A Comparison of Current Methods for the Determination of Ra-226 and Ra-228 in Water by a Modified Georgia Tech Gamma Method Vs. US Environmental Protection Agency Drinking Water Methodologies.

ABSTRACT: Radium is a significant source of human radiation exposure both from natural sources (NORM, or Naturally Occurring Radioactive Material) and from technologically enhanced natural radioactive material (TENORM). Gamma analysis for 226Ra and 228Ra in water using high purity germanium (HPGe) detectors was compared with current methods from the US Environmental Protection Agency (EPA) using alpha scintillation and gas proportional counters. Extensive evaluations of a modified version of the original Georgia Tech HPGe method were performed. Known value 226Ra samples from the US Department of Energy (DOE) Mixed-Analyte Performance Evaluation Program (MAPEP) program, mixed 226Ra and 228Ra samples from the Environmental Resource Associates Quality Assurance Program (ERA), and mixed 226Ra and 228Ra samples from the Laboratory Proficiency Testing Program of the International Atomic Energy Agency (IAEA) were used for cross-check comparisons of the modified Georgia Tech method with other methodologies (EPA 903.1 and Ra-05 for 226Ra and 228Ra, respectively). Minimum counting times for our gamma instrumentation to reach a minimum detectable activity (MDA) of 0.04 Bq L-1 were also determined.

A Simple Method to Screen for Radiostrontium in Water by Ion Exchange Chromatography.

Radiostrontium isotopes (Sr, Sr, and Sr) are major fission by-products in nuclear reactors, in radiological events, and in environmental radioactive contamination. A method to analyze Sr and Sr in water has been developed using gradient elution with dilute hydrochloric acid and cation exchange resin, followed by carbonate precipitation. Counting was done on a gas proportional counter. The sample was recounted a second time after 2 to 3 wk to permit Y, a progeny of Sr, to achieve secular equilibrium and to allow Sr and Sr to be determined. This method was found to be simple, exhibiting high recovery, reduced use of hazardous chemicals, and lower cost compared to other current methods. An extensive comparison of the performance of the cation exchange method vs. a method using strong nitric acid (US Environmental Protection Agency Method 905.0) and a method using a specific strontium resin was conducted on performance test samples containing Sr (in a number of matrices) from the US Department of Energy's Mixed Analyte Performance Evaluation Program and mixed Sr- and Sr-containing water samples from the Environmental Resource Associates quality assurance program. The method described here is shown to yield comparable results to others.

2011 investigation of internal contamination with radioactive strontium following rubidium Rb 82 cardiac PET scan.

During routine screening in 2011, US Customs and Border Protection (CBP) identified 2 persons with elevated radioactivity. CBP, in collaboration with Los Alamos National Laboratory, informed the Food and Drug Administration (FDA) that these people could have increased radiation exposure as a result of undergoing cardiac Positron Emission Tomography (PET) scans several months earlier with rubidium Rb 82 chloride injection from CardioGen-82. We conducted a multistate investigation to assess the potential extent and magnitude of radioactive strontium overexposure among patients who had undergone Rb 82 PET scans. We selected a convenience sample of clinical sites in 4 states and reviewed records to identify eligible study participants, defined as people who had had an Rb 82 PET scan between February and July 2011. All participants received direct radiation screening using a radioisotope identifier able to detect the gamma energy specific for strontium-85 (514 keV) and urine bioassay for excreted radioactive strontium. We referred a subset of participants with direct radiation screening counts above background readings for whole body counting (WBC) using a rank ordering of direct radiation screening. The rank order list, from highest to lowest, was used to contact and offer voluntary enrollment for WBC. Of 308 participants, 292 (95%) had direct radiation screening results indistinguishable from background radiation measurements; 261 of 265 (98%) participants with sufficient urine for analysis had radioactive strontium results below minimum detectable activity. None of the 23 participants who underwent WBC demonstrated elevated strontium activity above levels associated with routine use of the rubidium Rb 82 generator. Among investigation participants, we did not identify evidence of strontium internal contamination above permissible levels. This investigation might serve as a model for future investigations of radioactive internal contamination incidents.

The expanding role in preparedness and response for a state radiation control program.

Preparedness to respond to a radiological or nuclear event requires trained individuals starting at the local level. Training must encompass two broad audiences: those having expert knowledge of radiation protection principles and the general population of emergency responders who have varying levels of familiarity with these principles. Concern for the proper care of injured or contaminated individuals as the result of a significant radiological or nuclear incident has led Florida's Bureau of Radiation Control (BRC) to re-examine its preparedness and response efforts. This includes examining current roles and looking for other areas where the BRC's expertise can be used to train, advise, and support local emergency responders.