Fourth Quarter 2004
INEEL Quarterly Site Environmental Report
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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 reported below. 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 2004 produced only enough precipitation for a total of seven samples – three from CFA (including one split sample) and four the EFS (including two split samples).
Tritium was detected above the sample’s 3s value in all samples except the split from EFS on November 3, 2004. The maximum concentration of 200.00 ± 28.10 pCi/L (7.40 ± 1.04 Bq/L) from the EFS is well below the EPA limit for tritium in drinking water of 20,000 pCi/L.
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 1978 to 2001 tritium measured in those samples
ranged from -2.00 to 7.38 x 106 pCi/L (-7.4 to 2.7 x 104
Bq/L) (EPA 2003). Data for all fourth quarter 2004 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.
Gross alpha activity was not detected in any of the drinking water samples. Of the fourteen drinking water samples collected, all but five samples exceeded their 3s value for gross beta. Of those nine were positively detected (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, (6.75 ± 1.10) pCi/L ([0.25 ± 0.04] Bq/L), 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).
|
|
|
Limits for Comparisona |
|
|
Location |
Result ± 1s |
SDWA |
DOE DCG |
|
Atomic City |
4.92 ± 0.89 |
50 |
100 |
|
Fort Hall |
6.75 ± 1.10 |
50 |
100 |
|
Howe |
5.12 ± 1.01 |
50 |
100 |
|
Minidoka |
5.31 ± 0.93 |
50 |
100 |
|
Monteview |
3.04 ± 0.97 |
50 |
100 |
|
Monteview (duplicate) |
3.75 ± 0.87 |
50 |
100 |
|
Moreland |
4.18 ± 1.05 |
50 |
100 |
|
Mud Lake |
4.22 ± 0.95 |
50 |
100 |
|
Roberts |
2.99 ± 0.98 |
50 |
100 |
|
a. All values shown are in picocuries per liter (pCi/L). b. SDWA = Safe Drinking Water Act. c. DCG = Derived concentration Guide. |
|||
Tritium was detected in half of the samples well below the DCG and within historical data collected by ESER and within EPA measurements made from 1995-2005 in Region 10 (Alaska, Idaho, Oregon, and Washington.) The maximum tritium concentration was (142.00 ± 30.20) pCi/L ([5.26 ± 1.12] Bq/L).
All drinking water sample results may be found in Appendix C, Table C 7.
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.
Three 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) |
7.14 ± 0.98 |
50 |
100 |
|
Buhl (Clear Spring) |
3.85 ± 0.88 |
50 |
100 |
|
Hagerman (duplicate) |
2.90 ± 0.92 |
50 |
100 |
|
Twin Falls (Alpheus Spring) |
3.34 ± 1.06 |
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.
One sample, collected from Hagerman, had a detectable concentration of tritium of 86.8 ± 25.8 pCi/mL (3.21 ± 0.96 Bq/L). This is well below the DCG for tritium in drinking water and within historical results. In addition, it is well within measurements made in Region 10 by EPA during 1995-2005 in the ERAMS program.
All surface water results can be found in Appendix C, Table C-7.