Estimation of radiation risks due to ingestion of water in Ogba/Egbema/Ndoni Local Government Area of Rivers State, Nigeria using risk models

Abstract

The radiation dose is the amount of energy absorbed in the body from radiation interaction. The risk of damage to tissues, cells, DNA and other vital molecules increases with every exposure to radiation. Each exposure can cause cell death, genetic mutation, cancers, leukemia, birth defects and endocrine system disorders. The aim of this study is to estimate radiation risks due to ingestion of water in Ogba/Egbema/Ndoni Local Government Area of Rivers State in Nigeria using radiation risk models. Secondary data from radiological studies on water resources of Ogba land was obtained and used to estimate excess relative risks (ERR) and excess absolute risks (EAR) for babies, children and teens of the study area. The excess relative risk (ERR) and Excess absolute risk (EAR) was calculated using a particular radiation dose, estimated age at exposure and the attained age. The result shows that relative risks decreases with increasing time after exposure. Lifetime attributable risk (LAR) was calculated from the values of excess relative risk and excess absolute risks estimated. The result of LAR shows that 102 male babies per 100,000 will likely develop cancer of the thyroid during their lifetime while 547 female babies per 100,000 will likely have cancer of the thyroid during their lifetime due to ingestion of tap water. This implies that about 84% of female and 16% of male babies will have cancer in their lifetime. This risk parameter is presented as risk per million inhabitants because the real population number has spatial and temporal variation. LAR estimated for babies, children and teenagers for different organs show that colon and lungs recorded the highest values. This study show an increasing LAR as age-at-exposure reduces. It also shows that females have generally higher risk than their male counterparts. Also well water and river water was observed to present a higher risk when compared to tap water. Therefore this study recommends the intervention of the government in providing stricter measures in regulating the use of radioactive materials in oil exploration and the oil companies operating in the region to provide enough safe drinking water for the people.

Keywords: Lifetime Attributable Risk, Excess relative risk, Radiation, dose and Exposure