HR: 0830h
AN: H51C-1077    [PDF]
TI: Modeling the Relative Contributions of Sediments and Urban Runoff-Borne Particles to PCB (Polychlorinated Biphenyl) Levels in the Water and Foodchain of an Urbanized Waterway (Columbia Slough, Portland, OR, USA)
AU: * Fish, W
EM: fishw@cecs.pdx.edu
AF: Portland State Univ., Dept. of Civ. and Env. Eng. PO Box 751, Portland, OR 97214 United States
AU: Nakae, Y
EM: nakae@pdx.edu
AF: Portland State Univ., Dept. of Civ. and Env. Eng. PO Box 751, Portland, OR 97214 United States
AU: Jan, F
EM: faheem@cecs.pdx.edu
AF: Portland State Univ., Dept. of Civ. and Env. Eng. PO Box 751, Portland, OR 97214 United States
AB: The Columbia Slough is an urbanized waterway in Portland, OR, USA that provides important habitat for a wide range of species and recreational opportunities for humans. Of special concern in the Slough is the potential for human ingestion of fish containing elevated levels of persistent chlorinated compounds, particularly PCBs. Fish tissue analyses and exposure studies suggest the human population ingesting Slough fish may face a relatively high ($>$1:10 000) risk of an excess lifetime cancer fatality. Since only a few localized sources of PCB to the water way have been identified, attention has focused on two sources. The sediments are contaminated with PCB at relatively low levels ($<$30 ug/kg) but sediment inputs may be enhanced by a significant throughput of groundwater. The second potential source is urban runoff containing particles with PCB from historical low-level soil contamination or ongoing atmospheric inputs. We used a combination of field data and dynamic computer modeling to compare the relative contributions of PCB desorption from sediments (as enhanced by advective groundwater motion) and contaminated particulate matter from runoff. Most of the PCB in the trophic levels of the food chain studied can be attributed to input from legacy contamination in the sediments. However, urban runoff does present the potential for inducing a small long-term risk to fish-consumers.
DE: 1806 Chemistry of fresh water
DE: 1845 Limnology
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2003 Fall Meeting