Health Risk Assessment and Excess Lifetime Cancer Risk from Radon in Groundwater of Sulaymaniyah Governorate, Iraqi Kurdistan: Implications for Adults, Children, and Infants

Naturally occurring radioactive materials, especially radon, can contaminate groundwater and pose health risks through drinking and inhalation. This study analyzed radon activity in 30 groundwater samples from Sulaymaniyah Governorate, Iraq, alongside their physicochemical properties and radiological safety. Radon activity ranged from 2.1 to 33.7 Bq L-1, with an average of 12.6 Bq L-1. Nearly 47% of samples surpassed the US EPA threshold of 11.1 Bq L-1, though all remained well below the WHO maximum of 100 Bq L-1. Health risk parameters were computed for three age categories (adults, children, and infants), including annual doses from ingestion and inhalation, plus excess lifetime cancer risk. Combined annual doses stayed below the WHO's 0.1 mSv y-1 recommendation, and cancer risk estimates for all groups fell within acceptable USEPA limits. Statistical analyses (skewness, kurtosis, Shapiro-Wilk test, P-values, and Pearson correlation) explored relationships between radon and water quality parameters. Elevated radon levels in certain areas require targeted mitigation strategies. Continuous monitoring and public awareness programs are essential to minimize long-term health risks from waterborne radon exposure.