% at no discernible lack of fit (p > 0.05). The findings hereby demonstrated that Wistar rats exposed to these pollutants at varied doses had increased risks of developing liver cirrhosis and azotemia marked by metabolic stress.

Environmental exposures to cadmium and lead as potential causes of eye diseases

Humans are exposed to cadmium and lead in various regions of the world daily due to industrial development and climate change. Increasing numbers of preclinical and clinical studies indicate that heavy metals, such as cadmium and lead, play a role in the pathogenesis of eye diseases. Excessive exposure to heavy metals such as cadmium and lead can increase the risk of impaired vision. Therefore, it is essential to better characterize the role of these non-essential metals in disease etiology and progression. This article discusses the potential role of cadmium and lead in the development of age-related eye diseases, including age-related macular degeneration, cataracts, and glaucoma. Furthermore, we discuss how cadmium and lead affect ocular cells and provide an overview of putative pathological mechanisms associated with their propensity to damage the eye.

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.

Occurrence, distribution, source apportionment, ecological and health risk assessment of heavy metals in water, sediment, fish and prawn from Ojo River in Lagos, Nigeria

The study investigates the occurrence and bioaccumulation of heavy metals in water, sediment, fish, and prawn from the Ojo River with a view to identify the source of origin and the associated ecological and human health risks. The result shows that heavy metal concentrations in water [As = 0.010, Cd = 0.001, Cr = 0.041, Cu = 0.019, Co = 0.050, Fe = 0.099, Pb = 0.006, Ni = 0.003, and Zn = 0.452(mg/L)] were within the acceptable limits. The heavy metals in the sediment [As = 0.050, Cd = 0.287, Cr = 0.509, Cu = 0.207, Co = 0.086, Fe = 33.093, Pb = 0.548, Ni = 0.153 and Zn = 4.249 (mg/kg)] were within their respective background levels or earth's crust and the TEL and PEL standard limits. The bioaccumulation of heavy metals in fish and prawn tissues are in this hierarchical form: Fe > Zn > Cu > Cr > Ni > Co > Pb > Ar > Cd and Fe > Zn > Cu > Cr > Pb > Ar > Ni > Co > Cd, respectively. The bioaccumulation factors of heavy metals in fish ranged from 0.893 - 16.611 and 1.056 - 49.204 in prawn, which were higher than the biota-sedimentation factors (BSAF) values, inferring that the fish and prawns of this study ingested heavy metals highly from water column. The aggregated BSAF scores (fish = 5.584 and prawn = 9.137) showed that these organisms are good concentrators of heavy metals in sediments. The water quality index and other pollution indices (Single pollution index, Heavy metal assessment index, and Heavy metal pollution index) demonstrates slightly clean water, with a moderate level of contamination. The HI values of heavy metals in water, fish, and prawn were lower than 1, implying non-carcinogenic risk in children or adults. The ADD and EDI values of the metals were within their respective oral reference doses (RfD). The TCR values showed that exposure to water, either by ingestion or dermal absorption and the consumption of P. obscura and M. vollenhovenii from the Ojo River would not induce cancer risks in people, though As, Cr, Cd, and Pb showed carcinogenic potentials. The sediment contamination indices such as CF, mCd, EF, and Igeo showed a moderate level of pollution. The ecological risk values (NMPI, mCd = 0.068, PLI = 0.016, and R.I = 86.651) of heavy metals implies "no-moderate risk" except for Cd, which showed high risk. The ecotoxicological parameters,  m-PEL-Q (0.024) and m-ERM-Q (0.016) denotes low contamination and no probability of acute toxicity. The CV analysis showed high dispersions and variabilities in the distributions of the heavy metals in water. Other source analyses (Pearson's correlation matrix, PCA, and HCA) showed that both natural processes and anthropogenic activities are responsible for the occurrence of heavy metals in water and sediment from the Ojo River.

Prediction of human health risk and disability-adjusted life years induced by heavy metals exposure through drinking water in Fars Province, Iran

Exposure to heavy metals in contaminated drinking water is strongly correlated with various cancers, highlighting the burden of disease. This study aimed to assess the non-carcinogenic and carcinogenic risks associated with exposure to heavy metals (As, Pb, Cd, and Cr) in drinking water of Fars province and evaluate the attributed burden of disease. Non-carcinogenic risk assessment was performed using the hazard quotient (HQ) method, while the carcinogenic risk assessment utilized the excess lifetime cancer risk approach. The burden of disease was evaluated in terms of years of life lost, years lived with disability, and disability-adjusted life years (DALY) for three specific cancers: skin, lung, and kidney cancer. The average drinking water concentrations of arsenic (As), cadmium (Cd), chromium (Cr) and lead (Pb) were determined to be 0.72, 0.4, 1.10 and 0.72 μg/L, respectively. The total average HQ of heavy metals in drinking water in the study area were 0.127, 0.0047, 0.0009 and 0.0069, respectively. The average ILCRs of heavy metal in the entire country were in the following order: 1.15 × 10-5 for As, 2.22 × 10-7 for Cd and 3.41 × 10-7 for Cr. The results also indicated that among the various counties analyzed, Fasa experiences the greatest burden of disease in terms of DALYs, with a value of 87.56, specifically attributed to cancers caused by exposure to arsenic. Generally, it can be said that the burden of disease is a critical aspect of public health that requires comprehensive understanding and effective intervention.

Assessment of Hg pollution in stream waters and human health risk in areas impacted by mining activities in the Ecuadorian Amazon

Illegal gold mining activities have contributed to the release and mobilization of Hg and environmental degradation in many parts of the world. This study aims to determine the concentration of Hg in five provinces of the Amazon Region of Ecuador, in addition to assessing the risk to human health of exposed populations, applying deterministic and probabilistic methods. For this purpose, 147 water samples were collected in rivers and streams crossing and/or located near mining areas. As a result, 100% of the samples analyzed exceeded the maximum permissible limit (MPL) according to the water quality criteria for the preservation of aquatic life of the Ecuadorian regulations, while 7% of the samples exceeded the MPL for drinking water. On the other hand, considering the European Environmental Quality Standard (EQS) for surface water bodies, in our study, 100% of the samples exceed the maximum permissible limit (0.07 µg/L), and with respect to the Canadian water quality guidelines, 35% of the samples exceed the permissible limit (0.001 mg/l) for drinking water, and 100% of the samples exceed the limit for life in water bodies (0.0001 mg/l). The risk assessment revealed that the probability of developing adverse health effects from exposure to Hg is below the recommended limits according to the probabilistic assessment; this is in relation to the criterion of residential and recreational use of water resources. However, it was identified that the child population doubles the acceptable systemic risk level according to the results of the deterministic assessment in the residential scenario. This information can be used by decision-makers to implement strategies to reduce Hg contamination and exposure of the population in Ecuadorian Amazonian rivers.

Multifunctional cobalt oxide nanocomposites for efficient removal of heavy metals from aqueous solutions

In this study, co-precipitation synthesis of natural clay (NC) with Co₃O₄ nanoparticles (NPs) is carried out to elaborate the super NC@Co₃O₄ nanocomposites with admirable salinity confrontation, environmental stability and reusability, to eliminate heavy metal pollution such as toxic Pb(II) and Cd(II) ions. The advantages of using the NC@Co₃O₄ adsorbent are easy synthesis and biocompatibility. In addition, NC@Co₃O₄ can keep an excellent adsorption capacity by taking into account various environmental parameters such as the pH solution, NC@Co₃O₄ dose, adsorption process time and the initial heavy metals concentration. Furthermore, FTIR, XRD, TGA, SEM-EDS, TEM and AFM analyses were performed to confirm NC@Co₃O₄ nanocomposites synthesis and characterisation. The adsorption efficiencies of Pb(II) and Cd(II) ions by NC@Co₃O₄ nanocomposites were demonstrated to be up to 86.89% and 82.06% respectively. Regarding the adsorption from water onto the NC@Co₃O₄ nanocomposites, kinetics data were well fitted with PSO kinetic model, whereas a good agreement was found between the equilibrium adsorption and theoretical Langmuir isotherm model leading to maximum adsorption capacities of 55.24 and 52.91 mg/g, for Pb(II) and Cd(II) respectively. Monte Carlo (MC) simulations confirmed the spontaneous of this adsorption based on the negative values of E_ads. The MC simulations were performed to highlight the interactions occurring between heavy metal ions and the surface of NC@Co₃O₄ nanocomposites, these were well correlated with the experimental results. Overall the study showed that NC@Co₃O₄ nanoadsorbents have strongly versatile applications and are well designed for pollutant removal from wastewater due to their unique adsorptive properties.