DIN ISO 13165-1:2015-11

Drinking water can contain radionuclides at activity concentrations which present a risk to human health. In order to assess the quality of drinking water (including mineral waters and spring waters) with respect to its radionuclide content and to provide guidance on reducing health risks by taking measures to decrease radionuclide activity concentrations, water resources (groundwater, river, lake, sea, etcetera) and drinking water are monitored for their radioactivity content as recommended by the World Health Organization (WHO). This part of ISO 13165 specifies the determination of radium-226 (226Ra) activity concentration in nonsaline water samples by extraction of its daughter radon-222 (222Rn) and its measurement using liquid scintillation counting. Radium-226 activity concentrations which can be measured by this test method utilizing currently available liquid scintillation counters goes down to 50 mBq l-1. This method is not applicable to the measurement of other radium isotopes. An International Standard on a test method of radium-226 activity concentrations in water samples is justified for test laboratories carrying out these measurements, which are sometimes required by national authorities, as laboratories may have to obtain a specific accreditation for radionuclide measurement in drinking water samples. Radium-226 activity concentration can vary widely according to local geological and climatic characteristics and ranges from Bq l^-1 in surface waters up to 50 Bq l^-1 in natural groundwaters; the guidance level for radium-226 in drinking water as recommended by WHO is Bq l^-1. This document has been prepared by Technical Commitee ISO/TC 147 "Water quality", the secretariat of which is held by DIN (Germany). The responsible German body is Subcommittee NA 119-01-03-05 UA "Biologische Verfahren" ("Biological methods") of NA 119-01-03 AA "Wasseruntersuchung" ("Water analysis") at DIN Standards Committee Water Practice (NAW).