Determination of natural radioactivity by gross alpha and beta measurements in ground water samples

• Determination of the natural radioactivity in ground water.
• The activity concentrations of the gross α and β in the ground water samples are measured.
• Radiation exposure through ingestion of drinking water is assessed.
• Annual effective dose for adult members of the public is calculated.

In this study, the activity concentrations of the gross α and β in ground water samples collected from the different drilled wells in Nevşehir province were measured to assess annual effective dose due to the ingestion of the water samples. Nevşehir province is one of the major cities of Cappadocia Region which is a popular tourist destination as it has many areas with unique geological, historic, and cultural features. Sampling and measurements were carried out in the autumn of 2011 and the spring of 2012. The values of the activity concentrations of the gross α and β measured in the water samples ranged from 80 to 380 mBq L−1 with a mean of 192 mBq L−1 and 120–3470 mBq L−1 with a mean of 579 mBq L−1 respectively. All values of the gross α were lower than the limit value of 500 mBq L−1 while two ground water samples were found to have gross β activity concentrations of greater than 1000 mBq L−1. Therefore two water samples were the subject of further radioisotope-specific analysis. The obtained result indicated that the elevated activity concentrations of the gross β in these water samples are dominated by 40K activity. Annual effective doses ranged from 0.04 to 0.20 mSv y−1.