A study of physico-chemical properties of groundwater in a coastal aquifer sandwiched between marine and brackish water bodies

摘要

The present study was carried out to understand the quality of groundwater and to delineate the subsurface formations in an area of 30 km~2 situated between backwater Vembanad Lake on the eastern side and Arabian Sea on the western side. The physico chemical studies involve pH, conductivity, total hardness, cations (Ca,Mg,Na,K), anions (HCO_3, Cl, PO_4, SO_4) and Fe. Wells in this area are shallow with 2 to 4 m depth and the water table in these wells varies from 1.5 to 2 m. Industrial pollutants and sewages do not influence the wells in the area and are very well protected from seepage by proper lining inside the wells. Samples collected from 12 open wells were used for the study. The physico chemical properties of the samples were compared between the eastern side (the brackish water side) and the western side (marine side). The above properties were further compared with the drinking water standards set up by the World Health Organization. To delineate the subsurface formations electrical resistivity soundings were carried out at an interval of 3 km. in the study area.