• Results greater than 3s are reported as “detected”.

• Results less than 2s are reported as “undetected”.

• Results between 2-3s are reported as “questionable” (i.e., the radionuclide might have been detected but such detection may not be considered reliable.)

Gross alpha and gross beta measurements are used as general indicators of the presence of radionuclides. Gross alpha and gross beta results were found to have no discernable statistical distribution during the second quarter of 2003. Because of this, these data were statistically analyzed using nonparametric methods, including the use of the median to represent central tendency. At no time during the second quarter were weekly, monthly, or quarterly gross alpha or gross beta concentrations in air collected at Boundary locations statistically greater than corresponding data for Distant locations, as one would expect if the INEEL were a significant source of radionuclide contamination.

Iodine-131 (¹³¹I) was not detected in any batch of charcoal cartridges during the second quarter.

Selected quarterly composite filter samples were analyzed for gamma emitting radionuclides, strontium-90 (⁹⁰Sr), plutonium-238 (²³⁸Pu), plutonium-239/240 (^239/240Pu), and americium-241 (²⁴¹Am). None of these radionuclides were detected in any sample collected and composited during the second quarter.

Twelve atmospheric moisture samples were obtained during the second quarter of 2003; two each from Atomic City and Blackfoot, three from Rexburg, and five from Idaho Falls. None of the exceeded their respective 3s levels.

The ESER Program operates three PM₁₀ samplers, one each at Rexburg, Blackfoot, and Atomic City. Sampling of PM₁₀ is informational as no analyses are conducted for contaminants. PM₁₀ concentrations were well below all health standard levels for all samples. The maximum 24-hour concentration was 73.04 mg/m³ on June 19, 2003, at Atomic City. This below the EPA Air Quality Standard of 150 mg/m³.

Sufficient precipitation occurred to allow collection of three monthly composite samples from Idaho Falls, two monthly composite samples from the Central Facilities Area (CFA) on the INEEL, and eight weekly samples from the Experimental Field Station (EFS) on the INEEL. Tritium was not detected above the 3s level in any of the samples.

Thirteen drinking water samples and one duplicate were collected from selected taps throughout southeast Idaho during the second quarter 2003. Samples were analyzed for gross alpha, gross beta, and tritium (³H). None of the samples exceeded its 3s value for gross alpha or tritium. Ten samples exceeded the 3s value for gross beta. The maximum gross beta concentration measured, (9.72 ± 0.17) pCi/L, was from Monteview and was below the EPA Safe Water Drinking Water Act (SDWA) screening limit of 50 pCi/L and the DOE DCG of 100 pCi/L. Levels of gross beta activity observed are not unusual given the basaltic terrain.

Six surface water samples (including one duplicate) were collected from locations throughout southeast Idaho. Samples were analyzed for gross alpha, gross beta, and tritium (³H). None of the samples exceeded its 3s value for tritium. Gross alpha and gross beta activities were detected in three and four samples, respectively. Results were less that SDWA screening limits and DOE DCGs and were typical of historical and regional measurements.

Milk samples were collected weekly in Idaho Falls and monthly at eight other locations around the INEEL. All samples were analyzed for gamma-emitting radionuclides. Iodine 131 and ¹³⁷Cs concentrations were not detected in any milk sample.

Individual sheep from three separate flocks were sampled including a control flock in Dubois from the Experimental Sheep Station, a flock from a southern INEEL allotment, and a flock from a northern INEEL allotment. Two sheep were taken from each flock. Thyroid, muscle, and liver tissue were collected and analyzed for gamma emitting radionuclides. No ¹³¹I was found in any of the samples. Analysis for ¹³⁷Cs showed results greater than 3s in three samples from two different animals on the northern allotment: one liver and two muscle samples. All concentrations of ¹³⁷Cs were similar to those found in both onsite and offsite sheep samples during recent years.

Two large game animals (a mule deer and a pronghorn) were sampled during the second quarter of 2003. They were killed as a result of a vehicular collision. Thyroid, liver, and muscle tissues were sampled. Only the naturally occurring radionuclide potassium-40 was measured at concentrations greater than the associated 3s uncertainty values. No human-made radionuclides were detected.

Environmental dosimeter locations are also divided into Boundary and Distant groupings. Boundary exposure rates ranged from a low of 0.28 mR/day to 0.34 mR/day. The overall Boundary average was 0.31 mR/day. The Distant group ranged from 0.25 mR/day to 0.38 mR/day, with an overall average exposure also of 0.31 mR/day. No statistical difference existed between Boundary and Distant locations. All exposure results are consistent with those measured historically.

Quality assurance samples submitted for analysis during the first quarter 2003 demonstrate that the results were reasonably complete, accurate, precise, and free of field contamination, as measured by criteria established in the ESER Quality Assurance Project Plan.

No radionuclide in any of the samples taken during the second quarter of 2003 could be directly linked with INEEL activities. Levels of detected radionuclides were no different than values measured at other locations across the United States and consistent with levels measured in the past in this area. Radionuclide concentrations in all of the samples collected and analyzed during the second quarter, 2003 were below guidelines set by both the DOE and the U.S. Environmental Protection Agency (EPA) for protection of the public.

Table E-1       Summary of results for the first quarter of 2003.

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