Radiological Environmental Impact Assessment and Radon Contribution Due to Civil Engineering Works in Port City of Kribi, Cameroon

This study, conducted in Kribi, South Cameroon, assesses radioactivity levels, effective doses, and radiological risks. The aim is to show the impact of civil engineering activities on public exposure to natural radioactivity, particularly radon. Using the RESRAD-ONSITE 7.2 code, results were projected over 100 y. The maximum total effective dose was 0.4 mSv y-1 at t=10 y. The main contributions to this dose were 47.95%, 28.15%, 21.06%, 1.11%, 0.76%, 0.33%, and 0.30%, respectively, from radon inhalation, terrestrial radiation, plant ingestion, milk ingestion, 14C and 3H inhalation, meat ingestion, and accidental soil ingestion, respectively. The total excess risk of maximum cancer morbidity, estimated at 8.965 × 10-4 and achieved at time, was 3 times higher than the limit value of 3 × 10-4 given by the World Health Organization. The risk significantly decreased after the tenth year, coinciding with the completion of major construction projects, unlike areas with intensive agro-pastoral and mining activities. The study highlights that radon inhalation, terrestrial radiation, and consumption of contaminated plants were the main exposure pathways, likely due to high levels of dust and airborne particles. Thus, in a given locality, exposure pathways to radionuclide and associated radiological risk are strongly related to the type of anthropomorphic activity carried out and its duration.