Modeling Petroleum Hydrocarbon Degradation - Part I: Gasoline Statistics and Pattern Assemblage
Oral Presentation
Prepared by M. Wade1, J. Johnson2, U. Furrer3
1 - Wade Research, Inc., 110 Holly Road, Marshfield, MA, 02050-1724, United States
2 - NewFields Companies, LLC , 600 Jefferson Street, Suite 1040, Houston, TX, 77002, United States
3 - Harriton & Furrer, LLP, 84 Business Park Drive, Suite 302, Armonk, NY, 10504, United States
Contact Information: [email protected]; 781-837-5504
ABSTRACT
Understanding releases of petroleum products to the environment for purposes of allocating liability requires the application of a number of geochemical, hydrogeological and legal resources. Release(s) of automobile gasolines to the subsurface environment are often not discovered after years or even decades in the subsurface. Sorting out responsibility for the release(s) often is conducted by forensic investigations performed within litigation to determine the allocation of costs associated with site remediation and restoration.
Numerous forensic questions need to be addressed in any subsurface tank investigation. Detailed chemical hydrocarbon analyses of UST product contents, including residual sludge, are important evidence. Unfortunately, engineering contractors frequently fail to collect UST contents as well as sludge for subsequent geochemical laboratory analysis. If done, however, the resulting geochemical and geophysical data become the critically important pieces of information in any subsequent legal proceedings.
At the present time, a quantitative approach of comparing tank content chemistry with site chemical data has not been standardized. To address the issue, a numerical modeling approach, termed pattern assemblage modeling, with hypothesis testing has been developed. In pattern assemblage modeling, detailed forensic geochemical analysis of gasoline products are divided into individual hydrocarbon types of both UST contents and site samples and compared numerically. Calculations following classic petroleum refining simulated distillation methods, allow comparison by independent statistical testing of each petroleum fraction (paraffin, isoparaffin, aromatic, naphthenic and olefin) of the tank contents to site samples. Results provide multiple lines of evidence for evaluating the UST as a release source. An additional result is information on the type(s) of refinery processes evident in the released gasoline(s). Two different case studies are presented to illustrate the application of this modeling approach, and how the results were incorporated within the hydrogeological conditions and legal factors in the cases.
Oral Presentation
Prepared by M. Wade1, J. Johnson2, U. Furrer3
1 - Wade Research, Inc., 110 Holly Road, Marshfield, MA, 02050-1724, United States
2 - NewFields Companies, LLC , 600 Jefferson Street, Suite 1040, Houston, TX, 77002, United States
3 - Harriton & Furrer, LLP, 84 Business Park Drive, Suite 302, Armonk, NY, 10504, United States
Contact Information: [email protected]; 781-837-5504
ABSTRACT
Understanding releases of petroleum products to the environment for purposes of allocating liability requires the application of a number of geochemical, hydrogeological and legal resources. Release(s) of automobile gasolines to the subsurface environment are often not discovered after years or even decades in the subsurface. Sorting out responsibility for the release(s) often is conducted by forensic investigations performed within litigation to determine the allocation of costs associated with site remediation and restoration.
Numerous forensic questions need to be addressed in any subsurface tank investigation. Detailed chemical hydrocarbon analyses of UST product contents, including residual sludge, are important evidence. Unfortunately, engineering contractors frequently fail to collect UST contents as well as sludge for subsequent geochemical laboratory analysis. If done, however, the resulting geochemical and geophysical data become the critically important pieces of information in any subsequent legal proceedings.
At the present time, a quantitative approach of comparing tank content chemistry with site chemical data has not been standardized. To address the issue, a numerical modeling approach, termed pattern assemblage modeling, with hypothesis testing has been developed. In pattern assemblage modeling, detailed forensic geochemical analysis of gasoline products are divided into individual hydrocarbon types of both UST contents and site samples and compared numerically. Calculations following classic petroleum refining simulated distillation methods, allow comparison by independent statistical testing of each petroleum fraction (paraffin, isoparaffin, aromatic, naphthenic and olefin) of the tank contents to site samples. Results provide multiple lines of evidence for evaluating the UST as a release source. An additional result is information on the type(s) of refinery processes evident in the released gasoline(s). Two different case studies are presented to illustrate the application of this modeling approach, and how the results were incorporated within the hydrogeological conditions and legal factors in the cases.
