Ground Water Quality Maps of Paravanar River Sub Basin, Cuddalore District, Tamil Nadu, India

Ground water is an excellent solvent, which dissolves chemicals ions as it moves through rocks and subsurface soil. This leads to more mineralization in groundwater than surface water. The objective of the present study is to examine the groundwater quality of the Paravanar River Sub-basin, Cuddalore district, Tamil Nadu, India. The Electrical Conductivity (EC) values ranges between 160 and 2,580 mu S/cm in groundwater samples. The highest value of 2,580 mu S/cm was recorded in wells near the coast. pH values ranges from 7.2 to 8.6. NNE and southern part of the study area has low pH values, rest of the area represents the alkaline nature of groundwater. In south eastern part of the study area alkali values are slightly higher but it is within WHO's tolerable limits. The spatial distribution of chloride concentration shows that Meenatchipettai, Vazhisothani palayam and Allapakkam represents maximum Cl(2) concentration of 527, 320 and 374 ppm, which is above ISI drinking standards of 250 ppm. Increase in isochlore is observed from the coast up to the Neyveli lignite mine. Nitrate concentration of groundwater samples ranges from 0.1 mg/l to 64 mg/l. As most of the study area is cultivated, fertilizers used for agriculture may be the cause for increase in concentration of nitrates in few concentrated locations.