[en] Screening of public, non-community water supplies in a 12-county study area of Florida was undertaken. Fifty private water supplies in each county were also sampled. In six of the counties, more than 20% of all water supplies tested exceeded the Maximum Contaminant Level (MCL) for radium. Four of these counties were selected for study as affected counties and four others as control counties. The basis of this selection was the presence or absence of shallow deposits of phosphate ore, which was reported to be present in parts of the affected counties. It was concluded that the distribution of radium in drinking water is related to the presence of shallow deposits of phosphate ore. The geometric mean radium results for counties in the study area were compared with age adjusted cancer rates of the State of Florida and significant co-variance was indicated

No abstract available

No abstract available

[en] An area of 4,375 square miles in southwestern Florida with a 1981 population of 682,894 has been found to have more than 20 percent of drinking water supplies tested exceed the Maximum Contaminant Levels for radium established by the U.S. Environmental Protection Agency under the Federal Safe Drinking Water Act. The area is known to have extensive deposits of phosphate ore, with associated natural uranium and progeny. Results of testing of drinking water in this area for radium (²²⁶Ra) are reviewed and the occurrence of radium by geographical distribution is evaluated. Earlier reports by U.S. EPA that radium concentrations represent three statistical populations are confirmed and extended to apply to all sources of ground water in the area. Effects of elevated radiation dose on a large geographical area with a large, rapidly increasing population are considered. Co-variance of concentrations of radium with age adjusted rates of occurrence of cancers of all anatomic sites is described. (Auth.)

[en] Monte Carlo modelling has been performed in support of efforts to establish emergency dosimetry services based on optically or thermally stimulated luminescence (OSL/TL) of the Al_2O_3 substrate present on the resistors found in mobile phones, which can act as fortuitous retrospective dosemeters for photon exposures. Specifically, a range of exposure conditions has been modelled to assess the dependence of the dosimetry on factors such as the position of resistors within a phone, the orientation of the phone relative to the source, and the location of the phone relative to its owner. Variations due to the resistors’ positions and the phone’s orientation were generally found to contribute just a few percent to the uncertainty on the dose assessments, though the electrical contacts surrounding the resistors could potentially enhance these by several 10s of percent. But, the location of the phone was found to impact dosimetry greatly. The largest discrepancies in the results were found for low-energy exposures: for "1"9"2Ir, differences of up to an order-of-magnitude were found between resistor and whole body doses. The outcome of the work was to derive correction / calibration factors that can be applied to estimate whole body doses from OSL/TL readings, the accurate application of which would depend on the knowledge of the exposure geometry and the degree of conservatism acceptable for the dose assessment. (paper)

[en] The relative response of the new Health Protection Agency thermoluminescence dosemeter (TLD) has been calculated for Narrow Series X-ray distribution and ¹³⁷Cs photon sources using the Monte Carlo code MCNP5, and the results compared with those obtained during its design stage using the predecessor code, MCNP4c2. The results agreed at intermediate energies (∼0.1 MeV to ¹³⁷Cs), but differed at low energies (<0.1 MeV) by up to ∼10%. This disparity has been ascribed to differences in the default photon interaction data used by the two codes, and derives ultimately from the effect on absorbed dose of the recent updates to the photoelectric cross sections. The sources of these data have been reviewed. (authors)

[en] Uranium microparticles (radii: 50 nm-1.25 μm) were modelled surrounded by tissue and exposed to natural background radiation, in order to investigate potential dose enhancements from photon interactions. Generally, the results depended on the microparticle size. For a 0.5 μm radius microparticle in an isotropic field, it was found that the combined photon/electron doses deposited in 1 and 10 μm radii shells around it were raised by factors of ∼3.8 and ∼1.1, respectively; for a typical background photon fluence rate, these would correspond to increased energy depositions of a few 10's and a few 100's of eV y^-1, which are far less than the likely deposition rate resulting from the radioactive decay of a ²³⁸U microparticle. The health hazard from uranium microparticle interactions with background photons was concluded to be negligible. Published by Oxford Univ. Press on behalf of the Health Protection Agency 2010. (authors)

[en] The International Commission on Radiation Units and Measurements is considering revising the definitions of the operational dose quantities used for personal monitoring. This paper investigates the impacts of the proposed changes on the Public Health England two-element β/γ personal thermoluminescence dosemeter (TLD), in terms of its energy and angle dependences of responses for both skin and whole-body dose assessments. In general, the photon response of the skin element would be unaffected by the proposal, though technical issues may arise during calibration. For body photon doses, the current TLD design still produces acceptable response characteristics in some circumstances, but in general it will need to be redesigned to better match the requirements of the new operational quantity; to that end, a simple adaption is demonstrated that might provide a partial solution. For electron/beta exposures, matching the combined responses of both the body and skin elements to the dose quantities may be more challenging. The performance criteria against which dosemeters are judged may also need to be revised to reflect the proposed change. (paper)

[en] The ICRU is considering revising the definition of ambient dose equivalent. This paper investigates the impacts of the proposed change on four designs of neutron survey instrument, the GNU, HSREM, LB6411 and Studsvik 2202D, in terms of their respective energy dependences of response and their performances in realistic workplace fields. In some circumstances the current designs of instrument still produce acceptable characteristics, but in general they may need to be re-optimized to better match the requirements of the new operational quantity; to that end, a simple retrofit solution for the GNU is demonstrated. The performance criteria against which instruments are judged may also need to be revised to reflect the proposed change. (paper)

[en] The UK Health Protection Agency is currently commissioning a new personal dosimetry system based on the use of Harshaw^TM two-element thermoluminescent dosemeter cards using LiF:Mg,Cu,P. Results of extensive type testing carried out with reference to IEC 61066, 'Thermoluminescence Dosimetry Systems for Personal and Environmental Monitoring', have been presented. (authors)