My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
ARCHIVED REPORTS XR0012277
EnvironmentalHealth
>
EHD Program Facility Records by Street Name
>
E
>
ELEVENTH
>
7500
>
3500 - Local Oversight Program
>
PR0544801
>
ARCHIVED REPORTS XR0012277
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
11/19/2024 10:19:09 AM
Creation date
9/4/2019 11:16:58 AM
Metadata
Fields
Template:
EHD - Public
ProgramCode
3500 - Local Oversight Program
File Section
ARCHIVED REPORTS
FileName_PostFix
XR0012277
RECORD_ID
PR0544801
PE
3528
FACILITY_ID
FA0003210
FACILITY_NAME
TEXACO TRUCK STOP
STREET_NUMBER
7500
Direction
W
STREET_NAME
ELEVENTH
STREET_TYPE
ST
City
TRACY
Zip
95378
APN
25015018
CURRENT_STATUS
02
SITE_LOCATION
7500 W ELEVENTH ST
P_LOCATION
03
P_DISTRICT
005
QC Status
Approved
Scanner
SJGOV\wng
Tags
EHD - Public
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
140
PDF
Print
Pages to print
Enter page numbers and/or page ranges separated by commas. For example, 1,3,5-12.
After downloading, print the document using a PDF reader (e.g. Adobe Reader).
View images
View plain text
Report:Groundwater-quality Monitoring—March 29-31 2006, 7500 West Eleventh Street, Tracy, CA Page 19 <br /> p p <br /> The employs MAROS protocol s some modifications to the CES methodology. Instead of <br /> using a distribution-free version of the coefficient of variation to assess statistically rate <br /> of change in concentration of analytes of concern with time, MAROS uses Mann-Kendall <br /> statistical procedures. In addition, MAROS substitutes preliminary remediation goals <br /> (PRGs) promulgated by Region IX of the US-EPA (United States Environmental <br /> Protection Agency Region IX 2004) for the MCL criteria originally used by LLNL. <br /> The groundwater-monitoring program at the 7500 West Eleventh Street Site has extended <br /> from May 2000 thru March 2006. For each well, all of the data for each of the analytes of <br /> primary concern were used to mare an initial recommendation for optimal sampling <br /> frequency. To conservatively account for any more rigorous sampling frequency <br /> requirements called for by unusual variations in the concentrations of analytes of concern <br /> in groundwater in samples recovered from any of the wells on the site, the data obtained <br /> from the last six sampling rounds, extending over the period January 2004 to March <br /> 2006, were considered separately from the total compilation of available data. <br /> The results of the MAROS sampling frequency optimization are presented in the Table <br /> headed MAROS Sampling Frequency Optimization Results in Appendix A. <br /> Recommendations are made for sampling frequencies at each of the monitoring wells in <br /> the primary plume of contaminated groundwater emanating from the 7500 West Eleventh <br /> Street property and individual recommendations are made for each of the BTEX <br /> compounds. For toluene, ethylbenzene and total xylene isomers, a statistically-efficient <br /> groundwater monitoring program calls for samples to be recovered from more than 50% <br /> ! of the wells at a frequency no greater than once every two years (biennially) and at a <br /> frequency of no more than once per year in the remainder of the wells (annually). In the <br /> case of benzene, the recommended sampling frequency is similar to that of the other <br /> BTEX compounds, with two minor exceptions. <br /> In the case of benzene in Monitoring Well MWFP-4, the recommended frequency for <br /> sampling is semi-annual; however, examination of Table 2 shows that that frequency is <br /> due to the combination of its very low assigned cleanup goal of 0.5 µg/L and to a <br /> statistical perturbation caused by the appearance of a trace of benzene at a concentration <br /> of 5.6 µg/L that appeared in the sample recovered from that well on March 31, 2006. The <br /> samples from that well had previously been free of detectable concentrations of benzene. <br /> A statistical call for quarterly monitoring of groundwater in Monitoring Well MW-7 was <br /> similarly generated by temporal variations in the concentration of benzene over the recent <br /> series of groundwater-quality monitoring rounds. As is noted in the optimization results <br /> in Appendix A, the required sampling frequency for that well based on the complete <br /> database is once per year. In SJC's opinion, these slight statistical variations are not of <br /> practical significance and the design of a future groundwater monitoring program at the <br /> Navarra Site should be based on the annual frequency recommended by the MAROS <br /> analysis for all of the BTEX compounds in the 19 other wells. <br /> r <br /> sic <br />
The URL can be used to link to this page
Your browser does not support the video tag.