Assessment of potential impacts on the environment around the nuclear facilities requires precise estimation of prevailing background concentration and statistical inference of the measurement data. The current study was focused to understand the statistical variation associated with data generated for ¹³⁷Cs concentration in sea water and sediment for the west and east coat of India. The distribution followed was found to be lognormal and based on geometric mean and geometric standard deviation of the ¹³⁷Cs concentrations data, a screening level in terms of Environmental Increment factor has been evaluated which can form basis for future impact assessment.