Radon hazard in upper silesian region

Nowadays augmented risk of a lung and larynx cancers as a result of the exposure on radon is not onlyknown fact, but also the most important effect of the influence of the natural radioactivity on thegeneral public. There is no doubt, that quite often miners are more endangered by enhanced radonexposures as other members of the society.Upper Silesia is the region of the extended underground mining industry, mainly of a hard coal, butalso the metal ore mining. Measurements of radon concentration in the mines were started in 70tiesand since late 80ties are obligatory due to Polish mining law.In last few years measurements of radon concentration in dwellings have been performed in UpperSilesia. Due to the literature, radon exhalation from the soil is stated as the most important factor,influencing radon concentration in houses. The Upper Silesia is the region strongly affected bymining, where the influence of this industry on the structure of the upper layers of the strata maycause enhanced emission of radon from the ground and therefore the enhanced radiation hazard for theinhabitants.The measurements of radon concentrations in houses was performed in two different areas of UpperSilesia. The average radon concentration in the northern part of Upper Silesia (in all sampling points)is 99 Bq/m3, while in living areas the average value is lower and equal 65 Bq/m3. Results ofmeasurement varied from 8 Bq/m3 to 697 Bq/m3 in a cellar and to 362 Bq/m3 in a habitable room.In the southern and western parts of Upper Silesia, where thick, isolating layers of silts and claysoccur, results of radon measurements vary between 8 and 128 Bq/m3. The average radonconcentration for this part of USCB is of about 42 Bq/m3. We found no increase of radonconcentration in houses located near places contaminated by radium-bearing mine waste waters. Itleads to the conclusion, that even the close vicinity of the radioactive waters or deposits does notcause an increase of radon concentration in dwellings. Such conclusion can be drawn from the resultsof measurements, done nearby Jastrz?bianka river and settling ponds Bojszowy and Rontok.Results of the preliminary monitoring show, that the main factor, affecting the radon concentration indwellings is the lithology of the underlying strata. The influence of the geological structure may beintensified by coal mining. The presence of a shallow, abandoned workings near the surface as well asa big number of faults enables easier migration of different gases and of course, migration of radon.In this paper results of radiation risk assessment for coal miners will be presented. The highest valueof dose received by exposure to the short lived radon daughter products diminished from 16,2mSv/year in 1993 to 5-7 mSv/year in 1996-7. The collective dose was diminished too: from 296 man-Sv in 1993 to 56 man-Sv in 1997.