Heavy metal contamination of drinking water in Kamrup district, Assam, India

Atmospheric mercury species at Nam Co (4730 m a.s.l.), a highland background site in the inland Tibetan Plateau: implications of mercury potential sources

A field survey was conducted in the central Tibetan Plateau (Nam Co) in China for high-time resolution measurements of gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particle-bound mercury (PBM). Average concentrations (± 1 SD) of GEM, PBM, and GOM from November 2014 to March 2015 were 1.11 ± 0.20 ng m-3, 50.8 ± 26.5 pg m-3, and 3.6 ± 3.2 pg m-3, respectively. During the monitoring period, both GEM and GOM exhibited relative stability in their monthly variations, whereas PBM concentrations were significantly higher in winter compared to those in later autumn and early spring. In terms of diurnal variations, the maximum concentration of GEM was typically observed after sunrise, while PBM reached its peak before sunrise, and the highest concentration of GOM was recorded in the afternoon. Vertical convection conditions, photochemical production, and gas-particle partitioning were responsible for the diurnal cycle of atmospheric mercury. Based on modeling results, it was determined that the air mass transported from South Asia significantly impacted atmospheric mercury levels at Nam Co Station. The regions of western and central Nepal, central and eastern Pakistan, and northern India were identified as potential sources of atmospheric mercury at Nam Co.

Evaluation of hydrogeochemical processes and saltwater intrusion in the coastal aquifers in the southern part of Puri District, Odisha, India

Groundwater is widely regarded as being among the freshwater natural resources with the lowest levels of contamination. Nevertheless, the saltwater intrusion has resulted in the contamination of groundwater in coastal regions with lower elevation. The rationale of the present work is to investigate the chemistry of groundwater, to identify the various facies of groundwater, to identify the processes that influence groundwater chemistry and saltwater intrusion, and to evaluate the groundwater's aptness for use in drinking and farming. In order to gain an understanding of the groundwater quality as well as the salinization process that occurs in coastal aquifers as a result of hydrogeochemical processes, a total of 108 groundwater samples (54 each in pre- and post-monsoon) were taken and analyzed for several physiochemical parameters in the southern part of the Puri district in the Indian state of Odisha. The data has undergone analysis and examination to identify the factors (such as hydrological facies, potential solute source in water, and salinization process) that contribute to groundwater salinity. The result showed the chemistry controlling processes of rock-water interaction as per Gibbs diagram. The majority of shallow aquifers exhibit the Na-Cl type of facies as per the Piper plot. A total of 37% pre-monsoon and 33% post-monsoon samples having Na+/Cl- ratio below the threshold of 0.86 indicating the influence of saltwater intrusion. In both seasons, it was observed that 74% of the samples exhibited a Na+ concentration that exceeded the permissible limit set by the World Health Organization (WHO) for drinking purposes. The findings indicate that most groundwater failed to pass safe drinking water and irrigation standards due to saltwater intrusion. Consequently, the monitoring of coastal aquifer quality has become imperative in order to ensure the sustainability of aquifers and the development of groundwater resources. This is because coastal aquifers are highly vulnerable to saltwater intrusion, primarily as a result of the extensive extraction of groundwater for diverse purposes.

Hydrogeochemical characteristics of groundwater contamination in Guwahati city, Assam, India: Tracing the elemental Threads

Groundwater serves as an important resource for drinking and agriculture in many countries, including India. Assessing the quality of groundwater is essential for understanding its chemical characteristics and suitability for consumption. This study aims to explore the factors affecting the hydrogeochemical changes in groundwater within Guwahati City, Assam, India. Groundwater samples were collected and analyzed for major and trace elements, as well as anion concentrations. Concentrations of As, Al, Ba, Cu, F-, Fe, Mn, and Pb exceeded the permissible limits set by both World Health Organization (WHO) and Bureau of Indian Standards (BIS), indicating serious health concerns for the local inhabitants. The distribution pattern of trace elements exceeding the guideline values is intricate, suggesting widespread contamination of groundwater throughout the study area. The Heavy Metal Pollution Index (HPI) and Water Quality Index (WQI) revealed that, except for the central zone, groundwater across the entire study area requires intervention. Piper plot illustrated that the groundwater is predominantly of Ca-HCO3 type, indicating the dominance of alkaline earth and weak acids. Groundwater hydrogeochemistry is mainly controlled by rock-water interaction and evolves through silicate weathering, carbonate weathering, and cation exchange processes. Multivariate statistical analysis identified distinct groups of groundwater based on chemical characteristics, emphasizing the role of both natural processes and anthropogenic activities in influencing groundwater quality. Regular monitoring, management, and intervention of groundwater sources throughout the study area are crucial for long-term use. The findings of this study will assist stakeholders, regulators, and policymakers in formulating strategies for the sustainable use of groundwater.

Groundwater quality assessment using water quality index and principal component analysis in the Achnera block, Agra district, Uttar Pradesh, Northern India

The qualitative and quantitative assessment of groundwater is one of the important aspects for determining the suitability of potable water. Therefore, the present study has been performed to evaluate the groundwater quality for Achhnera block in the city of Taj, Agra, India, where groundwater is an important water resource. The groundwater samples, 50 in number were collected and analyzed for major ions along with some important trace element. This study has further investigated for the applicability of groundwater quality index (GWQI), and the principal component analysis (PCA) to mark out the major geochemical solutes responsible for origin and release of geochemical solutes into the groundwater. The results confirm that, majority of the collected groundwater samples were alkaline in nature. The variation of concentration of anions in collected groundwater samples were varied in the sequence as, HCO3- > Cl- > SO42- > F- while in contrast the sequence of cations in the groundwater as Na > Ca > Mg > K. The Piper diagram demonstrated the major hydro chemical facies which were found in groundwater (sodium bicarbonate or calcium chloride type). The plot of Schoellar diagram reconfirmed that the major cations were Na+ and Ca2+ ions, while in contrast; major anions were bicarbonates and chloride. The results showed water quality index mostly ranged between 105 and 185, hence, the study area fell in the category of unsuitable for drinking purpose category. The PCA showed pH, Na+, Ca2+, HCO3- and fluoride with strong loading, which pointed out geogenic source of fluoride contamination. Therefore, it was inferred that the groundwater of the contaminated areas must be treated and made potable before consumption. The outcomes of the present study will be helpful for the regulatory boards and policymaker for defining the actual impact and remediation goal.

Occurrence, Source and Dietary Exposure of Toxic and Essential Elements in the Indian Food Basket

In this study, representative urban and peri-urban Indian food baskets have been studied for the presence of toxic and essential elements. The concentration of target toxic and essential elements was used to estimate dietary intakes (EDIs) and health risks. Across all food matrices, toxic elements like Cd and Pb were dominant. The highest concentrations of the target elements were found in vegetables, with Cd, Pb, and Ni being beyond permissible limits of the Food and Agriculture Organization of the United Nations and the World Health organization (0.05 mg/kg, 0.1 mg/kg, and 1.5 mg/kg, respectively) in okra, spinach, and cauliflower. The sum of concentrations of the toxic elements (As, Ni, Hg, Cr, Cd, Pb) in vegetables had a range of 0.54-12.08 mg/kg, the highest sum was found in spinach (median 12.08 mg/kg), followed by okra (median 1.68 mg/kg). The EDI was observed for vegetables with a contribution as high as 92% for Cd. Dairy products were found with the highest loading for Ni with a dietary intake of 3.1 mg/kg/day for adults and twice as much for children. Carcinogenic risk for Ni was the highest and found above the threshold for all food categories, as was the case with As. Cumulative carcinogenic and non-carcinogenic risks were mostly contributed by milk and vegetables, in particular, spinach.

Groundwater contamination status in Malaysia: level of heavy metal, source, health impact, and remediation technologies

Groundwater is defined as water that exists underground in voids or gaps in sediments and is extracted for human consumption from aquifers. It is critical to our daily lives because it contributes to the sustainability of our natural ecosystem while also providing economic benefits. Heavy metals are metallic compounds with a relatively high atomic weight and density compared to water. In Malaysia, heavy metal contamination of groundwater has become a concern due to rapid population growth, economic development, and a lack of environmental awareness. Environmental factors or their behaviors, such as density, viscosity, or volume, affect the distribution and transportation of heavy metals. The article discusses the difficulties created by the presence of heavy metals in groundwater supplies and the resulting health problems. Additionally, remediation methods are discussed for managing contaminated water to preserve the ecological environment for current and future generations, as well as their advantages and disadvantages.

Distribution of self-reported health in India: The role of income and geography

An important new large-scale survey database is brought to bear on measuring and analysing self-reported health in India. The most important correlates are age, income and location. There is substantial variation of health across the 102 'homogeneous regions' within the country, after controlling for household and individual characteristics. Higher income is correlated with better health in only 40% of India. We create novel maps showing regions with poor health, that is attributable to the location, that diverge from the conventional wisdom. These results suggest the need for epidemiological studies in the hotspots of ill-health and in regions where higher income does not correlate with improved health.

Relationship between blood manganese and bone mineral density and bone mineral content in adults: A population-based cross-sectional study

PURPOSE

It has been reported that bone is the primary organ for manganese (Mn) accumulation, but the association between manganese and bone loss remains debatable. Therefore, this study aimed to evaluate the relationship between blood manganese and bone mineral density/bone mineral content (BMD/BMC) by using a representative sample from the National Health and Nutrition Examination Survey (NHANES).

METHODS

A total of 9732 subjects over the age of 18 with available data were enrolled in this study. The relationship between blood manganese and BMD/BMC of the total body, spine and femoral regions was evaluated using multivariate linear regression models. Subgroup analyses were also performed.

RESULTS

We observed a negative association between blood manganese and BMD/BMC in the femoral neck and total body in the fully adjusted model, especially femoral neck BMD in women aged 50-70 years.

CONCLUSION

In brief, people exposed to manganese should be aware of the increased risk of osteopenia or osteoporosis. Besides, due to the lack of available data, there are no definite values for the tolerable upper intake level (UL), average requirement (AR) and population reference intake (PRI) of manganese. The results of our study may provide some references for the establishment of AR, PRI and UL of Mn.

A comprehensive study on aquatic chemistry, health risk and remediation techniques of cadmium in groundwater

Cadmium (Cd), a non-essential trace element, it's intrusion in groundwater has ubiquitous implications on the environment and human health. This review is an approach to comprehensively emphasize on i) chemistry and occurrence of Cd in groundwater and its concomitant response on human health ii) sustainable Cd remediation techniques, iii) and associated costs. Current study is depending on meta-analysis of Cd contaminations in groundwater and discusses its distributions around the globe. Literature review primarily comprises from the last three decades online electronic published database, which mainly includes i) research literatures, ii) government reports. On the basis of meta-data, it was concluded that Cd mobility depends on multiple factors: such as pH, redox state, and ionic strength, dissolved organic (DOC) and inorganic carbon (DIC). A substantially high Cd concentration has been reported in Lagos, Nigeria (0.130 mg/L). In India, groundwater is continuing to be contaminated by Cd in the proximity of industrial, agricultural areas, high concentrations (>8.20 mg/L) were reported in Tamil Nadu and Maharashtra. Depending on chemical behavior and ionic radius cadmium disseminate into the food chain and ultimately cause health hazard that can be measured by various index-based assessment tools. Instead of chemical adsorbents, nanoparticles, phytoextraction, and bioremediation techniques can be very useful in the remediation and management of Cd polluted groundwater at a low-cost. For Cd pollution, the development of a comprehensive framework that links the hydro-geological, bio-geochemical processes to public health is important and need to be further studied.

Drinking water elements constituent profiles and health risk assessment in Wuxi, China

Water elements pollution has attracted public attention globally. Wuxi is located in East China, and its water source, Taihu Lake, has been severely polluted since 2007. Studies of elemental pollution profiles have yet to be conducted in this area. In this study, 56 water samples were collected in 2018, and 33 elements were determined using inductively coupled plasma-mass spectrometry (ICP-MS). The results showed that the levels of 33 elements ranged from 1.35 × 10^-3 μg/L(Tl) to 101 mg/L(Ca), with Sr, Al, Fe, B, Ti, Ba, and Zn levels being relatively higher. A comprehensive literature review showed spatial distribution of conspicuous elements in drinking water worldwide. Meanwhile, Monte Carlo simulations were applied to evaluate exposure health risks. The total hazard index(HI) for 14 non-carcinogens and the average incremental lifetime cancer risk (ILCR) of As and Pb exposure through drinking water were found acceptable. Sensitivity analyses suggested that Sb and As in the drinking water represent an increasing risk to human health. The results of this study provide key data on local metal pollution characteristics, help identify potential risk factors, and contribute to the development of effective environmental management policies for Taihu Lake.

Application of neural network in metal adsorption using biomaterials (BMs): a review

ANN models for predicting wastewater treatment efficacy of biomaterial adsorbents.

Heavy metals drinking water contamination and health risk assessment among primary school children of Pakistan

The purpose of this study was to characterize the concentrations of lead (Pb), cadmium (Cd), manganese (Mn), and Fe (Fe) in drinking water sources in primary schools in Sindh Province, Pakistan and to quantify potential health risks among those school children. We conducted a representative, cross-sectional study among 425 primary schools in Sindh province of Pakistan. We used risk assessment models to estimate the metal index, pollution index, lifetime cancer risk, and hazard quotient index. Across the 425 sampled schools, the levels of heavy metals in the drinking water often exceeded the WHO permissible limits (67% of schools exceeded Pb limit, 17% for Cd, 15% for Fe). The average incremental lifetime cancer risk (ILCR) for Pb exceeded tolerable limits in all of the districts under study. The findings, particularly for Pb, are of concern, as Pb may negatively influence children's growth, development, school performance, and long-term health.

Removal of Cd(II) from Micro-Polluted Water by Magnetic Core-Shell Fe3O4@Prussian Blue

A novel core-shell magnetic Prussian blue-coated Fe3O4 composites (Fe3O4@PB) were designed and synthesized by in-situ replication and controlled etching of iron oxide (Fe3O4) to eliminate Cd (II) from micro-polluted water. The core-shell structure was confirmed by TEM, and the composites were characterized by XRD and FTIR. The pore diameter distribution from BET measurement revealed the micropore-dominated structure of Fe3O4@PB. The effects of adsorbents dosage, pH, and co-existing ions were investigated. Batch results revealed that the Cd (II) adsorption was very fast initially and reached equilibrium after 4 h. A pH of 6 was favorable for Cd (II) adsorption on Fe3O4@PB. The adsorption rate reached 98.78% at an initial Cd (II) concentration of 100 μg/L. The adsorption kinetics indicated that the pseudo-first-order and Elovich models could best describe the Cd (II) adsorption onto Fe3O4@PB, indicating that the sorption of Cd (II) ions on the binding sites of Fe3O4@PB was the main rate-limiting step of adsorption. The adsorption isotherm well fitted the Freundlich model with a maximum capacity of 9.25 mg·g-1 of Cd (II). The adsorption of Cd (II) on the Fe3O4@PB was affected by co-existing ions, including Cu (II), Ni (II), and Zn (II), due to the competitive effect of the co-adsorption of Cd (II) with other co-existing ions.

Cadmium exposure as a key risk factor for residents in a world large-scale barite mining district, southwestern China

Cadmium (Cd) contamination is easily generated during the mining and manufacturing of barium (Ba). In this study, concentrations of both Ba and Cd in rice, vegetables, pork, fish, drinking water, and soil samples from an active barite mining district were determined. Daily intakes of Ba and Cd, as well as corresponding health risks, were evaluated. The average total daily exposure doses of Cd were 0.0035 and 0.0012 mg/kg BW/day (geometric mean) in the mining zone (MZ) and the chemical plant zone (PZ), respectively. These values significantly exceed the provisional tolerable monthly intake (25 μg/kg BW/month, equal to 0.00083 mg/kg BW/day). Based on the daily exposure doses, vegetable consumption was the most significant Ba exposure route for residents, contributing around 66.1% of the total exposure. In contrast, rice consumption was the major Cd exposure pathway, accounting for about 85.6% of the total exposure. Although the geometric mean (0.17) and 95th percentile (P95, 0.75) of the total hazard quotient (HQ) for Ba were below the acceptable level (1), suggesting that there were no significant health effects caused by Ba exposure, Cd exposure was associated with significant health risks, with the geometric mean of the HQ (1.7) and the P95 (21) well above the acceptable limit (1), indicating the unacceptable non-carcinogenic risk of Cd exposure. In summary, high Cd exposure risk, rather than Ba, was observed for populations living in a large-scale active Ba mining area.

The combined exposure of microplastics and toxic contaminants in the floodplains of north India: A review

Microplastics in aquatic ecosystem are an emerging environmental threat, primarily aggregating into sediments and living biota besides providing active transportation to toxic pollutants. Recent studies have revealed that a microplastic surface cannot be considered as "inert" and therefore the rate and stage of degradation of microplastic will determine its capability in adsorbing and transporting the solute to longer distances. Our concern is driven by the fact that there has been an absence of widescale research in India despite a country with one of the longest networks of rivers and a 7500 km long active coastline. Anthropogenic pollutants are expected to increase and the situation will further worsen when more persistent organic pollutants (POCs) and geogenic contaminants will find its sink via monsoon runoff. Studies on aquatic species including COD, daphnia magna and zebrafish suggest strong links of bio-accumulation, suspecting to a more serious situation for the coastal India where there is an almost three times increase in the density of the microplastics as the monsoon progresses. Evidences also suggests that microplastics can adsorb known carcinogens as well as endocrine disrupting chemicals leaving our aquatic life exposed to higher mortality. Our review is a first ever scientific attempt in compiling these evidences through researches done in this field to understand the risk that the major floodplains of North India are currently facing. We have adapted the theories and inferences of the available research to predict and postulate a probable mechanism that could explain the severity of the situation in India.

Drinking water pollutants may affect the immune system: concerns regarding COVID-19 health effects

The current coronavirus pandemic is leading to significant impacts on the planet, changing our way of life. Although the COVID-19 virus mechanisms of action and pathogenesis are still under extensive research, immune system effects are evident, leading, in many cases, to respiratory distress. Although apparent pollution reduction has been noticed by the population, environmental and human health impacts due to the increased use of plastic waste and disinfectants is concerning. One of the main routes of human exposure to pollutants is through drinking water. Thus, this point of view discusses some major contaminants in drinking water known to be immunotoxic, exploring sources and drinking water routes and emphasizing the known mechanisms of action that could likely compromise the effective immune response of humans, particularly raising concerns regarding people exposed to the COVID-19 virus. Based on a literature review, metals, plastic components, plasticizers, and per- and polyfluoroalkyl substances may display the potential to exacerbate COVID-19 respiratory symptoms, although epidemiological studies are still required to confirm the synergistic effects between these pollutants and the virus.

Occurrence of Heavy Metals in Groundwater Along the Lithological Interface of K/T Boundary, Peninsular India: A Special Focus on Source, Geochemical Mobility and Health Risk

Evaluation of the hydrogeochemical processes governing the heavy metal distribution and the associated health risk is important in managing and protecting the health of freshwater resources. This study mainly focused on the health impacts due to the heavy metals pollution in a known Cretaceous-Tertiary (K/T) contact region (Tiruchinopoly, Tamilnadu) of peninsular India, using various pollution indices, statistical, and geochemical analyses. A total of 63 samples were collected from the hard rock aquifers and sedimentary formations during southwest monsoon and analysed for heavy metals, such as Li, Be, Al, Rb, Sr, Cs, Ba, pb, Mn, Fe, Cr, Zn, Ga, Cu, As, Ni, and Co. Ba was the dominant element that ranged from 441 to 42,638 μg/l in hard rock aquifers, whereas Zn was the major element in sedimentary formations, with concentrations that ranged from 44 to 118,281 μg/l. The concentrations of Fe, Ni, Cr, Al, Cr, and Ni fell above the permissible limit in both of the formations. However, the calculated heavy metal evaluation index (HEI), heavy metal pollution index (HPI), and the degree of contamination (C_d) parameters were higher in the sedimentary formation along the contact zone of the K/T boundary. Excessive health risks from consumption of contaminated groundwater were mostly confined to populations in the northern and southwestern regions of the study area. Carcinogenic risk assessment suggests that there are elevated risks of cancer due to prolonged consumption of untreated groundwater. Ba, Sr, and Zn were found to be geochemically highly mobile due to the partitioning between the rock matrix and groundwater, aided by the formation of soluble carbonato-complexes. Factor analysis indicates that the metals are mainly derived from the host rocks and anthropogenic inputs are relatively insignificant. Overall, this study indicated that groundwater in K/T contact zones is vulnerable to contamination because of the favorable geochemical factors. Long-term monitoring of such contact zones is required to avert the potential health hazards associated with consumption of the contaminated groundwater.

Microbial and plant-assisted heavy metal remediation in aquatic ecosystems: a comprehensive review

Heavy metal (HM) pollution in aquatic ecosystems has an adverse effect on both aquatic life forms as well as terrestrial living beings, including humans. Since HMs are recalcitrant, they accumulate in the environment and are subsequently biomagnified through the food chain. Conventional physical and chemical methods used to remove the HMs from aquatic habitats are usually expensive, slow, non-environment friendly, and mostly inefficient. On the contrary, phytoremediation and microbe-assisted remediation technologies have attracted immense attention in recent years and offer a better solution to the problem. These newly emerged remediation technologies are eco-friendly, efficient and cost-effective. Both phytoremediation and microbe-assisted remediation technologies adopt different mechanisms for HM bioremediation in aquatic ecosystems. Recent advancement of molecular tools has contributed significantly to better understand the mechanisms of metal adsorption, translocation, sequestration, and tolerance in plants and microbes. Albeit immense possibilities to use such bioremediation as a successful environmental clean-up technology, it is yet to be successfully implemented in the field conditions. This review article comprehensively discusses HM accumulation in Indian aquatic environments. Furthermore, it describes the effect of HMs accumulation in the aquatic environment and the role of phytoremediation as well as microbe-assisted remediation in mitigation of the HM toxicity. Finally, the review concludes with a note on the challenges, opportunities and future directions for bioremediation in the aquatic ecosystems.

Heavy metals in drinking water: Occurrences, implications, and future needs in developing countries

Heavy metals in drinking water pose a threat to human health. Populations are exposed to heavy metals primarily through water consumption, but few heavy metals can bioaccumulate in the human body (e.g., in lipids and the gastrointestinal system) and may induce cancer and other risks. To date, few thousand publications have reported various aspects of heavy metals in drinking water, including the types and quantities of metals in drinking water, their sources, factors affecting their concentrations at exposure points, human exposure, potential risks, and their removal from drinking water. Many developing countries are faced with the challenge of reducing human exposure to heavy metals, mainly due to their limited economic capacities to use advanced technologies for heavy metal removal. This paper aims to review the state of research on heavy metals in drinking water in developing countries; understand their types and variability, sources, exposure, possible health effects, and removal; and analyze the factors contributing to heavy metals in drinking water. This study identifies the current challenges in developing countries, and future research needs to reduce the levels of heavy metals in drinking water.

Results of heavy metals and other water quality levels in tap water from Çan sourced from Ağı Dağı (Mt. Ağı) (Çanakkale, Turkey)

In this study, the concentrations of heavy metals Pb, Cu, Zn, Cd, Ni, Fe, Mn and Cr were determined using an inductively coupled plasma and optical emission spectrophotometer (ICP-OES), and water quality parameters pH, temperature, and conductivity were measured using the YSI 556 MPS water probe. The water samples were collected monthly from five different street tap water points sourced from Mt. Agi (Ağı Dağı in Turkish) spring waters between May 2012 and February 2013 in Çan (Canakkale, Turkey). All results were compared with the drinking water standards of the Turkish Standards Institute (TSE 266), World Health Organization, European Union and US Environmental Protection Agency. While concentrations of Cu, Zn, Fe, and Mn were within limit values, Pb, Cd, Ni, and Cr were at undetectable limits. The highest concentrations of Cu, Zn, Fe, and Mn were 0.010 ppm, 0.018 ppm, 0.058 ppm, and 0.014 ppm, respectively. The findings revealed that although there was no public health risk in view of heavy metal concentrations, there was an acidity problem due to lower pH levels correlated with some heavy metals such as Cu (R = 0.419), Fe (R = -0.421) and Mn (R = -0.687).

Human health risk assessment via drinking water pathway due to metal contamination in the groundwater of Subarnarekha River Basin, India

Groundwater samples were collected from 30 sampling sites throughout the Subarnarekha River Basin for source apportionment and risk assessment studies. The concentrations of As, Ba, Cd, Cr, Co, Cu, Fe, Mn, Mo, Ni, Se, Sr, V and Zn were determined using inductively coupled plasma-mass spectrometry (ICP-MS). The results demonstrated that concentrations of the metals showed significant spatial variation with some of the metals like As, Mn, Fe, Cu and Se exceeding the drinking water standards at some locations. Principal component analysis (PCA) outcome of four factors that together explained 84.99 % of the variance with >1 initial eigenvalue indicated that both innate and anthropogenic activities are contributing factors as source of metal in groundwater of Subarnarekha River Basin. Risk of metals on human health was then evaluated using hazard quotients (HQ) and cancer risk by ingestion for adult and child, and it was indicated that Mn was the most important pollutant leading to non-carcinogenic concerns. The carcinogenic risk of As for adult and child was within the acceptable cancer risk value of 1 × 10(-4). The largest contributors to chronic risks were Mn, Co and As. Considering the geometric mean concentration of metals, the hazard index (HI) for adult was above unity. Considering all the locations, the HI varied from 0.18 to 11.34 and 0.15 to 9.71 for adult and child, respectively, suggesting that the metals posed hazard by oral intake considering the drinking water pathway.

Metal leaching in drinking water domestic distribution system: an Italian case study

The objective of this study was to evaluate metal contamination of tap water in seven public buildings in Brescia (Italy). Two monitoring periods were performed using three different sampling methods (overnight stagnation, 30-min stagnation, and random daytime). The results show that the water parameters exceeding the international standards (Directive 98/83/EC) at the tap were lead (max = 363 μg/L), nickel (max = 184 μg/L), zinc (max = 4900 μg/L), and iron (max = 393 μg/L). Compared to the total number of tap water samples analyzed (122), the values higher than limits of Directive 98/83/EC were 17% for lead, 11% for nickel, 14% for zinc, and 7% for iron. Three buildings exceeded iron standard while five buildings exceeded the standard for nickel, lead, and zinc. Moreover, there is no evident correlation between the leaching of contaminants in the domestic distribution system and the age of the pipes while a significant influence is shown by the sampling methods.

The influence of drinking-water pollution with heavy metal on the expression of IL-4 and IFN-γ in mice by real-time polymerase chain reaction

In recent years, water pollution has been converted to a challenging discussion in health area of human being. Heavy elements are one of the most important water pollutants and their negative adverse effects on body systems have been confirmed. In this study, investigation of effects of two heavy elements including lead (Pb) and copper (Cu) on expression of interlukin-4 (IL-4) and interferon-gamma (IFN-γ) as humoral and cellular immunity biomarkers, respectively, was aimed and PCR, real-time PCR and electrophoresis techniques were used. In this study, BALB/c mice were studied that had free access to drinking water which contained Cu or Pb salts. After 2 weeks, spleens of mice were removed, RNA extracted, and cDNA was prepared for RT-PCR. Then the expression of IL-4 and IFN-γ genes were assessed by real-time PCR. The expression of IFN-γ was up-regulated in both treated groups and the expression of IL-4 was only up-regulated in the group treated with Cu and down-regulated in the group treated with Pb. This study shows that the presence of heavy elements as drinking-water pollutants results in a disproportion of natural cytokines balances, and thus may result in a negative effect on immune system.

Heavy metal contaminations in the groundwater of Brahmaputra flood plain: an assessment of water quality in Barpeta District, Assam (India)

A study was conducted to evaluate the heavy metal contamination status of groundwater in Brahmaputra flood plain Barpeta District, Assam, India. The Brahmaputra River flows from the southern part of the district and its many tributaries flow from north to south. Cd, Fe, Mn, Pb, and Zn are estimated by using atomic absorption spectrometer, Perkin Elmer AA 200. The quantity of heavy metals in drinking water should be checked time to time; as heavy metal accumulation will cause numerous problems to living being. Forty groundwater samples were collected mainly from tube wells from the flood plain area. As there is very little information available about the heavy metal contamination status in the heavily populated study area, the present work will help to be acquainted with the suitability of groundwater for drinking applications as well as it will enhance the database. The concentration of iron exceeds the WHO recommended levels of 0.3 mg/L in about 80% of the samples, manganese values exceed 0.4 mg/L in about 22.5% of the samples, and lead values also exceed limit in 22.5% of the samples. Cd is reported in only four sampling locations and three of them exceed the WHO permissible limit (0.003 mg/L). Zinc concentrations were found to be within the prescribed WHO limits. Therefore, pressing awareness is needed for the betterment of water quality; for the sake of safe drinking water. Statistical analysis of the data was carried out using Special Package for Social Sciences (SPSS 16).