Fox River/Green Bay
Lower 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
Overview (updated 2006.  Links to data, graphs, etc.,)

Mass Balance Concepts

Return to Kevin Fermanich's UWGB Home Page

Excel Spreadsheet click here  (2004)

The above Figure 2 is from the Green Bay/ Fox River Mass Balance Study. Link to Preliminary Management Summary. 
Link to Modeling Approach Figure 1 at the EPA site.

The following text is excerpted from the GB/Fox River Mass Balance Study:

"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."

A conceptual view of the food chain bioaccumulation model is shown in Figure 3.
The food chain model is depicted in more detail in Figure 4.