Tributary of Houston Ship Channel with contaminated sediments
Project Navigator, Ltd. is the PRP Group Coordinator for the Patrick Bayou Superfund Site in Deer Park, Texas. Patrick Bayou is a shallow, 3-mile-long tributary of the Houston Ship Channel, located in a mixed urban, highly industrialized petrochemical area in Deer Park, Texas. The Site contaminants of potential concern include PCBs, heavy hydrocarbons, VOCs, phthalates, and metals. The Site itself is bordered by industrial facilities.
The RI has been approved, and the FS is being finalized. PNL is also coordinating NRDA negotiations with Federal, State, and local trustees.
The project utilized the Adaptive Management approach to the RI/FS. Site and risk assessments were conducted in a phased approach. The expected remedy involves monitored natural recovery, sediment capping and in-situ treatment. Sediment capping will involve both reactive capping and Articulated Concrete Block Matting (ACBM). In-situ treatment involves placement of activated carbon in sections of the Site.
Technical Milestones
- The site has completed the Remedial Investigation/Feasibility study phase and is working with EPA on development of a Proposed Plan and the administrative path forward for the RD/RA.
- During the RI/FS, the use of Adaptive Management Strategies enhanced project flexibility. In this approach, work is completed and evaluated in a phased and prioritized manner so that the conceptual site models for contaminant sources and distribution, site hydrology, exposure pathways, and risk analyses are continually updated as new information becomes available.
- Initial site activities included development of a Preliminary Site Characterization Report and a bathymetry survey. Sediment sampling, radiometric profiling, sediment flume testing, and additional field investigations were conducted.
- A sediment transport model was used in the FS to support the Alternative Analysis for Monitored Natural Recovery (MNR). The model was a key risk management tool during the FS. The model was used to predict sediment deposition rates across the site and the expected time for MNR to achieve remediation targets.
- An innovated probabilistic risk assessment approach was tested at the site. Sediment sites typically have a high level of uncertainty and this approach aided understanding of the true risk to receptors at the site. Due to the relative new science involved, PNL coordinated training in this methodology for the state agency and Natural Resource Trustees.
- A Remedial Alternative Study was completed prior to the Feasibility Study, to provide initial screening of remedial technologies. This allowed the FS to focus on the most appropriate alternatives.
- The Feasibility Study evaluated MNR and various combinations of MNR and sediment capping as well as in-situ treatment with activated carbon. It is expected that the EPA recommended alternative will combine MNR, capping with Articulated Concrete Block Matting and In-Situ Treatment with Activated Carbon, potentially the first ROD specifying the use of In-Situ Treatment for sediments.
Stakeholder Relations
- PNL coordinates with the EPA, TCEQ, state and federal Natural Resource trustees and the City of Deer Park.