Radon isotope assessment of submarine groundwater discharge (SGD) in Coleroon River Estuary, Tamil Nadu, India

Submarine groundwater discharge is the fresh groundwater discharge to sea that impacts the coastal regions. Radon (222Rn) isotope has been used to quantify SGD in coleroon river estuary, India. Continuous 222Rn analyses were attempted for 10 days in groundwater and pore water samples at three different locations. 222Rn in groundwater ranges between 35.0 and 222.0 Bq m−3 and in pore water between 14.0 and 150.0 Bq m−3 irrespective of locations. The radon mass balance estimated total SGD rate ranges between 2.37 and 7.47 m days−1. The SGD increases with distance from coast, influenced by tides and hydrological features.