Annual effective dose and air absorbed dose based on airborne and ground gamma-ray spectrometry - Serra do Carambeí and Joaquim Murtinho granites, southern Brazil

Abstract

We investigated the air absorbed dose (AAD) and the annual effective dose (AED) of the Serra do Carambeí (CA) and Joaquim Murtinho (JM) granites, based on airborne and ground gamma-ray spectrometry data. Important relationships are considered between each radioelement (K, U eq and Th eq ) and the effective dose distribution, with effects of topographic and environmental variations. High values of potassium and uranium and very high values of thorium were confirmed. The mean average of AAD is 100% (airborne) and 170% (ground) in CA and 35% (airborne) 218% (ground) in JM upper the global mean average. Both granites showed values of AED superior to the recommended by international health organizations. The CA granite revealed approximately twice the safety value in both data types. For the JM granite the values are almost five times (ground data) and about one and a half times greater (airborne data) than those suggested for outdoor exposure.are filled with hematite, fluorite and/or sulfides (Mineropar 2006;Ulbrich et al. 2009).