Hydrogeochemical characterization and human health risk assessment for heavy metal contamination in coastal aquifers: A case study in Satkhira District, Bangladesh.

Heavy or toxic metals are metals which are harmful beyond the permissible level to human health and are heavier in density than water by more than five times. Living organisms require varying amounts of heavy metals. Heavy metals like copper, manganese, cobalt, iron, zinc and molybdenum are required by living organisms in a small amount. Soil is a crucial component of rural and urban environments, and in both places land management is the key to soil quality. This paper review was aimed to touch the accumulation, assessment and importance of some heavy metals in agricultural soils and to understand the present situation and the impact of heavy metal contamination of soils in the world, in this review, compare and analyze the contamination of various cities/countries, and explore background, impact and remediation methods of heavy metal contamination of soils. Their accumulation in crops and pollution to soil can decrease crop yield, quality and cause detrimental effect to human health through food chain. Heavy metals can enter to human through inhalation, ingestion, body contact and skin absorption. In recent years, with the development of the global economy, both type and content of heavy metals in the soil caused by human activities have gradually increased, resulting in the deterioration of the environment.

Toxic Environment of war: Maternal prenatal heavy metal load predicts infant emotional development

Heavy metal contamination poses significant risks to marine ecosystems and human health. This study investigates the impact of heavy metal contamination on the phytochemical profiles of two marine crustacean species, Farfantepenaeus notialis and Macrobrachium vollenhovenii. Samples of these crustaceans were collected from Bodija Market, Ibadan, Nigeria, and analyzed for heavy metal content (Cu, Cd, Pb, Hg, As) and phytochemical constituents including alkaloids, flavonoids, saponins, tannins, anthraquinones, terpenoids, cardiac glycosides, steroids, and phenols. The heavy metal analysis revealed that Farfantepenaeus notialis had concentrations of Cu at 0.592 ± 0.03 mg/g and Pb at 0.080 ± 0.06 mg/g, while Macrobrachium vollenhovenii had lower concentrations of Cu (0.331 ± 0.07 mg/g) and Pb (0.061 ± 0.02 mg/g). Phytochemical screening showed that Farfantepenaeus notialis had higher levels of alkaloids (1.65 ± 0.004% w/w), flavonoids (0.35 ± 0.17% w/w), and saponins (0.80 ± 0.002% w/w) compared to Macrobrachium vollenhovenii, which had lower concentrations of these compounds (alkaloids: 0.75 ± 0.002% w/w, flavonoids: 0.12 ± 0.10% w/w, saponins: 0.75 ± 0.001% w/w). Both species were positive for steroids and cardiac glycosides but lacked detectable levels of tannins and phenols. These results indicate that heavy metal contamination significantly influences the phytochemical composition of marine crustaceans. The higher heavy metal levels in Farfantepenaeus notialis correlated with higher phytochemical concentrations, whereas Macrobrachium vollenhovenii showed lower phytochemical levels, possibly due to its lower heavy metal accumulation. This comparative analysis underscores the need for ongoing monitoring of heavy metal pollution in marine environments and its effects on aquatic organisms' biochemical profiles.

Groundwater serves as a vital water source for a significant population in the Gujarat region of India. However, substantial contamination from heavy metals, pose a serious threat to human health through various pathways, including drinking water. The rapid industrial and agricultural growth in recent years has exacerbated heavy metal pollution in the state. This study focuses on assessing the heavy metal contamination in the groundwater of Gujarat using the Heavy Metal Pollution Index (HPI). The research covers the entire state, considering its diverse physical, climatic, topographical, and geographical conditions. The HPI scores obtained from individual studies highlight the extent of pollution caused by heavy metals. The overall findings underscore the severe problem of heavy metal contamination in Gujarat's groundwater and the associated health risks. Various other pollution indicators, including the Heavy Metal Evaluation Index, Degree of Contamination, Metal Index, and Water Pollution Index are discussed as tools to assess contamination levels. These indices compare concentrations of different heavy metals with established limits to determine the pollution level. The goal is to provide valuable insights for investors and policymakers in formulating strategies to manage and reduce heavy metal contamination across the state. Additionally, the paper explores effective, environmentally friendly, and economically viable treatment techniques to remove heavy metals from aquatic systems, safeguarding the environment. By employing pollution indicators and remedial actions, this study aims to guide efforts in mitigating the impact of heavy metal contamination in the groundwater of Gujarat.

Influence of seawater intrusion and heavy metals contamination on groundwater quality, Red Sea coast, Saudi Arabia

Comparison of microbial and meiofaunal community analyses for determining impact of heavy metal contamination

Rice is one of the major crops as well as the staple food in Malaysia. However, historical mining activity has raised a concern regarding heavy metal contamination in paddy plants, especially in Perak, a state with major tin mining during the late nineteenth century. Therefore, the objective of this study is to investigate the heavy metals (As, Cd, Pb, Cu, Cr) contamination in paddy soils and paddy plants in three districts in Perak. The content of heavy metals was determined using ICP-MS, while the absorption and transferability of heavy metals in the paddy plants were investigated through enrichment (EF) and translocation (TF) factors. Principal component analysis (PCA) was employed to recognize the pattern of heavy metal contaminations in different sampling areas. Health risk assessment was performed through calculation of various indices. The quantification results showed that root contained highest concentration of the studied heavy metals, with As exhibiting the highest concentration. The EF results revealed the accumulation of As, Cu, and Cr in the rice grains while PCA showed the different compositional pattern in the different sampling areas. The health risk assessment disclosed both noncarcinogenic and carcinogenic risks in the local adults and children. Overall, findings from this study show that heavy metal contamination poses potential health risks to the residents and control measure is required.

Soil resource availability regulates the response of micro-food web multitrophic interactions to heavy metal contamination.

Heavy metal contamination of agricultural fields has become a global concern as it causes a direct impact on human health. Rice is the major food crop for almost half of the world population and is grown under diverse environmental conditions, including heavy metal-contaminated soil. In recent years, the impact of heavy metal contamination on rice yield and grain quality has been shown through multiple approaches. In this review article, different aspects of heavy metal stress, that is uptake, transport, signaling and tolerance mechanisms, are comprehensively discussed with special emphasis on rice. For uptake, some of the transporters have specificity to one or two metal ions, whereas many other transporters are able to transport many different ions. After uptake, the intercellular signaling is mediated through different signaling pathways involving the regulation of various hormones, alteration of calcium levels, and the activation of mitogen-activated protein kinases. Heavy metal stress signals from various intermediate molecules activate various transcription factors, which triggers the expression of various antioxidant enzymes. Activated antioxidant enzymes then scavenge various reactive oxygen species, which eventually leads to stress tolerance in plants. Non-enzymatic antioxidants, such as ascorbate, metalloids, and even metal-binding peptides (metallothionein and phytochelatin) can also help to reduce metal toxicity in plants. Genetic engineering has been successfully used in rice and many other crops to increase metal tolerance and reduce heavy metals accumulation. A comprehensive understanding of uptake, transport, signaling, and tolerance mechanisms will help to grow rice plants in agricultural fields with less heavy metal accumulation in grains.

Background: Illegal gold mining activities around Kayeli Bay have led to increased heavy metal contamination that has the potential to impair water quality and growth of Enhalus acoroides, an important seaweed species. This study aimed to investigate the distribution and concentration of heavy metals Pb and Hg in Enhalus acoroides organs (roots, rhizomes, and leaves) using SEM-EDX techniques and evaluate the impact of mining activities on the surface microstructure of these organs. Methods: Enhalus acoroides samples were collected from ten sampling points in Kayeli Bay, which were selected based on potential heavy metal contamination. SEM-EDX analysis was performed to assess the surface microstructure and distribution of heavy metals in the seaweed samples. Results: Results showed significant differences in Pb and Hg concentrations among samples from different locations, with Hg content consistently higher than Pb. Surface microstructure analysis showed morphological changes in roots, rhizomes, and leaves exposed to heavy metals, indicating environmental stress in Enhalus acoroides. Conclusion: This study confirmed the negative impact of heavy metal contamination on Enhalus acoroides in Kayeli Bay due to illegal gold mining activities. High concentrations of heavy metals, especially Hg, in seaweed organs indicate potential risks to marine ecosystem health and the sustainability of fisheries resources. These findings emphasize the need for stricter environmental monitoring and management to protect this important marine habitat from heavy metal pollution.

The ecosystem and human health are seriously at risk from contamination of heavy metals in water. A variety of pollution indices are used in this study to analyze the presence of heavy metal contamination in groundwater and used Monte Carlo simulation to quantify the health hazards associated with it. In two seasons the pre‐monsoon and post‐monsoon groundwater samples were taken in triplicate from 25 sites in South Kashmir, which is situated in the southern portion of the northwest Himalayas. The research area had higher than average quantities of heavy metals, according to the results. The cold climate probably had no seasonal influence on groundwater quality, but concentrations were generally greater in pre‐monsoon than in the post‐monsoon. To evaluate contamination, the study employed the following pollution indices: NPI (80%), HEI (76%), MI (80%), CoD (76%), and HPI (0%). There were found to be strong correlations between these indices, with R2 values of 0.96, 0.94, 0.96, and 0.95 between HEI and HPI, HEI and MI, HEI and Cd, and HEI and NPI, among other high correlations. The results of the Monte Carlo simulation for many exposure pathways showed that youngsters had a greater 95th percentile of carcinogenic risk than adults. The heavy metals were graded according to their non‐carcinogenic risk using the Hazard Index (HI) as follows: Pb > Ni > Mn > Cd > Cu > Fe > Zn. For adults, the non‐carcinogenic risk was shown to be 4.92E‐01, while for children, it was 1.41E+01. Human health risk evaluations also showed that youngsters had a greater overall cancer risk (OCR) (1.61E‐01) than adults (4.74E‐03).Practitioner Points Groundwater Quality Monitoring: The study highlights the critical need for regular groundwater quality monitoring, particularly in areas prone to heavy metal contamination, like South Kashmir. This is essential for the early detection of hazardous metal levels and the mitigation of public health risks. Use of Pollution Indices: Pollution indices such as NPI, HEI, MI, and CoD can be effective tools for assessing and quantifying heavy metal contamination in water sources, providing a comprehensive understanding of the contamination levels. Health Risk Assessment: Monte Carlo simulations for human health risk assessments underscore the importance of prioritizing children's health, as they are at greater risk of carcinogenic and non‐carcinogenic effects from heavy metal exposure. Seasonal Impact on Contamination: While seasonal variations in groundwater quality were not significant due to the cold climate, higher contamination levels were detected during the pre‐monsoon period. This indicates the need for heightened monitoring before monsoon seasons in similar climatic regions.

Predicting the spatio-temporal distribution of absorbable heavy metals in soil is needed to identify the potential contaminant sources and develop appropriate management plans to control these hazardous pollutants. Therefore, our aim was to develop a model to predict soil adsorbable heavy metals in arid regions of Iran from 1986 to 2016. Soil adsorbable heavy metals were measured in 201 samples from locations selected using the Latin hypercube sampling method in 2016. A random forest (RF) model was used to determine the relationship between a suite of geospatial predictors derived from remote sensing and digital elevation model data with georeferenced measurements of soil absorbable heavy metals. The trained RF model from 2016 was used to reconstruct the spatial distribution of soil absorbable heavy metals at three historical timesteps (1986, 1999, and 2010). Results indicated that the RF model was effective at predicting the distribution of heavy metals with coefficients of determination of 0.53, 0.59, 0.41, 0.45, and 0.60 for Fe, Mn, Ni, Pb, and Zn, respectively. The predicted maps showed high spatio-temporal variability; for example, there were substantial increases in Pb (the 1.5–2 mg/kg−1 class) where its distribution increased by ~25% from 1988 to 2016—similar trends were observed for the other heavy metals. This study provides insights into the spatio-temporal trends and the potential causes of soil heavy metal contamination to facilitate appropriate planning and management strategies to prevent, control, and reduce the impact of heavy metal contamination in soils.

Although Iran’s Ghaen Plain provides saffron to much of the world, no regional groundwater quality (GQ) assessment has yet been undertaken. Given the region’s potential for saltwater intrusion and heavy metal contamination, it is important to assess the GQ and determine its main probable source of pollution (MPSP). Such knowledge would allow for informed mitigation or elimination of the potential adverse health effects of this groundwater through its use as drinking water, or indirectly as a result of the consumption of groundwater-irrigated crops. Total dissolved solids, sodium, and chloride in the water of the majority of 16 wells sampled within the region exceeded World Health Organization and Iranian permissible standards for drinking water. The groundwater proved to only be suitable for irrigating salt tolerant crops under good drainage conditions. Due to the precipitation of calcium carbonate in the water supply facilities, the water from all wells was deemed unsuitable for industrial purposes. Heavy metal pollution and contamination indices showed no groundwater contamination. Analysis of ionic ratios and the application of principal components analysis indicated the MPSP to be saltwater intrusion, with the geology subtending the plain, and to a lesser extent, anthropogenic activities. Reducing groundwater withdrawals, particularly those for agricultural production by using high performance irrigation methods could reduce saltwater intrusion and improve GQ in the Ghaen Plain.

ABSTRACTThis study investigates groundwater quality in Raebareli district, India, with a specific focus on heavy metal contamination and its implications for human health and ecological risk. The district, part of the central Indo‐Gangetic alluvium, is representative of regions facing significant groundwater pollution challenges. Using indices such as the heavy metal pollution index (HPI) and the ecological risk index (ERI), contamination levels were assessed through weighted arithmetic methods and sub‐index calculations. The study identified lead (Pb) as the predominant contaminant, affecting 93.75% of analyzed water samples, with 59.3% of sites classified as critically polluted and unsuitable for drinking or other purposes. Health risk assessments revealed that cadmium (Cd) posed the highest noncarcinogenic and carcinogenic risks among the detected metals. Hazard quotient analysis indicated that children were more vulnerable to noncarcinogenic chronic health risks, particularly from Pb ingestion, which exceeded safe thresholds at 20 stations for adults and 22 stations for children. Cd contributed to 78.2% of carcinogenic risks in children and 75% in adults. Ecological risk assessments showed that 50% of the samples posed low ecological risks, 46.8% moderate risks, and 3.1% considerable risks. Statistical tools, including Pearson's correlation, hierarchical cluster analysis (HCA), and principal component analysis (PCA), revealed significant associations between metal pairs, distinct clustering patterns, and contamination sources, both natural and anthropogenic. The findings emphasize the urgent need for public awareness programs and rapid mitigation measures to safeguard groundwater resources and public health. Prolonged exposure to the detected heavy metals is linked to severe health conditions, such as neurological disorders, kidney damage, cardiovascular issues, and cancer, highlighting the critical need for sustainable water resource management. This study provides essential baseline data and insights to support informed decision‐making and effective mitigation strategies for addressing heavy metal contamination in groundwater.

The current research study evaluated the health and environmental risks issues associated with potentially toxic elements (PTEs) in the complex terminal aquifer located in the Algerian desert. The methods used included principal component and cluster (dendrogram) analysis to estimate source of ions and contamination. Various indices such as the Heavy Metal Pollution Index (HPI), Metal Index, hazard quotient, hazard index (HI), and cancer risk (CR) were applied to assess both environmental and human health risks. Furthermore, the Monte Carlo method was applied for probabilistic assessment of carcinogenic and non-carcinogenic risks through oral and dermal exposure routes in both adults and children. The results revealed that approximately 16% of the samples fell within the low pollution category (HPI < 100), indicating relatively lower levels of heavy metal contamination. However, the remaining 84% of the samples exhibited high pollution levels, indicating a significant presence of heavy metal pollutants in the northeastern part of the investigated area. The calculated average risk index (RI) for the collected samples was 18.99, with a range from 0.03 to 103.21. This indicates that a large portion, 82% of the samples, could cause low ecological risk (RI < 30), whereas the remaining 18% indicate a significant environmental pollution risk. The HI for oral ingestion showed that adults had HI values ranging from 0.231 to 1.54, while children exhibited higher values, ranging from 0.884 to 5.9 (Fig. 5a). For dermal exposure, HI values in adults ranged from 2.71E−07 to 8.74E−06 and in children, from 2.18E−06 to 7.03E−05. These findings highlight the potential non-carcinogenic risks associated with oral exposure to PTEs and underscore the increased vulnerability of children to metals such as Fe, Mn, Pb, and Cr. Most samples showed CR exceeding 1 × 10−4 for chromium (Cr) and lead (Pb), indicating a significant vulnerability to carcinogenic effects in both children and adults.