Radioactivity survey and risk assessment study for drinking water in capital city Ankara, Turkey

In this study, the activity concentrations of gross alpha and gross beta in 125 drinking water samples (16 tap and 109 spring waters) collected from Ankara province were measured using a gas proportional alpha/beta counter. The average (range) activity concentrations of gross alpha and gross beta were determined as 105 (20-495) mBqL(-1) and 195 (70-850) mBqL(-1), respectively. Average annual effective dose to adults caused by ingestion of water samples was estimated as 74.1 +/- 43.2 mu Sv y(-1). The average estimated cancer risk value depending on irradiations was calculated as 3.8 x 10(-4) and 2.6 x 10(-4) for the region using the nominal probability coefficients recommended by ICRP 60 and ICRP 103, respectively. Annual effective dose values in 10.4% of samples exceeded the limit values suggested by WHO for drinking waters in terms of beta activity and this was 0.8% for alpha activity. Moreover, contribution of K-40 to the gross beta activity in drinking waters of the region was determined as 47%.