Complex Multi-PRP Sediment Sites
The Problem
Legacy contamination in large urban waterbodies often drive expensive investigation and cleanup. These sites often have numerous (tens to over one hundred) different potentially responsible parties (PRPs) that may be responsible for discharges over many decades. Untangling the contributions from different parties is complex and requires careful statistical analysis using state-of-the-art data analysis methods that use multiple lines of evidence.
The Solution
TIG Environmental is conducting a detailed investigation of chemical data in sediments and upland areas using multivariate forensics analysis, combined with detailed review of historical information. The document review is focused on the various sites, process chemistry, waste handling procedures and spill records, and other lines of evidence. TIG Environmental’s scientists have published a detailed chemical forensic analysis that demonstrates that, in contrast to previous findings suggesting a single dominant PRP, multiple PRPs are significant contributors. The forensic investigation is based on a scaled approach in which multiple lines of evidence ranging from simple analyses of concentration gradients to the multivariate data analysis methods such as principal component analysis (PCA), hierarchical cluster analysis (HCA), statistical unmixing and receptor modeling, are integrated into the analysis.
Value Added
The results are being used to support the client in obtaining a more equitable allocation of investigation, design, and remediation costs. The potential savings to the client could be in the hundreds of millions of dollars.
