Quantifying the age of paleo-groundwater in coastal area of West Bengal using carbon-14 dating technique

Renewability and sustainability of the fresh groundwater systems in the vicinity of the coastal region assumes paramount significance as the whole population thrives on it for drinking and irrigation purposes. The present coastal study area encompassing two districts of West Bengal i.e. South 24-Parganas and East Midnapur exhibit a complex multi-aquifer system. C-14, a radioactive isotope of carbon has half-life of 5730 years and is useful to date groundwater up to 40, 000 years old. ¹⁴C dating technique is generally employed to estimate the residence time of those groundwater samples which do not contain significant amount of modern recharge (i.e. negligible tritium). The C-14 values of the deep groundwater samples waters in the study area varies from zero to 32 pMC (percent modern carbon) whereas shallow well contains ~ 100 pMC value