Suomen ympäristökeskus

This document specifies laboratory methods for determination of the soil water-retention characteristic. This International Standard applies only to measurements of the drying or desorption curve. Four methods are described to cover the complete range of soil water pressures as follows: Guidelines are given to select the most suitable method in a particular case.

This standard specifies a method for the measurement of 99Tc in all types of waters by liquidscintillation counting (LSC).The detection limit depends on the sample volume and the instrument used. The method described inthis standard, using currently available LSC counters, has a detection limit of approximately 5 to 20Bq•kg-1, which is lower than the WHO criteria for safe consumption of drinking water (100 Bq•L-1).These values can be achieved with a counting time of 30 minutes for a sample volume varyingbetween 14 to 40 mL. The methods presented in this standard are not intended for the determination ofultra-trace amount of 99Tc.

This standard specifies a method for the measurement of 99Tc in all types of waters by inductively coupled plasma mass spectrometry (ICP-MS).The method described in this standard, using currently available ICP-MS, has a detection limit of approximately 0,2 to 0,5 ng•L-1 (0,1 to 0,3 Bq•kg-1), which is much lower than the WHO criteria for safe consumption of drinking water (100 Bq•L-1). The method presented in this standard is not intended for the determination of ultra-trace amount of 99Tc.

ISO 13164-4:2015 describes a test method for the determination of radon-222 (222Rn) activity concentration in non-saline waters by extraction and liquid scintillation counting.The radon-222 activity concentrations, which can be measured by this test method utilizing currently available instruments, are at least above 0,5 Bq l-1 for a 10 ml test sample and a measuring time of 1 h.This test method can be used successfully with drinking water samples and it is the responsibility of the laboratory to ensure the validity of this test method for water samples of untested matrices.Annex A gives indication on the necessary counting conditions to meet the required detection limits for drinking water monitoring.