AN ASSESSMENT OF NATURAL RADIOACTIVITY OF SOILS AND ITS EXTERNAL RADIOLOGICAL IMPACT IN SOUTHWESTERN NIGERIA
| Autor: | O S. Ajayi, T J. Ojo, S B. Ibikunle |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Veterinary medicine
Soil test Epidemiology Health Toxicology and Mutagenesis Nigeria Absorption Soil Air pollutants Activity concentration Background Radiation Humans Soil Pollutants Radioactive Radiology Nuclear Medicine and imaging Natural radioactivity Population Density Radioisotopes business.industry Altitude Collective dose Spectrometry Gamma Radioactivity Air Pollutants Radioactive Radiological weapon Absorbed dose Soil water Environmental science Nuclear medicine business |
| Zdroj: | Health Physics. 94:558-566 |
| ISSN: | 0017-9078 |
| Popis: | Soil samples collected from five states in the southwestern part of Nigeria have been analyzed for activity concentration of gamma-ray emitters. The States were Oyo, Lagos, Ondo, Ogun, and Osun. Activity concentration measurement was carried out using a co-axial type high purity germanium (HPGe) detector. Spectral analyses were performed using spectrometry software. The activity concentration measured ranged from 0.03 +/- 0.2 Bq kg(-1) for 137Cs to 1,358.6 +/- 28.5 Bq kg(-1) for (40)K. (40)K accounted for most of the activity. The calculated absorbed dose rates in air at 1.0 m above the ground ranged from 6 to 303 nGy h(-1) with a mean and standard deviation of 60.5 nGy h(-1) and 63.2 nGy h(-1), respectively. Estimated annual outdoor effective dose equivalent varied from 8 to 370 mSv y(-1). The calculated collective dose equivalent values for the five states ranged from 87,000 person-Sv to 600,000 person-Sv. The estimated annual outdoor effective values were considerably higher than the world soil average value of 70 microSv y(-1) reported by the International Commission on Radiological Protection. |
| Databáze: | OpenAIRE |
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