Geochemical signatures of groundwater along mountain front and riparian zone of Courtallam, Tamil Nadu

Abstract

Hydrochemical investigation had been carried out along the foothills of Courtallam to understand the predominant processes along the mountain front (MF) and the riparian zone (RZ). To unravel this process 21 number of MF samples and 32 number of RZ samples were collected and analyzed for major ions using standard procedures. The bivariate plot of selected parameters indicate most of the MF samples have lesser ionic strength, higher partial pressure of carbon dioxide (log pCO2) value, less pH and release more silica during weathering than that of the RZ samples. Furthermore impact of agriculture and feldspar weathering is also noted in the MF regions and the urban sewage signatures are found in few samples of MF and RZ region. Most of the RZ samples are represented by state of saturation to super saturation with respect to carbonate minerals. Thermodynamically the MF samples are more stable near the kaolinite boundaries in the silicate stabilities fields. The main factors governing the geochemistry of both the regions are interplay of leaching and dissolution, weathering and agriculture. It was also inferred that land-use and lithology play a significant role in groundwater composition of the region.