Abstract

This research measured the concentration levels of radon in groundwater and determined the  ingestion  and  inhalation  dose.  The  study  used  RAD7  detector  with  RAD7-H2O  accessory  from  Durridge  Company  to  determine  the  radon  levels.  Thirty  water  samplesin granitic dominated regions were collected from various areas of Bungoma County: ten from boreholes (BH), ten from hand dug wells (WL) and ten from springs (SP). The water samples were collected in 250 ml bottles which were tightly covered with lid to avoid radon leakage. The highest value was 303±4.00 KBq/m³ recorded in Kanduyi well and the lowest was 126±11.4kBq/m³ from where most of the samples recorded a high radon concentration with a mean of 269±5.25 KBq/m³ in wells, 213±7.96 KBq/m³ in boreholes and 290±7.70 KBq/m³ in springs. The average ingestion dose was found to be 1.5±0.07mSv/yr, 1.9±0.09mSv/yr  and  2.1±0.1 mSv/yr.  The  average  annual  effective  dose  rate  for  the  samples  collected were 2±0.1 mSv/yr for boreholes, 2.6±0.13 mSv/yr for wells and 2.7±0.14 mSv/yr for springs. The samples reported an average value of AED higher than the world average of 1.15 mSv/yr but below the exception limit of recommended action level of 10 mSv/yrhence the radon concentration levels in underground water in the study area has minimal health implications to the population.

Keywords

underground water, bungoma county, RAD-7 detector, dose rate, annual effective dose rate (AED)