Natural radioactivity in Brazilian mineral waters and its correlation with the water composition

During 1995, the Brazilian mineral water production was over 1.3 billion liters. At present, there are 170 producers spread all over the 8.106 km2 of the country. Circa 50% of the sources are classified as radioactive, that means that their 222 Rn content at the source is higher than 67 Bq/L. The brazilian mineral code includes also the classification based on the long-lived natural radionuclides, but their determination are not currently done. The present contribution describes the actual effort to determine the U, Th 226 Ra, 228 Ra and 210 Pb concentration in Brazilian mineral waters. The work includes also the analysis of 222 Rn and the chemical composition of the water. Until the present moment, circa 150 samples have been analyzed and their results show that both 226 Ra and 228 Ra are strongly correlated with magnesium, calcium, strontium and potassium, but not with sodium and, as a consequence, neither with the conductivity. (author)