Fox River/Green Bay
Fox River Contaminated Sediments Site at the Wis DNR
Fox R, Discharge Data
Fact Sheet from USGS: The
Fox River PCB Transport Study...
Lake Michigan Mass Balance
(updated 2006. Links to data, graphs, etc.,)
http://www.epa.gov/grtlakes/lmmb/mbc.html, Mass Balance Concepts
Return to Kevin
Fermanich's UWGB Home Page
||Fox River Exercise:
Excel Spreadsheet click
The above Figure 2 is from the Green
Bay/ Fox River Mass Balance Study. http://www.epa.gov/grtlakes/gbmb/Greenba1.htm, Link
to Preliminary Management Summary.
The following text is excerpted from the GB/Fox River Mass Balance
"Figure 2 shows the interactions occurring between air and water, water and sediment, and the food chain. The model, in essence, links the sources of the
contaminant to the mass in water, sediment, and biota in space and time. Therefore the model, once calibrated and deemed valid, can be used to compute future
concentrations under any altered load condition.
PCBs enter the Green Bay system from the atmosphere, and from tributaries, primarily the Fox River. There exists a reservoir of
PCBs in bottom sediments which may re-suspend with sediments during storm events, and then desorb and become available to
the food chain. PCBs are lost from the system through volatilization to the atmosphere, burial to deep sediment, and possible
transport to Lake Michigan.
The computer model program keeps track of the mass of PCBs in space and time. It is called a "mass balance model" because the
principal thermodynamic law of conservation of mass is maintained at all times. Thus, if mass is lost from one physical, chemical,
or biological component of the model it must be gained in another."