Assessment of sediment sampling techniques for ESS environmental monitoring programme

• Radionuclides released and discharged into the environment from nuclear and other radiation-related facilities, such as the European Spallation Source (ESS), may accumulate in aquatic bottom sediments. Sediments should therefore, as recommended by the IAEA, be monitored regularly. This report describes the setting up of a methodology for zero-point assessments of the radiation levels in sediments of relevance for possible future releases from the ESS.Two types of sediment sampling devices have been tested: a grab sampler of the Lamotte type, and a stationary bottom trap consisting of a 5-L bucket placed on the bottom of a pond. The Lamotte grab sampler worked well in the absence of obstacles such as vegetation and stones. Sampling from boat may be advantageous in finding suitable sampling spots for the grab sampler. The stationary bottom trap, tested for more than two years at one of the ponds at the ESS facility, proved functional. To be certain to obtain sufficient sediment during collection period of one year, we recommend using three 5-L buckets per pond. The bottom trap is most likely not suitable for sampling in rivers with flowing water.For the sample preparation, sieving the sediment in a laboratory was found to be more efficient and more convenient compared to sieving at the sampling site. Freeze-drying was found superior, in terms of efficiency and dried sample texture, to drying the sediment in open air. Measurements of total carbon, total nitrogen, and the carbon to nitrogen ratio proved to have the potential to provide relevant information about the sources of the sediment. The results of gamma-ray spectrometry confirmed sediments as a useful indicator of radionuclides, with activity concentrations above the MDA levels for all reported radionuclides and samples, except for one site. Gamma-ray spectrometry measurements on the samples can provide information on local elevated levels of anthropogenic radionuclides and add information to the sources of the sediment itself.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Environmental Sciences (hsv//eng)

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