Special Bd. of Aldermen — 10/26/15 Page 4
Mr. Millan-Ramos Yes, that one is probably better to look at. But the two lagoons, lagoon #1 which is the one
| am pointing to here, and lagoon #2 are right next to each other. So area 1, the open lagoon and area 2 the
closed lagoon right here. The plan as conceived right now is to basically contain all that waste that is already
in there, by building a containment structure or wall around it. We have three different technologies and we are
leaning to what is commonly called a secant wall, just to contain the waste in there and add the solid
contamination that is in satellite areas that you see here highlighted in beige as well.
One possibility that has been envisioned is to also add on top of that lagoon once it is contained, the waste
from the Fimbel Door landfill which you see here and the asbestos that is in the property owned by the city
would be dug into a cell adjacent to this site in here. So again the general idea or approach here is to basically
consolidate all this waste in this area by building that secant wall first up to the soil level and then on top of ita
containment wall that would hold the additional waste and then have it capped with an impermeable cap.
This figure here that Melissa is holding and before | go to that picture | just want to make sure the members of
the public here see this. This is what | was referring to. The two lagoons right here and satellite areas of
contamination and the Fimbel Door Landfill, all would be consolidated in this area. The southern parcel was
largely unused and the idea is for it to remain as open green space after the whole clean-up is done. So with
that | think we can move to the other figure.
Here is basically a cross-section of the area if you were to split the area in half and see it from the side, this
would be the river, this would be the neighborhood. It is a fairly steep grade, not as steep as shown in this
schematic, but still steep. The idea, as | said, is to contain the waste here with a secant wall, which is what
you see in purple and have the retaining wall would hold additional contamination on top of it and it would be
capped with an impermeable cap. Pretty much like you see here.
Ms. Taylor The only thing that this doesn’t really show is that the cap will go behind this wall. It is not going to
just be a wall that is holding the waste behind it. The cap is going to encapsulate all this material and then the
retaining wall is kind of like a belt and suspenders kind of thing. Same with the secant wall, that material is
staying where it is right now we just want to make sure nothing is going to happen to it at any point in the future
so we are kind of putting something extra on there.
Mr. Millan-Ramos Kelsey can you do me a favor and move in that direction so that the people here have an
opportunity to see. So the second cross-section of it, in purple, the secant wall in blue it would be that
retaining wall that would hold the additional contamination and it would be capped with an impermeable cap
and right next to it there would be a cell containing the asbestos from the other property. And it is just a
schematic to show a general depiction of what the remedy would be.
Moving on, | wanted to show you list of what we call contaminants of concern. This list is in order of toxicity
from the most toxic substance at the top to the last toxic substance at the bottom. The bulk of the
contamination is in those two former lagoons, areas 1 and 2. And basically some metal contamination in the
satellite areas that | showed you in the previous figure.
Ms. Taylor And even though that goes from the most toxic | guess you would say to the least toxic, it doesn’t
actually mean that this is the majority of the actual material that is in there. The majority of the material | think
is actually contaminated with what chromium, chromium and probably arsenic but we also think that a
component of the arsenic might be attributed to background.
Mr. Millan-Ramos Yes, correct.
Ms. Taylor Which is naturally occurring, I’m sorry, | am using scientific terms, | apologize.
