<p><sup> </sup><sup>226</sup>Ra is a radionuclide of much concern since it poses a high risk of radio-toxicity when ingested and is well known for its invariably long half life of 1600 years. As such <sup>226</sup>Ra concentrations were measured in whole body tissue of fathead minnows (Pimephales promelas) in an experimental set up. Fathead minnows obtained were about two months old and fed on a Radium-226 spiked diet until 115 days. A simple and direct method to determine <sup>226</sup>Ra ingested by fish using a homogeneous liquid scintillation counting was developed. The study consisted of three groups; a sham, Radium treatment and acid treatment. Fathead minnows were sampled 75 and 115 days after feeding, and the following end points; mass (w/w), length, specific growth rate, condition factor and radionuclide measurements obtained. Mean end point results were (0.24 ± 0.03 g), (2.78 ± 0.1 cm), (1.75 ± 0.13 % day<sup>-1</sup>), (1.10 ± 0.06 g cm<sup>-3</sup>) and (577.06 ± 572.13 mBq g<sup>-1</sup>) respectively. Also mean total <sup>226</sup>Ra level was calculated as (1911.43 ± 868.64 mBq g<sup>-1</sup>) while the activity in sham and acid treatment resulted in levels below the Minimum Detectable Activity of 7.46 mBq g<sup>-1</sup>. The mean rate of <sup>226</sup>Ra accumulation, known as the concentration factor, by the fathead minnows was determined as 0.35 ± 0.19. Assuming that the <sup>226</sup>Ra Isotope is evenly distributed in the fish whole body, the derived dose rate was found to be 5.26 μGy h<sup>-1</sup>.</p> / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/11836 |
| Date | 04 1900 |
| Creators | Thompson, Manuela A. |
| Contributors | Mothersill, Carmel, Seymour, Collin, Prestwich, William, Medical Physics |
| Source Sets | McMaster University |
| Detected Language | English |
| Type | thesis |
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