Evaluation Of Excess Life Cancer Risk Due To Background Gamma Radiation In Central Cross River, Nigeria

Human exposure to ionizing radiation from natural and artificial sources is an unavoidable phenomenon on Earth. Radiation indices and dose rate for some markets in Cross River State, central senatorial district Nigeria, have been measured utilizing a 451p ion chamber survey meter, and the following parameters of radiation were calculated; annual effective dose equivalent, and excess life cancer risk. The ranges of dose dose rate measured within Six major markets are as follows; Boki: 0.04sv/h to 0.510sv/h, Ikom: 0.08sv/h to 0.253sv/h, Etung: 0.00sv/h to 0.500sv/h, Obubra: 0.08sv/h to 0.320sv/h, Yakurr: 0.05sv/h to 0.25sv/h, and Abi: 0.06 sv/h to 0.160 sv/h .The mean value for the dose rate was 0.17 0.099 for Boki, 0.135 0.046 sv/h for Ikom, 0.157 0.112 for Etung, 0.165 0.053 for Obubra, 0.107 0.039sv/h for Abi, 0.146sv/h for Yahurr. Mean values of 0.379 0.510msvy-1, 0.210 0.081msv/y, 0.271 0.267msv/y, 0.252 0.090msv/y, and 0.223 0.081msv/y, 0.163 0.059 for AEDE were observed respectively for Boki, Ikom, Etung, Obubra, Yakurr, and Abi within the markets. Similarly, 0.622 0.238 x 10-3, 0.643 0.158 x 10-3, 0.876 0.853 x 10-3, 0.514 0.167 x 10-3, and 0.628 0.233 x 10-3, were recorded for ELCR, within the markets. The AEDE values are within the permissible limit as recommended by the international bodies, the ELCR values are also within the permissible limit. The AEDE & ELCR values indicates that the market areas are radiation safe for any radiological health burdens that might arise due to absorbing doses from background ionizing radiation, but the probability of occupants developing cancer over a lifetime exposure in market places is high. It is recommended that periodic background ionizing radiation monitoring and evaluation should be carried out, and radioactive concentration of nuclides in soil and rocks are been checked by local authority.