Three types of thin-layer caps with activated carbon (AC) were tested in situ in experimental plots (10 × 10 m) in Trondheim harbor, Norway, using AC + clay, AC-only or AC + sand. One year after capping, intact sediment cores were collected from the amended plots for ex situ surveys of the capping efficiency in reducing the PAH and PCB aqueous concentrations and bioaccumulation by the polychaete Hediste diversicolor and the clam Abra nitida. Reduced pore water concentrations were observed in all AC treatments.
View Article and Find Full Text PDFMeth ods involving polyoxymethylene (POM) as a passive sampler are increasing in popularity to assess contaminant freely dissolved porewater concentrations in soils and sediments. These methods require contaminant-specific POM-water partition coefficients, KPOM . Certain methods for determining KPOM perform reproducibly (within 0.
View Article and Find Full Text PDFActivated carbon (AC) amendment to polluted sediment or soil is an emerging in situ treatment technique that reduces freely dissolved porewater concentrations and subsequently reduces the ecological and human health risk of hydrophobic organic compounds (HOCs). An important question is the capacity of the amended AC after prolonged exposure in the field. To address this issue, sorption of freshly spiked and native HOCs to AC aged under natural field conditions and fresh AC amendments was compared for one soil and two sediments.
View Article and Find Full Text PDFIn situ amendment of contaminated sediments using activated carbon (AC) is a recent remediation technique, where the strong sorption of contaminants to added AC reduces their release from sediments and uptake into organisms. The current study describes a marine underwater field pilot study in Trondheim harbor, Norway, in which powdered AC alone or in combination with sand or clay was tested as a thin-layer capping material for polycyclic aromatic hydrocarbon (PAH)-contaminated sediment. Several novel elements were included, such as measuring PAH fluxes, no active mixing of AC into the sediment, and the testing of new manners of placing a thin AC cap on sediment, such as AC+clay and AC+sand combinations.
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