First page Back Continue Last page Overview Graphics

Graph of PCB Concentrations for BX-6 Fill (Post-construction)

Notes:

To get an idea of how often these changes occur, the NOAA panelists suggested we develop some frequency plots, and these plots essentially show for the very center of this change, how often a given concentration would occur over our modeled period. And an easy thing to look at is, under the zero scale, that is the maximum concentration we saw in the model period. Here is the water quality objective for PCB's in the Bay, this is the no project condition -- we call it the existing here -- and you can see that under current conditions, the Bay exceeds these water quality objectives and the maximum concentration we predicted was around nine parts per trillion. And with the project addition immediately following construction, we predict the concentrations in the middle, the worse part of this plume, would increase by about a factor of 2. And these concentrations would be predicted to decrease over time, or the change would be predicted to decrease as the Bay readjusts. As I have shown on the last slide, there are several parameters that the Bay currently exceeds. One of the things that we wanted to focus on for our analysis are perimeters that are not currently exceeded, or the areas