Appraisal of heavy metals in groundwater in Chennai city using a HPI model

Evaluation of heavy metals in ground and surface water in Ranipet, India utilizing HPI model

Ranipet is an industrial hub located 120 km away from Chennai houses around 250 tanneries beside other industries. Tanneries and Tamil Nadu Chromate and Chemicals Limited (TCCL) generated and dumped tons of chromium waste on land and water bodies which is the major threat to the people living in the area for several years. In this study, heavy metal pollution in Ranipet industrial zone was estimated using the Heavy Metal Pollution Index (HPI) model along with spatial distribution maps. The level of Cd, Cu, Cr, Pb, Ni and Zn in ground and surface water was measured using standard methods, and the results were utilized to make the HPI model. It was observed that the metal level was in the order of Zn > Pb > Ni > Cu > Cr > Cd and Cr > Pb > Zn > Cd > Cu > Ni in ground and surface water respectively. All the ground water samples exhibited high HPI of (> 38). Except one sample with low HPI (˂ 19), and three surface water samples held in midrange (19-38), the other surface water samples displayed high HPI of (> 38). The average HPI of ground and surface water is 500.42 and 523.78. The HPI and spatial distribution of heavy metals revealed that the Cr contamination in Ranipet industrial estate is originated from the premises of TCCL.

Impact of acid mine drainage on groundwater hydrogeochemistry at a pyrite mine (South China): a study using stable isotopes and multivariate statistical analyses

Combining environmental isotope analysis with principal component analysis can be an effective method to discriminate the inflows and sources of contamination in mining-affected watersheds. This paper presents a field-scale study conducted at an acid mine drainage (AMD)-contaminated site adjacent to a pyrite mine in South China. Samples of surface water and groundwater were collected to investigate transport in the vadose zone using stable isotopes of oxygen (δ¹⁸O) and hydrogen (δD) as environmental tracers. Principal component analysis of hydrogeochemical data was used to identify the probable sources of heavy metals in the AMD. The heavy metal pollution index (HPI) was applied to evaluate the pollution status of heavy metals in the groundwater. The groundwater associated with the Datai reservoir was recharged by atmospheric precipitation and surface water. On the side near the AMD pond, the groundwater was significantly affected by the soluble metals produced by pyrite oxidation. The concentrations of some metals (Al, Mn, and Pb) in all of the samples exceed the desirable limits prescribed by the World Health Organization (Guidelines for drinking-water quality, 4th edn. World Health Organization, Geneva, 2011). Among them, the concentration of Al is more than 30,000 times higher than the desirable limits prescribed by the World Health Organization (2011), and the concentration of Mn is more than 3000 times higher. The HPI values based on these heavy metal concentrations were found to be 10-1000 times higher than the critical pollution index value of 100. These findings provide a reference and guidance for research on the migration and evolution of heavy metals in vadose zone water in AMD-contaminated areas.

Assessment of environmental and toxicity impacts and potential health hazards of heavy metals pollution of agricultural drainage adjacent to industrial zones in Egypt

The objectives of this study were to assess the environmental impact of industrial wastewater disposal in the El-Khadrawiya agricultural drain, Menoufia Governorate, Egypt, as well as the effect on water, soil, and plant qualities in the drain's extension area, which was primarily adjacent to the industrial zone. The analyses results of wastewater at El-Khadrawiya drain revealed that heavy metal concentrations in water samples exceeded WHO permitted limits. Heavy metal levels followed the following pattern: (Pb > Zn > Cr > Cd > Ni > As), where Heavy metal levels average were: (1.8492 > 1.7857 > 0.1815 > 0.1578 > 0.059 > 0.0048. Wastewater, soil and plant samples were analyzed using (PerkinElmer AAnalyst 400 Atomic Absorption Spectrometer A Analyst 400), Heavy metal pollution evaluation indicators: Target hazard quotient (THQ), Hazard index (HI), Chronic daily intake (CDI), Carcinogenic risk (CR), and Heavy metals pollution index (HPI)) showed that a majority of samples discovered values referring to carcinogenic health risks for the population. In contrast, the soil contamination indices followed the same trend, with the contamination factor (CF) indicating that the majority of samples exposed low to medium levels of pollution for (Ni, Cd, and Zn), while Pb and Cr were between high and very high, and the contamination degree (Cd) and modified degree of contamination (mCd) indicating that the majority of samples revealed the medium level of pollution, with the exception of one site with a high level of contamination. The bioaccumulation factor (BAF) revealed that heavy metal accumulation in plants exceeds the critical range. This study should be expanded to include additional agricultural regions with comparable conditions in order to provide environmental monitoring of present challenges and work toward solutions.

Contamination level, source identification and health risk evaluation of potentially toxic elements (PTEs) in groundwater of an industrial city in eastern India

The present investigation explores the spatial and seasonal variations in potentially toxic element (PTEs) concentrations and contamination level assessment of groundwater samples in and around the Asansol industrial city, eastern India. The representative samples of groundwater from 24 different locations were analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH) and PTEs, e.g., Pb, Cu, Cd, Zn, Fe and Cr for pre-monsoon and post-monsoon. The pH level of examined groundwater samples is under the desirable limit with few exceptions (S5, S11 and S16 in pre-monsoon and S12 in post-monsoon). The recorded values for Pb, Cd, Fe and Cr in many sampling stations found higher than the prescribed limits of Indian standards (IS 10500: 2012) in both the seasons. The mean contamination factor (C_f) for PTEs in the groundwater is in the order of Cr > Fe > Cd > Pb > Cu > Zn and Fe > Cr > Cd > Pb > Cu > Zn, with mean contamination index (C_d) value of 2.83 and 2.72 in pre-monsoon and post-monsoon season, respectively, indicating moderate level of contamination in the examined area. Geospatial depiction of HPI values shows high level of contamination during pre-monsoon (58.3% sampling sites) and post-monsoon (45.8% sampling sites) in majority of sampling sites. Further, application of multivariate statistical analysis ascertains that the PTEs in groundwater are majorly derived from anthropogenic activities such as opencast mining, thermal power plants, iron and steel industries, sponge iron and other metallurgical industries, and leachate from urban and industrial wastes along with limited contribution from geogenic and lithogenic sources. The health risk assessment demonstrates that the non-carcinogenic risk (due to PTEs) in adults is in the sequence of Cr > Cd > Pb > Fe > Cu > Zn, while for children the order is Cr > Pb > Cd > Fe > Cu > Zn for both the seasons. The results also reveal higher chance of occurrence of carcinogenic risk due to Cr (ILCR > 1.0E-04) for children and adults in both the seasons.

In Situ Measurements of Domestic Water Quality and Health Risks by Elevated Concentration of Heavy Metals and Metalloids Using Monte Carlo and MLGI Methods

The domestic water (DW) quality of an island province in the Philippines that experienced two major mining disasters in the 1990s was assessed and evaluated in 2021 utilizing the heavy metals pollution index (MPI), Nemerow’s pollution index (NPI), and the total carcinogenic risk (TCR) index. The island province sources its DW supply from groundwater (GW), surface water (SW), tap water (TP), and water refilling stations (WRS). This DW supply is used for drinking and cooking by the population. In situ analyses were carried out using an Olympus Vanta X-ray fluorescence spectrometer (XRF) and Accusensing Metals Analysis System (MAS) G1 and the target heavy metals and metalloids (HMM) were arsenic (As), barium (Ba), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni), and zinc (Zn). The carcinogenic risk was evaluated using the Monte Carlo (MC) method while a machine learning geostatistical interpolation (MLGI) technique was employed to create spatial maps of the metal concentrations and health risk indices. The MPI values calculated at all sampling locations for all water samples indicated a high pollution. Additionally, the NPI values computed at all sampling locations for all DW samples were categorized as “highly polluted”. The results showed that the health quotient indices (HQI) for As and Pb were significantly greater than 1 in all water sources, indicating a probable significant health risk (HR) to the population of the island province. Additionally, As exhibited the highest carcinogenic risk (CR), which was observed in TW samples. This accounted for 89.7% of the total CR observed in TW. Furthermore, all sampling locations exceeded the recommended maximum threshold level of 1.0 × 10⁻⁴ by the USEPA. Spatial distribution maps of the contaminant concentrations and health risks provide valuable information to households and guide local government units as well as regional and national agencies in developing strategic interventions to improve DW quality in the island province.

Groundwater fauna downtown - Drivers, impacts and implications for subsurface ecosystems in urban areas

Groundwater fauna (stygofauna) comprises organisms that have adapted to the dark subterranean environment over a course of thousands and millions of years, typically having slow metabolisms and long life cycles. They are crucial players in the groundwater of oxygenic aquifers, and contribute to various ecosystem services. Today's knowledge of their sensitivity to anthropogenic impacts is incomplete and a critical analysis of the general relevance of local findings is lacking. In this review, we focus on those areas with the highest interference between humans and stygofauna: cities. Here is where local pollution by various contaminants and heat strongly stresses the unique groundwater ecosystems. It is demonstrated that it is difficult to discern the influence of individual factors from the findings reported in field studies, and to extrapolate laboratory results to field conditions. The effects of temperature increase and chemical pollution vary strongly between tested species and test conditions. In general, previous findings indicate that heating, especially in the long-term, will increase mortality, and less adapted species are at risk of vanishing from their habitats. The same may be true for salinity caused by road de-icing in cold urban areas. Furthermore, high sensitivities were shown for ammonium, which will probably be even more pronounced with rising temperatures resulting in altered biodiversity patterns. Toxicity of heavy metals, for a variety of invertebrates, increases with time and chronic exposure. Our current knowledge reveals diverse potential impacts on groundwater fauna by urban pollution, but our insights gained so far can only be validated by standardized and long-term test concepts.

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.

Provincial and seasonal influences on heavy metals in the Noyyal River of South India and their human health hazards

This study was carried out to evaluate the heavy metals (Lead (Pb), Nickel (Ni), Chromium (Cr), Copper (Cu), Cadmium (Cd) and Zinc (Zn)) pollution in the Noyyal River of South India by collecting 130 river water samples (65 each in pre- and post-monsoon). The heavy metals were measured using Atomic Absorption Spectrophotometer (AAS). The data were used to calculate the associated health hazards for the inhabitants consume river water. Correlation analyses and average concentration of heavy metals denoted that post-monsoon metal concentrations were lesser compared to the pre-monsoon due to dilution effect. Modified Contamination Degree (MCD) indicated that 45% of pre-monsoon and 25% of post-monsoon samples were classified under extremely polluted category. Heavy metal pollution index (HPI) showed that all the regions fall under highly polluted category except 'Region I' where 20% of samples were under safe category during the pre-monsoon, whereas 9%,28%, 17% and 26% of samples in Regions I, II, III and IV were highly polluted during the post-monsoon season, respectively. Ecological Risk Index (ERI) revealed that high risks attained in Regions II (78%) and III (82%) during pre-monsoon, and reduced risks found in Regions II (28%) and III (45%) during post-monsoon season due to dilution by monsoon rainfall. Non-carcinogenic risks as inferred by the Hazard Index (HI) indicated that 78% and 52% of samples for infants, 75% and 49% of samples for teens and 71% and 45% of samples for adults exceeded the threshold limits of USEPA (HI > 1) and possessed risks during pre- and post-monsoon, respectively. The cancer risk assessment based on ingestion of heavy metals indicated that the order of risk is Ni > Cr > Cu. The HI for infants and teens was notably high to that of adults in both the seasons. This study will be useful to develop effective strategies for improving river water quality and to reduce human health hazards.

COVID-19 lockdown impacts on heavy metals and microbes in shallow groundwater and expected health risks in an industrial city of South India

In this investigation, the positive impact of COVID-19 lockdown on heavy metals concentration and biological parameters in the shallow groundwater samples of Coimbatore city of South India was ascertained. The groundwater samples (n=15) were obtained from shallow open wells during before lockdown (24-25 February 2020) and after lockdown (2-3 June 2020) periods. These samples were analysed for heavy metals (Fe, Mn, Ni, Cr and Pb) and biological parameters (E. coli, Fecal coliforms, Fecal streptococci and Total coliforms). Fe concentration was within the permissible limit but, the concentrations of Mn, Ni, Cr and Pb were above the allowable limits for drinking uses as per the WHO. However, after lockdown the number of samples crossing the cutoff limit had considerably decreased (Mn: from 2 to 0 mg/L; Ni: from 13 to 10 mg/L; Cr: 7 to 5 mg/L and Pb: from 13 to 8 mg/L). The heavy metal pollution index (HPI) revealed that 176.75 km² (67.4%) and 85.35 km² (32.6%) areas fell under unsuitable and very poor categories, respectively, during the pre-lockdown period, whereas 138.23 km² (52.6%), 118.98 km² (45.3%) and 4.89 km² (2.1%) areas fell under very poor, poor and good categories, respectively, during the post-lockdown period. Similarly, Total coliform, Fecal coliform and E. coli had decreased distinctly due to the pandemic lockdown. Therefore, the shutdown of small and large-scale industries during the lockdown period had improved the groundwater quality. The health risk assessment showed that 93%, 87% and 80% of pre-lockdown samples, and 87%, 80% and 73% of post-lockdown samples possessed non-carcinogenic risks (HI > 1) for children, female and male categories, respectively.

The use of statistical methods to assess groundwater contamination in the Lower Tano river basin, Ghana, West Africa

In this study, descriptive statistics, correlation matrix, multiple regression model, and geostatistical models were used to assess the contamination of groundwater with respect to trace elements in the Lower Tano river basin, Ghana, West Africa. A total number of 48 boreholes drilled across the basin with depths ranging from 18 to 60 m were used as data sources in this study. The results of the descriptive statistics showed that the average lead, iron, and aluminium concentrations exceeded the WHO permissible limits of 0.3 mg/L, 0.01 mg/L, and 0.2 mg/L respectively. Furthermore, copper, chromium, aluminium, zinc, manganese, nickel, iron, arsenic, electrical conductivity, and total dissolved solids were found to be extreme and highly positively skewed. Even though significant correlations exist among some variables, the statistical results showed that the quality of the boreholes drilled across the basin was mainly originating from geogenic and anthropogenic sources. In addition, each pair of correlated physical parameters and trace elements in the drilled boreholes were predicted using multiple regression models. Likewise, geostatistical modelling was used to assess the spatial analysis of each pair of correlated physical parameters and trace elements in the drilled boreholes. The cross-validation results revealed kriging model, as the most precise model for the spatial distribution maps for the correlated physical parameters, and correlated trace elements concentration in the boreholes drilled across the study region. The semivariogram models showed that most of the correlated physical parameters and correlated trace elements were weak moderately and strongly spatially dependent, suggesting fewer agronomic influences. The results of the spatial analysis were consistent with the multiple regression model and the Pearson correlation matrix.

A Hybrid Neural Network-Particle Swarm Optimization Informed Spatial Interpolation Technique for Groundwater Quality Mapping in a Small Island Province of the Philippines

Water quality monitoring demands the use of spatial interpolation techniques due to on-ground challenges. The implementation of various spatial interpolation methods results in significant variations from the true spatial distribution of water quality in a specific location. The aim of this research is to improve mapping prediction capabilities of spatial interpolation algorithms by using a neural network with the particle swarm optimization (NN-PSO) technique. Hybrid interpolation approaches were evaluated and compared by cross-validation using mean absolute error (MAE) and Pearson’s correlation coefficient (R). The governing interpolation techniques for the physicochemical parameters of groundwater (GW) and heavy metal concentrations were the geostatistical approaches combined with NN-PSO. The best methods for physicochemical characteristics and heavy metal concentrations were observed to have the least MAE and R values, ranging from 1.7 to 4.3 times and 1.2 to 5.6 times higher than the interpolation technique without the NN-PSO for the dry and wet season, respectively. The hybrid interpolation methods exhibit an improved performance as compared to the non-hybrid methods. The application of NN-PSO technique to spatial interpolation methods was found to be a promising approach for improving the accuracy of spatial maps for GW quality.

Spatial Analysis of Groundwater Hydrochemistry through Integrated Multivariate Analysis: A Case Study in the Urbanized Langat Basin, Malaysia

Rapid urbanization and industrial development in the Langat Basin has disturbed the groundwater quality. The populations' reliance on groundwater sources may induce possible risks to human health such as cancer and endocrine dysfunction. This study aims to determine the groundwater quality of an urbanized basin through 24 studied hydrochemical parameters from 45 groundwater samples obtained from 15 different sampling stations by employing integrated multivariate analysis. The abundance of the major ions was in the following order: bicarbonate (HCO₃^-) > chloride (Cl^-) > sodium (Na⁺) > sulphate (SO₄^2-) > calcium (Ca²⁺) > potassium (K⁺) > magnesium (Mg²⁺). Heavy metal dominance was in the following order: Fe > Mn > Zn > As > Hg > Pb > Ni > Cu > Cd > Se > Sr. Classification of the groundwater facies indicated that the studied groundwater belongs to the Na-Cl with saline water type and Na-HCO₃ with mix water type characteristics. The saline water type characteristics are derived from agricultural activities, while the mixed water types occur from water-rock interaction. Multivariate analysis performance suggests that industrial, agricultural, and weathering activities have contributed to groundwater contamination. The study will help in the understanding of the groundwater quality issue and serve as a reference for other basins with similar characteristics.

Metal Contamination of Groundwater Sources in the Environs of a Tropical Estuary in South India

The study was conducted to evaluate the metal pollution of groundwater sources in the residential areas in the surroundings of Kadinamkulam estuary, South India using the Heavy metal Pollution Index (HPI). For the study, forty one groundwater samples were collected during pre monsoon season from the dug wells of two gramapanchayaths and the concentration of heavy metals Cd, Cu, Zn, Cr, Pb and Fe were estimated and HPI was determined. Results of HPI show that 16.66% of groundwater sources in Azhoor and 21.73% in Kadinamkulam gramapanchayaths are in the low category and the remaining wells are classified in the high and medium category. The correlation analysis revealed that the sources of metals in groundwater in the study area are the leachates from the Kadinamkulam estuary, agricultural activities and solid wastes dumped in the nearby residential area. So the present study points out the metal pollution causes the degradation of the quality of groundwater which is the drinking water source of these gramapanchayaths.

Trace elements contamination in groundwater and associated human health risk in the industrial region of southern Sonbhadra, Uttar Pradesh, India

The present study assesses the pollution load of the groundwater with reference to the trace elements (i.e. As, Hg, Cd, Cr, Cu, Fe, Mn, Zn, Ni, Co and Pb) and the potential health risk by its consumption for the residents of Obra, Renukoot and Anpara industrial clusters of Southern Sonbhadra, Uttar Pradesh, India. For this, 220 groundwater samples were collected during post- and premonsoon seasons in 2015. pH varied from slightly acidic to alkaline in both the seasons. Geochemical analysis of the area showed that all the three clusters are severely contaminated with Fe, Pb, Cd, Cr, As and Hg during both the seasons. High concentration of heavy metals indicates that groundwater was contaminated with natural as well as anthropogenic sources. For all the three clusters, the mean values of heavy metal pollution index were found above the critical index in both the seasons with Anpara in lead. For the majority of groundwater samples across the clusters during both the seasons, substantial non-cancer health risk was observed due to target hazard quotient values of Cr, Cd, As, Pb and Hg higher than unity. The hazard index value for children was very high compared to adults which means that children are more susceptible to health impairment in terms of non-carcinogenic health risk. Carcinogenic risk was higher for adults than children in the entire study area.

Ecotoxicological effects of anthropogenic stressors in subterranean organisms: A review

How anthropogenic stressors affect biodiversity is a central question in a changing world. Subterranean ecosystems and their biodiversity are particularly vulnerable to change, yet, these species are frequently neglected in analyses of global biodiversity and assessments of ecological status and risk. Are these hidden species affected by anthropogenic stressors? Do they survive outside of the current thermal limits of their ecosystems? These and other important questions can be addressed with ecotoxicological testing, relating contaminants and temperature resistance of species with measured environmental concentrations and climatic data. Ecotoxicological knowledge specific to subterranean ecosystems is crucial for establishing thresholds for their protection, but such data are both scarce and scattered. Here, we review the existing ecotoxicological studies of these impacts to subterranean-adapted species. An effort that includes 167 measured endpoints and presents a database containing experimentally derived species' tolerance data for 28 contaminants and temperature, for 46 terrestrial and groundwater species, including fungi and animals. The lack of standard data among the studies is currently the major impediment to evaluate how stressors affect subterranean-adapted species and how differently they respond from their relatives at surface. Improving understanding of ecotoxicological effects on subterranean-adapted species will require extensive analysis of physiological responses to a wide range of untested stressors, standardization of testing protocols and evaluation of exposures under realistic scenarios.

Evaluation of groundwater contamination in Chandigarh: Source identification and health risk assessment

The major objective of the current study is to estimate the groundwater quality and identify the likely sources of contamination in Chandigarh, India. Total 80 groundwater samples were collected from different locations and at various depths. Further, physcio-chemical analysis was done to estimate pH, electrical conductivity (EC), total dissolved solids, total hardness (TH), total alkalinity (TA), Na⁺, K⁺, Cl^-, SO₄^2-, PO₄^3- and NO₃^-. The groundwater samples collected from shallow water sources contain higher concentration of total dissolved salts. EC, TA, Cl^-, TH, Na⁺, and K⁺ were found relatively higher in the shallow aquifer (<150 ft). Based on the location of pollution sources at the surface and consecutive geo-statistical distribution of physicochemical characteristics, this study suggests that non-scientific disposal of municipal solid waste, dumping of industrial waste and agricultural activities, in the nearby areas lead to the deterioration of groundwater of shallow aquifer. These observations were also confirmed using various water quality indices and outcomes of multivariate modeling, including principal component analysis. Health risk assessment for nitrates indicated that 29 groundwater samples pose non-carcinogenic health risk for children due to dermal and oral exposure. Hence, there is a need to establish a system for regularly assessing the groundwater quality to minimize public health risks.

Environmentally Sensitive Elements in Groundwater of an Industrial Town in India: Spatial Distribution and Human Health Risk

This paper presents the results of a study to assess the groundwater quality in an industrial town located in Punjab, India. A total of 99 samples of groundwater were analyzed during the premonsoon and postmonsoon periods of 2018, which revealed the presence of numerous environmentally sensitive elements (ESEs), namely, arsenic (As), aluminum (Al), chromium (Cr), iron (Fe), mercury (Hg), nickel (Ni), selenium (Se), and lead (Pb). Geographic information system (GIS)-based spatial interpolation showed higher contamination levels around the industrial areas and the drainage channel where industrial effluent is generally discharged. Further, groundwater quality was assessed using the heavy metal pollution index (HPI) and the metal index (MI), which indicated poor drinkability of the groundwater. Human exposure to groundwater contaminated with ESEs can pose serious health risks; therefore, noncarcinogenic and carcinogenic health risks due to presence of these elements were also evaluated. Reported health risks to humans from exposure to contaminated groundwater indicate the importance of regular monitoring of groundwater for ESEs vis-a-vis industrial effluent disposal practices.

Distribution and health risk assessment of arsenic and selected heavy metals in Groundwater of Chandigarh, India

Groundwater quality of Chandigarh was assessed by collecting 80 groundwater samples from different depths varying between 10 ft and 1200 ft. These samples were analyzed for possible contamination with metal pollutants such as Al, Cd, Co, Cr, Cu, Fe, Mo, Mg, Ni, Pb, V, Zn. Geospatial interpolation of the contaminants identified poor sanitary practices of waste management, agrarian activities, and industrial pollution as the prominent sources of groundwater contamination. Quality assessment of groundwater performed using Heavy metal Pollution Index (HPI), and Metal Index (MI) revealed HPI as a better method for health risk assessment. HPI indicate poor groundwater quality near municipal solid waste dumping sites and industrial areas of Chandigarh. The shallow aquifer was reported to be more contaminated than deeper aquifer. Further, health risk assessment of Chandigarh's groundwater indicated non-carcinogenic health impacts due to contamination of As, Cr, Co, Cd, Cu, Ni, Pb, Zn and carcinogenic health impacts from As, Cd, Cr, Cu, Pb. The study suggests that groundwater should also be regularly monitored for metal contamination as over-extraction, industrialization, disposal of municipal solid waste and informal E-waste recycling activities increases the public health risks in countries worldwide, facing similar environmental pollution problems of the groundwater.

A critical assay of heavy metal pollution index for the groundwaters of Peenya Industrial Area, Bangalore, India

Heavy metals, due to their non-biodegradability and tendency to cause detrimental effects in human beings, are considered as the most hazardous and toxic pollutants. The present investigation was taken up to evaluate the heavy metal concentrations in the groundwaters of Peenya Industrial Area in Bangalore. The concentration of six eco-toxic metals such as chromium, copper, cadmium, iron, nickel, and lead were analyzed for 30 groundwater sampling stations in the study area using atomic absorption spectrometer. The concentration of heavy metals followed the order Cr> Fe >Pb>Cu> Ni> Cd. The analysis results have been used to compute two pollution indices in the groundwater, namely heavy metal pollution index and metal index. Heavy metal pollution index is an effective method of rating and ascertaining the water quality with respect to heavy metals. An index value of 100 is considered to be critical, and on the basis of mean concentration, this value in the study area was observed to be 146.32, which is considerably higher than the stipulated critical index value. 63.33% of the groundwater samples are seen to be having an index far above the critical figure of 100. The mean concentration of metal index was 10.36 and it was seen that 46.67% of the groundwater samples fell under the seriously affected category (metal index values above 6). The results not only show that groundwater of the present study is unacceptable for drinking but also clearly indicate the influence of urban, industrial, and agricultural activities on the groundwaters of the said area. This study has massive relevance in designing control measures and action plans for reducing the pollutant influx into the groundwaters. Prompt enforcement of environmental protection laws is needed to prevent continuous pollution of the area. Further, an immediate and sustainable collective action by all stakeholders to control the pollution level is highly recommended, as this issue poses a severe public health threat.

Spatial and Temporal Heavy Metal Distribution and Surface Water Characterization of Kanjli Wetland (a Ramsar site), India Using Different Indices

Suitability of surface water of Kanjli wetland, Punjab (India) during the period of 2013-2015 was assessed for drinking, irrigation and aquatic life using a water quality index (WQI), heavy metal pollution index (HPI) and aquatic toxicity index (ATI). WQI was calculated using 14 physico-chemical parameters while HPI determination used nine heavy metals like As, Cd, Co, Cr, Cu, Fe, Mn, Pb and Zn. WQI revealed that Kanjli wetland contained medium quality water (irrigation and aquatic life). Cr, Cd and Co exceeded desirable limits of World Health Organization (WHO, Guidelines for drinking-water quality, World Health Organization, Geneva, 2011) and Indian drinking water standard (2012) during all the three seasons (monsoon, post monsoon and winter). HPI values from all sites exceeded critical pollution index value of 100 during monsoon season. Few sites were unsuitable for normal fish life as per ATI. The study recommends planned spatial, temporal and periodic monitoring of wetland using WQI and HPI to sustain good water quality (drinking, irrigation and aquatic life).

Assessment of Heavy Metal Pollution in the Groundwater of the Northern Develi Closed Basin, Kayseri, Turkey

This study was carried out to assess the groundwater pollution in the northern Develi Closed Basin by using the heavy metal pollution index (HPI). Samples from 10 wells and 5 springs were collected in dry and wet seasons and concentrations of Pb, Zn, Cr, Mn, Fe, Cu, Cd, As and B were determined. In both seasons, for more than half of the samples, As, B and Fe concentrations exceeded the Turkish drinking water guideline values. Due to the occurrence of these metals in high concentrations in some samples HPI values are up to 1740. The source of these metals is geogenic and attributed to the interaction of these waters with highly altered volcanic and pyroclastic rocks. The overall HPI for wet and dry periods are reported as 360 and 440, respectively. Accordingly, the pollution level in the groundwater of this area is unacceptable.

Assessment of Mine Water Quality Using Heavy Metal Pollution Index in a Coal Mining Area of Damodar River Basin, India

A total no. of 16 mine water (underground and opencast coal mine pump discharges) samples were collected from East Bokaro coalfield during pre-monsoon, monsoon and post-monsoon seasons. The concentrations of Fe, Mn, Cu, Pb, Zn, Ni, As, Se, Al, Cd and Cr were determined using inductively coupled plasma mass spectrometry for the assessment of spatio-temporal variations, source apportionment and heavy metal pollution indexing. The results demonstrated that concentrations of the metals showed significant seasonality and most variables exhibited higher levels in the pre-monsoon season. The principle component analysis for ionic source identification was synthesized into three factors with eigen values cut off at greater than unity and explained about 64.8% of the total variance. The extracted factors seemed to be associated to the geogenic, extensive mining and allied transportation sources of the elements. The heavy metal pollution index (HPI) of the mine water calculated for the individual locations varied from 7.1 to 49.5. Most of the locations fall under low to medium classes of HPI except few locations which are under the influence of surface mining and associated transportation.

Estimation of Heavy Metal Contamination in Groundwater and Development of a Heavy Metal Pollution Index by Using GIS Technique

Heavy metal (Al, As, Ba, Cr, Cu, Fe, Mn, Ni, Se and Zn) concentration in sixty-six groundwater samples of the West Bokaro coalfield were analyzed using inductively coupled plasma-mass spectroscopy for determination of seasonal fluctuation, source apportionment and heavy metal pollution index (HPI). Metal concentrations were found higher in the pre-monsoon season as compared to the post-monsoon season. Geographic information system (GIS) tool was attributed to study the metals risk in groundwater of the West Bokaro coalfield. The results show that 94 % of water samples were found as low class and 6 % of water samples were in medium class in the post-monsoon season. However, 79 % of water samples were found in low class, 18 % in medium class and 3 % in high class in the pre-monsoon season. The HPI values were below the critical pollution index value of 100. The concentrations of Al, Fe, Mn, and Ni are exceeding the desirable limits in many groundwater samples in both seasons.

Evaluation of Surface Water Quality by Using GIS and a Heavy Metal Pollution Index (HPI) Model in a Coal Mining Area, India

Twenty eight surface water samples were collected from fourteen sites of the West Bokaro coalfield, India. The concentration of Mn, Cu, Zn, Ni, As, Se, Al, Cr, Ba, and Fe were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) for determination of seasonal fluctuations and a heavy metal pollution index (HPI). The HPI values were below the critical pollution index value of 100. Metal concentrations were higher in the pre-monsoon season as compared to the post-monsoon season. The Zn, Ni, Mn, As, Se, Al, Ba, Cu, and Cr concentrations did not exceed the desirable limits for drinking water in either season. However, at many sites, concentrations of Fe were above the desirable limit of the WHO (2006) and Indian drinking water standard (BIS 2003) in both seasons. The water that contained higher concentrations of Fe would require treatment before domestic use.

Metal pollution of groundwater in the vicinity of Valiathura Sewage Farm in Kerala, south India

A comprehensive study was conducted to evaluate metal pollution of groundwater in the vicinity of Valiathura Sewage Farm in Thiruvananthapuram district, Kerala using the Heavy Metal Pollution Index (HPI). Forty two groundwater samples were collected during the summer season (April 2010) and the concentration of metals Fe, Cu, Zn, Cd and Pb were analyzed. Results showed that groundwater was contaminated mainly with Fe, Cu and Pb. Correlation analysis revealed that the sources of metals in groundwater in the study area are the same, and it may be due to the leachates from the nearby Sewage Farm, Parvathy Puthanar canal and solid wastes dumped in the residential area. Of the groundwater samples studied, 47.62 % were medium and 2.68 % were classified in HPI high category. HPI was highest (41.79) in DW29, which was adjacent to the polluted Parvathy Puthanar canal and Sewage Farm. The present study points out that the metal pollution causes the degradation of groundwater quality around the Sewage Farm during the study period.

Assessment of ammonium, nitrate, phosphate, and heavy metal pollution in groundwater from Amik Plain, southern Turkey

Amik Plain is one of the most important agricultural areas of Turkey. Because the groundwater resources have been used not only for irrigation but also for drinking purpose, groundwater resources play a vital role in this area. However, there exist no or a very limited number of studies on groundwater quality and its physicochemical and heavy metal composition for Amik Plain. This study aimed to assess groundwater of Amik Plain in terms of human health and suitability for irrigation based on physicochemical variables, heavy metals, and their spatial distribution. A total of 92 groundwater samples were collected from wells and were analyzed for temperature (T), salt content (SC), dissolved oxygen (DO), ammonium (NH4(+)), nitrate (NO3(-)), and phosphorus (P) and such heavy metals as cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn). The temperature, SC, DO, NH4(+), and NO3(-) parameters were measured in situ immediately with YSI Professional plus instrument (Pro Plus). Water depth was taken from owner of the wells. Heavy metal analyses were carried out in triplicate using inductively coupled atomic emission spectrometer (ICP-AES). The ICP-AES was calibrated for all the metals by running different concentrations of standard solutions. Descriptive statistical analyses were calculated to characterize distribution of physicochemical properties and heavy metal contents of groundwater. Correlation analysis was used to assess the possible relationships among heavy metals and physicochemical properties of the groundwater. Spatial variability in groundwater parameters were determined by geostatistical methods. Result shows that the highest and lowest coefficient of variation occurred for NO3(-) and T, respectively. Mean water table depth was 92.1 m, and only 12 of all the samples exceeded the desirable limit of 50 mg/L for NO3(-) content. The metal concentrations showed a dominance in the order of Fe > Mn > Ni > Cr > Cu > Zn > Co > Cd > Pb. All the samples had much higher Cd concentration than the guideline value for drinking water while Cu and Fe concentrations were below the guideline limit recommended by WHO.