Radionuclide activity concentration in soil, granites and water in a fluorosis endemic area of India: An oral health perspective

Abstract

BackgroundThe idea that hilly areas have a high background radiation which in turn is linked to dental fluorosis is widely held by many in India. There is little evidence to confirm this. ObjectiveThe study aimed to investigate the level of environmental radionuclide in order to determine any interrelationship between radionuclide and dental fluorosis in Pavagada, a fluorosis endemic area of Karnataka, India. MethodsGamma radionuclides (Th232, Ra226 and K40) were determined by high purity germanium (HPGe) gamma-ray spectrometer (Bq Kg-1) using a 50% relative efficiency p-type broad energy HPGe detector. Fluoride was estimated using fluoride Ion-selective electrode (ISE). Fluorosis was assessed using WHO diagnostic criteria. ResultsThe average mean +_SD activity concentration in soil for K40 was detected between 416.6 ± 9.3 and 769.1 ± 15.0. Th232 was estimated between 13.6 ± 0.6 and 57.6 ± 1.3; and Ra226 was found between 6.4 ± 0.4 and 21.6 ± 0.7. Similarly, the mean activity concentration detected (Bq kg-1) in granite for K40 ranged between 259.8 ± 6.9 and 1608.5 ± 26.9. The activity concentration of Th232 ranged between 26.4 ± 0.8 and 57.6 ± 1.3: and that of Ra226 was between 6.6 ± 0.3 and 21.6 ± 07. Drinking water contains 2.98 ppm of fluoride. Dental fluorosis was diagnosed as mild to moderate. ConclusionThe radionuclide activity in water, soil and granites were below the detection limit. Hence, the study revealed no association of fluorosis and radionuclide level in Pavagada, Karnataka, India. This helps resolve an ambiguity.