Environmental Gamma Radiation and Natural Radioactivity in Soils in Centro Experimental Aramar (CTMSP-BRAZIL) and Region

Natural radioactivity in Brazilian groundwater

“…5 no secondary enrichment of U, 228 Ra is normally the dominant isotope in solution (Michel, 1991). Not surprising, Brazilian soils, normally contain 228 Ra/ 226 Ra activity ratio higher than one (Linsalata et al, 1991;Malanca et al, 1996;Roque and Ribeiro, 1997;de Moraes and Daltro, 2000;Carlos et al, 2004) and, in general, the observed 228 Ra/ 226 Ra activity concentration ratio follows this trend being higher than one as shown in Fig. 6.…”

Environmental Impact of using actinium (228Ac)-contaminated sludge as soil conditioner and sand substitute

“…There is no suitable record in the literature on the acceptable levels of 228 Ac in petroleum sludge. However, the documented level of such radioactivity in soil and regular sludge is roughly of the order of 60 Bq/kg (see De Moraes and Daltro, 2000). As can be seen from our results (Figure 3) about 40% of the samples exceeded this value, and in Figure 3.…”

“…Actinium-228 has relatively intense gamma rays at 911 and 969 keV, which makes it suitable and facile to measure. A brief survey of the documented literature reveals that the 'acceptable' level of 228 Ac in soil and regular sludge is roughly 60 Bq/kg (De Moraes and Daltro, 2000). We obtained values up to 600 Bq/kg, ten times higher.…”

“…Our concern in this respect prompted the investigation. 228 Ac is the daughter of 228 Ra that originates in the Thorium series (Bou-Rabee, 1997; Baggoura et al, 1998;De Moraes and Daltro, 2000;Spera et al, 2003;Chang, 2004). The actinium is in secular equilibrium with the parent, and its presence at elevated levels in the environment constitutes a significant long-term health hazard because of the well-known toxicity of radioactive materials (Faure, 1986;BouRabee, 1997;Baggoura et al, 1998;Salih et al, 2004).…”

Radiometric and chemical parameters in freshwater samples of Centro Experimental Aramar (CTMSP/Brazil) environmental monitoring programme

“…The 232 Th natural series' activity was estimated from the 228 Ac emission at 911.1 keV. The samples were sealed and the measurements were made one month later to ensure equilibrium between the isotopes and their decaying products [11]. The gamma spectrometry system calibration has been periodically checked through the National Intercomparison Programme (PNI) for water sample analysis, conducted by the Secondary Standard Dosimetry Laboratory (IRD/CNEN/BRAZIL) [12].…”