HomeMy WebLinkAboutDSHW-2008-025763 - 0901a068801e25a0
David P. Gosen, P.E.
Director, Environmental Services
ATK Launch Systems – Promontory
P.O. Box 707
Brigham City, UT 84302-0707
RE: Review of the HydraSleeve Discrete Interval No-Purge Sampler Evaluation, ATK Launch Systems - Promontory Facility, EPA I.D. #UTD009081357
Dear Mr. Gosen:
The Division of Solid and Hazardous Waste has completed its review of the HydraSleeve sampler evaluation report that was submitted to our office on February 21, 2008. Our questions
and comments on the report are enclosed with this letter. Please address the questions and comments and provide a response within 30 days of receipt of this letter. Once it is determined
that ATK has adequately addressed these issues, a revised report can be submitted for approval.
Thank you for your cooperation. If you have any questions, please contact Jeff Vandel at 538-6170.
Sincerely,
ORIGINAL DOCUMENT SIGNED BY DENNIS R. DOWNS ON 3/21/08
Dennis R. Downs, Director
Utah Division of Solid and Hazardous Waste
DRD\JV\tjm
Enclosure
c: Paul Hancock, ATK Launch Systems
David Covington, ATK Launch Systems
File to: ATK Launch Systems – Promontory
Comments on the Results of the HydraSleeve Discrete Interval,
No-Purge Sampler Evaluation
1. Figure 2, Monitoring Wells Sampled during Study: The monitoring wells used for this study are not highlighted. It is impossible to discern the pertinent wells’ spatial distribution.
Please modify Figure 2 to highlight the wells used in the study.
2. Section 3.2, Sampling Results Comparison, p.7: The text mentions six categories; however, 11 dataset comparisons were performed. It is unclear how many individual metal and how
many individual VOC subcategories were set up. Please revise the evaluation report to correct this issue.
3. Section 3.2, Sampling Results Comparison, p.8: The text states that non-detects were either eliminated from the dataset, or substituted by one-half their respective detection limits
(depending on whether both or only one of the results being compared was not detected). However, eliminating the non-detects can skew the remaining comparisons, and substituting one-half
the detection limits can likely decrease the true variance of the data. Both these methods are to be avoided (see Helsel, D., 2005, Nondetects and Data Analysis, Wiley Interscience).
Instead, methods from the statistical field of survival analysis could be used here, such as the generalized Wilcoxon test (Helsel, 2005, pp. 145).
4. Section 3.3.2, Wilcoxon Matched-Pairs Signed Ranks Test. It is not clear if the Wilcoxon T statistic, as computed, is compared to a two-sided or one-sided probability value (p-value).
The desired level of significance should be pre-specified (e.g., 0.05, two-sided), before comparing the T statistic to the tabled, critical T value (see Sheskin, D., 1997, Handbook
of Parametric and Non-Parametric Statistical Procedures, CRC Press, Test 13, pp. 295). Please clarify.
5. Section 3.3.4, Linear Regression, pp10: It seems inappropriate to perform linear regression on data which are not distributed normally (as demonstrated in Appendix A). Essentially,
we have to question the value of performing slope and R2 calculations for these data sets, if the underlying assumptions for a least squares, linear regression analysis are not met (i.e.,
linearity between the data sets, independence of the observation errors of the dependant variable, normality of the residuals, and equal variance of the distribution of errors). Please
explain why this is an appropriate statistical method to use for comparing the data.
6. Section 2.2 Groundwater Sampling and Well Selection
In the third paragraph of page four, it is stated that concentrations of perchlorate range from less than the MDL to 495 ug/L and the range for TCE is from less than the MDL to 221 ug/L.
In Table 1, it is indicated that these high-end concentrations for perchlorate and TCE were collected in 2003 and 2004. According to the laboratory data reports included in Appendix
C, the range of concentrations detected for perchlorate is from less than the MDL to 41.5 ug/L. Based on Table 5, the statistical summary for VOC’s, the range of concentrations detected
for TCE is from 1.5 ug/L to 426 ug/L. The actual concentrations measured during the study should be the ranges shown in this paragraph of Section 2.2, not the data from 2003 and 2004.
Please modify the text accordingly.
7. Section 3.4 Quality Assurance/Quality Control
It is stated in this section that duplicate samples were collected at wells J-2 and H-3, but according to the laboratory reports included in Appendix C of the report, the duplicate samples
were collected from wells H-4, J-5 and J-6. Please clarify.
8. Tables
It is unknown what range of concentrations was measured for perchlorate during the study. In addition, it is unclear what the range was for TCE. A statistical summary for perchlorate
analyses is not included in the report. Please include one that shows the well sampled and the results for all of the perchlorate data collected for the study and revise Table 5 so
that this information is shown for TCE.
The Division requested that well M39-B1 be included in the HydraSleeve evaluation due to the relatively high concentrations of perchlorate that have been detected in the well in the
past. Based on the range of perchlorate data that the Division asked for above, we may request that ATK collect additional samples to improve the range of sampling results that are
compared in the study.
9. Table 5 Statistical Summary for VOCs
It is not clear where some of the data in the TCE column of this table came from. The wells where these results were obtained are not shown and the laboratory reports in Appendix C
don’t include the following results that are shown in the table (all ug/L): 426, 456, 0.355, 16.2, 24.7. Are some lab reports missing from Appendix C? Please see comment ten below.
10. Appendix C
It is unclear exactly what data was used in the statistical analysis. Perchlorate and TCE are considered to be the two main contaminants of concern in groundwater. It is recommended
that the sample results for at least these two compounds, that were included in the analysis, be tabulated. The data from the lab results that were included in Appendix C are summarized
below. It is not clear if samples were collected with the HydraSleeve from the following wells: H-2, H-3, H-9, H-10, J-1, J-3, J-7.
Summary of Data From Appendix C Lab Reports
Well Cl04 ClO4 HS TCE TCE HS H1 <MDL <MDL <MDL <MDL H2 10.6 <MDL H3 <MDL <MDL H4 41.5 41.4 2.0 J <MDL H4 HSD 36.9 <MDL H4 D H5 12.2 14.5 <MDL <MDL H6 <MDL <MDL 5.0
J 5.0 J H7 <MDL <MDL <MDL <MDL H8 <MDL <MDL <MDL <MDL H9 <MDL <MDL H10 <MDL <MDL J1 426 J3 4.0 J J5 10.9 13.7 3.6 J 3.9 J J5 D 11.8 4.0 J J6 12.8 11.5 1.5
J 1.5 J J6 D 13.8 <MDL J7 16.2 J8 <MDL <MDL <MDL <MDL
Data in italics was taken from the Spring 2007 Groundwater Monitoring Report
1
March 21, 2008
288 North 1460 West • Salt Lake City, UT
Mailing Address: P.O. Box 144880 • Salt Lake City, UT 84114-4880
Telephone (801) 538-6170 • Fax (801) 538-6715 • T.D.D. (801) 536-4414
www.deq.utah.gov
TN200800221
State of Utah
Department of Environmental Quality
Richard W. Sprott
Executive Director
DIVISION OF SOLID AND HAZARDOUS WASTE
Dennis R. Downs
Director
JON M. HUNTSMAN, JR.
Governor
GARY HERBERT
Lieutenant Governor