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.

Potential VOC Sources Identified in a PRP Search

Potential VOC Sources Identified in a PRP Search

Example Projects

PRP Search for Regional Chlorinated Solvent Plume

Full Description

Gradient performed a PRP search related to a regional chlorinated solvent plume. We reviewed environmental databases and historical records using automated text analytics to identify potential sources for the alleged contamination of public water supply wells. We analyzed and synthesized historical photographs, aerial images and maps, and information from environmental investigations to understand the evolution of land use and industrial/commercial operations over time.

Hydrocarbon Source PRP Research for Cost Recovery Claim

Full Description

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

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.

PRP Search to Identify PAH Sources

Full Description

Gradient performed a comprehensive historical review from the 1880s through current day to guide site characterization efforts and identify PRPs at a former MGP site and in its vicinity and developed a web-based GIS mapping application to help communicate the results of the analyses to key stakeholders.