Groundwater samples were collected for premonsoon and post-monsoon seasons based on the variation in the geomorphological, geological, and hydrogeological factors for assessment of groundwater quality for drinking and irrigation use in a shallow hard rock aquifer of Pudunagaram area, Palakkad district, Kerala. The samples were analyzed for various physico-chemical parameters and major ion chemistry. Based on analytical results, Gibbs diagram and Wilcox plots were plotted and groundwater quality has been distinguished for drinking and irrigation use. Gibbs diagram shows that the samples are rock dominance and controlling the mechanism for groundwater chemistry in the study area, while Wilcox plot suggest that most of the samples are within the permissible limit of drinking and irrigation use. Further, the suitability of water for irrigation was determined by analyzing sodium adsorption ratio, residual sodium carbonate, sodium percent (%Na), Kelly's ratio, residual sodium carbonate, soluble sodium percentage, permeability index, and water quality index. It has been concluded that, the water from the study area is good for drinking and irrigation use, apart few samples which are exceeding the limits due to anthropogenic activities and those samples were indisposed for irrigation.

This paper deals with a systematic hydrogeological, geophysical, and hydrochemical investigations carried out in SIPCOT area in Southern India to demarcate groundwater pollution and saline intrusion through Uppanar River, which flows parallel to sea coast with high salinity (average TDS 28, 870 mg/l) due to back waters as well as discharge of industrial and domestic effluents. Hydrogeological and geophysical investigations comprising topographic survey, self-potential, multi-electrode resistivity imaging, and water quality monitoring were found the extent of saline water intrusion in the south and pockets of subsurface pollution in the north of the study area. Since the area is beset with highly permeable unconfined quaternary alluvium forming potential aquifer at shallow depth, long-term excessive pumping and influence of the River have led to lowering of the water table and degradation of water quality through increased salinity there by generating reversal of hydraulic gradient in the south. The improper management of industrial wastes and left over chemicals by closed industries has led surface and subsurface pollution in the north of the study area.

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The objective of this article is to develop a groundwater flow model for a tannery belt using Visual MOD-FLOW Premium 4.4 for analyzing groundwater velocity and its response to various pumping strategies in two stages, viz., steady and transient conditions. The steady state model was calibrated for April 2001, whereas the transient model was employed to forecast groundwater flow under various pumping strategies. The results showed that the total groundwater abstraction was about 80.43% of the groundwater recharge, but 10.25% was used up by evapotranspiration. The groundwater velocity, which is important for contaminant migration, varied from 0.21 to 0.52 m/d in the tannery cluster. The model was more sensitive to recharge from rainfall, hydraulic conductivity and specific yield. Finally, the model showed that the aquifer could sustain a pumping rate of 24892 m3/day without further decline in water level

A combined geophysical investigation consisting of vertical electrical sounding (VES) and multielectrode system was carried out to map the subsurface resistivity in all major lakes which are highly polluted by the discharge of sewage and other chemical effluents in greater Hyderabad, India. The structural features identified in the study area play a major role in groundwater flow and storage. The interpretation of geophysical data and lithologs indicates that a silt/clay zone (predominantly silt) has a thickness of 5-10 m all along the drainage from Patelcheruvu to the Musi River. The silt/clay zone inferred close to the lakes is a mixture of clay, silt and sand with more silt content as indicated from the lithologs during drilling. The low resistivity values obtained can be attributed to the pollutant accumulated in the silt which can reduce the resistivity values. Further, the TDS of the water samples in these wells are more than 1,000 mg/l which further confirms the above scenario. The pollution spread is less in the upstream areas whereas it is more in the downstream which can be attributed to the shallow water table conditions and also due to the interaction of surface water and groundwater.

A chemical factory near Ranipet town in Vellore district, in the state of Tamil Nadu, India produced chromium-based inorganic chemicals. The factory area in granite gnessic terrain receives an average annual rainfall of 1,000 mm. About 1.5 lakh tons of solid wastes rich in hexavalent chromium (Cr 6? ), spreading over an area of 14,000 m 2 (about 3.5 acres), having about 4 m thickness, is accumulated in an open yard within the factory premises. The soil and groundwater in and around the factory area are contaminated with Cr 6? leached from dump site. Cr 6? is carcinogenic in nature and when leached in water can lead to respiratory disorders. Resistivity surveys comprising vertical electrical sounding, multielectrode resistivity imaging, drilling of bore wells, chemical analysis of soil, formation and groundwater samples and bore hole tracer studies were carried out within the factory and adjoining areas to decipher subsurface geology, hydraulic behavior of dyke as natural barrier and lateral and vertical extent of pollution zone in and around the chromium dump site. The data obtained were integrated and interpreted for understanding the pollution migration and its impact on environment. Remedial measures are suggested for containing the contamination.

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