Long Term Monitoring of Activated Carbon Amendment to Reduce Bioavailability of Polychlorinated Biphenyls (PCBs) in Sediments at an Active Shipyard
Abstract
Activated carbon (AC)-based amendments have been demonstrated widely in recent years as an effective, and relatively non-disruptive means of sequestering sediment associated with hydrophobic organic contaminants (HOC), such as polychlorinated biphenyls (PCBs). In 2012, under an earlier project (ESTCP no. ER-201131), an AC amendment (AquaGate+PAC tm) was placed at a half-acre plot adjacent to and underneath Pier 7 at the Puget Sound Naval Shipyard and Intermediated Maintenance Facility (PSNS and IMF) to reduce PCB availability. This study site was unique to other AC amendment demonstrations by being at a high-energy hydrodynamic environment at an active military harbor. Post-placement monitoring conducted over a 3-year period showed a persistent 80-90% reduction in available PCBs when compared with those made prior to placement. Benthic invertebrate census and sediment profile imagery (SPI) did not indicate significant differences in benthic community ecological metrics among the pre-amendment and 3 post-amendment monitoring events, supporting existing scientific literature that the approximate activated carbon dosage level (4%, by weight addition of AC (particle diameter 74 mm) in the uppermost 10 cm of surface sediment) does not significantly impair native benthic invertebrate communities. The results reported herein are from a follow-on monitoring effort, conducted in 2019 (~7 years post placement), to help answer ongoing questions about the longevity of AC remedies. This report should be considered an addendum to the larger project ER-201131 report (Kirtay et al. 2017), where more detail can be found on various components including amendment placement, earlier monitoring results, and costs and implementation of the technology.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2023
- Accession Number
- AD1210201
Entities
People
- Alice Wang
- Bart Chadwick
- Gunther Rosen
- Jason Conder
- Jay Word
- Jennifer Arblaster
- Joel Guerrero
- Meg Jalalizadeh
- Molly Colvin
- Nicholas Hayman
Organizations
- Naval Information Warfare Center Pacific