This document specifies a method for the determination of gross alpha and gross beta activity concentration for alpha- and beta-emitting radionuclides. Gross alpha and gross beta activity measurement is not intended to give an absolute determination of the activity concentration of all alpha and beta emitting radionuclides in a test sample, but is a screening analysis to ensure particular reference levels of specific alpha and beta emitters have not been exceeded. This type of determination is also known as gross alpha and gross beta index. Gross alpha and gross beta analysis is not expected to be as accurate nor as precise as specific radionuclide analysis after radiochemical separations.
Maximum beta energies of approximately 0,1 MeV or higher are well measured. It is possible that low energy beta emitters can not detected (e.g. 3H, 55Fe, 241Pu) or can only be partially detected (e.g. 14C, 35S, 63Ni, 210Pb, 228Ra).
The method covers non-volatile radionuclides, since some gaseous or volatile radionuclides (e.g. radon and radioiodine) can be lost during the source preparation.
The method is applicable to test samples of drinking water, rainwater, surface and ground water as well as cooling water, industrial water, domestic and industrial wastewater after proper sampling, sample handling, and test sample preparation (filtration when necessary and taking into account the amount of dissolved material in the water).
The method described in this document is applicable in the event of an emergency situation, because the results can be obtained in less than 1 h. Detection limits reached for gross alpha and gross beta are less than 10 Bq/l and 20 Bq/l respectively. The evaporation of 10 ml sample is carried out in 20 min followed by 10 min counting with window-proportional counters.
It is the laboratory's responsibility to ensure the suitability of this test method for the water samples tested.
