Importance of DOC in sediments for contaminant transport modelling

Contaminants in the interstitial waters are not only dissolved but also ass ociated with a filterable colloidal phase such as DOG. The DOC plays an imp ortant role regulating the distribution of chemicals between particulate an d dissolved phases since it binds chemicals and makes them unavailable for vertical diffusive exchange. A three-phase partitioning model that consists of free-dissolved, DOG-bound, particulate-bound components of the chemical s involved is used for the contaminant transport model in order to include the effect of DOC on the partition coefficient. The contaminant model is li nked to WASP modeling framework to predict remobilization of PCBs in sedime nts and the fate and transport of the contaminant in overlying waters of th e New Bedford Harbor where the harbor has been contaminated with PCBs and h eavy metals released from electronic capacitor manufacturers. Simulation of remedial controls indicates that if no action is taken, PCB concentrations will continue tb be at elevated levels. Several scenarios for the removal of contaminated sediments have been performed to reduce the elevated PCB co ncentrations to background levels. (C) 1998 Published by Elsevier Science L td on behalf of the IAWQ. All rights reserved.