Executive Summary

This report for the third quarter 2001 (July 1 through September 30, 2001), consists of results from the Environmental Surveillance, Education, and Research (ESER) Program’s monitoring of the Department of Energy’s Idaho National Engineering and Environmental Laboratory’s (INEEL) offsite environment.  All sample types (media) and the sampling schedule followed during 2001 are listed in Appendix A.  Specifically, this report contains results for the following:

• Air sampling, including particulate filters, charcoal cartridges, PM₁₀, and atmospheric moisture;

• Precipitation, and; 

• Agricultural products and wildlife sampling, including milk, wheat, lettuce, and large game animals.

Air Sampling

Radioactivity, associated with airborne particulates, was monitored continuously by 18 ESER Program air samplers at 16 locations during the third quarter of 2001. Particulate filters and charcoal cartridges were sampled weekly. The gross alpha and gross beta concentrations measured in air at Boundary locations were not statistically greater than those measured at Distant locations during any of the 13 weeks evaluated.  This indicates that the INEEL was not a significant source of offsite concentrations.

No Iodine-131 was detected in any of the weekly charcoal cartridges during the third quarter.   Weekly particulate filters for the third quarter of 2001 were composited by location.  All samples were analyzed for gamma emitting radionuclides including cesium-137 (¹³⁷Cs).  Cesium-137 was not detected in any third quarter composite samples.  Composites are also analyzed by 

Strontium-90 was detected in the Mud Lake, Atomic City, Arco, Dubois, and Arco Q/A-1 quarterly air particulate filter composite samples.  Plutonium-238 was detected at Monteview, Craters of the Moon, Van Buren Gate and Rexburg CMS locations.  Plutonium-239/240 was detected at the Idaho Falls, Howe, and Federal Aviation Administration (FAA) Tower locations.  Americium-241 was detected only in the Experimental Field Station (EFS) sample. 

Levels of ⁹⁰Sr measured in quarterly composite particulate air filters were well below the associated Derived Concentration Guide (DCG) value.  The DCG values are established by the Department of Energy to ensure protection of the public and the environment from potential releases of radionuclides.  Levels of ^239/240Pu were far less than the associated DCG value.  Levels of ²³⁸Pu were well below the associated DCG value.  The level of ²⁴¹Am detected was many times lower than its associated DCG value.  

Fourteen atmospheric moisture samples for the third quarter of 2001 were obtained as follows:  two from Atomic City, four from the Blackfoot Community Monitoring Station (CMS), three from Idaho Falls, and five from the Rexburg CMS.  The samples were analyzed for tritium using liquid scintillation.  Tritium was detected in seven of the samples with results that were significantly less than the DCG value for tritium in air. 

Three PM₁₀ samplers collect particulate matter less than 10 microns at Rexburg CMS, Blackfoot CMS, and Atomic City.  PM₁₀ concentrations for the third quarter of 2001 were below all air quality standard levels.  The maximum 24-hour concentration was 47.1 µg/m³ on July 5, in Atomic City, which is 3 times less than the applicable EPA air quality standard. 

Precipitation

When adequate precipitation occurred, samples were taken on a monthly interval from Idaho Falls and Central Facilities Area (CFA), and on a weekly interval from EFS and analyzed for tritium.  For the third quarter of 2001, there was enough precipitation for a total of seven samples – three from Idaho Falls, three from CFA, and one from EFS.  Tritium was detected in three samples, one from Idaho Falls and two from CFA.  While there is no regulatory restriction on tritium in precipitation, the DOE DCG and maximum contaminant level (MCL) set by the EPA for tritium in drinking water can be used as a measure.  The highest value was many times below the DOE DCG and much lower than the EPA MCL. 

Agriculture and Game Animals

A total of 39 milk samples were collected during the third quarter, 2001.  All samples were analyzed for gamma emitting radionuclides.  The September sample from Roberts had initial detections of both ¹³¹I and ¹³⁷Cs.  However, reanalysis could not support either detection, suggesting these were false positives.

Five mule deer, one elk, and one pronghorn killed by vehicle collisions on the INEEL were sampled during the third quarter, 2001.  Thyroid, muscle, and liver tissue were collected from each and analyzed for gamma emitting radionuclides.  Cesium-137 was detected in the muscle of two mule deer (collected on 07/09/01 and 08/07/01) and the liver of another mule deer (collected on 08/30/01).   The level of ¹³⁷Cs detected in big game on the INEEL during the third quarter was very low and indistinguishable from fallout, nuclear weapons tests or Chernobyl. 

Nine lettuce samples were collected from private gardens and analyzed for gamma emitting radionuclides and ⁹⁰Sr.  Cesium-137 was the only gamma emitting radionuclide detected, and then in only the Arco samples.  Strontium-90 was detected in three samples, those from Carey, Firth, and Idaho Falls, all at very low levels.

A total of 14 wheat samples were collected during the third quarter.  All samples were analyzed for gamma-emitting radionuclides and ⁹⁰Sr.  The only human-made radionuclide detected was ¹³⁷Cs in the sample from American Falls. 

Conclusions

There were no radionuclides measured in third quarter, 2001, ESER samples that could be directly linked with INEEL activities.  Levels of detected radionuclides were below regulatory limits and were not different from values measured at other locations across the United States.  Based on these results, it is the conclusion of the ESER Program that the INEEL did not measurably contribute to offsite radionuclide concentrations during the third quarter of 2001 for constituents sampled.

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