Executive Summary

None of the radionuclides detected in any of the samples collected during the second quarter of 2002 could be directly linked with INEEL activities. Levels of detected radionuclides were no different than values measured at other locations across the United States or were consistent with levels measured historically at the INEEL. All detected radionuclide concentrations were well below guidelines set by the U.S. Department of Energy (DOE) and regulatory standards established by the U.S. Environmental Protection Agency (EPA) for protection of the public. (See Table ES-1.)

This report for the second quarter, 2002, contains 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, April 1 through May 30, 2002. All sample types (media) and the sampling schedule followed during 2002 are listed in Appendix A. Specifically, this report contains the results for the following:

Air sampling, including air filters and charcoal cartridges, atmospheric moisture, and 10-micron particulate matter (PM₁₀);
Water sampling, including precipitation, surface water, and drinking water;
Agricultural product sampling, including milk, sheep, and large game;
Measurement of external exposure, using environmental dosimetry.

Results are presented in this report with an analytical uncertainty term, 2s, where “s” is an estimate of the population standard deviation (s), assuming a Guassian distribution. The result plus or minus (±) the uncertainty term represents the 95 confidence interval. That is, there is 95 percent confidence that the real concentration in the sample lies somewhere between the measured concentration minus the uncertainty term and the measured concentration plus the uncertainty term. Results that are greater than the 2s uncertainty are considered “detected”.

At no time during the second quarter were weekly, monthly, or quarterly gross alpha or gross beta concentrations in air for Boundary locations statistically higher than corresponding data for Distant locations, as one would expect if the INEEL were a significant source of radionuclide contamination. During the second quarter, analysis of charcoal cartridges in ten-cartridge batches for iodine-131 (¹³¹I) did not detect any ¹³¹I above the respective 2s values. Selected quarterly composite air filter samples were analyzed for gamma emitting radionuclides, strontium-90 (⁹⁰Sr), plutonium-238 (²³⁸Pu), plutonium-239/240 (^239/240Pu), and americium-241 (²⁴¹Am). Nine samples collected from air monitoring stations located at Arco, Arco QA, Atomic City, Blackfoot CMS, Blue Dome, Dubois, Main Gate, Mud Lake, and Jackson, Wyoming showed at least one human-made radionuclide greater than its related 2s value. These values are within the range of those measured in the past and are likely due to collection on the filter of resuspended fallout particles. All results were far less than their respective DOE Derived Concentration Guide (DCG) values.

Twenty-one atmospheric moisture samples were obtained during the second quarter of 2002. However, only eleven of the samples were determined by the analytical laboratory to produce valid results: five from Atomic City and six from Idaho Falls. All results exceeded their respective 2s values. The maximum value was well below the DCG for tritium in water.

The ESER Program operates three PM₁₀samplers, 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 46.8 µg/m³on May 19, 2002, in Atomic City.

Little precipitation occurred during the second quarter of 2002. Only five samples, two monthly composite samples from the Central Facilities Area (CFA), one monthly composite sample from Idaho Falls and two weekly samples from the Experimental Field Station (EFS) on the INEEL. No tritium was detected above the respective 2s values in any of the samples.

Fourteen drinking water samples and one duplicate were collected from selected taps throughout southeast Idaho. Samples were analyzed for gross alpha, gross beta, and tritium (³H). None of the samples exceeded the 2s value for gross alpha. Gross beta was measured at concentrations above the 2s value in eleven of the samples collected. The maximum gross beta concentration measured was from Minidoka and was below the EPA screening. Levels of gross alpha and gross beta observed are not unusual given the basaltic terrain.

Only the drinking water samples from Howe and Aberdeen were above the 2s level for tritium. The level of tritium detected in the samples from Howe and Aberdeen that were above 2s were much lower than the EPA limit. The measured levels were also within the range of background tritium that exists throughout the world. All values are similar to those recorded in previous years, and are well below the regulatory standards for drinking water.

Five surface water samples and one duplicate sample were collected from locations throughout southeast Idaho and analyzed for tritium, gross alpha, and gross beta. None of the results for either tritium or gross alpha analyses were above their 2s values. Results for gross beta for three of the five surface water samples were greater than their associated 2s values. The gross beta values were lower than the EPA screening level and below the DCG values and are consistent with historical 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. No ¹³¹I or cesium-137 (¹³⁷Cs) was detected in any of the collected samples.

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 2s in three samples from three different animals: one liver sample collected from an animal on the Northern allotment, and two muscle samples collected from each animal from the Southern allotment. All concentrations of ¹³⁷Cs were similar to those found in both onsite and offsite sheep samples during recent years.

No large game animals were sampled during the second quarter of 2002.

Environmental dosimeter locations are divided into Boundary and Distant groupings. Boundary exposure rates ranged from 0.30 to 0.38 mR/day. The overall average was 0.33 mR/day. The Distant set ranged from 0.30 to 0.41 mR/day. The average Distant value was 0.34 mR/day. No statistical difference existed between Boundary and Distant locations. All exposure results are consistent with those measured historically.

No radionuclides in any of the samples taken during the second quarter of 2002 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, 2002 were below guidelines set by both the DOE and the U.S. Environmental Protection Agency (EPA) for protection of the public.

Table ES-1 Summary of results for the second quarter of 2002.

Media	Sample Type	Analysis	Results
Air	Filters	Gross alpha, gross beta, ¹³¹I	There were no statistical differences noted for weekly, monthly or quarterly gross alpha or gross beta concentrations measured at INEEL, Boundary, and Distant locations.
		Gamma emitting radionuclides, select actinides, ⁹⁰Sr	Quarterly composite samples had measurable levels of ²⁴¹Am and ^239/240Pu in samples from Arco, Arco QA, Atomic City, Blackfoot CMS, Blue Dome, Dubois, Main Gate, Mud Lake, and Jackson, WY. Results were well below DOE DCGs and historical measurements.
	Charcoal Cartridge	Iodine-131	No detections of ¹³¹I were made during the quarter.
	PM10	Particulate matter	Thirty-eight total samples were collected from three locations. No regulatory limits were exceeded.
Atmospheric Moisture	Liquid	Tritium	Twenty-six atmospheric moisture samples were collected. Only eleven of the results were determined to be valid by the laboratory and were measurable tritium concentrations. No result exceeded the DCG for tritium in air.
Precipitation	Liquid	Tritium	No measurable concentrations of tritium were recorded during the quarter.
Drinking Water	Liquid	Gross alpha, gross beta, tritium	No gross alpha activity was detected in any sample. Gross beta activity was measured in eleven of fifteen samples. The maximum concentration was well below the screening level estimated using the EPA Safe Drinking Water Act limit. Tritium was detected in two samples at concentrations many times lower than the EPA screening level.
Surface Water	Liquid	Gross alpha, gross beta, tritium	No tritium or gross alpha activity was detected in any sample. Gross beta activity was measured above the 2s values in three of five samples. All concentrations were below EPA and DOE limits.
Milk	Liquid	Iodine-131, gamma emitting radionuclides	Iodine-131 and ¹³⁷Cs were not detected in any sample during the quarter.
Sheep	Tissue	Iodine-131, gamma emitting radionuclides	Cs-137 was detected in three samples: two muscle samples from sheep collected off the Southern allotment and one liver from a Northern allotment animal. All results were within historical measurements.
Game Animals	Tissue	Iodine-131, gamma emitting radionuclides	No game animals were collected during this quarter.
Environmental Radiation	TLD	Ambient ionizing radiation	Values were consistent with expected exposures given the altitude and location of the TLD's. There were no statistical differences between Boundary and Distant location results.

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