Gradient

Potentially Responsible Party (PRP) Search

Overview
Example Projects

Overview

Gradient routinely researches and identifies potential sources of contamination and potentially responsible parties (PRPs).  Our work, which includes site-specific research as well as the evaluation of industry practices, is done in the context of litigation (e.g., CERCLA cost recovery) and legacy site characterization and remediation efforts.  The broad scope of our research has included, for example, identifying Civil War era sources of PAHs in sediments; metals and PCB release sites in urban watersheds; and VOC sources impacting a regional groundwater plume.  We have experience mining environmental databases and historical records, customizing searches based on project-specific factors, and using text analytics software to optimize search results so that pertinent information can be efficiently indexed and extracted from documents.  Gradient scientists also have expertise using Geographic Information Systems (GIS) and data management software to analyze historical aerial and satellite imagery, and forensic techniques to identify and differentiate contaminant sources.  Gradient's clients can be confident that our expert analysis and innovative solutions are supported by extensive research and reliable, accurate information.

PRP Search intersecting highway contamination

Example Projects

PRP Search for Regional Chlorinated Solvent Plume

Full Description

To assist with litigation related to a regional chlorinated solvent plume, Gradient performed a PRP search. We reviewed environmental databases and collections of historical records to identify potential sources for the alleged contamination of public water supply wells. We obtained, analyzed, and synthesized historical photographs, aerial images, maps, and other information from environmental investigation reports to understand the evolution of land use and industrial/commercial operations over time.

Hydrocarbon Source PRP Research for Cost Recovery Claim

Full Description

Gradient researched and identified possible sources of hydrocarbons encountered during site redevelopment activities. Using a combination of aerial imagery, historical records, environmental reports and datasets, and chemical fingerprinting techniques, we identified at least 20 potential sources of the hydrocarbons that had been previously attributed to a single assumed source. We used a web based GIS mapping platform to present our research to stakeholders.

Chemical Source Identification in an Urban Watershed

Full Description

For a product liability case involving the presence of chemicals in coastal water bodies and sediment, Gradient identified PRPs within an urban watershed by identifying permitted discharges and upland sites with historical operations that resulted in discharges. Gradient applied knowledge of the fate and transport pathways of the chemicals from their points of use to the surface water and sediment beds along with historical sampling from the watershed to understand how the PRPs could have contributed chemicals to the surface water bodies.