The ESER program samples precipitation, surface water, and drinking water. Monthly composite precipitation samples are collected from Idaho Falls and the Central Facilities Area (CFA) on the INEEL. Weekly precipitation samples are collected from the Experimental Field Station (EFS) on the INEEL. Surface and/or drinking water are sampled twice each year at 19 locations around the INEEL. This occurs during the second and fourth quarters and is therefore not reported here. A summary of approximate minimum detectable concentrations (MDCs) for radiological analyses and DOE Derived Concentration Guide (DCG) (DOE 1993) values is provided in Appendix B.
Precipitation samples are gathered when sufficient precipitation occurs to allow for the collection of the minimum sample volume of approximately 20 mL. Samples are taken of a monthly composite from Idaho Falls and CFA, and weekly from the EFS. Precipitation samples are analyzed for tritium. Storm events in the fourth quarter of 2003 produced enough precipitation for a total of 10 samples – two Idaho Falls, three from CFA, and five from the EFS.
Tritium was measured above the sample’s 3s value in four samples: two each from CFA and the EFS all collected in October. Tritium was also questionably detected in two additional samples, one each from Idaho Falls and EFS. 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 a measure for comparison. The highest tritium concentration, 363.0 ± 61.8 pCi/L (13.4 ± 2.3 Bq/L), was measured in a sample collected from the EFS in the October 8. This value is many times lower than the DCG value (2 x 106 pCi/L) and the EPA Safe Drinking Water Act (SDWA) maximum contaminant level (20,000 pCi/L) for tritium in drinking water.
Low levels of tritium exist in the environment at all times as a result of cosmic ray reactions with water molecules in the upper atmosphere. Tritium measured in fourth quarter ESER samples were within the range of values measured elsewhere. The EPA’s ERAMS program collects precipitation samples from across the United States. From 1996 through 2002, tritium measured in Region 10 (Alaska, Idaho, Oregon, and Washington) samples ranged from 0 to 1953 ± 71pCi/L (72.53 ± 2.63 Bq/L) (EPA 2004). Data for all fourth quarter 2003 precipitation samples collected by the ESER Program are listed in Table C-6 (Appendix C).
Thirteen drinking water samples and one duplicate were collected
from selected taps throughout southeast Idaho (Figure 11). Samples were analyzed
for gross alpha, gross beta, and tritium.
Due to samples not meeting the ESER Program quality assurance requirements for
analysis gross alpha and tritium results are not reported. The ESER Program is
pursuing this issue with the laboratory.
Of the fourteen drinking water samples collected, nine had positively detections of gross beta activity (results were greater than 3s). These results are listed in Table 2. The EPA SDWA limits gross beta in drinking water based on an annual exposure of 4 mrem/yr. Since data are reported from the laboratory as a concentration (i.e., pCi/L) a screening concentration of 50 pCi/L is used to meet this level. The maximum concentration of gross beta detected was once again from Fort Hall and was lower than the SDWA screening value. Levels of gross beta observed in drinking water are not unusual given the basaltic terrain (Twinning and Rattray 2003). All values are similar to those recorded in previous years, and are well below the levels outlined for drinking water protection (Table B-1). All drinking water sample results may be found in Appendix C, Table C 7.
|
|
|
Limits for Comparisona |
|
|
Location |
Result ± 1s |
SDWA |
DOE DCG |
|
Aberdeen |
5.08 ± 1.00 |
50 |
100 |
|
Atomic City |
2.89 ± 0.85 |
50 |
100 |
|
Fort Hall |
8.37 ± 0.11 |
50 |
100 |
|
Minidoka |
3.86 ± 0.92 |
50 |
100 |
|
Monteview |
4.13 ± 0.89 |
50 |
100 |
|
Moreland |
7.79 ± 0.12 |
50 |
100 |
|
Mud Lake |
5.38 ± 0.91 |
50 |
100 |
|
Mud Lake (Duplicate) |
4.35 ± 0.93 |
50 |
100 |
|
Taber |
5.16 ± 0.99 |
50 |
100 |
|
a. All values shown are in picocuries per liter (pCi/L). b. SDWA = Safe Drinking Water Act. c. DCG = Derived concentration Guide. |
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Five surface water samples and one duplicate sample were collected from locations throughout southeast Idaho and were analyzed for tritium, gross alpha, and gross beta. Again due to QA concerns no gross alpha or tritium results are reported. The ESER Program is pursuing this issue with the laboratory.
Four samples and the duplicate surface water sample were greater than their associated 3s values for gross beta (Table 3). Even at reported levels, the gross beta values are lower than the EPA SDWA screening value of 50 pCi/L and the DCG values (Table B-1).
|
|
|
Limits for Comparisona |
|
|
Location |
Result ± 1s |
SDWA |
DOE DCG |
|
Bliss (Bliss Boat Dock) |
4.89 ± 0.97 |
50 |
100 |
|
Buhl (Clear Spring) |
3.13 ± 0.89 |
50 |
100 |
|
Hagerman (Bill Jones Fish Farm) |
4.55 ± 0.91 |
50 |
100 |
|
Twin Falls (Alpheus Spring) |
7.14 ± 0.11 |
50 |
100 |
|
Twin Falls (duplicate) |
7.47 ± 0.11 |
50 |
100 |
|
a. All values shown are in picocuries per liter (pCi/L). |
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The presence of gross beta in surface water (particularly the springs) is typically related to dissolution of naturally occurring radionuclides (i.e., uranium, radium, potassium) by groundwater as it flows through the surrounding basalts (Twinning and Rattray 2003). Levels of gross beta in all samples are similar to results from recent years. All gross beta results can be found in Appendix C, Table C-7.