Radioactivity of the gas pipeline network in Poland.

The paper presents the study of the radioactivity connected with the transport of natural gas by the gas pipeline network in the selected points in Poland. In the scope of the study the measurements of activity concentration of radon (222Rn) in the gas samples, radiolead (210Pb) in spent filter cartridges and dust samples (black powder) collected from the gas pipeline network were performed. The results show that the 222Rn activity concentration in natural gas varies from the detection limit of the applied method (30 Bq/m3) to around 1400 Bq/m3. The 210Pb activity concentration in black powder samples and spent filter cartridges varies from 500 to 17000 Bq/kg and from 200 to 2900 Bq/kg respectively. The black powder with highest 210Pb concentration should be classified as low-radioactive waste according to nuclear regulations.

Determination of the self-attenuation based on the sample composition in gamma-ray spectrometry of 210Pb: requirements for the scope of chemical analyses.

In the presented paper analysis of sensitivity of self-attenuation correction Cs to the accuracy of chemical composition analysis is presented. The analyses were done by means of Monte Carlo simulation for cylindrical samples and for four sample materials: peat, water, ash and soil. For each of these materials the major elements were selected whose determination in the analysed material is necessary. For the remaining elements threshold levels of their concentration were determined-if expected element concentration in a sample exceeds this value, its determination is indispensable, assuming the accuracy of Cs determination at 3 %.

Airborne radionuclides in the proglacial environment as indicators of sources and transfers of soil material.

A survey of artificial (137Cs, 238Pu, 239+240Pu, 241Am) and natural (226Ra, 232Th, 40K, 210Pb) radioactive isotopes in proglacial soils of an Arctic glacier have revealed high spatial variability of activity concentrations and inventories of the airborne radionuclides. Soil column 137Cs inventories range from below the detection limit to nearly 120 kBq m-2, this value significantly exceeding direct atmospheric deposition. This variability may result from the mixing of materials characterised by different contents of airborne radionuclides. The highest activity concentrations observed in the proglacial soils may result from the deposition of cryoconites, which have been shown to accumulate airborne radionuclides on the surface of glaciers. The role of cryoconites in radionuclide accumulation is supported by the concordant enrichment of the naturally occurring airborne 210Pb in proglacial soil cores showing elevated levels of artificial radionuclides. The lithogenic radionuclides show less variability than the airborne radionuclides because their activity concentrations are controlled only by the mixing of material derived from the weathering of different parent rocks. Soil properties vary little within and between the profiles and there is no unequivocal relationship between them and the radionuclide contents. The inventories reflect the pathways and time variable inputs of soil material to particular sites of the proglacial zone. Lack of the airborne radionuclides reflects no deposition of material exposed to the atmosphere after the 1950s or its removal by erosion. Inventories above the direct atmospheric deposition indicate secondary deposition of radionuclide-bearing material. Very high inventories indicate sites where transport pathways of cryoconite material terminated.

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.

A revision factor to the Cutshall self-attenuation correction in (210)Pb gamma-spectrometry measurements.

The Cutshall transmission method of determination of self-attenuation correction in (210)Pb measurements by gamma-spectrometry gives the results burdened with errors of up to 10%. The author proposes introducing into the Cutshall correction Cs,Cuts an additional revision factor CCs,Cuts to eliminate errors. The proposed formula of the revision factor describes the CCs,Cuts value depending on the experimentally obtained Cs,Cuts correction. Formula holds true in wide ranges of the measurement geometries and linear attenuation coefficients of both the standard and 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.

Monte Carlo validation of the self-attenuation correction determination with the Cutshall transmission method in ²¹°Pb measurements by gamma-spectrometry.

The accuracy of estimation of the self-attenuation correction Cs with the Cutshall transmission method in (210)Pb measurements by gamma-spectrometry was assessed using the Monte Carlo method. The Cutshall method overestimates the correction for samples with linear attenuation coefficient at 46.5 keV higher than that of the standard and underestimates it in the opposite case. The highest bias was found for thick samples. C(s,Cuts)/C(s) ratio grows linearly with sample linear attenuation coefficient.

Natural radioactivity in groundwater--a review.

The issue of natural radioactivity in groundwater is reviewed, with emphasis on those radioisotopes which contribute in a significant way to the overall effective dose received by members of the public due to the intake of drinking water originating from groundwater systems. The term 'natural radioactivity' is used in this context to cover all radioactivity present in the environment, including man-made (anthropogenic) radioactivity. Comprehensive discussion of radiological aspects of the presence of natural radionuclides in groundwater, including an overview of current regulations dealing with radioactivity in drinking water, is provided. The presented data indicate that thorough assessments of the committed doses resulting from the presence of natural radioactivity in groundwater are needed, particularly when such water is envisaged for regular intake by infants. They should be based on a precise determination of radioactivity concentration levels of the whole suite of radionuclides, including characterisation of their temporal variability. Equally important is a realistic assessment of water intake values for specific age groups. Only such an evaluation may provide the basis for possible remedial actions.