The measurement of freely-dissolved chemicals (Cfree) is a powerful approach for improving the assessment and management of sediment sites.
This presentation will present an overview of a pilot scale demonstration of innovative approaches to measure freely-dissolved PCBs in the Choccolocco Creek portion of the Anniston PCB Site (Alabama, USA). Freely-dissolved PCBs were measured using a custom-modified approach using commercially available polyethylene passive samplers (SP3s). PCBs absorbed by the SP3s were quantified using an innovative approach measuring PCB homologues and Aroclors (instead of PCB congeners), and sampling kinetics were tracked using seven isotopically-labeled PCB congener Performance Reference Compounds (PRCs) added to each SP3 prior to deployment. SP3 were deployed for 35 days at two locations representing different hydrodynamic conditions (high-energy, low-energy) in Choccolocco Creek. At the high-energy location, SP3s were deployed in surface water, within the rocky substrate, and at the substrate-water interface using SCUBA divers. At the low-energy location, SP3 were deployed in surface water, within the soft sediment substrate, and the substrate-water interface using a push-pole device that allowed deployment of the SP3s from a vessel without the aid of divers. A sample of sediment was also collected and used for an ex situ Cfree measurement via agitation with an SP3 for 35 days. PRC results indicated that the deployment time period was sufficient for absorption of PCB analytes in situ. Measurement of PCBs via the homologue method indicated a detection frequency of 66%, and Cfree detection limits (0.1 pg/L on average) were similar to Cfree approaches that rely on the measurement of individual PCB congeners. In contrast, the Aroclor method was less sensitive. Only 25% of the Aroclor results yielded detectable values for the SP3s, and sum of the Cfree Aroclors for the samples (non-detect to 20 ng/L) was less than that of the sum of the Cfree homologues (3 to 48 ng/L). Overall, the pilot scale evaluation was successful and indicated that the approach for PCB homologues provides sensitive and versatile measurement capabilities for Cfree PCBs.
- Geosyntec Authors: Alice Wang
- All Authors: Alice Wang
- Title: The Society of Environmental Toxicology and Chemistry (SETAC) North America 41st Annual Meeting
- Event or Publication: Event
- Practice Areas: Per- and Polyfluoroalkyl Substances (PFAS)
- Citation: Jason Conder, Ph.D., (California), Jennifer Arblaster (Vermont), and Alice Wang, Ph.D., (Massachusetts) will present at the Society of Environmental Toxicology and Chemistry (SETAC) North America 41st Annual Meeting at 8:00-12:00 PM CST on November 15, 2020.
- Date: November 15, 2020
- Location: Virtual
- Publication Type: Platform Presentation