Measurement of 224 Ra and 223 Ra activity using MnO 2 based in situ pre-concentration technique coupled with delayed coincidence counting in creek ecosystem of Mumbai Harbour Bay

Measurement of short lived radium isotopes ( 224 Ra and 223 Ra) in seawater samples collected from Mumbai Harbour Bay was carried out using MnO 2 based in situ pre-concentration technique coupled with delayed coincidence counting. Standardisation and validation of various parameters required for quantification was carried out. Longitudinal variation of 224 Ra and 223 Ra found in the range 17.74–98.66 and 0.56–2.26 dpm 100 L −1 respectively. Elevated concentration of 224 Ra and 223 Ra was found near shore sampling points where reused seawater and surface water from land intrudes in creek. Higher concentration in creek compared to offshore locations indicates presence of submarine groundwater discharge.