Radioactivity in waters of Mt. Etna (Italy)

EVALUATION OF RADON CONCENTRATION IN IRRIGATION AND DRINKING WATERS FROM THE EASTERN PART OF OMAN AND ESTIMATION OF EFFECTIVE DOSES TO OMANIS

The present study concerns measurement of the radon concentration in drinking and irrigation waters obtained from the eastern part of Oman, in particular in regard to water quality assessment of the region. The samples were collected from different places covering most types of water sources in the region. A passive and time-integrated track etch detector (LR-115 type II) combined with a high-resolution optical microscope has been used to obtain the radon concentration in the studied samples. Values of dissolved radon in water varied among the water sources; the highest concentration of radon was found to be 363 Bq m-3 in a drinking water sample while well water used for irrigation showed the lowest value, at 140 Bq m-3. Measured data for all water sources are below the permissible limit of 11.1 kBq m-3 recommended by the US-EPA. Annual effective doses for the studied samples were in the range 0.38-0.99 μSv y-1 which is significantly less than the action level recommended by the WHO (0.1 mSv y-1), indicating that the water sources in the Jalan BBH region of Oman are safe to use. The obtained data may serve as a reference for any future radiological study of the waterbody of this region.

DETERMINATION AND DOSE CONTRIBUTION OF URANIUM ISOTOPES AND 210Po ACTIVITY CONCENTRATIONS OF NATURAL SPRING WATERS IN THE PROVINCE OF GRANADA, SPAIN

The activity concentrations of alpha-emitters comprising isotopes of uranium (238, 234, 235U) and polonium (210Po) were measured using alpha-particle spectrometry in natural spring waters in the province of Granada, Spain. These water are consumed by the population of the zone who live in villages. This is almost half of the population of the whole region. Mean values of activity concentrations found are 42.61 ± 2.66; 49.55 ± 3.03; 1.64 ± 0.28 and 1.74 ± 0.15 mBq L-1 for 238U, 234U, 235U and 210Po, respectively. Finally, the radiological impact of the analysed waters has been determined, in terms of the estimation of the committed annual effective dose due to the ingestion of the water. The assessment has been carried out for five age groups with the aim to cover all the population. The calculated annual effective doses are observed to be below the prescribed dose limit of 100 μSv y-1 recommended by WHO.

Impact of water environmental change and migration of radionuclides on Hokutolite conservation in Peito (Taiwan)

Chemical factors (including pH, redox potential, content of total organic compound (TOC) and major ions) and U/Th-series radionuclides in the hot-spring water environment of Peito were determined to investigate the impact of environmental change and migration of radionuclides in water on conserving the precious mineral, hokutolite, in Peito (Taiwan). The activity concentrations of U/Th increased withEhand those of Cl−and SO42−.234U/238U ratios were nearly >1 ascribed to Szilárd–Chalmers effect andα-recoil.230Th/234U ratios were <1 resulting from complexation with chloride and sulfate ions.228Ra and226Ra activities were governed by pH,Ehand SO42−concentration. Disequilibria of228Th/228Ra and228Ra/232Th were evident attributed to complexation of Th with major anions and co-precipitation of radium with (Ba,Pb)SO4. Alpha-recoil caused the enrichment of228Ra and apparent disequilibrium of232Th/228Th. A mechanism illustrating the radiochemistry involving the formation of hokutolite in Peito was derived accordingly. The water environment of the studied area was found apparently changed in light of the variation of temperature, TOC and concentration ratio of Ba/Pb, which resulted from the channeling of hot spring water and the release of household waste water. The water environmental change can thus hinder the migration of radionuclides as well as the formation of hokutolite so that the performance of hokutolite conservation can be decreased. Immediate enactment of regulations for conserving hokutolite in Peito was therefore suggested in this research.

Radon concentrations in water in the region of Tokat city in Turkey

The aim of this study is to measure the radon ((222)Rn) concentrations in drinking water and river water in the region of Tokat city in Turkey. The measurements were performed by analysing the water samples collected from tap water, spring water and Yesilırmak river water flowing through the centre of the city of Tokat. The obtained radon concentrations ranged from 0.48 ± 0.22 to 1.30 ± 0.27 Bq l(-1) in tap water, from 0.13 ± 0.17 to 1.20 ± 0.29 Bq l(-1) in spring water and from 0.09 ± 0.12 to 0.83 ± 0.17 Bq l(-1) in the Yesilirmak river water. The results are presented and compared with other studies. From these data, the average effective dose equivalent from radon in tap water and in spring water has been estimated as 5.0 and 3.0 µSv y(-1), respectively.