Summary and Conclusions

There were no observed gradients of gross alpha concentrations in air increasing towards the INEEL from Distant locations. Gross beta activity was statistically higher during February at Boundary locations than at Distant locations. This was found to be due higher gross beta levels at Mud Lake during this month. However, this appears to be linked to natural variations in the data, not INEEL releases. Gross beta results were also statistically higher at Boundary locations, as compared with Distant locations, during the week of January 23, 2002. Meteorological data obtained from NOAA demonstrate temperature inversion conditions at Boundary locations during this week that typically result in increased levels of naturally occurring radionuclides associated with fine particulates. Levels of specific radionuclides detected in composited air filters (^239,240Pu and ²⁴¹Am) and 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 the INEEL.

Tritium was detected in two of 11 precipitation samples collected during the first quarter. The concentrations were consistent with measurements made by EPA at other locations across the United States and reported by the ERAMS program.

Milk sample samples collected during the first quarter had no detectable ¹³¹I. Cesium-137 was detected in one milk sample collected from Idaho Falls in January. The result was indistinguishable from historical measurements.

Results of analyses of game animal tissues indicate detectable levels of ⁴⁰K, a naturally occurring radionuclide in all samples, and ¹³⁷Cs in two pronghorn muscle samples. All results are within concentrations measured historically at the INEEL.

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