INEEL Annual Site Environmental Report -
Chapter 4 - Environmental Monitoring Programs - Air
The Idaho National Engineering and Environmental Laboratory (INEEL) environmental surveillance programs, conducted by the Management and Operating (M&O) contractor and the Environmental Surveillance, Education and Research (ESER) contractor, emphasizes measurement of airborne radionuclides because air transport is considered the major potential pathway from INEEL releases to receptors. The M&O contractor monitors airborne effluents at individual INEEL facilities and ambient air outside the facilities to comply with appropriate regulations and Department of Energy (DOE) Orders. The ESER contractor samples ambient air at locations within, around, and distant from the INEEL.
An estimated total of 10,442 curies of
radioactivity, primarily in the form of short-lived noble gas isotopes, was
released as airborne effluents in 2002. Samples of airborne particulates,
atmospheric moisture, and precipitation were analyzed for gross alpha and gross
beta activity, as well as for specific radionuclides, primarily tritium,
iodine-131, cesium-137, plutonium-239/240, and americium-241. Results do not indicate any link between radionuclides released from the INEEL and environmental concentrations measured offsite. All concentrations were well below regulatory standards and within historical measurements.
Nonradiological pollutants, including nitrogen dioxide and particulates, were monitored at select locations around the INEEL. All results were well below regulatory standards.
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The facilities operating on the INEEL release both radioactive and nonradioactive constituents into the air. Various pathways (such as air, soil, plants, animals and groundwater) may transport radioactive and nonradioactive materials from the INEEL to nearby populations. These transport pathways have been ranked in terms of relative importance (EG&G 1993). The results of the ranking analysis indicates that air is the most important transport pathway. The INEEL environmental surveillance programs, conducted by the M&O contractor and the ESER contractor, emphasize measurement of airborne radionuclides because air has the potential to transport a large amount of activity to a receptor in a relatively short period and can result in direct exposure to offsite receptors. Table 4-1 summarizes the air monitoring activities conducted by each organization at the INEEL.
The M&O contractor monitors airborne effluents at individual INEEL facilities and ambient air outside the facilities to comply with applicable statutory requirements and DOE orders. The M&O contractor collected approximately 3400 air samples, primarily on the INEEL, for analyses in 2002.
The ESER contractor collects samples from over an approximately 23,309 km2 (9,000 mi2) area of southeastern Idaho at locations on,around, and distant to the INEEL. The ESER Program collected approximately 2600 air samples, primarily off the INEEL for analyses in 2002.
Section 4.2 summarizes results of air monitoring by the M&O and ESER contractors. Section 4.3 discusses air sampling performed by the M&O contractor in support of waste management activities. Section 4.4 summarizes selected air results.
Unless specified otherwise, the radiological results presented in the following sections are those that are greater than two times the associated analytical uncertainty (see Appendix B for information on statistical methods). Each individual result is reported as the measurement plus or minus 2 standard deviations (± 2s) uncertainty for that radiological analysis.
Airborne effluents are measured at regulated facilities as required under Idaho State regulations. Monitoring or estimating effluent data is the responsibility of programs associated with the operation of each INEEL facility and not the environmental surveillance programs.
Environmental surveillance of air pathways is the responsibility of the M&O contractor (specifically, the Site Environmental Surveillance Program) and the ESER contractor. Figure 4-1 shows the surveillance air monitoring locations for the INEEL environmental surveillance programs.
The INEEL environmental surveillance programs contractors collect filters from a network of low-volume air monitors weekly. Air flows at an average of about 57 L/min (2 cfm) through a set of filters consisting of a 5-cm (2 in.) 1.2-µm pore membrane filter followed by a charcoal cartridge. The membrane filters are analyzed weekly for gross alpha and gross beta activity.
Filters are then composited quarterly by location for analyses of gamma-emitting radionuclides using gamma spectrometry and for specific alpha- and beta-emitting radionuclides using radiochemical techniques. In addition to the membrane filter samples, charcoal cartridges are collected and analyzed weekly specifically for iodine-131 (131I), using gamma spectrometry.
There is no requirement to monitor the dust burden at the INEEL, but the M&O and the ESER contractors monitor this to provide comparison information for other monitoring programs and to the DOE-Idaho Operations Office (DOE-ID). The suspended particulate dust burden is monitored with the same low-volume filters used to collect the radioactive particulate samples by weighing the filters before and after their use in the field.
The M&O and the ESER contractors also monitor particles with an aerodynamic diameter less than or equal to 10 microns (PM10) to comply with EPA air quality standards.
Sulfur dioxide measurements were recorded in past years to confirm that the INEEL does not release significant amounts of sulfur dioxide with respect to national ambient air quality standards. The M&O contractor no longer monitors sulfur dioxide.
Tritium in water vapor in the atmosphere is monitored by the M&O and ESER contractors using samplers located at two onsite locations (Experimental Field Station [EFS] and Van Buren Boulevard) and five offsite locations (Atomic City, Blackfoot, Craters of the Moon, Idaho Falls, and Rexburg). Air passes through a column of absorbent material (silica gel or molecular sieve) that absorbs water vapor in the air. Columns are changed when the material absorbs sufficient moisture to obtain a sample. Water is extracted from the material by distillation and collected.
Tritium concentrations are then determined by liquid scintillation counting of the water extracted from the columns.
During 2002, a reported 10,442 Ci of radioactivity was released to the atmosphere from all INEEL sources. The National Emissions Standards for Hazardous Air Pollutants (NESHAP) Calendar Year 2002 INEEL Report for Radionuclides (DOE-ID 2002) describes three categories of airborne emissions. The first category includes sources that require continuous monitoring under the NESHAP regulation. The second category consists of releases from other point sources. The final category is nonpoint, or diffuse, sources. These include radioactive waste ponds and contaminated soil areas. The NESHAP document only reports the first category results, whereas all three categories are included in Table 4-2 of this report.
The largest facility contributions to the total emissions came from the Idaho Nuclear Technology and Engineering Center (INTEC) at over 80 percent, Test Reactor Area (TRA) at 13 percent, and Argonne National Laboratory-West at 6 percent (Table 4-2). Approximately 88 percent of the radioactive effluent was in the form of noble gases (argon, krypton, and xenon). Most of the remaining 12 percent was tritium.
Both the ESER and M&O contractors collected charcoal cartridges weekly and analyzed them for gamma-emitting radionuclides. Charcoal cartridges are used primarily to collect gaseous radioiodines. If traces of any human-made radionuclide were detected, the filters were individually analyzed. During 2002, the ESER contractor analyzed 841 cartridges, looking specifically for 131I. No 131I was detected in any of the individual ESER samples. No iodine was detected in samples collected by the M&O contractor.
Particulates filtered from the air were sampled from 28 locations weekly as part of the INEEL environmental surveillance programs (see Figure 4-1). All were analyzed for gross alpha activity and gross beta activity. Gross alpha concentrations found in ESER contractor samples, both on and offsite, tended to be higher than those found in M&O contractor samples at common locations. Reasons for differences in concentrations measured at the same locations are likely due to differences in laboratory analytical techniques and instrumentation, as different analytical laboratories were used. Both sets of data indicated gross alpha concentrations at distant locations were generally equal to or higher than at boundary and onsite locations.
Weekly gross alpha concentrations in ESER contractor samples that exceeded their 2s uncertainty ranged from a minimum of (0.62 ± 0.59) x 10-15 µCi/mL at Blue Dome in April to a maximum of (7.0 ± 1.2) x 10-15 µCi/mL during December at the Blackfoot Community Monitoring Stations (CMS). Concentrations measured by the M&O contractor that exceeded their 2s uncertainty ranged from a low of (1.1 ± 1.0) x 10-15 µCi/mL in January at TRA to a high of (5.1 ± 1.3) x 10-15 µCi/mL at TRA in December.
Figure 4-2 displays the median weekly gross alpha concentrations for the ESER and M&O contractors at INEEL, boundary, and distant station groups. Each weekly median was computed using all measurements, including those less than their associated 2s uncertainties. These data are typical of the annual natural fluctuation pattern for gross alpha concentrations in air. The highest median weekly concentration of gross alpha occurred for the distant group in the third quarter of 2000. The maximum median weekly gross alpha concentration was 5.5 x 10-15 µCi/mL and is below the DCG for the most restrictive alpha-emitting radionuclide in air [americium-241 (241Am)] of 20 x 10-15 µCi/mL.
Annual median gross alpha concentrations calculated by the ESER contractor (Table 4-3) ranged from 1.1 x 10-15 µCi/mL at Blue Dome to 2.0 x 10-15 µCi/mL at Rexburg CMS. M&O contractor data indicated an annual median range of 0.5 x 10-15 µCi/mL at the Radioactive Waste Management Complex (RWMC) and INTEC to 1.6 x 10-15 µCi/mL at Rexburg (Table 4-3). Confidence intervals are not calculated for annual medians.
Gross alpha concentrations were, in general, typical of those measured previously and well within the range of measurements observed historically. Gross alpha activity measured in filters from 1997 through 2002 at levels greater than their 2s uncertainty ranged from a minimum of (0.3 ± 0.2) x 10-15 to (7.4 ± 5.1) x 10-15 µCi/mL.
Gross beta concentrations in ESER contractor samples were fairly consistent with those found in M&O contractor samples.
Weekly gross beta concentrations in ESER contractor samples that exceeded their 2s uncertainty ranged from a low of (0.7 ± 0.1) x 10-14 µCi/mL during November at the Blackfoot CMS to a high of (13.1 ± 0.4) x 10-14 µCi/mL at the Main Gate in December. Concentrations measured above 2s by the M&O contractor ranged from a low of (0.6 ± 0.4) x 10-14 µCi/mL at the Rest Area in April to a high of (11.3 ± 0.8) x 10-14 µCi/mL at the EFS in December.
Figure 4-3 displays the median weekly gross beta concentrations for the ESER and M&O contractors at INEEL, boundary, and distant station groups. These data are typical of the annual natural fluctuation pattern for gross beta concentrations in air, with higher values generally occurring at the beginning and end of the calendar year during winter inversion conditions. The highest median weekly concentration of gross beta was detected in the fourth quarter of 2002. Each median value was calculated using all measurements, including those less than their associated 2s uncertainties. The maximum median gross beta concentration was 1.2 x 10-14 µCi/mL and is significantly below the DCG of 300 x 10-14 µCi/mL for the most restrictive beta-emitting radionuclide in air (radium-228 [228Ra]).Annual median gross beta concentrations are shown in Table 4-4. ESER contractor annual median gross beta concentrations ranged from 2.5 x 10-14 µCi/mL at Rexburg CMS to 2.9 x 10-14 µCi/mL at EFS. M&O contractor data indicated an annual median range of 2.1 x 10-14 µCi/mL at the RWMC to 3.2 x 10-14 µCi/mL at EFS. In general, the levels of airborne radioactivity for the three groups (INEEL, boundary, and distant locations) tracked each other closely throughout the year. This indicates that the pattern of fluctuations occurred over the entire sampling network, is representative of natural conditions, and is not caused by a localized source such as a facility or activity at the INEEL.
In addition, all results greater than 2s reported by the ESER contractor are well within measurements taken within the last seven years (Figure 4-4). Figure 4-4 is a histogram of all measurements (greater than 2s) made from 1996 through 2002. The results are grouped by category and then plotted by frequency of occurrence of each category of values. The curve drawn on the figure best fits the frequency distribution of observed results and represents a lognormal function. This type of fit is typical of environmental measurements. The best estimate of central tendency of data that are lognormally distributed is the geometric mean, which is the mean of the logarithms of the results. The geometric mean of the historical data measured above the 2s uncertainty level is 3.3 x 10-14 Ci/mL, and the 95 percent confidence interval of these data (based on two standard geometric deviations of the mean) ranges from 0.8 x 10-14 to 14.5 x 10-14 µCi/mL. The maximum concentration measured in 2002 is within this confidence interval.
Figure 4-4. Frequency distribution of gross beta activity detected above the 2s level in air filters collected by the ESER contractor from 1996 to 2002.
Gross beta concentrations can vary widely from location to location as a result of a variety of factors, such as local soil type and meteorological conditions. When statistical differences are found in gross beta activity, these and other factors are examined to identify the cause for the differences, including a possible INEEL release.
Statistical comparisons were made using the gross beta radioactivity data collected from the onsite, boundary, and distant locations (see Appendix B for a description of statistical methods). Figure 4-5 is a graphical comparison of all gross beta concentrations measured during 2002 by the ESER contractor. The results are grouped by location (i.e., INEEL, boundary and distant stations). Visually, there appeared to be no difference between locations. The figure also shows that the largest measurement was well below the DCG for the most restrictive beta-emitting radionuclide (228Ra) in air of 300 x 10-14 µCi/mL. If the INEEL were a significant source of offsite contamination, concentrations of contaminants would be statistically greater at boundary locations than at distant locations. There were no statistical differences between annual concentrations collected from INEEL, boundary, and distant locations in 2002.
Figure 4-5. Comparison of gross beta concentrations measured in air at distant, boundary, and INEEL locations by the ESER contractor (2002). (Terms are defined in Appendix B.)
There were a few statistical differences between weekly boundary and distant data sets collected by the ESER contractor during seven weeks of 2002. Concentrations collected during one week in January and two weeks each in November and December were greater for the boundary group than for the distant group. Results measured for the distant group were greater than boundary results during one week in July and one week in August. The differences observed in the winter months are associated with northern boundary locations (Howe, Monteview, and Mud Lake) and appear to be related to wind-driven suspension of particulates from surrounding fields and to the influence of inversion conditions. The differences observed in the summer months are attributed to natural variation in the data.
The M&O contractor data were grouped into INEEL and distant data sets. There were no statistical differences between data obtained from INEEL and distant locations.
Specific Radionuclides in Air
Human-made radionuclides were observed in some ESER contractor quarterly composite samples (Table 4-5). Most of these values were in the range where actual detection is questionable (that is, they just exceeded their respective 2s values).
No anthropogenic radionuclides were detected in quarterly samples collected by the M&O contractor.
Since mid-1995, the ESER contractor has detected 241Am in air samples, although there has been no discernable pattern with respect to time or location. Americium-241 was again detected in fifteen 2002 quarterly composite samples. A frequency plot of 241Am concentrations detected in both ESER and M&O contractors sample over the past 10 years is shown in Figure 4-6. The data appear to be lognormally distributed, which is typical of environmental data. All results detected above the 2s level during 2002 were within the range measured for the ten-year set of data and are well below the 241Am DCG of 20,000 x 10-18 µCi/mL.
Figure 4-6. Frequency distribution of 241Am concentrations detected above the 2s level in air filters
collected by the ESER and M&O contractors from 1993 to 2002.
Plutonium-238 (238Pu) was detected in one sample at a level significantly below the DCG of 30,000 x 10-18 µCi/mL. Plutonium-239/240 (239/240Pu) was also detected in 25 composite samples. These levels were also significantly below the 239/240Pu DCG of 20,000 x 10-18 µCi/mL. Plutonium is a residual product of nuclear fission. The concentrations measured in ESER samples are consistent with worldwide levels related to atmospheric nuclear weapons testing and are well within measurements taken within the past 10 years by the ESER and M&O contractors (Figure 4-7).
Figure 4-7. Frequency distribution of 239/240Pu concentrations detected above the 2s level in air filters
collected by the ESER and M&O contractors from 1993 to 2002.
Cesium-137 (137Cs) was detected in one sample at a level below the DCG of 4 x 10-10 µCi/mL. Strontium-90 (90Sr) was detected in one sample. The value measured is much below the DCG of 9,000,000 x 10-18 µCi/mL.
During 2002, the ESER contractor collected a total of 44 atmospheric moisture samples using silica gel from four locations, including Atomic City, Blackfoot, Idaho Falls, and Rexburg. Table 4-6 presents the range of values for each station by quarter. Atmospheric moisture samples were also collected at these locations using drierite (primarily CaSO4)during the first two quarters of 2002. However, it was determined that the material contains a contaminant that is released during the extraction process and this contaminant interfers with the liquid scintillation analysis. For this reason, the drierite results are considered to be invalid and the material is no longer used as a collection medium.
Tritium was detected in 34 of the samples. Samples that exceeded their respective 2s values ranged from a low at Idaho Falls of (1.2 ± 0.9) x 10-13 µCi/mL in the third quarter of 2002, to a high of (93.4 ± 4.9) x 10-13 µCi/mL at Idaho Falls in the second quarter of 2002.
These detected radioactive concentrations were similar at distant and boundary locations. This similarity suggests that the detections probably represent tritium from natural production in the atmosphere by cosmic ray bombardment, residual weapons testing fallout, and possible analytical variations, rather than tritium from INEEL operations. The highest observed tritium concentration (from the fourth quarter at Atomic City) is over nine orders of magnitude below the DCG for tritium in air (as HTO) of 2 x 10-2 µCi/mL.
The M&O contractor also collected atmospheric moisture samples at the EFS and at Van Buren Boulevard on the INEEL. They collected from one to three samples at each location each quarter. Laboratory analyses indicated that all samples were below the detection limit of 1 x 10-11 µCi/mL.
The ESER contractor collects precipitation samples weekly at
the EFS and monthly at the Central Facilities Area (CFA) and offsite in
Idaho Falls. A total of 39 precipitation samples were collected during 2002
from the three sites. Tritium concentrations were measured above the 2s
level in 20 samples and results ranged from 15.9 ± 14.3 to 290.0 ± 59.4 pCi/L.
Table 4-7 shows the maximum concentration by quarter for each location. The
highest radioactivity was from a sample collected at CFA during the third
quarter and is far below the DCG level for tritium in water of 2 x 106 pCi/L.
The concentrations are well within the normal range observed historically at
the INEEL. The maximum concentration measured since 1998 was
553 ± 78 pCi/L, measured at the EFS in 2000. The results are also well within measurements made by the EPA in Region 10 (Alaska, Idaho, Oregon, and Washington) for the past ten years (http://www.epa.gov/enviro/html/erams/).
In 2002, both the ESER and M&O contractors measured concentrations of suspended particulates using filters collected from the low-volume air samplers. The filters are 99 percent efficient for collection of particles greater than 0.3 µm in diameter. Unlike the fine particulate samplers discussed in the next section, these samplers do not selectively filter out particles of a certain size range, so they collect the total particulate load greater than 0.3 µm in diameter.
Mean annual particulate concentrations from ESER contractor samples ranged from 7.83 µg/m3 at Blue Dome to 34.8 µg/m3 at the Rexburg CMS. In general, particulate concentrations were higher at distant locations than at the INEEL stations. This is mostly due to agricultural activities in offsite areas.
The annual means of total suspended particulate concentrations measured by the M&O contractor ranged from 11.6 µg/m3 at TAN to 37.0 µg/m3 at Rexburg. Sample particulate concentrations were generally higher at distant locations than at the INEEL stations.
The EPA's air quality standard is based on concenrations of "particles with an aerodynamic diameter less than or equal to 10 microns" (PM10) (40 Code of Federal Regulations [CFR] 50.6 2001). Particles of this size can reach the lungs and are considered to be responsible for most of the adverse health effects associated with airborne particulate pollution. The air quality standards for PM10 are an annual average of 50 µg/m3, with a maximum 24-hour concentration of 150 µg/m3.
The ESER contractor collected 49 valid 24-hour samples at Rexburg from January through December 2002. A valid sample is one that has run for the proper length of time (24 hours continuously) and that has a beginning weight less than the ending weight (does not yield a negative weight). Concentrations of PM10 particulates collected at Rexburg ranged from 0.07 to 58.4 µg/m3. At the Blackfoot CMS, 52 valid samples were collected from January through December. Concentrations ranged from 0.5 to 79.0 µg/m3. At Atomic City, 49 valid samples were collected from January through December. Concentrations ranged from 16.7 to 92.5 µg/m3. All results were less than the EPA standard for a maximum 24-hour concentration.
The M&O contractor monitored ambient nitrogen dioxide continuously at Van Buren Boulevard and the EFS (Figure 4-1) throughout 2002. At Van Buren Boulevard, quarterly mean concentrations ranged from 0.6 µg/m3 (0.6 ppb) to 1.3 µg/m3 (1.2 ppb), with an annual mean of 1.1 µg/m3 (1.1 ppb). These concentrations are significantly lower than the EPA national primary ambient air quality standard of 100 µg/m3 (54 ppb) (40 CFR 50.4 2001). The maximum 24 hour concentration measured was 11.7 µg/m3 (3.9 ppb) on December 10.
Quarterly means at EFS ranged from 1.5 µg/m3 (1.5 ppb) in the fourth quarter to 2.4 µg/m3 (2.4 ppb) in the third quarter. Because of equipment failure no data were collected in the fourth quarter of 2002. For the three quarters collected, the mean concentration was 1.8 µg/m3 (1.8 ppb), again well below the EPA standard of 100 µg/m3 (54 ppb). The maximum 24 hour average concentration was 4.1 µg/m3 (4.1 ppb) on September 7.
All quarterly concentrations in 2002 remained below 50 percent of the annual standard throughout the period of monitoring.
Interagency Monitoring of Protected Visual Environments (IMPROVE) samplers began continuous operation at Craters of the Moon National Monument and CFA during the spring of 1992. The EPA removed the CFA sampler from the national network in May 2000, when the location was determined to be no longer necessary. The most recent data available for the station at Craters of the Moon are through November 2002.
The IMPROVE samplers measure several elements, including aluminum, silicon, calcium, titanium, and iron. These elements are derived primarily from soils and show a seasonal variation, with lower values during the winter when the ground is often covered by snow. Potassium is also measured and may be derived from soils, but it is also a component of smoke.
Other elements are considered tracers of various industrial and urban activities. Lead and bromine, for example, result from automobile emissions. Annual concentrations of lead at IMPROVE sites in the mid-Atlantic states are commonly in the range of 2 to 6 ng/m3, or up to ten times higher than at the two southeast Idaho sites. Selenium, in the 0.1 ng/m3 range at Craters of the Moon, is a tracer of emissions from coal-fired plants. At Mammoth Cave in Kentucky, annual selenium concentrations of 1.4 ng/m3 from natural sources have been reported.
Fine particles with a diameter less than 2.5 microns (PM2.5) are the size fraction most commonly associated with visibility impairment. At Craters of the Moon, PM2.5 has ranged over the period of sampler operation from 409 to 25,103 ng/m3, with a mean of 3443 ng/m3.
4.3 Waste Management Surveillance Monitoring
2002 Gross Alpha and Gross Beta Air Monitoring Results
Gross alpha and gross beta concentration data were obtained from PM10 monitors for most ambient air measurement locations during 2002. Five of the locations with PM10 monitors also had suspended particulate monitors in place, and suspended particulate monitors were used exclusively at five locations in the Test Area North/Special Manufacturing Capability (TAN/SMC) area (locations 101, 102, 103, 104, and 105).
Measurements from the five locations with both PM10 and suspended particulate monitors were compared by analyzing the paired data from both types of monitors. These five locations included
Location 2 at the Subsurface Disposal Area (SDA);
Based on these paired data, the average 2002 gross alpha and beta concentrations measured by suspended particulate monitors are still larger than that measured by PM10 monitors. The mean difference in gross alpha concentration measured by the suspended particulate monitors as compared to paired values measured by PM10 monitors was 0.32 x 10-15 µCi/mL. For gross beta concentrations, the mean difference was 3.46 x 10-15 µCi/mL. The difference in the gross alpha and gross beta measurements for 2002 were statistically significant (using a paired t-test).
To determine if the difference between the PM10 and suspended particulate monitors is a function of the level of activity, the concentration difference was plotted against the concentration from the suspended particulate monitors for both gross alpha and gross beta (refer to Figures 4-8 and 4-9, respectively). The horizontal axis shown on Figures 4-8 and 4-9 represents the activity as measured by the suspended particulate monitors. The vertical axis corresponds to the difference between the PM10 measurement and the suspended particulate measurement at the same location and time. If there were no difference between the two monitors, the graph should show a horizontal line at 0. If the measurements differed only because of random error, the data points in the graphs should be scattered randomly about a horizontal line centered at zero. The significant downward sloping regression line indicates that, as the measurements got larger, the differences between the two monitor types increased. At low concentrations, where the analytical error is a big component of measurements, PM10 concentrations may be higher or lower than suspended particulate concentrations. However, the higher the concentration, the more likely the 10 monitors will measure less activity than the suspended particulate monitors and the greater the difference between the two monitor types.
Figure 4-8. Gross alpha regression plot of differences between PM10 and suspended particulate monitors (2002) (locations 2, 15, 20, 26, and 300).
Figure 4-9. Gross beta regression plot of differences between PM10 and suspended particulate monitors (2002) (locations 2, 15, 20, 26, and 300).
Average concentrations of PM10 and suspended particulate monitor data from the paired locations over a 2-year period are presented in Figures 4-10 and 4-11 for gross alpha and gross beta, respectively. Data in the graphs were smoothed using polynomial smoothing to indicate the general trend in monitor type differences over time. Average monitor concentration from the suspended particulate monitors are higher than the average concentration from the PM10 monitors throughout most of the period presented for both gross alpha and gross beta, with average monitor concentrations being higher at the end of 2002 for both gross alpha and gross beta.
The differences in the average monitor concentrations might be attributed in part to fluctuations in the size of the particles released from processes operating at a particular time and/or differences in monitor design. PM10 monitors are designed to only admit particles less than 10 microns in diameter, while the suspended particulate monitors admit larger particles. Therefore, since the suspended particulate monitors admit larger particles, the suspended particulate monitors would, on average, measure higher concentrations than the PM10 monitors. In summary, the significant differences in monitor design or possible air flow around the monitors must be taken into account when analyzing the data.
To indicate the general trend in concentrations over the year, graphs of gross alpha and gross beta concentrations from all locations (except the three control locations) are presented in Figures 4-12 through 4-15. Data were smoothed using polynomial smoothing and second or third degree polynomials were fit to the four data sets (gross alpha and beta for both suspended particulate and PM10 monitors).
Figure 4-12. Gross alpha concentrations from suspended particulate monitors (2002) (third order polynomial).
Figure 4-13. Gross alpha concentrations from PM10 monitors (2002) (third order polynomial).
Figure 4-14. Gross beta concentrations from suspended particulate monitors (2002).
Figure 4-15. Gross beta concentrations from PM10 monitors (2002) (third order polynomial).
Trends in gross alpha concentrations for both suspended particulate and PM10 monitors (Figures 4-12 and 4-13) cycled during the year, but they were generally higher at the end of the year than at the start of the year. Gross beta concentrations from both monitor types (Figures 4-14 and 4-15) were the lowest during the early summer.
Comparisons by Facility
Figures 4-16 and 4-17 are box and whisker plots that compare gross alpha and gross beta concentrations for each monitor type by facility. Box and whisker plots are used to graphically display the differences in median values between groupings. For each group, the figures show the median value of all the data and a box indicating the 25th and 75th percentile range based on all the data. As stated on the plots, the whiskers indicate the nonoutlier minimum and maximum values within each grouping. For these plots, an outlier is defined as those values that are either greater than or less than one and one-half times the range of the box. Extreme values are those that are either greater than or less than three times the range of the box. The intent of using this type of graph is to visually depict differences in the medians of the groupings; therefore, the outliers are not shown since the scale required to show the extremes could mask most of the visual differences in the median values. While these outliers are not presented in these plots, they are included in the calculation of the median values.
Figures 4-16 and 4-17 present summarized 2001 and 2002 data by facility and monitor type to indicate short-term changes in levels. The data are the same for the suspended particulate monitors from the WERF control location and for the SWEPP control location.
Figure 4-16. Gross alpha concentrations by year, facility and monitor type.
Figure 4-17. Gross beta concentrations by year, facility, and monitor type.
As with past analysis of gross alpha values, values varied very little among facility groupings during 2002 (see Figure 4-16). Median suspended particulate monitor concentrations slightly decreased from 2001 to 2002 for all facility groupings except the WERF and the TAN/SMC control grouping, which slightly increased. For this analysis, the data presented for the suspended particulate monitors from the WERF control location are the same as that from the SWEPP control location. For the PM10 monitors, the median concentrations decreased for the SDA and the SWEPP control groupings and increased for the other groupings. To test for statistical significance of the variations in medians of gross alpha concentrations from 2001 to 2002, the Kruskal-Wallis significance tests were performed on data from each facility grouping. Only the changes in median values from 2001 to 2002 for the gross alpha PM10 monitors at WERF were found to be statistically significant at the 0.05 level. For the remaining facility/monitor type groupings, the changes in gross alpha median values from 2001 and 2002 were found to be not significant.
Variability among facility groupings during 2002 for median gross beta concentrations is graphically presented in Figure 4-17. Median gross beta concentrations from suspended particulate monitors increased slightly from 2001 to 2002 for most location groupings, while the TAN/SMC control grouping decreased slightly. Median gross beta concentrations from PM10 monitors increased for the WERF and WERF control location and decreased for all other groupings. Only the change in the median PM10 monitor concentrations from 2001 to 2002 for the SDA grouping was found to be significant at the 0.05 level using the Kruskal-Wallace test, while none of the changes in suspended particulate monitor gross beta concentrations from 2001 to 2002 were found to be significant.
Cesium-137 was the only human-made, gamma emitting radionuclide that exceeded the laboratory stated detection limit in 2002. It was detected at TAN-102 at a level of 1.5 ± 0.4 x 10-15 (Ci/mL). This represents 0.0004 percent of the DCG.
Plutonium-239/240 was detected on the second quarter 2002 alpha/beta composite at location SDA 4.2 at a concentration on 1.82 ± 0.31 x 10-17 Ci/mL. This is 0.091 percent of the DCG. No other alpha- or beta-emitting isotopes were detected.
Tables 4-8 and 4-9 summarize 2001 and 2002 gross alpha and gross beta means, medians, maximum, and minimum values.
Table 4-8. Summary of statistics for gross alpha concentrations.
Table 4-9. Summary statistics for gross beta concentrations.
An estimated total of 10,442 Ci of radioactivity, primarily in the form of short-lived noble gas isotopes, was released as airborne effluents. The M&O, and ESER contractors sampled a variety of media in 2002 to assess if operations at the INEEL are releasing contaminants to the environment in significant levels. Although some contaminants were detected, they could not be directly linked to operations at the INEEL. The maximum levels for the contaminants found were all well below regulatory health based limits for protection of human health and the environment. Nonradiological pollutants, including nitrogen dioxide and particulates, were monitored at select locations around the INEEL. All results were well below regulatory standards.
40 CFR 50.6, 2001, "National Primary and Secondary Ambient Air Quality Standards for Particulate Matter," Code of Federal Regulations, Office of the Federal Register.
40 CFR 50.4, 2001, "National Primary Ambient Air Quality Standards for Nitrogen Oxides," Code of Federal Regulations, Office of the Federal Register.
DOE-ID, 2002, National Emissions Standards for Hazardous Air Pollutants (NESHAPs) Calendar Year 2002 INEEL Report for Radionuclides, DOE/ID 10890(02), June.
EG&G, 1993, New Production Reactor Exposure Pathways at the INEEL, EGG NPR-8957.