Determination of total alpha and beta activity in water for human consumption by LSC(Liquid Scintillation Counter)

The Ordinance Brazilian of Ministry of Health (MS 2914/2011) establishes the standards for quality of water intended for human consumption, being limits values of 5.0 Bq/L for gross alpha, and 1.0 Bq/L for gross beta radioactivity. The liquid scintillation spectrometry (LSC) technique has been presented as an alternative to conventional procedure using gas flow proportional counter. The present work shows a review of the methods for determination of gross alpha and gross beta in water by using LSC. Between the factors that influence the accuracy and repeatability of the analytical results we can highlight: thermal preconcentration, type of the acid and calibration standard. A procedure was established and carried out to samples of the National Program of Intercomparison of Radionuclides in Environmental Samples for evaluation of its performance. The gross alpha and gross beta analysis in samples of the public water supplies in the Metropolitan Region of Goiania, state of Goias was carried out. The results are consistent with the guideline values form the Ministry of Health concerning radioactivity. (author)