Natural radioactivity in Brazilian groundwater

Tracing anthropogenically driven groundwater discharge into a coastal lagoon from southern Brazil

“…Radon in groundwater did not show any clear covariance with conductivity, pH, or Eh, implying multiple source terms that are a function of the little known local geology and variable residence times of shallow groundwaters . Groundwater 222 Rn concentrations from a large countrywide survey in Brazil were highly variable, but the average value (3462 dpm/L) was one order of magnitude higher than observed in our study (Godoy and Godoy, 2006). Low-radon values in groundwater are usually associated with low uranium contents in soil, conditions favoring radon emanation to the atmosphere, and/or very short residence times.…”

“…By dividing those calculated fluxes by the estimated 222 Rn concentrations in the groundwater source, we can calculate the advective transport required to satisfy the 222 Rn mass balance. Selecting a groundwater endmember can be challenging because of the large variability usually associated with 222 Rn distributions in groundwater (Crusius et al, 2005;Godoy and Godoy, 2006;Mullinger et al, 2007). We may consider using either the average concentrations measured in deep (>3 m) groundwater (380 ± 130 dpm/L; n = 34) or the concentrations in pore water derived from the sediment equilibration experiments (115 ± 50 dpm/L; n = 6).…”

Dissolved 210Po and 210Pb in Guarani aquifer groundwater, Brazil

“…Furthermore, 210 Pb in water samples has been estimated from counts of the daughter 210 Bi using a gas-flow proportional counter after allowing 30 days for ingrowth (Peck and Smith, 2000), as well by the liquid scintillation counting from beta spectra of PbSO 4 precipitates purified with EDTA solution (Kim et al, 2001) or by the ICP-MS technique that also provides the data acquisition for some additional elements (Godoy and Godoy, 2006). Because 210 Po is a radionuclide that emits a-particles of energy equal 5.3 MeV that are unequivocally detected, since after Flynn (1968) the alpha counting is a technique widely utilized for acquiring the activity concentration data for this radionuclide in different matrices (Laul et al, 1987;Benoit and Hemond, 1987;El-Daoushy and GarciaTenorio, 1988;Narita et al, 1989;Ivanovich and Harmon, 1992;Church et al, 1994;Nozaki et al, 1990Nozaki et al, , 1991Nozaki et al, , 1997Hong et al, 1999;Kim et al, 2005;Vesterbacka and Ikä -heimonen, 2005).…”

Radiological Characterization of Natural Spring Waters in Eastern Black Sea Region, Turkey

“…The measured mean activity concentrations of 226 Ra, 232 Th, and 40 K in spring water samples were compared with various water samples from different countries of the world in Table 5. As shown in the Table, 226 Ra activity concentrations are higher than the values from Pakistan, Sudan, and Greece, but lower than the values from Egypt, Finland, Italy, Sweden, and Brazil (ElArabi et al, 2006;Osman et al, 2008;Salonen, 1994;Sgorbati and Forte, 1997;Karamanis et al, 2007;Isam Salih et al, 2002;Godoy and Godoy, 2006;Fatima et al, 2006). Alam et al (1999) estimated the effective dose due to the intake of natural radionuclides from drinking water as shown below:…”