Fission track analysis (FTA) has been used to investigate the biological uptake of uranium. Examination of fission track maps of black spruce twigs (from areas of uranium mineralization and mill tailings) shows uranium to be concentrated in the inner bark while decreasing in the outer bark of the twigs. Track clusters in the bark, too large to be uraniferous airborne particulate matter, are identified as being associated with resin canals in the twigs. The results of this work help clarify the mechanisms by which uranium is incorporated in black spruce twigs. The observation of decreasing uranium content with the increasing age of black spruce twigs by an earlier worker, can now be explained by the relative reduction in volume of the uranium enriched inner bark with age.
A study has been carried out of the uptake of uranium and other radionuclides by plants growing on abandoned tailings from an uranium mining operation. Assay methods included instrumental neutron activation analysis, delayed neutron counting, fission track imaging, and counting of natural radioactivity. Care was taken to avoid contamination of the plant material and a number of methods are described to identify such contamination. All plants observed showed high uptake of radionuclides, compared to plants studied from naturally uraniferous and control areas. Graminoid (grass-like) plants showed significant uptake in the above-ground parts while woody plants showed exceedingly high uranium accumulation in the root portions. These results have significance in determination of the spread of radioactive material from such sites.
The whole-body clearance of18F-fluoride injected intravenously into chronically uremic rats was found to proceed more slowly (7.6% of the dose in the first
hour, vs 28%) and to a lesser total amount (18.5% vs 46.7%) in 4 hrs than in normal rats of the same age. The concentration
of radiofluoride in the urine of uremies during the first hour was about 10% of that observed in normals. No changes in24Na and42K whole-body clearance rates were detected in this surgically-induced model of chronic uremia. Statistically significant elevations
in central compartment fluoride concentrations were observed 4 hrs after injection. Fluorine and calcium in bones of uremic
and normal animals were measured using Instrumental Neutron Activation Analysis techniques. The ratios μg F/mg Ca were highly
significantly greater in uremics (2.2±0.3 vs 1.1±0.3). These differences were primarily brought about by elevations in bone
fluoride rather than by decreases in calcium content of the uremic bone.
Authors:T. Sykes, L. Stephens-Newsham, M. Apps, and A. Noujaim
Compounds of both gold and platinum are used in medicine, the former as salts to treat arthritides and the latter as the metal
complex cisplatin to treat cancer. We have investigated neutron activation analysis with the Slowpoke II reactor as an assay
method for both elements using human blood plasma as a matrix. Neutron activation of platinum gives rise to 3.15 day199Au while that of gold produces 2.7 day198Au. Activated samples are dissolved during heating in test tubes and the gold extracted by adding dibutyl sulphide to the
same tube. The latter is formed to able to quantitate Pt down to 60 ng and Au down to 60 pg. The dissolution technique and
possible interferences in the assay are discussed.