This report for the fourth quarter, 2003, 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, 2003. All sample media and the sampling schedule followed during 2003 are listed in Appendix A. Specifically, this report contains the results for the following:

• Air sampling, including low-volume air sampling with air filters and charcoal cartridges, collection of atmospheric moisture, and sampling of particulate matter with an aerodynamic diameter less than or equal to 10 micrometers (PM₁₀) (Section 3);
• Water sampling, including precipitation, surface water, and drinking water (Section 4);
• Agricultural product sampling, including collection of milk, potatoes, large game animals, and waterfowl (Section 5);
• Environmental radiation (Section 6); and
• Quality assurance program information (Section 7).

Results are presented in this report with an analytical uncertainty term, s, where “s” is an estimate of the population standard deviation (s), assuming a normal (Guassian) distribution. The following guidelines, based on Currie (1984), are used to interpret the analytical results.

• Results greater than 3s are reported as “detected”.
• Results less than 2s are reported as “undetected”.
• Results between 2s and 3s are reported as “questionable” (i.e., the radionuclide might have been detected but such detection may not be considered reliable.)

Gross alpha and gross beta measurements are used as general indicators of the presence of radionuclides in many media. Gross alpha and gross beta in air, as measured on air filters, results were found to have no discernable statistical distribution during the fourth quarter of 2003. Because of this, these data were statistically analyzed using nonparametric methods, including the use of the median to represent central tendency. Neither quarterly nor monthly statistical analyses of gross alpha and gross beta concentrations during the fourth quarter showed statistical variation between INEEL, Boundary or Distant locations. One would expect to see significant variation if the INEEL were a significant source of radionuclide contamination. Gross alpha concentrations were statistically different for the week ending December 3, 2003, with the Boundary locations being higher than the Distant locations. Gross beta concentrations measured at Boundary locations were greater than those measured at Distant locations during the weeks ending November 12, December 3, and December 10, 2003. There was no discernable pattern (a particular station being consistently high or low) for any of the weeks evaluated. This suggests natural variation in atmospheric concentrations most likely related to weather conditions near the stations.

During the fourth quarter, iodine-131 (¹³¹I) was not detected in any batch of charcoal cartridges.

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). Americium-241 was detected in one sample collected from Blackfoot. The result was within the range of those measured in the past and is likely due to the resuspension of fallout from past nuclear weapons testing. In addition, the result was far less than DOE Derived Concentration Guide (DCG) value.

Twenty-six atmospheric moisture samples were obtained during the fourth quarter of 2003 and analyzed for tritium; one from Blackfoot, six from Rexburg, six and one duplicate from Idaho Falls, and twelve from Atomic City. Four sample results, two from Idaho Falls and one each from Atomic City and Rexburg exceeded their respective 3s values. The maximum value from Atomic City of (6.8 ± 2.1) x 10^-13 Ci/mL_air ([2.5 ± 0.8] x 10^-7 Bq/mL_air) is well below the DCG for tritium in air of 1 x 10 7 Ci/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. The maximum 24-hour concentration of particulates was 173.7 µg/m³ on October 23, 2003, in Blackfoot. This value exceeds the EPA maximum 24-hour concentration of 150 µg/m³. The 24-hour maximum was also exceeded at Rexburg for the same week. These high concentrations for this week are most likely related to agricultural activities in the areas of the samplers.

Sufficient precipitation occurred to allow collection of two monthly composite samples from Idaho Falls, three monthly composite samples from the Central Facilities Area (CFA) on the INEEL, and five weekly samples from the Experimental Field Station (EFS) on the INEEL. Tritium was detected in four samples: two each from CFA and 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 in drinking water. The maximum level of tritium measured in fourth quarter precipitation samples ([363.0 ± 61.8] pCi/L or [13.4 ± 2.3] Bq/L) were well below the DCG value and the Safe Drinking Water Act Limit.

During the fourth quarter of 2003, 14 drinking water samples (13 and a duplicate) were collected from tap locations around the Snake River Plain. Due to quality assurance concerns no gross alpha or tritium results are available. Gross beta was detected in 13 samples. The maximum concentration of 8.3 ± 0.1 pCi/L was from Fort Hall. This value is below the EPA screening level of 50 pCi/L.

Surface water samples from five locations were collected in November 2003. No gross alpha or tritium concentrations are available due to quality assurance concerns. Four samples plus the duplicate had detectable gross beta. The maximum concentration of 7.4 ± 0.1 pCi/L was from Twin Falls. This level is consistent with naturally occurring beta concentrations and in line with historical measurements. It is also below the EPA screening level of 50 pCi/L.

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 and ¹³⁷Cs concentrations were not detected in any milk sample. Selected samples were also analyzed for tritium and strontium-90 during the fourth quarter. No tritium was detected in any sample. Strontium-90 was detected in three samples with a maximum concentration of 1.3 ± 0.5 pCi/L from Dietrich. This value is well below the EPA limit of 8 pCi/L for ⁹⁰Sr in drinking water.

Potatoes were collected early in the fourth quarter. A total of eleven samples were collected from in state and out of state locations and analyzed for gamma-emitting radionuclides and ⁹⁰Sr. No gamma emitters were detected in any sample. Strontium-90 was detected in four samples with the maximum concentration detected from the Howe area of 4040 ± 960 pCi/kg.

Nine large game animals (six mule deer, two pronghorn, and an elk) were sampled during the fourth quarter of 2003. All were killed as a result of vehicular collisions. Thyroid, liver, and muscle tissue was sampled. Only one animal, a pronghorn collected on the INEEL at the end of October had measurable radionuclides in its tissue. Cesium-137 was detected in the liver and muscle tissue of this animal. Iodine-131 was also detected in the liver of the animal.

Waterfowl have been collected since the mid-1980s to evaluate the potential movement of radionuclides off the INEEL through ducks using the various waste ponds on the site. During 2003, a total of eleven waterfowl were collected, three each from a control location (Mud Lake) and ANL-W sewage lagoon, and five from the TRA sewage lagoon. All samples are analyzed for gamma-emitters, ⁹⁰Sr, and actinides. Four waterfowl, two each from Mud Lake and TRA had detectable ⁹⁰Sr in the edible portion of the sample. The sample from TRA also had a detectable concentration of cerium-141. Based on the assumption of immediate consumption of 225 g of the most contaminated sample the potential dose to an individual would be 0.002 mrem, far less than the EPA annual dose limit of 10 mrem.

Environmental dosimeter locations are also divided into Boundary and Distant groupings. Boundary exposure rates ranged from a low of 0.27 mR/day to 0.36 mR/day. The overall Boundary average was 0.30 mR/day. The Distant group ranged from 0.24 mR/day to 0.37 mR/day, with an overall average exposure also of 0.31 mR/day. No statistical difference existed between Boundary and Distant locations. All exposure results are consistent with those measured historically.

Quality assurance checks and samples submitted for analysis during the fourth quarter 2003 met most QA requirements. QA issues arose with method uncertainty and recount accuracy for tritium and gross alpha measurements in water, as measured by criteria established in the ESER Quality Assurance Project Plan. These issues are being resolved with the laboratory to avoid future problems.

Table E-1       Summary of results for the third quarter of 2003.

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