Two traditional methods are used, often in combination, for assessing the intake and resulting dose from the inhalation of radioactive aerosols. The first calculates the intake based on air sampling programs and assessing and assigning dose using published dose conversion factors. The second approach assigns dose from the results of bioassay programs using measurements of radionuclides in human excreta (ex vivo, sometimes referred to as "in vitro") or via direct measurements of radionuclides in the body (in vivo) in combination with metabolic models.
View Article and Find Full Text PDFIonizing radiation exposure to the lens of the eye is a known cause of cataractogenesis. Historically, it was believed that the acute threshold dose for cataract formation was 5 Sv, and annual dose limits to the lens were set at 150 mSv. Recently, however, the International Commission on Radiological Protection has reduced their threshold dose estimate for deterministic effects to 0.
View Article and Find Full Text PDFIn January 2014, approximately 37 800 L of crude 4-methylcyclohexanemethanol (crude MCHM) spilled into the Elk River, West Virginia. To understand the long-term fate of 4-MCHM, we conducted experiments under environmentally relevant conditions to assess the potential for the 2 primary compounds in crude MCHM (1) to undergo biodegradation and (2) for sediments to serve as a long-term source of 4-MCHM. We developed a solid phase microextraction (SPME) method to quantify the cis- and trans-isomers of 4-MCHM.
View Article and Find Full Text PDFAll soils and rocks contain naturally occurring radioactive materials (NORM). Many ores and raw materials contain relatively elevated levels of natural radionuclides, and processing such materials can further increase the concentrations of naturally occurring radionuclides. In the U.
View Article and Find Full Text PDFA heated purge-and-trap gas chromatography/mass spectrometry method was used to determine the cis- and trans-isomers of (4-methylcyclohexyl)methanol (4-MCHM), the reported major component of the Crude MCHM/Dowanol™ PPh glycol ether material spilled into the Elk River upriver from Charleston, West Virginia, on January 9, 2014. The trans-isomer eluted first and method detection limits were 0.16-μg L(-1)trans-, 0.
View Article and Find Full Text PDFThis paper presents an analysis of the implications of some recent studies performed to characterize uranium products from modern uranium recovery facilities important for worker protection. Assumptions about the solubility (related to the molecular species being produced) of these materials in humans are critical to properly assess radiation dose from intakes, understand chemotoxic implications, and establish protective exposure standards (airborne concentrations, limits on intake, etc.).
View Article and Find Full Text PDFRadiat Prot Dosimetry
July 2011
On the basis of a review of recent epidemiology, the ICRP recently issued a statement outlining a new approach to radon. The ICRP indicates that the Publication 65 dose conversion convention will be replaced using the dosimetric approach currently used for other radionuclides. Moreover, the ICRP indicates that the dose conversion factor is expected to increase by about a factor of 2.
View Article and Find Full Text PDFJ Environ Radioact
September 2006
The risk to non-human biota from exposure to ionizing radiation is of current international interest. In calculating radiation doses to humans, it is common to multiply the absorbed dose by a factor to account for the relative biological effectiveness (RBE) of the radiation type. However, there is no international consensus on the appropriate value of such a factor for weighting doses to non-human biota.
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