BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Memento EPFL//
BEGIN:VEVENT
SUMMARY:Laboratory and Field Evaluation of Amendment for In-situ Stabiliza
 tion of Organic Pollutants in Sediments
DTSTART:20090928T161500
DTSTAMP:20260406T153427Z
UID:e52d93d09779a5402e819fde139e97b9bcd44d318469ae498e65a9f4
CATEGORIES:Conferences - Seminars
DESCRIPTION:Professor Richard G. Luthy\nStudies 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 a
 dding highly-sorbent black carbonaceous material to the biologically-activ
 e sediment layer may stabilize PCBs and PAHs and reduce exposure and risk.
  Laboratory tests with activated carbon-amended sediments showed as much a
 s 95% reduction in PCB bioaccumulation by clams and worms and more than 99
 % reduction in aqueous PCBs depending on dose and sediment composition.  \
 nWe recently completed a three-year field experiment at an inter-tidal mud
 flat in San Francisco Bay to sequester PCBs in sediment through addition o
 f 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\, limite
 d contact between AC and sediment under field conditions slows mass transf
 er and the stabilization of PCBs. Still\, the sequestration potential of A
 C 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 P
 CB contaminant sources are eliminated and freshly deposited sediments are 
 clean\, in-situ AC amendment of contaminated sediments may provide a suita
 ble method for reducing exposure to the water column and biota where the s
 ource of the contaminant is from within the sediment.\nAs time permits\, I
  will mention briefly other research: PFCs and protein binding\; and multi
 -university initiatives on re-inventing urban water infrastructure and imp
 roving water management in the American West.
LOCATION:GR B3 30
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR