Tarek Saba, Ph.D.

Dr. Saba has 10 years of consulting experience in combining chemical fingerprinting methods with hydrogeologic and numerical analysis to identify sources of PAHs, PCBs, chlorinated solvents, NAPL, and petroleum hydrocarbons at contaminated sites. He serves as a consulting expert in these areas. His experience also includes conducting detailed technical reviews of expert reports and assisting attorneys in preparation for depositions and trials.

He uses chemical forensic techniques to identify contaminant sources and timing of spills (age-dating) in environmental liability, cost allocation, and NRD cases at Superfund sites, landfills, major waterways, and petroleum refineries. He has evaluated historical operations at more than 10 manufactured gas plant sites to identify sources of tar and NAPL contamination in remedial cost recovery disputes. He has also used chemical and isotopic forensic techniques to distinguish gas from natural gas pipelines from native gases at several sites.

Dr. Saba has developed several numerical models to simulate the transport and fate of chemicals in groundwater, including models that simulate oil dissolution in the subsurface, contaminant transport in heterogeneous aquifers, optimization of well locations in pump-and-treat systems, and a decision support model to evaluate cost effectiveness of source-zone treatment. He is the lead author on several publications on chemical transport in groundwater.

Saenton S, Illangasekare TH, Soga K, Saba T. Effects of source zone heterogeneity on surfactant enhanced NAPL dissolution and resulting remediation end-points. J Contam Hydrol 2002; 59(1–2):27–44.

Saba T, Illangasekare TH, Ewing J. Effect of flow dimensionality on mass transfer rate coefficient estimations under enhanced conditions. J Contam Hydrol 2001; 51(1–2):63–82.

Saba T, Illangasekare TH. Effect of groundwater flow dimensionality on mass transfer from entrapped nonaqueous phase liquid contaminants. Water Resour Res 2000; 36(4):971–979.

Conference Proceedings and Presentations

Boehm P, Brown J, Saba T, O’Reilly K. The three-part approach to PAH source identification and apportionment in sediments as applied to petroleum, coal tars, and combustion sources. SETAC North America 30th Annual Meeting, New Orleans, LA, November 19–23, 2009.

Saba T. Environmental weathering of PCBs in sediments. The 26th Annual International Conference on Soils, Sediments, and Water, University of Massachusetts at Amherst, MA, October 18–21, 2009.

Boehm P, Shields W, Fairbrother A, Saba T. Determination of the chemical background for sediment—Approaches and conundrums. SMWG meeting in Saratoga Springs, NY, September 29, 2009.

Boehm P, Saba T. Using chemical forensics and other lines of evidence to distinguish PAH contributions from different pyrogenic sources to the sediments of the Hylebos Waterway Superfund Site—A CERCLA and MTCA cost recovery case. SMWG Spring Sponsor Forum, Kalamazoo, MI, April 29–30, 2008.

Boehm P, Saba T, Benton L. Identification of natural gas sources using geochemical forensic tools. The 23ed Annual International Conference on Soils, Sediments, and Water, University of Massachusetts at Amherst, October 15–18, 2007.

Butler E, Saba T. Use of PCB congener and homolog analysis in source apportionment at a rail yard Superfund site. The Annual International Conference on Soils, Sediments, and Water, University of Massachusetts at Amherst, October 16–19, 2006.

Biemer T, Brown M, Butler E, Saba T. Better litigation through chemistry. Presentation to the Boston Bar Association, October 6, 2005.

Saxe JK, Saba T, Wannamaker EJ. Do arsenic-containing products influence arsenic concentrations in subsurface drinking water supplies? Society of Environmental Toxicology and Chemistry 24th Annual Meeting, Austin, TX, November 9–13, 2003.

Sharma M, Saba T, Bittner A. Optimization of groundwater pump and treat systems using numerical modeling and the Monte Carlo approach. 2003 NGWA Midsouth Focus Conference, Philadelphia, PA, 2003.

Sharma M, Saba T, Bittner A. Optimization of groundwater pump and treat systems using numerical modeling and the Monte Carlo Approach. Presented at the National Ground Water Association Mid-South Focus Conference, Nashville, TN, September 19, 2003.

Illangasekare TH, Saenton S, Saba T, Wilson CS. Up-scaling of NAPL dissolution from entrapped sources: Implications on end-points for risk assessment. Proceedings, Contaminated Site Remediation Conference, Melbourne, Australia, December 4–-8, 2000.

Illangasekare TH, Dai D, Saba T, Barranco Jr FT. The influence of heterogeneity on NAPL zone detection with subsurface multiple tracers: Column and intermediate scale laboratory results. Proceedings, Groundwater 2000 International Conference on Groundwater Research, Copenhagen, Denmark, 2000.

Illangasekare TH, Saba T. Upscaling of contaminant transport in heterogeneous aquifers: Dissolution of entrapped separate phase organic chemicals. Proceedings, Engineering Jubilee Congress, Engineering of Peradeniya 2000; (2):127–132.

Illangasekare TH, Saba T. Intermediate scale physical model testing to investigate upscaling of dissolution of non-aqueous phase liquids in aquifers. Proceedings, Physical Modeling and Testing Environmental Geotechnics, Network of European Centrifuges for Environmental Geotechnic Research (NECER). Garnier J, Thorel E, and Haze E (eds), pp. 285–292, La Baule, France, May 15–17, 2000.

Saba T, Illangasekare TH. Surfactant-enhanced dissolution of non-aqueous phase waste chemicals: Effect of flow dimensionality. Conference of Hazardous Waste Research, St. Louis, MO, April 1999.

Saba T, Illangasekare TH. Effects of aquifer heterogeneity and groundwater flow dimensionality on upscaling of natural and surfactant enhanced dissolution of non-aqueous phase liquid waste chemicals. Conference on Hazardous Water Research, Snowbird, UT, 1998.

Saba T, Illangasekare TH. Effect of aqueous phase flow dimensionality on surfactant enhanced dissolution from entrapped non-aqueous phase liquid contaminants at the spill-site scale. American Geophysical Union, San Francisco, CA, December 6, 1998.

Illangasekare TH, Saba T. Upscaling of mass transfer from zones with entrapped nonaqueous phase chemicals. American Geophysical Union, San Francisco, CA, December 6, 1998.

Vestal EW, Illangasekare TH, Ramaswami A, Bielefeldt A, Riffel AM, Saba T. Modeling of net interphase mass exchange in NAPL-water systems undergoing biodegradation at the spill-site scale. American Geophysical Union, San Francisco, CA, December 6, 1998.

Saba T, Illangasekare TH. Natural dissolution of organic chemicals entrapped in a two-dimensional groundwater systems. AGU 18th Annual Hydrology Days, Colorado State University, Fort Collins, CO, 1998.

Polycyclic Aromatic Hydrocarbons (PAHs)

For a confidential client in the northeast U.S., evaluated the sources of PAHs and metals at a petroleum refinery, as part of a defense against a multibillion-dollar natural resource damage claim. Identified which areas of the refinery were associated with urban background, as opposed to refinery operations.

For a client in northwestern U.S., evaluated PAH sources to the sediments of a major waterway as part of a dredging cost allocation case. Determined the relative importance of candidate sources (primarily creosoted pilings, aluminum smelter sludge and urban runoff) through chemical fingerprinting, sediment age dating, and PAH concentration gradients.

For residential owners in Rhode Island, reviewed expert reports on the sources of PAH contamination in the resident yards. Identified deficiencies in the experts’ analysis methods to distinguish PAHs from a nearby former manufactured gas plant and natural background. Case settled.

At a former refinery Superfund site in the Midwest, evaluated the impacts of refinery waste units on a petroleum NAPL plume underneath the waste. Provided evidence showing that the refinery waste did not affect the plume, and that CERCLA’s “petroleum exclusion” is applicable to the plume.

At a steel manufacturing site, evaluated the connection between sediment PAH contamination and surface water sheens using chemical fingerprinting techniques. Found that sediment PAHs resulted in the sheens observed on the surface water and that impacts to both media were not related to the steel manufacturer activities.

Manufactured Gas Plants

For multiple energy companies in the northeastern U.S., linked historical MGP operations and practices to present-day contaminant distribution at over 15 former plants. Used forensic analysis to identify approximate time frame of historical leaks and spills. Analyzed tar, oil, and NAPL entrapment and migration patterns to identify contamination sources. Co-author of several expert reports for insurance remedial cost recovery cases.

PCBs

For a confidential client on the U.S. West Coast, investigated PCB sources to a major waterway. Designed and oversaw a field sampling program to collect source samples and sediment samples from the waterway. Analyzed the congener and homologue data, and identified the source of contamination with a high degree of certainty.

For Southeastern Pennsylvania Transit Authority (SEPTA), identified PCB sources and approximate spill timing at the former Paoli rail yard Superfund site in support of a $60 million remedial cost allocation case. Work included forensic analysis to identify PCB Aroclor and congener patterns. Co-author of expert report sections. Case settled.

For a confidential client on the U.S. East Coast, analyzed homologue and congener patterns to identify PCB sources to a major bay. Identified congeners associated with specific sources. Analysis included conducting PCA analysis, and analysis of PCB profiles in sediment cores. Work is part of a remedial investigation report for the bay.

For a confidential client in the Midwest, conducted fingerprinting analysis to identify sources of PCB contamination to river sediments and banks abutting client’s property. Directed the collection and laboratory congener analysis of sediment samples.

For an industrial client in the Midwest, reviewed and critiqued calculations of PCB contribution from a former paper mill to a river.

For a major manufacturer, assisted client in developing technical defense in response to plaintiff claims relating to PCB and dioxin contamination at an electrical transformer manufacturing site in the Southeastern U.S.

For a confidential client in Georgia, evaluated the feasibility of proposed remedial alternative at a PCB- and VOC-contaminated landfill. Recommendations included modifications to the proposed design to optimize the remediation process.

Chlorinated Solvents

Evaluated sources of tetrachloroethene (PCE) at a former petroleum hydrocarbon distribution facility in the Western U.S. Used different evaporation models to estimate the approximate start date of PCE release(s) to the surface soil.

For a confidential client in Illinois, conducted fingerprinting and fate-and-transport analysis to age date multiple chlorinated solvent plumes. Used multiple lines of evidence, including groundwater travel times, daughter/parent compound ratios, and historical construction of contamination to determine the age of the different plumes. Presented findings to the Illinois EPA.

Reviewed cost recovery documents for municipal water treatment due to alleged contamination from dry cleaning activities. Found approximately $350,000 in overestimated treatment costs.

For a confidential client in MA, identified a client’s share of chlorinated solvents plume affecting residential areas downgradient from several chlorinated solvent PRPs. Used multiple lines of evidence, including PCE degradation pathways and groundwater modeling. Case settled.

For a dry cleaner in Canada, evaluated carbon isotope data for trichloroethene (TCE) in groundwater to identify different sources of chlorinated solvents contamination downgradient from the dry cleaner.

For a Superfund site in New Hampshire, optimized injection and extraction well locations and flow rates for faster PCE recovery in a pump and treat system. Optimized system reduced total remediation time by 25%. Computer modeling work involved modifying MODFLOW and MT3D to fit the Superfund site-specific characteristics, and linking the modified versions to a USGS optimization code.

Natural Gas

For multiple confidential gas companies, designed and implemented forensic field programs to differentiate native gas from storage gas using composition and isotope analysis. Co-author of reports to FERC and the State’s Conservation Commission.

For a confidential gas company, investigated sources of natural gas bubbling in residential water wells. Concluded that the gas is naturally occurring and is not related to storing natural gas in a formation several thousand feet below ground surface.

Multiple Contaminants

At a contaminated waterway in Louisiana, linked creek sediment contamination to multiple responsible parties in support of remedial cost allocation. Data evaluation included identification of marker chemicals used by different industries located on the creek.

For a major paint manufacturer, used statistical methods (variogram analysis) to show the sufficiency of a soil-sampling program in characterizing a lead-contaminated site.

Hydrogeology and Fate and Transport

For a confidential client in Argentina, designed and modeled a hydraulic barrier system to mitigate offsite contamination transport. Responsibilities included groundwater and solute transport modeling.

For a consulting company in Houston, Texas, developed a proprietary model for NAPL dissolution as part of a Department of Defense contract to develop a decision support system to evaluate effectiveness and cost of source-zone treatment.

For the USEPA, served as technical reviewer for BIOCHLOR and provided technical assistance in using selected EPA groundwater models offered via the Internet.

For the Hazardous Substance Research Center, created a numerical code to simulate NAPL entrapment and dissolution in groundwater.