Summary and Conclusions

There were no observed gradients of gross alpha or gross beta concentrations in air increasing outwards from the INEEL toward Distant locations for any month of the quarter. Weekly statistical comparisons of Boundary locations with Distant locations showed differences in gross alpha concentrations for the weeks of September 4 and September 18, 2002 and in gross beta concentrations for July 10 and August 28, 2002. In all cases the Distant locations were higher than the Boundary locations. Levels of specific radionuclides measured in composited air filters (²⁴¹Am, ¹³⁷Cs, and ^239,240Pu) and detected in atmospheric moisture samples (tritium) were well below regulatory guidelines set by both the DOE and the EPA for protection of the public, and were not different from values measured historically at other locations across the United States.

Tritium was measured in 16 precipitation samples collected during the third quarter. The concentrations were consistent with measurements made by EPA at other locations across the United States and reported by the ERAMS program.

Milk samples collected during the third quarter had no measurable ¹³¹I or ¹³⁷Cs in any samples above their 2s or 3s values. Strontium-90 was detected in two milk samples, one collected from Idaho Falls in May and one from Carey also in May. Another two samples had ⁹⁰Sr measured above only the 2s value.

Lettuce samples collected from local area gardens had no measurable gamma-emitting radionuclides. Strontium-90 was detected in four samples at levels consistent with historical concentrations. One additional sample had ⁹⁰Sr above only the 2s value.

Of 15 wheat samples collected during the third quarter of 2002 only two samples had measurable radionuclides present. The sample from Aberdeen contained ¹³⁷Cs, while the sample from Monteview contained ⁹⁰Sr, both above the 2s concentration. The ¹³⁷Cs result also exceeded the 3s concentration. Both concentrations were within the range of past values.

Results of analyses of tissues from four game animals indicated detectable levels of ¹³⁷Cs in the liver tissue and measurable amounts of ¹³⁷Cs in the muscle tissue and thyroid from a single animal.

In conclusion, no radionuclides, measured or detected, in any of the samples taken during the third quarter of 2002 could be directly linked with INEEL activities. Concentrations in all of the samples collected and analyzed during the third quarter, 2002 were similar to levels recorded in the past in the INEEL environment or in other locations in the United States and were well below regulatory standards for public health.