PARENT SESSION
MA9- Contaminant Mass Budgets in Urbanized Estuaries
Chair: Baker, Joel¹, ¹ PO Box 38, 1 Williams Street, Solomons, MD, USA
8:00 AM to 12:00 PM - Monday, 18 November 2002
Room Ballroom E

(247) A spatially-explicit model of hydrophobic organic contaminants in Baltimore Harbor, Chesapeake Bay.

Chang, Chihwei^*,1, Sanford, Lawrence², Baker, Joel¹, ¹ University of Maryland Center for Environmental Science, Solomons, MD, USA² University of Maryland Center for Environmental Science, Cambridge, MD, USA

ABSTRACT- Many numerical models have been used to simulate the fate and transfer of hydrophobic organic contaminants (HOCs) in natural waters. One important consideration in contaminant modeling is the partitioning between dissolved HOCs and organic carbon. Recent studies and field measurements indicate that partition coefficients (K_d) vary tremendously temporally and spatially and are impacted by many factors. In this modeling study, we allowed K_d values to varying dynamically in response to mass transfer-limited sorption kinetics rather than holding them constant. Baltimore Harbor is a seriously contaminated urban tributary subestuary of the Chesapeake Bay. To simulate HOC transport in Baltimore Harbor, we divided the harbor area into 24 regions. Each region has its own nutrient, light, and temperature regime, and particle erosion and sinking rates. Adjacent regions are linked by advection of particles and dissolved components. Two scenarios have been evaluated with this model to project the long term HOC mass budgets in the Baltimore Harbor, including external loading of HOCs into the water and release from the sediments. The results show that HOCs tend to accumulate in the western part of harbor, in agreement with observations. This model will assist in the development of Total Maximum Daily Loads for the Baltimore Harbor.

Key words: HOCs, box model, partition coefficient