Evaluation of Gross Alpha and Gross Beta Radioactivity in Crude Oil Polluted Soil, Sediment and Water in the Niger Delta Region of Nigeria

摘要

The evaluation of gross alpha and beta activities in crude oil contaminated soil, sediment and water samples was conducted in ten oil polluted environment of Delta State using Gas-flow proportional counter. Samples were collected from the oil polluted environment in each oil field and samples were prepared and analyzed following standard procedures. The mean gross alpha and beta activities obtained are 331.4 ± 24.5 Bq kg-1 and 11,335 ± 112 Bq kg-1 respectively for soil, 259.2 ± 17.6 Bq kg-1 and 4508 ± 96 Bq kg-1 respectively for sediment, and 1.00 ± 0.09 Bq kg-1 and 20.3 ± 1.7 Bq kg-1 respectively for water. The estimated average values of the total annual effective dose equivalent (AEDET (α,β)), the total annual gonadal dose equivalent (AGDET (α,β))), and the total excess lifetime cancer risk (ELCRT (α,β)) are 10.64 mSv y-1, 0.037 μSv y-1 and 0.037 μSv y-1 respectively. The gross alpha and beta activities values obtained in soil and sediment were relatively high compared to values reported in some parts of the country and other regions and countries of the world. The radiological risk parameters examined show that AEDET (α,β) and AGDET (α,β) are above recommended permissible limits while ELCRT (α,β) is within the recommended permissible limit. The overall results obtained in this study indicate that the environmental samples have been radiologically impaired due to the crude oil spillage. An appropriate remediation technique was therefore recommended to remediate the polluted soil, sediment, and water to their near original state.