Executive Summary

This report for the fourth 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, October 1 through December 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, including collection of precipitation and drinking and surface water samples (Section 4);
• Agricultural product sampling, including milk and potatoes, and wildlife samples including waterfowl and large game animals (Section 5); and
• Environmental radiation measurements (Section 6).

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 fourth 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 fourth 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 alpha or gross beta results when grouped by location on a quarterly or monthly basis. No statistical gross alpha differences were noted in weekly analyses of Boundary and Distant locations. Gross beta concentrations measured at Boundary locations were statistically greater than those measured at Distant locations during the weeks of November 13, November 20, and December 3 and 17, 2002. Additional investigation on a weekly basis concluded that the Mud Lake sample was much higher than the other locations. The values during these weeks were still within the range of historical levels, and are attributed to resuspension of particulates from the surrounding recently harvested or fallow fields. Also, the collection week ending on December 3, 2002 was subject to a series of strong temperature inversion conditions, which act to trap radon gas and its progeny.

During the fourth quarter, no iodine-131 (¹³¹I) was measured in any cartridge batch above the associated 2s or MDC values.

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). Seven samples collected from air monitoring stations located at the Experimental Field Station (EFS), FAA Tower, Howe and Howe Q/A, Idaho Falls, Monteview, and Van Buren Gate showed at least one human-made radionuclide (²⁴¹Am, ^239,240Pu, ⁹⁰Sr or cesium-137 [¹³⁷Cs]) greater than their related 2s values. All values were within the range of those measured in the past and are likely due to resuspension of particulate fallout from past nuclear weapons testing. All results were far less than their respective DOE Derived Concentration Guide (DCG) values.

Eight atmospheric moisture samples and three duplicates were obtained during the fourth quarter of 2002. Seven samples exceeded their respective 2s values. The maximum value (3.8 x 10^-12 mCi/mL of air [1.4 x 10^-7 Bq/mL of air]) from these seven sample results was well below the DOE 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 92.5 µg/m³ on October 22, 2002, at Atomic City.

Storm events in the fourth quarter of 2002 produced enough precipitation for a total of eight samples and one split – three and a split from Idaho Falls, two from CFA, and three from the EFS. Tritium was detected above the 2s concentration in six samples. While there is no regulatory limit for tritium in precipitation, the DOE DCG and maximum contaminant level set by EPA for tritium in drinking water can be used as screening values. The highest tritium concentration, 212.0 ± 58.7 pCi/L (7.9 ± 2.2 Bq/L), was measured in the split sample collected from CFA on December 12, 2002. This value is many times lower than the DCG value (2 x 10⁶ pCi/L) and the Safe Drinking Water Act limit (20,000 pCi/L) for tritium in drinking water.

Drinking water samples were collected from fourteen locations around the Snake River Plain. Samples are analyzed for gross alpha, gross beta, and tritium. Gross alpha in a single sample from Minidoka was greater than its associated 2s value. All samples exceeded their 2s value for gross beta.  Six samples exceeded their respective 2s value for tritium. Detections of gross alpha and gross beta are not unusual on the Snake River Plain and are attributable to dissolution of naturally occurring radionuclides into the groundwater as it flows beneath the Plain. The gross alpha detection and tritium measurement were well below the EPA MCLs of 8 pCi/L and 20,000 pCi/L, respectively. The maximum gross beta detection of 8.31 ± 1.05 pCi/l was also below the EPA screening value of 50 pCi/L.

Five surface water samples and a duplicate were collected from various locations near the discharge of the Snake River Plain Aquifer into the Snake River. None of the samples had measurable levels of gross alpha. The Twin Falls sample and duplicate were the only samples to exceed the 2s value for tritium. The maximum concentration was well below the DOE and EPA regulatory limits. All six samples had gross beta concentrations above their 2s value. The maximum concentration of gross beta detected was below the EPA screening concentration of 50 pCi/L. As discussed above for drinking water it is not unusual to detect gross activity in water discharging from groundwater.

Milk samples were collected weekly in Idaho Falls and monthly at nine other locations around the INEEL. All samples were analyzed for gamma emitting radionuclides. None of the samples had ¹³⁷Cs concentrations above the 2s concentration. Only one sample, from Roberts in October, had detectable ¹³¹I. Strontium-90 was measured in four samples above the 2s value. There are no established limits for radionuclides in milk but, for comparison, the EPA limits set for radionuclides in water can be used. The EPA has set the limit for ⁹⁰Sr in drinking water at 8 pCi/L (0.3 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 ⁹⁰Sr concentrations detected in milk during the fourth quarter were all lower than this limit.

Potatoes were collected from a total of nine local and out-of-state locations in 2002. Samples were analyzed for gamma emitting radionuclides and ⁹⁰Sr. None of the samples contained measurable ⁹⁰Sr. Only one sample had measurable ¹³⁷Cs above the 2s value.

Three large game animals were sampled during the fourth quarter of 2002. All were killed as a result of vehicular collisions. These accidents all involved two mule deer (Odocoileus hemionus) and an elk (Cervus elaphus). 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. No ¹³¹I was measured in any game sample collected during the fourth quarter of 2002. One sample of elk liver tissue contained ¹³⁷Cs above the 2s uncertainty.

Eleven waterfowl were collected during 2002: two each from the control locations of Mud Lake and Heise, three from the northeast Test Reactor Area (TRA) pond, and four from the TAN pond. All were analyzed for gamma emitting radionuclides with a subset analyzed for ⁹⁰Sr, ²³⁸Pu, ^239/240Pu, and ²⁴¹Am. Seven waterfowl had measurable levels of at least one radionuclide in edible tissue. Only curium-141 (¹⁴¹Cm), niobium-95 (⁹⁵Nb) and ⁹⁰Sr were detected at greater than their respective 2s concentration in the edible portion of three of the waterfowl. The birds came one each from Mud Lake, the NE TRA cold pond, and INEEL TAN, respectively. The maximum potential dose from eating 225 g (8 oz) of meat from ducks collected in 2002 was estimated to be 0.004 mrem. This dose is far less than the 10 mrem per year dose set by EPA and well below the 100 mrem per year regulatory dose limit set by DOE.

Environmental dosimeter locations are divided into Boundary and Distant groupings. Exposure rates measured during the later half of 2002 were similar to those recorded in the past. The boundary exposure rates ranged from 0.28 to 0.37 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 also 0.33 mR/day. No statistical difference existed between Boundary and Distant locations.


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

Media	Sample Type	Analysis	Results
Air	Filters	Gross alpha, gross beta, 131I	Quarterly and monthly statistical comparisons of gross alpha and gross beta data indicate no differences between INEEL, Boundary, and Distant locations. Statistical differences in gross beta results were observed in four weekly analyses 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, 239/240Pu, 90Sr and/or 137Cs in samples collected from seven locations exceeding their 2s values. The results were well below DOE DCGs and within historical measurements.
	Charcoal Cartridge	Iodine-131	Cartridges analyzed for the quarter had no measurable 131I.
	PM10	Particulate matter	No regulatory limits were exceeded for atmospheric particulates.
Atmospheric Moisture	Liquid	Tritium	Seven of eleven atmospheric moisture samples had tritium measured in them above their respective 2s values. No sample result exceeded the DCG for tritium in air.
Precipitation	Liquid	Tritium	Six of nine samples had measurable concentrations of tritium exceeding the 2s value. No samples were above regulatory limits for tritium in drinking water.
Drinking Water	Liquid	Gross alpha, gross beta, and tritium	One sample from Minidoka had gross alpha above its respective 2s value. One sample from Fort Hall had measurable tritium above its respective 2s value. All samples had gross beta above their 2s values. All concentrations were within the range of past detections and below health based limits.
Surface Water	Liquid	Gross alpha, gross beta, and tritium	No gross alpha was measured in any sample. All six samples exceeded their 2s values for gross beta. All concentrations were below the EPA screening value. The sample and duplicate from Twin Falls also had tritium above the 2s value. All concentrations were below regulatory limits for radionuclides in drinking water.
Milk	Liquid	Iodine-131, gamma emitting radionuclides (including 137Cs)	No samples had measurable 137Cs during this quarter. Iodine-131 was detected in only one sample from Roberts above the 2s value. Four samples had measurable concentrations of 90Sr greater than their respective 2s values. The concentrations of both 131I and 90Sr were well below regulatory limits for these radionuclides in drinking water.
Potatoes	Solid	Gamma emitting radionuclides (including 137Cs), and 90Sr	No 90Sr was measured in any of the nine samples collected. One sample had a 137Cs concentration above the 2s value.
Game Animals	Tissue	Iodine-131, gamma emitting radionuclides (including 137Cs)	Cesium-137 was reported above the 2s level in one liver sample taken from an elk. All concentrations were within the range of historical values for game animals.
Waterfowl	Tissue	Gamma emitting radionuclides (including 137Cs), select actinides (238Pu, 239,240Pu, & 241Am) and 90Sr	Seven of eleven waterfowl had measurable concentrations of at least one radionuclide in the edible portion of the sample (muscle, gizzard, liver). No 238Pu was measured in any sample. Of the seven birds with measurable radionuclide concentrations only three (one 141Cm, one 95Nb, and one 90Sr) results were above the 2s value. The dose of 0.006 mrem was estimated from eating the tissue containing both radionuclides.
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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