This report for the first quarter, 2001, consists of results from the Environmental Surveillance, Education, and Research (ESER) Program’s monitoring of the Department of Energy’s (DOE) Idaho National Engineering and Environmental Laboratory’s (INEEL) offsite environment. All sample types (media) and the sampling schedule followed during 2001 are listed in Appendix A. Specifically, this report contains results for the following:
Air monitors were operated continuously at 15 locations, plus 2 replicate samplers, with particulate filters and charcoal cartridges sampled weekly. No 131I was detected in any of the weekly charcoal cartridges during the first quarter, 2001. The average gross alpha concentration at INEEL locations was higher than at Boundary locations in two of the thirteen weeks (weeks of January 31 and March 28). However, also during the week of January 31, the average gross alpha concentration at Distant locations was significantly higher than Boundary locations, which is the opposite of what would be expected if the INEEL were the source of contamination. No other significant differences in gross alpha concentrations were observed.
Average gross beta concentrations at INEEL locations were significantly higher than the average at either Boundary or Distant locations during the weeks of February 21, February 28, March 14, and March 21 (31% of the weeks in the first quarter). The average gross beta concentration at INEEL locations was also significantly higher than the averages at Boundary and Distant locations during the week of March 28. Examination of the average value for the week of March 28, in comparison to other weeks in the same quarter, shows that overall, the value was low and well within range of past data.
Quarterly particulate filters were composited and analyzed for gamma-emitting radionuclides with a subset analyzed for 90Sr, 238Pu, 239/240Pu, and 241Am. No 90Sr, 238Pu, 239/240Pu, or 137Cs were detected in any sample. The only human-made gamma emitting radionuclide detected was 241Am. The 241Am results for Howe, Monteview, Van Buren, FAA Tower, and Rexburg Community Monitoring Station (CMS) were all greater than their associated two standard deviation (2s) uncertainty, and all but the Van Buren sample were also above the minimum detectable concentration (MDC). However, levels of 241Am in composited filter samples were within the range of values observed in the past and were well below the Derived Concentration Guide (DCG) values set by the DOE to ensure dose limits are not exceeded.
Two atmospheric moisture samples were obtained from Blackfoot CMS, two from Atomic City, one from Idaho Falls, and one from Rexburg CMS during the first quarter, 2001. All six atmospheric moisture samples had tritium results greater than their 2s uncertainty and MDC. These results are not believed to be significant due to comparable levels detected in sample blanks submitted for precipitation sampling (which are analyzed with the same instrumentation as the atmospheric moisture samples) whose results were also greater than 2s and MDC. However, even with this potential bias, the concentrations were low. For comparison, the DCG value for tritium in air (as atmospheric moisture) is 1 x 10-7 µCi/mL (3.7 x 10-3 Bq/mL). The tritium results measured at these locations during the first quarter of 2001 were between 100,000 to nearly 800,000 times lower than this limit.
ESER Program personnel operate three PM10 samplers, one at Rexburg CMS, one at Blackfoot CMS, and one at Atomic City. PM10 concentrations for the first quarter of 2001 were well below all air quality standard levels. The maximum 24-hour concentration was 58.6 µg/m3 on March 1 at Rexburg CMS.
For the first quarter of 2001, there was enough precipitation for a total of ten samples – three monthly composites from Idaho Falls, four weekly composites from Experimental Field Station (EFS), and three monthly composites from the Central Facilities Area (CFA). Of the samples collected from Idaho Falls, two (January and March samples) had tritium results greater than their associated 2s values. One sample (January) was below the MDC, and one sample (March) was above the MDC. Of the four weekly composite samples collected from EFS, all were above 2s, but only one (week of January 17) was above the MDC. Of the samples collected from CFA, one sample (January) was above 2s, but was below the MDC. Sample blanks (submitted as part of normal quality assurance/quality control [QA/QC] procedures) for precipitation sampling also had results greater than their associated 2s uncertainties and MDCs. Therefore, there is a high probability that one or more of these results were false positives. While there is not a DCG for precipitation, the Safe Drinking Water Act (SDWA) sets a limit for tritium in drinking water of 2 x 104 pCi/L. The levels of tritium detected in the samples that were above their associated 2s and MDC values were between 110 and 160 times lower than the level set for drinking water, and were within the range of background tritium that exists throughout the world.
A total of 39 milk samples were collected during the first quarter of 2001. Of all the milk samples collected, two (February 6 and March 6, 2001) from Dietrich had concentrations of 131I greater than their 2s uncertainty. However, immediate recounts of these samples yielded results less than their 2s uncertainty levels. This is not unusual because values that are tested against the 2s level will be false positives 2.5% of the time. Cesium-137 was detected in the following samples at concentrations greater than their associated 2s uncertainty: Howe (January 9), Moreland (January 9), Carey (February 6), and Idaho Falls (March 14). However, immediate recounts of these samples gave results less than the associated 2s uncertainty.
All concentrations of radioactivity found in samples collected by the
ESER program during the first quarter, 2001 were consistent with
concentrations that have been found in samples taken during recent
years. The ESER
Program could not directly attribute measured concentrations to
operations at the INEEL. Radionuclide
concentrations in all of the samples collected and analyzed were below guidelines
set by both the DOE and the Environmental Protection Agency (EPA) for
protection of human health.