Indoor radon and its relationship with rock uranium concentration in western Liguria (Italy)

We recorded indoor radon concentrations in dwellings and measured uranium, thorium and potassium contents in rocks of western Liguria (Italy). This area, characterised by a wide geo-lithological variability with rocks spanning from sedimentary to metasedimentary and metavolcanic, was never deeply investigated for indoor radon or uranium concentration. High levels of indoor radon concentration, exceeding 200 Bq m-3, were recorded in buildings located on the pre-Mesozoic basement that crops out for approximately 65 % of the survey area and shows a maximum average uranium concentration of about 7 mg kg-1. The uranium and the indoor radon concentrations measured on the same lithological groups are strictly correlated. Indoor radon concentrations >200 Bq m-3 are mostly recorded when the rock uranium content exceeds 4.5 mg kg-1. We suggest that the uranium‑radon correlation can be used as an effective baseline for studies of radon potential evaluation.