Executive Summary

This report for the first 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, January 1 through March 31, 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) (Section 3);

• Water sampling, specifically collection of precipitation (Section 4);

• Agricultural product sampling, including milk and large game animals (Section 5).

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 normal (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 2s are considered “detected”.

Gross alpha and gross beta measurements are used as general indicators of the presence of alpha-emitting and beta-emitting radionuclides in air. Gross alpha and gross beta results were found to have no discernable statistical distribution during the first quarter of 2002. 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 first quarter were gross alpha concentrations from Boundary locations statistically higher than corresponding data sets for Distant locations, as one would expect if the INEEL were a significant source of radionuclide contamination. There were no statistical differences between gross beta results analyzed by location group on a quarterly basis. However, comparisons of monthly gross beta results show that Boundary results were statistically greater than Distant results during February. Further investigation indicates that the Mud Lake data tended to be higher than those measured at other locations during the month of February, but additional information indicates that the higher results probably reflect natural variation in data and do not implicate any INEEL releases. Gross beta concentrations measured at Boundary locations were also greater than those measured at Distant locations during the week of January 23, 2002. This difference was attributed to temperature inversion conditions, which act to trap gases and fine particulates, that existed at the Boundary locations during this week.

During the first quarter, analysis of three batches containing 8-10 cartridges detected 131I greater than the associated 2s values. Immediate reanalysis of each individual cartridge yielded results below the 2s values. Because initial counting is done as a batch sample, it appears that the cumulative activity for these ten cartridge batches was above the 2s values but was not attributable to any single location (cartridge).

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). Six samples collected from air monitoring stations located at Arco (Q/A-1), Atomic City, Blackfoot Community Monitoring Station (CMS), Dubois, and Mud lake showed at least one human-made radionuclide greater than its related 2s value. Plutonium-239/240 and ²⁴¹Am were detected most frequently. Cesium-137 and ²³⁸Pu were each detected once. All values were within the range of those measured in the past and are likely due to fallout from past nuclear weapons testing. All results were far less than their respective DOE Derived Concentration Guide (DCG) values.

Seventeen atmospheric moisture samples were obtained during the first quarter of 2002; two from Blackfoot, three from Rexburg, and six each Idaho Falls and Atomic City. All but two sample results, one from Idaho Falls in February and one from Rexburg in March, exceeded their respective 2s values. Of the remaining fifteen samples, the analytical laboratory flagged three as questionable due to small sample size (less than 9 mL), and reanalysis did not support a positive detection for two others (an indication that the initial result was a false positive). The ten remaining samples are considered positive detections. The maximum value of
4.9 ± 7.8 x 10^-13 mCi/mL_air  (1.8 ± 0.7 x 10^-8 Bq/mL) is well below the DCG for tritium in air of 1 x 10^-7 mCi/mL (3.7 x 10^-3 Bq/mL).

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 37.4 µg/m³ on February 12, 2002, in Rexburg.

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 six weekly samples from the Experimental Field Station (EFS) on the INEEL. Tritium was detected in two samples: one from Idaho Falls and one from the EFS. There is no DCG for tritium in precipitation, but in drinking water it is 2.0 x 10⁶ pCi/L (74,074 Bq/L). The Safe Drinking Water Act sets a limit of 20,000 pCi/L (740 Bq/L) for tritium. The levels of tritium measured in first quarter precipitation samples were well below the DCG value and the Safe Drinking Water Act Limit.

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 (¹³¹I) was not detected in any of the collected samples. One sample had a ¹³⁷Cs concentration greater than its 2s uncertainty. There are no established limits for ¹³⁷Cs in milk but, for comparison, the EPA has set the limit for ¹³⁷Cs in drinking water at 120 pCi/L (4.44 Bq/L). The Safe Drinking Water limit is based on a 4 mrem per year maximum allowable dose and the assumption that two liters per day are consumed. The maximum 137Cs concentration (1.6 ± 1.5 pCi/L) measured in milk collected at Idaho Falls during the first quarter, 2002 was many times lower than the 120 pCi/L limit.

Fourteen large game animals were sampled during the first quarter of 2002. All were killed as a result of vehicular collisions. These accidents all involved six mule deer (Odocoileus hemionus) and eight pronghorn antelope (Antilocapra americana). Every effort was made to collect thyroid, liver, and muscle tissue from each animal. However, certain tissues could not be collected from all animals due to their condition at the time of collection.  Two of the pronghorn muscle samples contained radionuclides at concentrations greater than the associated 2s uncertainty values.  The concentrations were well within historical measurements.

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

Media	Sample Type	Analysis	Results
Air	Filters	Gross alpha, gross beta	Statistical comparisons of gross alpha data indicate no differences between INEEL, Boundary, and Distant locations.  A few statistical differences in gross beta results were observed between location groups. However, these differences can be attributed to natural variation in the data and to meteorological conditions (i.e.,temperature inversions).  All gross alpha and gross beta results were within historical levels and were far less than applicable DOE DCGs.
		Gamma emitting radionuclides (including 137Cs), select actinides (238Pu, 239,240Pu, & 241Am) and 90Sr	Quarterly composite samples had measurable levels of 241Am and/or 239/240Pu in samples collected from Arco (Q/A-1), Atomic City, Blackfoot CMS, Dubois, and Mud Lake. Pu-238 was detected in the Arco (Q/A-1) composite. Cesium-137 was detected in the Main Gate sample. The results were well below DOE DCGs and within historical measurements.
	Charcoal Cartridge	Iodine-131	Three multiple-cartridge batches, one collected on January 23 and two collected on March 20, had initial detections of 131I.  Immediate recounts of individual cartridges resulted in no measurable 131I.
	PM10	Particulate matter	No regulatory limits were exceeded for atmospheric particulates.
Atmospheric Moisture	Liquid	Tritium	Fifteen of 17 atmospheric moisture samples had tritium detected in them. Three of these results are invalid due to insufficient sample size. No sample result exceeded the DCG for tritium in air.
Precipitation	Liquid	Tritium	Two of 11 samples (one collected at Idaho Falls and one collected at the EFS in February) had measurable concentrations of tritium. Both samples were well below regulatory limits for tritium in drinking water.
Milk	Liquid	Iodine-131, gamma emitting radionuclides (including 137Cs)	Iodine-131 was not detected in any sample.  One weekly sample from Idaho Falls in mid-January had measurable 137Cs.  The concentration was well below regulatory limits for 137Cs in drinking water.
Game Animals	Tissue	Iodine-131, gamma emitting radionuclides (including 137Cs)	Cs-137 was reported above the 2s level in two muscle samples taken from pronghorn antelope.  The concentrations were within the range of historical values for game animals collected at the INEEL.

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