Limiting Liability & Maximizing Clarity at PAH-Impacted Sediment Sites
Authored by: Deborah A. Chiavelli, PhD
Polycyclic aromatic hydrocarbons (PAHs) are persistent compounds commonly found at sediment sites that can be toxic at elevated concentrations, particularly in urban waterways affected by historical and ongoing industrial activity. Their widespread presence and potential for human and ecological harm make them a potential driver of remedial actions under both Federal Superfund and state programs.
Sediments typically contain PAHs from multiple sources, including petroleum releases, manufactured gas plant operations, creosote and coal residuals, and stormwater runoff containing fuel and combustion-related PAHs (often referred to as urban background). This complex mixture complicates efforts to apportion liability among contributors, delineate the extent of contamination from any given source, and determine appropriate remedial actions. While common remedial approaches such as capping and dredging are effective in many cases, they are also expensive, protracted, and can disrupt surrounding communities and ecosystems.
Key Challenges at PAH-Contaminated Sediment Sites
- Source Commingling and Over-Remediation: Without refined forensic analysis, multiple overlapping source contributions can make site delineation difficult and put increased cleanup burdens on individual responsible parties.
- Site-Specific Risk Mischaracterization: Default toxicity assumptions may overestimate risk by failing to account for differences in PAH bioavailability, aging, and site-specific sediment chemistry that limit actual exposure.
- Ongoing Urban Inputs and Recontamination: Present-day discharges from stormwater or nonpoint sources may result in recontamination that challenges the long-term effectiveness of remedial actions.
- Natural Resources Damage Claims: Trustees may apply generic models or screening benchmarks to estimate injuries and damages, which can result in overstated claims not supported by site-specific conditions or defensible science.
How can Roux help?
Roux delivers technical and strategic expertise for clients facing complex sediment site challenges, including PAH source identification, risk evaluation, and liability apportionment. Our services include:
- Forensic PAH Source Apportionment: We use state of the practice hydrocarbon forensic analytical techniques and historical research to identify and distinguish between PAH sources and support equitable responsibility allocation.
- Site-Specific PAH Risk Assessment and Bioavailability Analysis: We develop site-specific toxicity evaluations based on chemical aging, sediment characteristics, and exposure potential to avoid over quantification of risk.
- Litigation and Regulatory Strategy Support: We assist in technical negotiations and offer expert support during allocation proceedings, enforcement actions, and Natural Resource Damages claims.
Roux’s integrated approach combines environmental forensics, sediment science, and strategic advisory services to help clients limit unnecessary liability and pursue defensible cleanup outcomes. Contact our team below to learn how we can assist with your site-specific challenges.
