Pathways of Water Column Exposure to Contaminants via Natural
Processes
- Direct exposure due to resuspension of bottom sediment
- Riverine systems and shallow water environments subject
to storms
- Water column tends to equilibrate with resuspended sediment
- At sufficiently high sediment loads, water column
approaches equilibration with bed
sediment levels
- Analogous to exposure during dredging events
- Indirect exposure due to contaminants moving into the food
chain
- Contact of benthic organisms to contaminated sediment
followed by predation by higher
animals
- Benthic organisms tend to equilibrate with the bed sediment
- Basis for sediment quality criteria
- Direct exposure due to contaminant releast from stable
sediments
- Variety of natural processes result in contaminant
migration to overlying water
- Degree of equilibration of overlying water dependent
upon rate of these processes
- Natural recovery and in-situ remediation requires assessment
and/or intervention to control these
natural pathways.
