Fourth Quarter 2006
INL Quarterly Site Environmental Report
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Quality Assurance

The ESER Quality Assurance Program consists of five ongoing tasks which measure:

1. data completeness
2. data accuracy, using spike, performance evaluation and laboratory control samples
3. data precision, using split samples, duplicate samples and recounts
4. presence of contamination in samples, using blanks.

The following discussion briefly summarizes the results of the quality assurance program for the period from October 1 to December 31, 2006.

Method Uncertainty

The Quality Assurance Project Plan (QAPP) establishes data quality and method quality objectives for the ESER surveillance program (Stoller 2007).  Since the primary concern is with detection, the lower bound for the method uncertainty is set at zero.  The upper bound is defined by the ESER program as the maximum concentration for the range of data over the past ten years, excepting those values determined to be extremes using box plots generated by a statistical data program.  Each individual result is checked for acceptance on the basis of the result, whether it is below the lower limit (i.e., a negative value), greater than the upper limit, or between the lower and upper limit (the most common occurrence).  The calculated method uncertainty is then compared to the 1s measured uncertainty.  A sample is deemed acceptable when the measured 1s uncertainty is less than the calculated uncertainty.  The upper bound values were recently re-evaluated and revised.  Preliminary results indicate that more calculated method uncertainties for detected results were acceptable.  In the fourth quarter of 2006, approximately 97.2 percent of method uncertainties were in the acceptable categories.

Data Completeness

The Quality Assurance Project Plan specifies a 98 percent completeness goal for all regularly scheduled sample types.  This goal does not include variable sample types such as game animals and precipitation, where the ability to produce a sample is not controllable. Data completeness for sample collection and delivery was 100 percent during the fourth quarter for all samples types with the following exceptions.

One paper air filter from Craters of the Moon during the week of November 8 was found to missing from the filter head upon return to the office.  The completeness of the air filter data set is therefore 99.6 percent for the fourth quarter. 

The following results were lost in analysis during the fourth quarter:  one Pu-238 result in air, one Pu-239/240 result in air, 1 Am-241 result in waterfowl and three Pu-239/240 results in waterfowl.

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Data Accuracy

Spike Samples Submitted with Field Samples

The ESER obtains spike samples from the Department of Energy’s Radiological and Environmental Sciences Laboratory, which prepares the spikes and issues data reports with the results. Some spikes are also obtained from private vendors, such as Analytics and Environmental Resource Associates, who provide a certificate of analysis with the sample. During the fourth quarter of 2006, data were obtained for the following spikes:

• Milk spike analyzed for Iodine-131 by the EAL.

Table 5.  Results for Milk Spike-Sample ID 06-MI-0114

Performance Evaluation Samples

The QAP program was discontinued following the March 2004 distribution. Performance evaluation samples are now prepared through the Mixed Analyte Performance Evaluation Program (MAPEP), administered by the Department of Energy’s Radiological and Environmental Sciences Laboratory. DOE has mandated that all laboratories performing analyses in support of the Office of Environmental Management shall participate in MAPEP. The program distributes samples of air, water, vegetation and soil for analysis in approximately January and June. Both radiological and nonradiological constituents are included in the program.

Both the Idaho State University EAL and Teledyne Brown Engineering participated in the MAPEP Study reported in November 2006. Results are tabulated below for those analyses performed by each laboratory. (A = Acceptable, W = Acceptable with warning, N = Not acceptable)
 

Table 6. MAPEP Results for November 2006

Idaho State University Environmental Assessment Laboratory
Matrix: Air (Bq)
Analyte	EAL Result	MAPEP Result	Bias (percent)	Acceptable Range	Evaluation
Cesium-134	2.9	3.147	-7.8	2.20-4.09	A
Cesium-137	1.8	1.805	-0.3	1.26-2.35	A
Cobalt-57	2.6	2.582	0.7	1.81-3.36	A
Cobalt-60	1.6	1.577	1.5	1.10-2.05	A
Manganese-54	2.0	1.92	4.2	1.34-2.5	A
Gross alpha	0.08	0.290	-72.4	0.0-0.580	A
Gross beta	0.34	0.359	-5.3	0.180-0.538	A
Matrix: Water (Bq/L)
Cesium-134	97.9	112.82	-13.2	78.97-146.66	A
Cesium-137	193.6	196.14	-1.3	137.30-254.98	A
Cobalt-57	209.3	213.08	-1.8	149.16-277.00	A
Cobalt-60	47.7	47.5	0.4	33.2-61.8	A
Tritium	401.4	428.85	-6.4	300.20-557.50	A
Gross alpha	0.45	1.033	-56.4	0.0-2.066	A
Gross beta	1.05	1.03	1.9	0.52-1.54	A
Matrix: Soil (Bq/kg)
Cesium-134	530.1	452.13	17.2	316.49-587.77	A
Cesium-137	687.5	525.73	30.8	368.01-683.45	N
Cobalt-57	845.6	676.33	25.0	473.43-879.23	W
Manganese-54	791.1	594.25	33.1	415.98-772.52	N
Potassium-40	955.9	604	58.3	423-785	N
Zinc-65	1214.9	903.61	34.5	632.53-1174.69	N
Matrix: Vegetation (Bq)
Cesium-134	7.06	7.487	-5.7	5.24-9.73	A
Cesium-137	5.71	5.495	3.9	3.85-7.14	A
Cobalt-60	5.82	5.806	0.2	4.06-7.55	A
Manganese-54	8.28	8.351	-0.9	5.85-10.86	A
Zinc-65	6.30	5.984	5.3	4.19-7.78	A

 

Teledyne Brown Engineering
Matrix: Air (Bq)
Analyte	TBE Result	MAPEP Result	Bias (%)	Acceptable Range	Evaluation
Americium-241	0.124	0.142	-12.7	0.10-0.18	A
Cesium-134	2.62	3.147	-16.7	2.20-4.09	A
Cesium-137	1.98	1.805	9.7	1.26-2.35	A
Cobalt-57	2.65	2.582	2.6	1.81-3.36	A
Cobalt-60	1.63	1.577	3.4	1.10-2.05	A
Manganese-54	2.10	1.92	9.4	1.34-2.50	A
Plutonium-238	.0123	0.118	4.2	0.08-0.15	A
Plutonium-239/240	8.22e-3	--a			A
Strontium-90	0.549	0.62	-11.5	0.43-0.81	A
Uranium-234/233	0.140	0.134	4.5	0.09-0.17	A
Uranium-238	0.136	0.139	-2.2	0.10-0.18	A
Zinc-65	-0.163	--a			A
Gross Alpha	0.134	0.290	-53.8	0.0-0.580	A
Gross Beta	0.358	0.359	-0.3	0.180-0.538	A
Matrix: Water (Bq/L)
Americium-241	2.09	2.31	-9.5	1.62-3.00	A
Cesium-134	99.8	112.82	-11.5	78.97-146.66	A
Cesium-137	191	196.14	-2.6	137.30-254.98	A
Cobalt-57	203	213.08	-4.7	149.16-277.00	A
Cobalt-60	46.2	47.5	-2.7	33.2-61.8	A
Tritium	471	428.85	9.8	300.20-557.50	A
Iron-55	173	165.4	4.6	115.8-215.0	A
Manganese-54	0.186	--a			A
Nickel-63	109	118.62	-8.1	83.03-154.21	A
Plutonium-238	1.50	1.39	7.9	0.97-1.81	A
Plutonium-239/240	2.01	1.94	3.6	1.36-2.52	A
Strontium-90	13.7	15.69	-12.7	10.98-20.40	A
Technetium-99	29.0	27.15	6.8	19.00-35.29	A
Uranium-234/233	2.19	2.15	1.9	1.50-2.80	A
Uranium-238	2.25	2.22	1.4	1.55-2.89	A
Zinc-65	178	176.37	0.9	123.46-229.28	A
Gross Alpha	1.52	1.033	47.1	0.0-2.066	A
Gross Beta	1.18	1.03	14.6	0.52-1.54	A
Matrix: Soil (Bq/kg)
Americium-241	83.6	105.47	-20.7	73.83-137.11	W
Cesium-134	393	452.13	-13.1	316.49-587.77	A
Cesium-137	522	525.73	-0.7	368.01-683.45	A
Cobalt-57	636	676.33	-6.0	473.43-879.23	A
Cobalt-60	3.78	--a			A
Manganese-54	598	594.25	0.6	415.98-772.52	A
Nickel-63	571	672.3	-15.1	470.6-874.0	A
Plutonium-238	71.2	82	-13.2	57-107	A
Plutonium-239/240	0.487	--a
Potassium-40	615	604	1.8	423-785	A
Strontium-90	178	223.3	-20.3	156.3-290.3	W
Technetium-99	175	218.01	-19.7	152.61-283.41	A
Uranium-234/233	119	152.44	-21.9	106.71-198.17	W
Uranium-238	115	158.73	-27.5	111.11-206.35	W
Zinc-65	937	903.61	3.7	632.53-1174.69	A
Matrix: Vegetation (Bq)
Americium-241	-0.128	--a			A
Cesium-134	7.46	7.487	-0.4	5.24-9.73	A
Cesium-137	5.99	5.495	9.0	3.85-7.14	A
Cobalt-57	-1.15e-2	--a			A
Cobalt-60	5.95	5.806	2.5	4.06-7.55	A
Manganese-54	9.04	8.351	8.3	5.85-10.86	A
Strontium-90	1.19	1.095	8.7	0.77-1.42	A
Uranium-234/233	0.250	0.243	2.9	0.17-0.32	A
Uranium-238	0.216	0.253	-14.6	0.18-0.33	A
Zinc-65	6.16	5.984	2.9	4.19-7.78	A
a.  False positive test.  Value reported by laboratory was statistically zero.

 

Internal Laboratory Spikes

The Idaho State University Environmental Assessment Laboratory uses NIST standards to prepare spiked water samples and uses commercially prepared calibration standards as NIST-traceable spiked samples.  ISU considers a performance to be acceptable if results pass either the ±20 percent test specified by the ESER program or the three-sigma test described in the data precision section.  A variety of checks are made each quarter on different geometries.

During the fourth quarter of 2006, 15 analyses were conducted on NIST-traceable standards for gamma-emitting radionuclides.  The geometries tested were single charcoal cartridge, low-volume composite, 500-mL 1.0 g/cc and 1 L 1.0 g/cc.  A total of 71 analytical results were generated.  All of the results were within the ±20 percent range, with the exception of four analyses for Cobalt-57, which had gone through approximately nine half-lives at the time of analysis.  All of these results were within the three standard deviation criterion. 

Four gross alpha and two gross beta spiked water samples were analyzed in the fourth quarter.  One of the gross alpha results was outside the 20 percent range, but was within the three standard deviation criterion.  All other results were within 20 percent.

 Water samples spiked with tritium received 11 analyses during the quarterly reporting period.  All were well within the ±20 percent criterion, generally about 6 percent.  A tritium in milk spike also had a result within approximately 6% of the known value.

Teledyne Brown analyzed a laboratory control sample (LCS) with each batch of samples submitted by the ESER.  During the fourth quarter this consisted of strontium-90 and actinides in air, strontium-90 in potatoes, and strontium-90 and actinides in waterfowl.  

DATA PRECISION

Data precision is measured using duplicate samples, split samples, and recounts.  The Quality Assurance Project Plan specifies that sample results should agree within ±20 percent or 3σ, whichever is greater.  For environmental samples at levels that are within the normal range found by the ESER, the 3 standard deviation criterion is the one that applies in nearly all cases.  The standard deviation criterion is considered to be met if the values of the duplicate samples differ by less than the root mean square of three standard deviations of each sample result.  Mathematically, this is expressed as:

│X-Y│< 3 (sqrt(σ_x² + σ_y²)),  where:
            X is the result of the regular sample
            Y is the result of the duplicate sample
            σ_x is the uncertainty of the regular sample
            σ_y is the uncertainty of the duplicate sample

Another measure of duplicate sample results is the relative percent difference.  This value is the difference in the two results divided by the mean of the two results.  The following sections of this report first check the sample results using the 3 standard deviation criterion.  If this criterion is not met, the results are then listed for the relative percent difference.  Other pertinent information that may have affected the sample analysis is also included under Notes.

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Field Duplicate Samples

Duplicate milk samples were collected from Roberts on December 5 and analyzed for gamma-emitting radionuclides.  The following results were reported:

Duplicate potato samples were collected from Blackfoot on September 25 and analyzed for gamma-emitting radionuclides and strontium-90.  The following results were reported:

Duplicate drinking water samples were obtained from Arco on November 15 and analyzed for gross alpha, gross beta and tritium.  Results for this sample were as follows.

Duplicate surface water samples were obtained from Buhl on November 14 and analyzed for gross alpha, gross beta, and tritium.  Results for this sample were as follows.

Duplicate air samplers are operated at two locations adjacent to regular air samplers.  In the fourth quarter of 2006 these samplers, designated as QA-1 and QA-2, were in operation at the Experimental Field Station and Mud Lake, respectively.  Particulate filters receive the standard analysis for gross alpha and gross beta; charcoal cartridges are analyzed specifically for iodine-131.  The following table presents gross alpha and gross beta results for the co-located samplers.  Charcoal cartridge results are difficult to present because cartridges are counted in batches of ten.

A comparison of duplicate results can also show bias in the sampling system, such as if one set of results is consistently lower or higher than the other. For air sampling equipment this bias can result from a leak in the system or variations in the calibration of the flow meter. The following figures show graphs comparing the difference in the gross alpha and gross beta results for the fourth quarter of 2006.

Lab Split Samples

Idaho State University splits and analyzes a number of milk, precipitation, and atmospheric moisture samples each quarter.  The laboratory tests each result using both the ±20 percent criterion and the 3σ criterion, although it considers the former test meaningless for analyses producing fewer than 15 total counts and questionable even where counts are on the order of 100.  The latter criterion is applied in nearly all cases at the levels seen in environmental samples analyzed for the ESER program.

The ISU Quality Assurance Report contains spreadsheets that analyze split and recount data using a logical equation that tests for the above two criteria.  The spreadsheet first tests for the ±20 percent criterion; if this test is not met, the 3σ criterion is used.  Acceptable performance is considered if either test is passed.

Results of EAL split sample analyses-fourth quarter 2006

Sample Recounts

The ISU EAL recounts a number of samples of each media type. The lab tests each recount using both the 20 percent criterion and the 3σ criterion, subject to the limitations described in the previous section.

A summary of the recount results for the fourth quarter is presented below.

• 68 low-volume air filters were recounted for alpha activity. All results were within the 3σ criterion.
• 68 low-volume air filters were recounted for beta activity. One result was outside the 3σ criterion but within the 20 percent criterion.
• 12 milk samples were recounted for potassium-40; two were recounted twice. All results were within the 3σ criterion.
• 8 sets of charcoal cartridges samples were recounted for iodine-131. All results were within the 3σ criterion.
• 14 quarterly composites were recounted for beryllium-7; one was recounted twice. One result was outside the 3σ criterion, but just within the 20 percent criterion.
• 6 potato samples were recounted for potassium-40; two were recounted twice. All results were within the 3σ criterion.
• 3 water samples were recounted for tritium activity. All results were within the 3σ criterion.
• 2 precipitation samples were recounted for tritium activity. Both results were within the 3σ criterion.
• 1 atmospheric moisture sample was recounted for tritium activity. The result was within the 3σ criterion.
• 1 milk sample was recounted for tritium activity. The result was within the 3σ criterion.
   

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BLANKS

Field blanks

The ESER program submits field blanks along with the regular samples to test for the introduction of contamination during the process of field collection, laboratory preparation, and laboratory analysis. The current program includes the use of two field blanks, designated as Blank A and Blank B, that each accompanies one of the air filter routes. Quarterly composites of the blanks are also submitted. After gamma spectrometry analysis, one of the blanks is analyzed for Sr-90 and the other for transuranics.

Ideally, blank results should be within ±2σ of zero and preferably within ±1σ of zero on most analyses. It would be expected, based on counting statistics for a sample that was truly a blank (i.e., the true value of the analyte was zero), that 68.3 percent of analyses would fall within one standard deviation, 95.5 percent would fall within two standard deviations, and 99.7 percent would fall within three standard deviations.

The following tables contain the results of fourth quarter field blanks. The significance level describes the multiple of the uncertainty that the result lies from zero. Those designated as <1 are within ±1σ, those designated as 1 are between ±1σ and ±2σ, and so forth.

Results for Blank A weekly analyses

Results for Blank B weekly analyses

Results for quarterly air filter composite blanks-ISU

Results for quarterly air filter composite blanks-Teledyne Brown

Results for Iodine-131 in milk blanks

Reagent Blanks

The Environmental Assessment Laboratory prepares and analyzes reagent blanks to help determine if the analysis will yield a zero result when no activity is present. ISU considers the result within specification if the concentration is less than the minimum detectable concentration (MDC) for the analysis. Fourth quarter blanks for gross alpha, gross beta and tritium met this criterion.

Teledyne Brown analyzes a blank with each set of results. All blanks for fourth quarter samples met Teledyne Brown’s acceptance limits.
 

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OTHER QA PROBLEMS NOTED

There were no additional QA problems noted in the fourth quarter.

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