Gross alpha and gross beta activities in selected marine species in Vietnam.

The measured gross alpha and gross beta activities in the edible muscle tissues of eleven selected marine species along the coast of North Vietnam varied from 10.2 ± 1.5 to 73.2 ± 8.1 Bq/kg (wwt) and from 10.6 ± 0.4 to 68.8 ± 2.8 Bq/kg (wwt), respectively. The lowest gross alpha activity was recorded for bigfin reef squid (Sepioteuthis lessoniana) as a result of its carnivorous diet, and the highest alpha activity was noted for blood cockle (Anadara granosa) as a result of its omnivorous diet. However, the gross beta activities in both carnivorous and omnivorous species were similar. The highest and lowest gross beta activities were observed for narrow-barred Spanish mackerel (Scomberomorus commerson) and for bigfin reef squid and squid (Teuthida), respectively. All three aforementioned species have carnivorous diets. The calculated annual committed effective dose resulting from the consumption of 25 kg of muscle tissue per year varied from 192 to 1375 µS with an average of 689 µS.

Radon as a potential health hazard for clients and workers of selected thermal spas in Poland.

The radiation exposure due to 222Rn and its progeny inhalation for clients and employees of selected thermal water spas was assessed. The radon risk was calculated using the measured 222Rn activity concentrations in the investigated thermal waters and radon transfer coefficient, defined as a fraction of radon released from the swimming pool water to the indoor air of swimming pool. The total radon in air concentration was not measured. The annual effective doses for workers and clients of the studied spa centers excluding Ladek-Zdrój ranged from 0.02 to 2.69 mSv and 0.40 to 48 µSv, respectively. For thermal water from Ladek-Zdrój (Ladek-Zdrój L-2), significantly elevated doses were observed both for workers (10.8 mSv) and clients (194 µSv).

Radioactivity in wastes generated from shale gas exploration and production - North-Eastern Poland.

In the present study, the K-40, U-238, Ra-226, Pb-210, Ra-228 and Th-228 activity concentrations were measured in 64 samples of wastes generated from shale gas exploration in North-Eastern Poland. The measured samples consist of drill cuttings, solid phase of waste drilling muds, fracking fluids, return fracking fluids and waste proppants. The measured activity concentrations in solid samples vary in a wide range from 116 to around 1100 Bq/kg for K-40, from 14 to 393 Bq/kg for U-238, from 15 to 415 Bq/kg for Ra-226, from 12 to 391 Bq/kg for Pb-210, from a few Bq/kg to 516 Bq/kg for Ra-228 and from a few Bq/kg to 515 Bq/kg for Th-228. Excluding the waste proppants, the measured activity concentrations in solid samples oscillate around their worldwide average values in soil. In the case of the waste proppants, the activity concentrations of radionuclides from uranium and thorium decay series are significantly elevated and equal to several hundreds of Bq/kg but it is connected with the mineralogical composition of proppants. The significant enhancement of Ra-226 and Ra-228 activity concentrations after fracking process was observed in the case of return fracking fluids, but the radium isotopes content in these fluids is comparable with that in waste waters from copper and coal mines in Poland.

Factors controlling measurements of radon mass exhalation rate.

Radon mass exhalation rate of soil samples was measured using an exhalation chamber of 10 dm(3) volume and a Lucas cell. The results show that mass of sample, grain size and water content influence the radon mass exhalation rate. For soil of (226)Ra activity concentration about 2500 Bq kg(-1) and samples within the range from 0.20 kg to 0.50 kg, the radon mass exhalation rate values are higher than those for samples of other masses. The observed radon exhalation rate is an inverse function of the average grain size. At the water content about 6% by weight, the radon mass exhalation rate reaches maximum, then it decreases with both increasing and decreasing of the water content in the sample.

Cs-137 in the natural environment of the Gorce Mountains (Poland).

Concentration of activity of Cs-137 and its spatial distribution in soils and lichen Hypogymnia physodes were determined in the Gorce Mts. (several hundred km2) in S Poland. The authors distinguished two areas of the Gorce Mts. on the basis of markedly different Cs-137 depositions, whose respective average values are 4.4 and 9.9 kBq/m2 as at 1st July 2005. The average Cs-137 activity concentration in the lichen H. physodes from the Gorce is 47 Bq/kg d.m. A significant local variability of quantities measured amounts to a few dozen percent was found.