In-situ treatment of PCBs in sediments
PCBs are among the most persistent and bioaccumulative substances and lead to the majority of fish consumption advisories nationwide. Lack of in-situ treatment ability has resulted in the need to dredge hotspots, as in the upper Hudson River among other coastal, inland, and riverine locations.
The technique being investigated works by the corrosion of colloidal (~50 nm diameter) Fe0, which reduces and dechlorinates PCBs. Successful treatment of PCBs in sediments has been demonstrated in the laboratory; further work is continuing to parameterize this process to determine its feasibility in the field.
Scanning electron micrograph showing colloidal Fe0; the scale in the lower right indicates the diameter of each particle is on the order of 50 nm.
This scanning electron micrograph shows colloidal Fe0 (bright spots) deposited onto a silica sand media. Depositing Fe0 onto a sand support prior to mixing into sediments is one possible introduction method.
Dr. Kevin Gardner
Center for Contaminated Sediments Research
336 Environmental Technology Building
University of New Hampshire
Durham, NH 03824
(603) 862-4334 [phone]
(603) 862-3957 [fax]