Excess Lifetime Cancer Risk Assessment from Ionising Radiation around Omoku and Obrikom Gas Plant, River State, Nigeria

Abstract

The excess lifetime cancer risks (ECLR) describe the potential carcinogenic effects, calculated based on the probability of cancer-induced incidence in a population. This is a result of exposure to radiation or the intake of harmful chemical substances for a lifetime. This study assessed excess lifetime cancer risk from ionising radiation around Omoku and Obrikom, River State, Nigeria. Excess lifetime cancer risk for Obrikom and Omoku communities has been computed from Background ionising radiation using GQ GMC 300E Plus. The background ionising radiation levels obtained from Obrikom community vary from 0.01 to 0.014mR/hr with an overall average of 0.108±0.0014mR/hr. Also, the background ionising radiation from Omoku community varies from 0.006 to 0.013 mR/h with an overall average of 0.0099±0.0023mR/hr. The annual effective dose rate varies from 0.11 to 0.19mSv/y with an overall average of 0.145±0.0272. Also, from Omoku community's values range from 0.08 to 0.17mSv/y, with an overall average of 0.131±0.03 are lower than the recommended safe limits by (ICRP, 2000). The Average background ionising radiation varied from 0.009 to 0.013mR/hr with a mean value of 0.0107±0.00142mR/hr and 0.007 to 0.013mR/hr with a mean value of 0.0107±0.00617mR/hr within Rukpokwu and Aluu sample locations, respectively. The annual effective dose rate (AEDR) for the sample sites varied from 0.12 to 0.17 mSv/yr and 0.09 to 0.18 mSv/yr, with mean values of 0.140±0.06 mSv/yr and 0.142±0.08 mSv/yr for both Rukpokwu and Aluu sample locations. Also, the Annual absorbed dose from Obrikom community varies from 78.3nGy/hr to 121.8nGy/hr with an overall average of 93.96±16.81nGy/hr. For the Omoku community, the average annual absorbed dose varied from 52.2nGy/hr to 113.1nGy/hr with an overall average of 86.13 6.54nGy/hr.  The Excess lifetime cancer risk from the Obrikom community varies from 0.37 to 0.65x10-3 with an overall average of 0.50±0.089. The Excess lifetime cancer risk for the Omoku community varied from 0.28 to 0.61x10-3 with an overall average of 0.46±0.04x10-3. These values are higher than the recommended safe limits by (ICRP, 2000). These results indicate that people within these locations may be exposed to Cancer due to background ionising radiation. However, there is presently no indication of people suffering from Cancer among the populace of the sample locations.