I. Lopes

Implementation of the quality management system at the Laboratory of Radiological Protection and Safety (LPSR) in Portugal

The paper describes the activities carried out for the implementation of the quality management system (QMS) at the Laboratory of Radiological Protection and Safety (LPSR) in Portugal in order to achieve the management and technical requirements of ISO/IEC 17025:2005 and to get the accreditation for ten tests. The implementation of the QMS based on this international standard allowed LPSR to improve the methods, to identify problems, to implement preventive and corrective actions, to generate valid results and to achieve a stable level of high-quality output recognized by an independent body in the scope of waters, metrology, radiation and radiochemistry.

Contamination of Hydrographic Bassins in Uranium Mining Areas of Portugal

The uranium-radium mining industry generated about six million tons of radioactive by-products composed mainly by the tailings of uranium milling facilities and by fine mud deposits resulting from treatment of acid mine waters. Most of these radioactive materials are deposited on the ground in the village of Urgeirica, near Viseu, and are currently exposed to weathering. Following rains, leaching and surface runoff of these tailings drain into a stream, Ribeira da Pantanha that joins the river Mondego. In this river a wide artificial lake, Barragem da Aguieira, is the main water reservoir for the centre region of the country. Other rivers flowing through the mining region, namely the rivers Dao, Vouga and Tavora, may also receive drainage from the areas of old uranium mines. The radioactive contamination that uranium mining and milling wastes may have originated in rivers and water reservoirs is assessed.

Naturally‐Occurring Radionuclides In Drinking Water From Surface And Groundwater Reservoirs

Radioactivity in water for human consumption is under closer scrutiny than ever before and many countries adopted guideline values based on total alpha and total beta activity measurements. Although most waters from surface circulation meet these guidelines, it is frequently found that groundwater exceed guideline values. Results of water analyses by alpha spectrometry clarified that the main radionuclides present are from the uranium decay series, such as uranium isotopes, radium (226Ra), radon (222Rn), and also 210Pb and 210Po. Occasionally, groundwater displayed 226Ra concentrations higher than 1 Bq L−1 and 222Rn concentrations above 1000 Bq L−1. Nevertheless, lack of conformity of these waters with guidelines adopted, generally, is not due to anthropogenic inputs.

Quality control assurance of strontium-90 in foodstuffs by LSC

A method based on the separation of Sr-90 by extraction chromatography and beta determination by Liquid Scintillation Counting (LSC) technique was used for strontium analysis in food samples. The methodology consisted in prior sample treatment (drying and incineration) followed by radiochemical separation of Sr-90 by extraction chromatography, using the Sr-resin. The chemical yield was determined by gravimetric method, adding stable strontium to the matrix. Beta activity (Sr-90/Y-90) was determined using a low background liquid scintillation spectrometer (Tri-Carb 3170 TR/SL, Packard). The accuracy and the precision of the method, was performed previously through recovery trials with Sr-90 spiked samples, using the same type of matrices (milk, complete meals, meat and vegetables). A reference material (IAEA_321) was now used to measure the accuracy of the procedure. Participation in interlaboratory comparison exercises was also performed in order to establish an external control on the measurements and to ensure the adequacy of the method.