Identifying Roadway Pavement in Proximal Soils and Sediments 
Stephen Emsbo-Mattingly, Allen Uhler , Scott Stout, Gregory Douglas, and Kevin McCarthy, NewFields Environmental Forensics Practice, LLC, Rockland, MA

Groundwater Plume Forensics Using Minor Ions
Robert D. Mutch, Jr., P.Hg., P.E., HydroQual, Inc., Mahwah , NJ
Richard F. Carbonaro, Ph.D., Manhattan College , Riverdale , NY

Forensic NAPL Determination and Plume Differentiation – A Case Study
Nathan A. Stevens, CarriageHouse Consulting, Natick , MA
Brian D. Moore, CarriageHouse Consulting, Inc., Natick , MA  
Carrie A. Vinch, Ryder Truck Rental, Inc. – Environmental Services, Lawrenceville , NJ

Identifying Roadway Pavement in Proximal Soils and Sediments 
Stephen Emsbo-Mattingly, Allen Uhler , Scott Stout, Gregory Douglas, and Kevin McCarthy, NewFields Environmental Forensics Practice, LLC, 100 Ledgewood Place, Suite 305, Rockland, MA 02370, Tel: 781-681-5040

Roadways are a significant source of total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs) to proximal drainage systems and sediments.  In some locations, municipalities sprayed tar and petroleum products onto unpaved roads for dust suppression.  In other locations, roadways were covered with pavement consisting of sand and gravel solidified with an organic binder.  The organic binder typically consists of residual tar or petroleum.  Modern roadways are paved and repaired with tar and petroleum products. 

The weathering of roadbeds made from these materials results in the migration of hydrocarbons into proximal residential yards, drainage systems, and sediments.  Case studies will be presented to illustrate the variable composition of pavements in New England .  Comparisons will be drawn between the fingerprint of the PAH and saturated hydrocarbons in roadway pavement, surface soils, and proximal sediments.  These comparisons help associate TPH and PAH concentrations with neighboring roadway drainage systems.

Groundwater Plume Forensics Using Minor Ions 
Robert D. Mutch, Jr., P.Hg., P.E., HydroQual, Inc., 1200 MacArthur Blvd. , Mahwah , NJ 07430 Tel: 201-529-5151, Fax: 201-529-5728, Email: rmutch@hydroqual.com
Richard F. Carbonaro, Ph.D., Manhattan College , Manhattan College Parkway , Riverdale , NY Tel: 718-860-7469, Email: richard.carbonaro@manhattan.edu

Increasingly groundwater professionals are being called upon to determine the source of plumes of groundwater contamination or to apportion the contributions of multiple sources to a plume. While, the principal contaminants in these plumes are commonly volatile organic compounds or heavy metals, often the sources can be more defin it ively identified through analysis of other trace const it uents in the plumes. The minor ions, bromide and iodide, can be particularly diagnostic in some cases because they behave conservatively as they move through the aquifer (Panno, 2006).  These halides are rarely analyzed for in groundwater qual it y investigations and are typically present in very low concentrations in natural waters. Neutron activation analysis usually affords low enough detection limits to quantify the concentration of these minor ions. 

Cross-plots of I/Na versus Br, or Cl/Br versus Cl can often distinguish the source of contaminants from landfills, septic systems, animal wastes, and road salting. Two case studies will be presented. In one case, use of these minor ions enabled differentiation of landfill leachate-related groundwater contamination from septic system-related contamination and, thereby, identified the source of accompanying volatile organic contamination. In the second case, these minor ions were able to pos it ively identify the intrusion of landfill leachate into a deeper aquifer in sp it e of complex hydrogeologic cond it ions and overlapping plumes of contamination.

 

Forensic NAPL Determination and Plume Differentiation – A Case Study
Nathan A. Stevens, CarriageHouse Consulting, Inc., 74 West Central Street , Natick , MA 01760 USA , Tel: 978-733-1806,  Fax: 508-720-0629,  Email: nstevens@carriagehouseinfo.com
Brian D. Moore, CarriageHouse Consulting, Inc., 74 West Central Street , Natick , MA 01760 USA , Tel: 508-315 3146,  Fax: 508-720-0629,  Email: bmoore@carriagehouseinfo.com
Carrie A. Vinch, Ryder Truck Rental, Inc. – Environmental Services, 160 Lawrenceville-Pennington Road, Suite 16, PMB 119, Lawrenceville, NJ 08648 USA  Tel: 609-631-8584  Email: CVinch@Ryder.com

Recent developments in laboratory analytical techniques, when combined with application of multivariate statistical analyses allow differentiation and delineation of comingled NAPLs and resultant contaminant plumes.  The increase in laboratory expertise and a growing body of relevant studies in case literature have made possible evaluation of petroleum impacted media through relatively standard techniques a reality, and well within the realm of economical site assessments.  The application of several methods to determine the number, type, and timing of multiple NAPL releases at a commercial facility in an urban setting will be summarized.  The combination of chemical, historical, and statistical techniques has allowed for a more complete evaluation of NAPL sources and release histories than was initially thought possible.  In the examined case, overlapping NAPL plumes are defined, delineated, and identified; areas of dissolved-phase impact are associated with NAPL sources; the demobilization, retention, and re-mobilization of NAPL sources are evaluated; and source identification for individual releases are completed.  These evaluations resulted in identification of previously unconfirmed sources, improved characterization of the nature of NAPL present, and refined fate, transport, and feasability evaluations from the conceptual site model.