The capabilities of the LowBackground Gamma Spectrometer (LBGS) at InSTEC were studied for environmental purposes. Fifty three glines were identified in the LBGS background spectrum. The Minimum Detectable Activity for , , , , and were calculated using the detector’s volumetric efficiency simulated by Monte Carlo method. Validation was performed by absolute and relative analysis of radionuclide activities present in a marine sediment certified material.