EarthVision Model Supports Environmental Assessment of PCBs

Modeling demonstrates everincreasing relevance for environmental scientists as advances in computing technologies and interdisciplinary studies help stimulate the growth of this dynamic field. Collaborative efforts between Battelle's Environmental Restoration and Coastal Resource and Environmental Management and Safety groups established a framework for strategically compiling and synthesizing large quantities of geological and chemical data to help address pressing questions faced by environmental managers. This synthesis has been essential for projects that extend over numerous years and thousands of samples.

Photo above of New Bedford Harbor, MA. Site Chemistry Nature and Extent of PCBs.

At the New Bedford Harbor Superfund Site in Massachusetts, Battelle's EarthVision software helped describe the nature and extent of polychlorinated biphenyls (PCBs) in the harbor sediments. In one series of site rotations, this software visually and quantitatively represented more than 10 years of data and 4000 sediment samples measured for PCBs. Moreover, EarthVision can calculate the cumulative volume of material within the project boundary, based on site-specific criteria, as well as calculate volumes bounded within contaminant isoconcentration shells in three-dimensional space, thus enabling researchers to calculate contaminant mass at the site.

This is no small task for a remediation project that focuses on four location-specific cleanup goals: 1 ppm total PCBs for beaches adjacent to residential areas, 10 ppm for sediments inhabited by organisms that humans might eat, 25 ppm for marsh areas subject to human beach combing, and 50 ppm for less accessible salt marsh and outer harbor areas. Dredging logistics vary for different environments, but based on estimates of dredging volume, engineers can more accurately prepare their remediation design plans for each area. In the New Bedford situation, site engineers were also able to evaluate logistical aspects of the remediation and determine that lithology could be used in the lower harbor. However, EarthVision also revealed that PCBs frequently penetrated below the organic sediments in the upper harbor where deeper dredge cuts would be required.

Quantitative models of environmental sites offer additional benefits to environmental forensic investigators. For example, the mass of sediments that require remediation can be further divided by PCB type or other compositional feature. The use of chemical fingerprinting extends the value of EarthVision models by enabling them to calculate the mass of sediment containing Aroclor 1254 and 1242 in New Bedford Harbor. Thereafter, remediation costs can be allocated on a mass or volume basis. In similar fashion, sources of petroleum, tar, pesticides, and other materials of environmental concern can be visualized and quantified for site-specific purposes. The Battelle toolbox, including advanced chemistry, geology, and EarthVision, provides state-of-the-art methods for visualizing and quantifying environmental data.

For additional information, contact Mr. Steven Emsbo-Mattingly at (781) 952-5246, emsbo-mattinglys@battelle.org or Mr. Jim Hicks at (614) 424-3958, hicksj@battelle.org.