First Quarter 2006
INL Quarterly Site Environmental Report
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The ESER program samples precipitation, surface water and drinking water. Monthly composite precipitation samples are collected from Idaho Falls and the Central Facilities Area (CFA) on the INL Site. Weekly precipitation samples are collected from the Experimental Field Station (EFS) on the INL Site. Surface and/or drinking water are sampled twice each year at 19 locations around the INL Site. This occurs during the second and fourth quarters.
Precipitation samples are gathered when sufficient precipitation occurs to allow for the collection of the minimum sample volume of approximately 20 mL. Samples are taken of monthly composites from Idaho Falls and CFA, and weekly from the EFS. Precipitation samples are analyzed for tritium. Storm events in the first quarter of 2006 produced sufficient precipitation to yield 16 samples – four from Idaho Falls, three from CFA, and nine weekly samples from the EFS.
Tritium was measured above the 3s value in only one of the 16
samples collected during the first quarter of 2006. Low levels of tritium exist
in the environment at all times as a result of cosmic ray reactions with water
molecules in the upper atmosphere. The EPA’s RadNet program collects
precipitation samples from across the United States. From 1980 to 2005, tritium
measured in samples from Region 10 (which includes Idaho) ranged from -200 to
7500 pCi/L (EPA 2006). Tritium measured in all first quarter ESER samples were
within this range, with a maximum of 217 ± 28 pCi/L at CFA. Data for all first
quarter 2006 precipitation samples collected by the ESER Program are listed in
Table C-6 (Appendix C).