ASSESSMENT OF CANCER RISK AND HEREDITARY GENETIC DAMAGE TO BAGHDAD S POPULATION RELATED TO RADIOLOGICAL EXPOSURE TO NATURAL BACKGROUND RADIATION

The risk of cancer incidence (morbidity) and mortality to individuals in Baghdad’s population related to external exposure to ambient gamma radiation is evaluated in this study by using linear, no-threshold (lnt) dose-response model. Exposure rate measurements are carried out outdoors and in a house built from bricks and a building constructed from concrete by using BGS-4 gamma-ray scintillation counter (Scintrex, Canada). Absorbed dose rates in air and in human tissues are determined by applying typical conversion factors available in the literature. Age-dependent radiation dose is calculated for infants, children, and adults. Dose-to-risk conversion factors are applied to estimate potential risk to various body organs and tissues as a result of exposure to ambient gamma radiation. The effective dose equivalents to individuals living in houses and in buildings are found to be less than the allowable dose limit for the public. However, the results indicate that there is one cancer risk incident (morbidity) expected for every 329 individuals (0.3%) exposed to ambient gamma radiation. The lifetime fatal cancer probability (mortality) is found to be occurs at a rate of 0.21% (1 per 473 exposed individuals). Other consequences of radiation injury (genetic effects transmitted to succeeding generations) are expected to occur at a rate of 0.0325% in the offspring of Baghdad population as a result of changes transmitted via the genetic mechanisms due to irradiation of gonads.