Marshall Islands Dose Assessment and Radioecology Program
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Providing Follow Up on Results

All volunteers participating in the Marshall Islands Radiological Surveillance Program are issued a preliminary copy of their dose report immediately after receiving a whole body count. Scientists from the Lawrence Livermore National Laboratory verify the measurement data and, if required, issue a revised dose report. Individual whole body counter or plutonium bioassay measurement data that yield statistical significant doses in excess of 10 mrem will normally evoke some type of pre-determined action or investigation (refer discussion outline below). These actions will nearly always lead to follow-up verfication measurements but may also include a dietary evaluation and/or a work history review. Below this level, default assumptions for assigning doses (Daniels et al., 2007) are assumed to be valid and no further action is taken. Data may be withheld from the website and hard copy reports while these investigations are on-going. The Lawrence Livermore National Laboratory Marshall Islands Program action level is one-tenth of the investigation level used throughout the U.S. Department of Energy and two-thirds of the U.S. Environmental Protection Agency guideline for cleanup of radioactively contaminated sites. In addition, at the end of each calendar year, all program volunteers receive a former written report containing an estimate of their 'calendar year dose' based on all available verified data for the year. Program volunteers are also invited to discuss their concerns with local technicians and/or to contact Dr. Terry Hamilton at Lawrence Livermore National Laboratory for more information.

Due to the very conservative nature of our dose methodology and preference not to trivialize doses no matter what the level, we anticipate that the default assumptions for calculating committed doses from low-level plutonium bioassay measurements will occasionally yield values that exceed the 10 mrem investigation level. In some cases, doses in excess of 10 mrem will not necessarily evoke a follow-up response. The reasoning for this is that the low-level plutonium bioassay measurements usually contain a relatively large uncertainty where the confidence interval (nominally tested at 3 × measurement MDA) spans the investigation action level. As such, dose estimates are computed for all the measurement data but the scope of any follow-up action may be limited to those sample analyses that are clearly distinguishable from the measurement MDA (e.g., 3 × MDA) or upon receiving specific requests from concerned individuals.

Last Modified: 7-APR-2015 | LLNL-WEB-400363 | Contact Us
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