Radiological hazard of coffee to humans: a comparative study of Arabian and Turkish coffees

Thirty-nine Arabian and Turkish coffee powder samples purchased from various markets in Saudi Arabia were analyzed by High Pure Germanium (HPGe) gamma spectrometry to determine the activity concentrations of the natural and artificial radionuclides 238U, 226Ra, 232Th, 137Cs, and 40K. All samples, (except for two samples of Turkish coffee) were found to contain a high mean content of 40K, ranging from 839.83 to 1197.11 Bq/kg and from 161.312 to 2411.215 Bq/kg for Arabian and Turkish coffee powders, respectively. The concentrations of 226Ra and 232Th were found to be 2.57 to 10.63 Bq/kg and nondetectable to 8.01 Bq/kg for Arabian coffee and nondetectable to 10.09 Bq/kg and nondetectable to 9.75 Bq/kg for Turkish coffee, respectively. Based on these values, we estimated the potential radiological hazards to consumer health from coffee powder. We determined the radium equivalent, annual effective dose rate, and external and internal hazard for each element, and all were found to be below the limit recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation. However, absorbed dose rate values for some samples were higher than the permissible limit. In all samples, the 137Cs concentration was below the detection limit. The average annual committed effective dose values reported in this study were far below the world average value of 0.30 mSv/yr for an individual. In addition, the limit for the threshold consumption rate was calculated. The statistical methods were applied to study the relationship between all the calculated natural radionuclides and their hazard parameters. Results indicated that the use of these types of coffee had no significant radiological health risks. This study may contribute data on coffee powder for formulating regulations related to radiological health care. Key words: Arabian and Turkish coffees, natural radioactivity, radiological hazard parameters.