National intercomparison program applied to water radionuclide analysis in SEAMB - CRCN/NE, Brazil

Water is essential for mankind in its most diverse uses and an evaluation of its quality is necessary, especially when used for human consumption. The Brazilian Ministry of Health established through the Ordinance 36 in 1990 the standards and norms of water potability, and among the parameters to be monitored are the concentrations of activities present in the water bodies. Given the importance of water as one of the main ways of exposure to natural radionuclide emissions due to its frequent ingestion, by providing man with higher natural radiation doses than those normally received by terrestrial radiation, it is necessary the continuous radiological control of waters used for consumption. The existence of laboratories that have certified quality in the analysis of these radioisotopes in water is essential and for this, programs have been created that seek to integrate the results of analysis of environmental samples of water for the determination of radionuclides at the national level, such as the National Intercomparison Program (PNI), promoted by the Institute of Radioprotection and Dosimetry (IRD) of which the Regional Nuclear Science Center of the Northeast (CRCN-NE) is a member since 2011. Until the year 2016, were reported to IRD, the program manager, for statistical evaluation and for analytical performance, 17 analyzes that presented average values of 1,67BqL^-1 for ⁶⁰Co, 3,712 Bq L^-1 for ⁶⁵Zn, 7,812 Bq L^-1 for ¹'0⁶Ru, 3,06 Bq L^-1 for ¹³³Ba, 1,19 Bq L^-1 for the ¹³⁴Cs and 1,50 Bq L^-1 for the ¹³⁷Cs. These analysis were reported by the PNI, certifying the analytical capacity of the Environmental Monitoring Service of the Regional Center of Nuclear Sciences Northeastern Brazil in the determination of radioisotopes in water by Gamma Spectrometry using Hyperpure Germanium - HPGe detectors