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Passive Soil Gas Surveys Using GORE-SORBER® Modules
Bob Jurgens, Kansas Drycleaning Program
Kansas Department of Health and Environment
What is a GORE-SORBER® Module?
� Patented soil gas sampler
� W.L. Gore & Associates � Makers of GORE-TEX material
� Outdoor clothing
� Floss
� Module contains polymeric & carbonaceous adsorbents
� Expanded polytetrafluoroethylene � Chemically & biologically
inert
� Waterproof
� Vapor permeable
� Strong & durable
ePTFE - 50,000 x
GORE-SORBER® Module
magnification
GORE-SORBER® Module
How it works
Insertion/retrieval cord
Adsorbent
Water & soil
particles repelled
Vapors pass through
membrane
Create installation hole
Place insertion rod in module
Insert module into hole
Secure module, mark field location, record map information and field notes
Module installation 1 2
3 4
Installation Tools
Hammer & Probe
Slide Hammer& Tile Probe
Rotary Hammer Drill & Carbide Tipped-Drill Bit
Geoprobe
Installation Lessons Learned
� KDHE uses a direct push probe to install modules in outdoor hard surface lots.
� KDHE installs to a depth of 4 feet bgs and leaves a minimum of two weeks.
� Explain the project to the property owner. They will often watch out for the locations and help prevent vandalism.
� Bury beneath the ground surface to avoid problems with lawn mowers and snow removal equipment.
Installation Lessons Learned
� Hide/cover the locations to prevent vandalism (removal of the modules).
� Place a metal washer above the cork plug to allow use of metal detector to locate the hole
� Measure exact locations from secure structures
� Flags and paint will disappear
� Beware of surface water or hydrated bentonite during the winter (frozen media) � Will need to chip out the material in the hole
Indoor Locations
Retrieval Process 1 2
3 4
Hole Cover
Cork Plug
Place module in jar
Shipping Jar
Completing the Job
Outdoor Installation
Installation Hole
Cork Plug
Sample Analysis
� Thermal desorption/gas chromatography/ � mass spectroscopy (TD/GC/MS) � Modified EPA method 8260/8270
� Accepted for CERCLA/RCRA investigations � Compound specific reporting
� Rigorous QA/QC Program � Accurate, reproducible results
� Analytical options include � Target and non-target compounds � TICs, TPH, GRPH, DRPH
Final Reporting GORE-SORBER® SURVEYS � Pre- and post-survey consultation
� Survey design and data interpretation
� Bound final report includes � Chain of Custody � QA/QC summary � Data tables, TICs � Color contour maps � Survey comments
� Available electronically
Quick & Easy Wash-O-Mat PCE Soil Gas Survey Map
Quick & Easy Wash-O-Mat TCE Soil Gas Survey Map
Quick & Easy Wash-O-Mat cis-1,2 DCE Soil Gas Survey Map
Comparing the Maps PCE
TCE
Cis-1,2 DCE
Cost
� KDHE Cost – 1999 � GORE-SORBERS: $181.50/each*
� KDHE Cost – March 2002 � GORE-SORBERS: $258.50/each*
� Neodesha Project: $10,300 � Detailed investigation
� 27 GORE-SORBERS
� Geoprobe Installation
* = includes 10% subcontractor markup
GORE-SORBER® SURVEYS Advantages
� All soils - low to high permeability � All soil moisture conditions - dry to
saturated settings � Waterproof, vapor-permeable membrane
� Relative correlation to matrix data � Elevated soil gas levels = elevated levels in
subsurface
� Concentrations are not a “snapshot” � Collected over a longer period of time
GORE-SORBER® SURVEYS Advantages Cont.
� Relatively unobtrusive, quick installation & retrieval - field technician � Indoor or outdoor � Install – KDHE projects 20-30 in one day � Retrieval - KDHE projects 20-30 in 1/2 day
� Replicate samples per collector � Duplicate analysis - QA/QC � Back-up analysis
installation
GORE-SORBER® SURVEYS Disadvantages � Two trips to the field
� Lengthier sampling and reporting period
� Data reported as mass (ug) not a concentration
� Compound detection in vapor limited due to volatility and Henry’s Law
� True for all soil gas sampling
� Vandals can pull out modules if not hidden properly
Why does KDHE use this technology?
� Helps identify “hot spots”
� Works very good for PCE
� Active soil gas sampling was not providing dependable results
� Soil sampling – easy to miss contaminated area
Contacts
� KDHE – Bob Jurgens, Project Manager � Phone 785-291-3250
� W.L. Gore & Associates � George Shaw – 410-506-4776 *
*As a state agency, KDHE does not endorse specific companies. information only.
This information is provided for contact
Questions or Comments?