Tuukka Turtiainen

210Pb and 210Po in Finnish cereals.

A survey was carried out on the activity concentrations of (210)Pb and (210)Po in cereal grains produced in Finland. The cereal species were wheat (Triticum aestivum), rye (Secale cereale), oats (Avena sativa) and barley (Hordeum vulgare), which account for 90% of the Finnish consumption of cereal products. The survey consisted of 18 flour and 13 unprocessed cereal samples and one hulled grain sample from 22 flour mills. According to the results, the mean (210)Pb/(210)Po concentrations in wheat grains, wheat flour, rye flour, oat grains and barley grains were 0.29, 0.12, 0.29, 0.36 and 0.36 Bq kg(-1), respectively. Combined with the consumption rates of the products, we assess that the mean effective doses from (210)Pb and (210)Po in cereal products for the adult male and female population are 22 and 17 μSv per year, respectively.

Multidisciplinary analysis of Finnish esker sediment in radon source identification.

In order to define the naturally-occurring radioactive materials that are the source of radon in natural environments, a comprehensive analytical (geochemical, physical and chemical) methodology was employed to study sand samples from the Hollola esker in the city of Hollola (Lahti area, Finland). Techniques such as gamma-spectrometry, emanation measurements, sequential chemical extraction, scanning electron microscopy (SEM), electron probe microanalyses (EPMA) and inductively-coupled plasma mass spectrometry (ICP-MS) were used to determine the potential source of radon. Monazite and xenotime, uranium- and thorium-bearing minerals and potential radon sources, occurred in significant amounts in the samples and were also the main reason for the distribution of uranium and thereby radium in separate grain-size fractions. Following deposition, the esker sand has been exposed to no significant weathering, and radium has not therefore been much separated from uranium. However, considering its non-compatibility with crystal lattices, it was recognized rather in easily leachable species (44% of the total (226)Ra) than uranium (21% of the total (238)U) in our analyses. The smallest grain-size fraction of the esker sand had a higher emanation power (0.24) than the other fractions (around 0.17). Due to the small relative proportion of this fraction, however, it contributed only slightly to the total emanation (4%). The emanation power of the leachable species was about three times higher (ca. 0.20) than that of the species tightly bound to the crystal lattice (ca. 0.07).

Radon Removal from Different Types of Groundwater Applying Granular Activated Carbon Filtration

Granular activated carbon (GAC) filters were installed in 12 private homes or vacation homes for removing unacceptably high concentrations of radon from household water. Radon removal efficiency was nearly 100% in most locations, although different water types were encountered. Other radionuclides such as uranium, radium, lead and polonium were removed less efficiently. Treated water quality remained good and no significant external radiation dose was caused to the residents.

Artificial radioactivity of Finnish vegetables in the 2000s

A survey on long-lived artificial radionuclides 137Cs and 90Sr in vegetables produced in Finland was carried out in 2009–2010. The mean 137Cs concentrations of all the outdoor vegetables were well below 0.5 Bq kg−1, ranging from <0.01 to 8.15 Bq kg–1 (fresh weight). The highest 137Cs contents were found in potato and root vegetables. The uneven distribution of the 137Cs deposition after the Chernobyl accident in 1986 was still seen in the 137Cs contents of outdoor vegetables. The 137Cs contents of greenhouse vegetables varied from <0.01 to 9.3 Bq kg−1, and the highest concentrations were found in organic lettuce grown in peat pots. The concentrations of 90Sr in the vegetables varied from 0.0087 to 0.17 Bq kg−1 fresh weight. The mean effective dose resulting from 137Cs and 90Sr in vegetables in 2009–2010 was <0.3 µSv a−1 and poses no health risk to the consumers.

Prevention measures against radiation exposure to radon in well waters: analysis of the present situation in Finland.

Naturally occurring radioactive elements are found in all groundwaters, especially in bedrock waters. Exposure to these radioactive elements increases the risk of cancer. The most significant of these elements is radon which, as a gas, is mobile and dissolves in groundwater. In Finland, water supply plants are obliged to carry out statutory monitoring of the water quality, including radon. Monitoring of private wells, however, is often neglected. In this paper, we outline the problem by reviewing the outcomes of the studies conducted in Finland since the 1960s. We also summarise the development of legislation, regulations and political decisions made so far that have affected the amount of public exposure to radon in drinking water. A review of the studies on radon removal techniques is provided, together with newly obtained results. New data on the transfer of radon from water into indoor air are presented. The new assessments also take into account the expanding use of domestic radionuclide removal units by Finnish households.