Pathways of heavy metals contamination and associated human health risk in Ajay River basin, India.

Study on chemical characteristics of groundwater and impacts of groundwater quality on human health, plant growth, and industrial sector is essential to control and improve the water quality in every part of the country. The area of the Varaha River Basin is chosen for the present study, where the Precambrian Eastern Ghats underlain the Recent sediments. Groundwater quality is of mostly brackish and very hard, caused by the sources of geogenic, anthropogenic, and marine origin. The resulting groundwater is characterized by Na+ > Mg2+ > Ca2+ : \( {\text{HCO}}_3^{ - } \) > Cl− > \( {\text{SO}}_4^{{2 - }} \), Na+ > Mg2+ > Ca2+ : \( {\text{HCO}}_3^{ - } \) > Cl− > \( {\text{SO}}_4^{{2 - }} \) > \( {\text{NO}}_3^{ - } \), Na+ > Mg2+ > Ca2+ : \( {\text{HCO}}_3^{ - } \) > Cl−, and Na+ > Mg2+ > Ca2+ : Cl− > \( {\text{HCO}}_3^{ - } \) > \( {\text{SO}}_4^{{2 - }} \) facies, following the topographical and water flow-path conditions. The genetic geochemical evolution of groundwater (\( {\text{HCO}}_3^{ - } \) and Cl−–\( {\text{HCO}}_3^{ - } \) types under major group of \( {\text{HCO}}_3^{ - } \)) and the hydrogeochemical signatures (Na+/Cl−, >1 and \( {\text{HCO}}_3^{ - } \)/Cl−, <1) indicate that the groundwater is of originally fresh quality, but is subsequently modified to brackish by the influences of anthropogenic and marine sources, which also supported by the statistical analysis. The concentrations of total dissolved solids (TDS), TH, Mg2+, Na+, K+, \( {\text{HCO}}_3^{ - } \), Cl−, \( {\text{NO}}_3^{ - } \), and F− are above the recommended limits prescribed for drinking water in many locations. The quality of groundwater is of mostly moderate in comparison with the salinity hazard versus sodium hazard, the total salt concentration versus percent sodium, the residual sodium carbonate, and the magnesium hazard, but is of mostly suitable with respect to the permeability index for irrigation. The higher concentrations of TDS, TH, \( {\text{HCO}}_3^{ - } \), Cl−, and \( {\text{SO}}_4^{{2 - }} \) in the groundwater cause the undesirable effects of incrustation and corrosion in many locations. Appropriate management measures are, therefore, suggested to improve the groundwater quality.

Chemical characteristics of groundwater and assessment of groundwater quality in Varaha River Basin, Visakhapatnam District, Andhra Pradesh, India

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Hydrochemical characterization and quality appraisal of groundwater from Pungar sub basin, Tamilnadu, India

A review on experimental design for pollutants removal in water treatment with the aid of artificial intelligence.

The present work aims at assessing the water quality index (WQI) in the surface water of Sankey tank and Mallathahalli lake situated in Bangalore Urban district by monitoring three sampling locations within Sankey tank (viz., A, B and C) and Mallathahalli lake (viz., Inlet, Centre and outlet) for a period of 3 months from March to May 2012. The surface water samples were subjected to comprehensive physico-chemical analysis involving major cations (Ca2+, Mg2+, Na+, K+, Fe2+), anions (HCO3−, Cl−, SO42−, NO3−, F−, PO43−) besides general parameters (pH, EC, TDS, alkalinity, total hardness, DO, BOD, COD, CO2, SiO2, colour, turbidity). For calculating the WQI, 14 parameters namely, pH, electrical conductivity, total dissolved solids, total hardness, alkalinity, calcium, magnesium, sodium, potassium, chloride, sulphate, nitrate, fluorides and iron were considered. SAR values indicated that both Sankey tank and Mallathahalli lake waters are excellent (S1) for irrigation, while electrical conductivity values classified these lake water, respectively under medium salinity (C2) and high (C3) salinity category. Correlation between SAR and electrical conductivity revealed that Sankey tank water is C2S1 (medium salinity-low sodium) type while Mallathahalli lake water is C3S1 (high salinity-low sodium) type. Sankey tank and Mallathahalli lake water were, respectively hard and very hard in nature. Further, it is apparent from WQI values that Sankey tank water belongs to good water class with WQI values ranging from 50.34 to 63.38. The Mallathahalli lake water with WQI value ranging from 111.69 to 137.09, fall under poor water category.

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Water quality index to determine the surface water quality of Sankey tank and Mallathahalli lake, Bangalore urban district, Karnataka, India

Hydrogeochemical investigations are carried out in the different blocks of Burdwan district, West Bengal, India in order to assess its suitability for drinking as well as irrigation water purpose. Altogether 49 representative groundwater samples are collected from bore wells and the water chemistry of various ions viz. Ca2+, Mg2+, Na+, K+, CO
 3
 2−
 , HCO
 3
 −
 , Cl−, SO
 4
 2−
 and NO
 3
 −
 are carried out. The chemical relationships in Piper and Gibbs diagram suggest that the groundwater mainly belongs to alkali type and Cl− group and are controlled by rock dominance. A comparison of groundwater quality in relation to drinking water quality standards proves that most of the water samples are suitable for drinking water purpose whereas groundwater in some areas of the district has high salinity and high sodium adsorption ratio (SAR), indicating unsuitability for irrigation water and needs adequate drainage.

Geochemistry of groundwater, Burdwan District, West Bengal, India

Arsenic in drinking water has been recognized as a serious community health problem because of its toxic nature and therefore, its removal is highly essential. A series of adsorption experiments (batch and column) were performed utilizing iron impregnated sugarcane carbon (Fe–SCC), a composite adsorbent, to remove arsenic from aqueous systems. Under optimized batch conditions, the Fe–SCC could remove up to 94.5% of arsenic from contaminated water. The artificial neural network (ANN) model was developed from batch experimental data sets which provided reasonable predictive performance (R2 = 0.964; 0.963) of arsenic adsorption. In batch operation, the adsorbent dose had the most significant impact on the adsorption process. For column operation, central composite design (CCD) in response surface methodology (RSM) was applied to investigate the influence on the breakthrough time for optimization and evaluation of interacting effects of different operating variables. The perturbation plot depicted that the breakthrough time is more sensitive to initial concentration and adsorbent dose than flow rate. The optimized result obtained from bar plot revealed that the Fe–SCC was an effective and economically feasible adsorbent; whereas more than 93% desorption efficiency showed the reusability of the adsorbent. The high arsenic adsorptive removal ability and regeneration efficiency of this adsorbent suggest its applicability in industrial/household systems and data generated would help in further upscaling of the adsorption process.

Modeling of the adsorptive removal of arsenic: A statistical approach

Threats of climate and land use change on future flood susceptibility

In the present study, adsorption of lead (II) ions from aqueous solution by alluvial soil of Bhagirathi River was investigated under batch mode. The influence of solution pH, sorbent dose, initial lead (II) concentration, contact time, stirring rate and temperature on the removal process were investigated. The lead adsorption was favored with maximum adsorption at pH 6.0. Sorption equilibrium time was observed in 60 min. The equilibrium adsorption data were analyzed by the Freundlich, Langmuir, Dubinin–Radushkevich and Temkin adsorption isotherm models. The kinetics of lead (II) ion was discussed by pseudo first-order, pseudo second-order, intra-particle diffusion, and surface mass transfer models. It was shown that the adsorption of lead ions could be described by the pseudo second-order kinetic model. The activation energy of the adsorption process (E
 a) was found to be −38.33 kJ mol−1 using the Arrhenius equation, indicating exothermic nature of lead adsorption onto alluvial soil. Thermodynamic parameters, such as Gibbs free energy (∆G
 0), the enthalpy (∆H
 0), and the entropy change of sorption (∆S
 0) have also been evaluated and it has been found that the adsorption process was spontaneous, feasible, and exothermic in nature. The results indicated that alluvial soil of Bhagirathi River can be used as an effective and low cost adsorbent to remove lead ions from aqueous solutions.

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Paramita Roy

Papers

Geochemistry of groundwater, Burdwan District, West Bengal, India

Modeling of the adsorptive removal of arsenic: A statistical approach

Threats of climate and land use change on future flood susceptibility

Insight into adsorption equilibrium, kinetics and thermodynamics of lead onto alluvial soil

Changing climate and land use of 21st century influences soil erosion in India