Laboratory and Field Evaluation of Amendment for In-situ Stabilization of Organic Pollutants in Sediments
Event details
| Date | 28.09.2009 |
| Hour | 16:15 |
| Speaker | Professor Richard G. Luthy |
| Location |
GR B3 30
|
| Category | Conferences - Seminars |
Studies with field sediments show that the presence of black carbon particles diminishes the bioavailability of hydrophobic organic compounds like PCBs and PAHs. This suggests that adding highly-sorbent black carbonaceous material to the biologically-active sediment layer may stabilize PCBs and PAHs and reduce exposure and risk. Laboratory tests with activated carbon-amended sediments showed as much as 95% reduction in PCB bioaccumulation by clams and worms and more than 99% reduction in aqueous PCBs depending on dose and sediment composition.
We recently completed a three-year field experiment at an inter-tidal mudflat in San Francisco Bay to sequester PCBs in sediment through addition of activated carbon (AC). We found that PCB bioaccumulation in marine clams and PCB release to water were reduced for sediment treated with 2% to 3% AC. In comparison to laboratory studies with well-mixed sediment, limited contact between AC and sediment under field conditions slows mass transfer and the stabilization of PCBs. Still, the sequestration potential of AC was evident during the entire project period. The study revealed several field-related factors that can confound the results of in-situ bioassays. Slow PCB mass transfer under field conditions calls for predictive models to assess long-term trends in PCB-pore water concentrations. If ongoing PCB contaminant sources are eliminated and freshly deposited sediments are clean, in-situ AC amendment of contaminated sediments may provide a suitable method for reducing exposure to the water column and biota where the source of the contaminant is from within the sediment.
As time permits, I will mention briefly other research: PFCs and protein binding; and multi-university initiatives on re-inventing urban water infrastructure and improving water management in the American West.
We recently completed a three-year field experiment at an inter-tidal mudflat in San Francisco Bay to sequester PCBs in sediment through addition of activated carbon (AC). We found that PCB bioaccumulation in marine clams and PCB release to water were reduced for sediment treated with 2% to 3% AC. In comparison to laboratory studies with well-mixed sediment, limited contact between AC and sediment under field conditions slows mass transfer and the stabilization of PCBs. Still, the sequestration potential of AC was evident during the entire project period. The study revealed several field-related factors that can confound the results of in-situ bioassays. Slow PCB mass transfer under field conditions calls for predictive models to assess long-term trends in PCB-pore water concentrations. If ongoing PCB contaminant sources are eliminated and freshly deposited sediments are clean, in-situ AC amendment of contaminated sediments may provide a suitable method for reducing exposure to the water column and biota where the source of the contaminant is from within the sediment.
As time permits, I will mention briefly other research: PFCs and protein binding; and multi-university initiatives on re-inventing urban water infrastructure and improving water management in the American West.
Practical information
- General public
- Free
Contact
- Barbara Tinguely