ASSESSMENT OF RADIATION LEVELS IN SOIL OBTAINED FROM OTTAMIRI AND NWORIE RIVER EXCAVATION SITES AND THEIR IMPACTS ON CONSTRUCTION PROJECTS IN OWERRI METROPOLIS, IMO STATE, NIGERIA

Abstract

When ionizing radiation interacts with the human body, it can damage living cells and lead to various health effects. The challenge always, is how we can determine the threshold that can lead to this damage. This study tends to assess radiation levels in soil obtained from Otamiri and Nwaorie River Excavation sites and some Construction Sites in the Owerri Metropolis, Imo State, Nigeria. We also measured the back ground radiation of both sites. 5 soil samples were collected from the Excavation and 5 from Construction Site respectively, 10 samples in total were measured using a Durridge Rad7 detector. The background radiation of both sites was also measured; a total numbers of 100 readings were taken, 50 from Excavation and 50 from Construction Site, 10 readings from a point of distance from each location, using a Digital Geiger-Mueller Counter(GCA- 07). Soil gas radon was measured with the concentration values obtained ranging from 0.1 ± 4.6Bq/ m³ to 28 ± 1.4Bq/m³, the total  across all sampling location is 101.3 Bq/m³ with average of  10.13 Bq/m³. Absorbed dose was estimated to be 25.3nGy^-1,equivalent dose rate is 2.53mSvy^-1 with Annual Effective dose equivalent (AEDE) of 3.63mSvy^-1.  For Background Radiation, from the construction site, the absorbed dose is 28.15nGy^-1, Equivalent dose rate is 0.776 mSvy^-1. Annual Effective dose equivalent (AEDE) is 0.212mSvy^-1, Excess Life Cancer Risk (ELCR) of 0.813. The Excavation site, estimated absorbed dose is 0.0105nGy^-1, equivalent dose rate of 0.878mSvy^-1, annual effective dose equivalent (AEDE) of 0.0849mSvy^-1. Excess Life Cancer Risk (ELCR) of 0.728. All these values are within or even lower than the recommended value level of 1.0mSvy^-1 The background radiation is not an issue of health concern from this resaerch. In 2017, the Imo State Local Government issued a warning against using water from the river, suggest radioactively contaminated water, any radionuclide found in the water reflects in the soil, but in this case, it is different. However, the government has to do more by regulating human activities that goes on at the excavation site.