MODELLING OF 226Ra ACTIVITY CONCENTRATIONS ALONG OGUN RIVER, SOUTH WESTERN NIGERIA
This work was aimed at generating a model using least square approximation technique to predict values of activity concentrations of 226Ra in any location along Ogun river in Nigeria using experimental data. Sediment samples were collected in thirty two locations along the river of about 400 km in length. NaI(Tl) gamma-ray spectrometer system was used to obtain activity concentrations of 226Ra.The aver-age value of activity concentration of 226Ra in the sediment samples from the upper region through the middle to the lower region of the river was found to be 12.65 Â± 3.48 Bq/kg, having values ranging from 5.57 Â± 2.36 Bq/kg (at Ekerin) to 20.40 Â± 4.52 Bq/kg (at Sokori). From this work, it was observed that the generated model and experimental data could be used to predict values of activity concentrations of 226Ra in any location along the river once the latitude and longitude (position) are known. Statistical tests on the model also showed that there were no significant differences between the experimental and predicted data of 226Ra and that 98.70% of the experimental data were predicted by the model.