Database Analysis of State Surface Soil Regulatory Guidance Values
Amy Hanna, Case Western Reserve University, Cleveland, OH

Removal of Chlorinated DNAPL below the Water Table Using Thermal Conduction Heating
Gorm Heron, TerraTherm, Inc., Keene, CA

Database Analysis of State Surface Soil Regulatory Guidance Values

Student Presenter

Amy Hanna, Case Western Reserve University, Department of Civil Engineering, Cleveland, OH 44106-7201, Email: AMY.L.HANNA@saic.com
Aaron A. Jennings, Case Western Reserve University, Department of Civil Engineering, Cleveland, OH 44106-7201, Tel: 216-368-4998, Email: aqaj2@case.edu

A 2001 study of Cleveland , Ohio Brownfield surface soil contamination led to the examination of state regulatory guidance values for soils.  Surface soils were of particular interest since these generally pose the greatest risk to human health at Brownfield sites.  This investigation initially focused on heavy metals, common contaminants at Cleveland Brownfields. However, the discovery of significant variability in guidance values applied to Cd, Cr, Cu, Pb, Ni, and Zn led to questions regarding all remaining state-regulated components.  The state-by-state inconsistencies encountered led to an ongoing program of research that is examining the origins, magnitudes and explanations for guidance value variability.

The results presented here are based on the compilation of a 18,776 state surface soil guidance value database assembled from regulatory guidance available in 2006 for organic, inorganic and element contaminants. All guidance values were captured electronically from internet sources using procedures designed to preserve the original content of each standard.  The structure of each guidance value set was then standardized to a database-compatible format. Chemical Abstract Service (CAS) registry numbers were added to each record if they were not provided by the regulatory agency.  Identification of all records by CAS number resolves the problem of component synonyms.  For example, Ethyl Chloride (CAS 75-00-3) also commonly identified as Chloroethane can be identified by as many as 33 other generic and product-specific names, so searching for it by name would not yield comprehensive results.  All value sets were then assembled into an ACCESS database that may be interrogated for data about the current state of regulatory guidance values.

Statistical analysis will be presented to characterize the nature and extent of variability in state surface soil guidance values. For example, toluene is currently one of the most commonly regulated components in the United States .  Residential surface soil guidance values for toluene range from 0.7 to 16000 mg/kg.  The organics, inorganics and elements most and least commonly regulated and the range of guidance values are discussed.  Explanations for the orders-of-magnitude variability observed for selected components are explored, and opportunities to reduce the observed variability are identified.

Removal of Chlorinated DNAPL below the Water Table Using Thermal Conduction Heating

Gorm Heron, TerraTherm, Inc., 28900 Indian Point, Keene, CA 93531, Tel: 661-823-1615, Fax: 978-343-2727, Email: gheron@terratherm.com
James P. Galligan, TerraTherm, Inc., 10 Stevens Road , Fitchburg, MA 01420, Tel: 978-343-0300, Fax: 978-343-2727
John LaChance, TerraTherm, Inc., 10 Stevens Road, Fitchburg, MA 01420, Tel: 978-343-0300, Fax: 978-343-2727
Ralph Baker, TerraTherm, Inc., 10 Stevens Road, Fitchburg, MA 01420, Tel: 978-343-0300, Fax: 978-343-2727
Steven Vinci, C&S Engineers, 499 Col. Eileen Collins Blvd., Syracuse, NY 13212, Tel: 315-455-2000, Fax: 315-455-9667

An In-Situ Thermal Desorption ISTD-system was used to remediate three separate source zones at the Midler Avenue Redevelopment Brownfield Cleanup Program BCP-Project in Syracuse , NY . The three CVOC source zones covered a total area of 22,300 square ft, and averaged a depth of 20 ft below the ground surface. A volume of 16,200 cubic yards was treated by thermal conduction heating. Ninety percent of the treated sediments were below the water table, located ~ 3 ft below grade. A significant mass of DNAPL constituents, primarily PCE was present within the treatment volume. To address these source areas, a thermal treatment system was installed, consisting of 211 heater wells and 17 horizontal vapor collection wells. Monitoring included temperature profiling using 30 thermocouple wells.  A power supply of 2,500 KVA was used to raise the subsurface temperatures to an average of 100°C in approximately 150 days. Effluent vapors were treated using thermal oxidation and acid gas scrubbing to meet the air emissions standards. Interim and final confirmatory soil sampling was performed to demonstrate compliance with the stringent remedial objectives set by New York State Department of Environmental Conservation NYSDEC). This paper presents the subsurface design, remediation mechanisms utilized, implementation sequence, and the operational adjustments made to ensure effective treatment. A related paper by Vinci et al. presents the site background, regulatory framework, and overall remedial results.

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