Application of reference materials in the accurate calibration of the detection efficiency of a low-level gamma-ray spectrometry assembly for environmental samples

Natural radioactivity levels in lake sediment samples

The radioactivity concentrations of nuclides (238)U, (232)Th and (40)K in lake sediments collected from 15 different stations at Altınkaya dam lake and 12 different stations at Derbent dam lake in Turkey were measured using high-resolution gamma-ray spectrometry. The measurement was done using a coaxial HPGe detector system coupled to the Ortec-Dspect jr digital MCA system. The average measured activity concentrations of the nuclides (238)U, (232)Th and (40)K were found to be 19.5, 27.7 and 460 Bq kg(-1) in Altınkaya dam, whereas the activity concentrations were 18.8, 25.5 and 365 Bq kg(-1) in Derbent dam, respectively. The measured activity concentrations in the present study have been compared with similar measurements from different locations in the world.

First characterisation of natural radioactivity in building materials manufactured in Albania

This study focuses on the radiological characterisation of building materials manufactured in Albania by using a high-resolution gamma-ray spectrometer. The average activity concentrations of (40)K, (226)Ra and (232)Th were, respectively, 644.1±64.2, 33.4 ± 6.4 and 42.2 ± 7.6 Bq kg(-1) in the clay brick samples and 179.7 ± 48.9, 55.0 ± 5.8 and 17.0 ± 3.3 Bq kg(-1) in the cement samples. The calculated activity concentration index (ACI), varied from 0.48±0.02 to 0.63±0.04 in the clay brick samples and from 0.29±0.03 to 0.37±0.02 in the cement samples. Based on the ACI, all of the clay brick and cement samples were categorised as A1 materials. The authors can exclude (at 3σ level) any restriction of their use as bulk materials.

Natural activity concentrations in bottled drinking water and consequent doses

The radioactivity concentrations of nuclides (238)U, (232)Th and (40)K in bottled drinking water from six different manufacturers from Turkey were measured using high-resolution gamma-ray spectrometry. The measurement was done using a coaxial high-purity germanium detector system coupled to Ortec-Dspect jr digital MCA system. The average measured activity concentrations of the nuclides (238)U, (232)Th and (40)K are found to be 0.781, 1.05 and 2.19 Bq l(-1), respectively. The measured activity concentrations have been compared with similar studies from different locations. The annual effective doses for ingestion of radionuclides in the water are found to be 0.0246 mSv for (238)U and 0.169 mSv for (232)Th.

Concentrations of natural radionuclides in imported mineral substances

Levels of natural radionuclides, such as thorium-232 (232Th), radium-226 (226Ra) and potassium-40 (40K), were determined in about 2,000 samples of imported mineral substances using gamma spectrometry. The maximum concentration levels of 232Th, 226Ra and 40K were 1,260 +/- 54, 13,400 +/- 94 and 1,256 +/- 260 Bq kg(-1), respectively, in zirconium compounds. Due to relatively high concentrations of the above-mentioned radionuclides in some imported mineral substances, the National Radiation Protection Department (NRPD), as the competent authority, has established national limits (900 Bq kg(-1) for 232Th, 1800 Bq kg(-1) for 226Ra and 11,000 Bq kg(-1) for 40K), based on the external exposures, for general importation permits of these materials.

Role of reference materials in analysis of environmental pollutants

This paper discusses the importance and use of reference materials for quality assurance and quality control in environmental analysis. The general classification of reference materials and categorisation of those for chemical composition are presented. The most common reference materials for pollutants in air, water, waste water, soil, sediments, sludge and some biological materials and their producers are tabulated. Definitions, practical recommendations on selection and handling, and application areas of reference materials are also presented.