Simultaneous measurement of 226Ra and 228Ra in natural water by liquid scintillation counting

Several types of bottled drinking water originating from three different areas in Egypt are studied through measurement of radium activity, assessment of related annual dose for adults and finally to define the role of water quality on radium levels. The mean levels of Ra-226 activity range from 0.44 to 0.92 Bq/L and the mean levels of Ra-228 from 0.30 to 0.78 Bq/L, with related Ra-226/Ra-228 ratios ranging from 2.61 to 0.56. Water types originating from the Eastern Nile Delta area are characterized by low Ra-226 levels and relatively high Ra-228 activity, presumably due to the muddy agricultural nature of this area, which is subject to water from several surface resources for irrigation. In general, the mean activity levels for both Ra-226 and Ra-228 are within those in drinking water in several other countries and the annual ingested dose is comparable with the typical range reported by UNSCEAR. Also, the effect of TDS, pH, calcium, bicarbonate, sulphate and chloride ion concentrations on radium levels is studied and discussed. (c) 2007 Elsevier Ltd. All rights reserved.