CHEMTURA'S SCHEMATIC CONCEPTUAL HYDROGEOLOGIC MODEL - THICKER & DEEPER YOU KNOW WHAT?

So what is a Schematic Conceptual Hydrogeologic Model? It is a map or representative picture of the subsurface of a fairly large area of ground. It is a larger version of what is known as a Cross-Section or a Hydrogeological Section of a specific area in which the depths of overburden (soil, gravel, silts and clays) as well as of the Bedrock are clearly shown as if one had cut down through the surface to a depth for example of 40-50 metres and then stood at the face of the excavation and drawn a picture of the various layers down to the 40-50 metre depth. With a Cross-Section the sub-surface layers and their depths are determined from specific depth measurements in boreholes or wells that have been drilled.

Chemtura's consultants have been producing and updating their Conceptual Hydrogeologic Model for many years. It is a good approximation of the stratigraphy of the subsurface from Chemtura Canada in the north to the former south wellfield (E7/E9) in the south end of Elmira. It clearly shows the three main and recognized aquifers known as the Upper Aquifer (shallow) as well as the Municipal Upper and Municipal Lower Aquifers (drinking water aquifers). These aquifers are all coloured blue (appropriately) while the Surficial Aquitard (SAT), Upper Aquitard (UAT) and the Municpal Aquitard (MAT) are a sort of brown colour. These Aquitards are of course lower permeability units which retard or delay the downwards migration (under gravity) of water through their smaller pore spaces. Oddly the Bedrock (Aquifer) is coloured green albeit it is shown as a cross-hatch pattern which could accurately indicate that it is a Fractured Bedrock Aquifer (FBA). Also oddly while former Conceptual Hydrogeologic Models (2005, 2007, 2012, 2014) referred to it as the Bedrock Aquifer the most recent (2016) simply refers to it as Bedrock.

Either a skeptic or a person knowledgable in the wiles of Chemtura and their consultants might believe that this is an intentional deflection/omission of the facts so as not to draw attention to an issue somewhat subtly raised by Dr. Dick Jackson at the RAC meeting last Thursday evening. Dr. Jackson was referring to the F-bomb ie. Fractures in the till or aquitards. These fractures both horizantal and vertical through either denser silts or through clay would allow much faster contaminant migration to depth even through what Uniroyal Chemical and the Ontario M.O.E. long ago liked to refer to as impenetrable clay aquitards. Guess how many of those impenetrable aquitards actually exist beneth Chemtura Canada? Between fractures and multiple windows through the aquitards the answer is ZERO. Alan Deal of GHD did confirm that fractures exist both at the 5-10 metre depth (UAT) and even much deeper in the Municipal Aquitard (approx. 16-30 metres depth). Whether they also exist in the Lower Aquitard (LAT) while likely is also moot due to the number of "windows" through this aquitard both on and off the Chemtura site.

The result is that the Bedrock Aquifer is contaminated at a minimum with NDMA and Ammonia. These two contaminants are admitted by Chemtura and their consultants. To date they have not admitted to Chlorobenzene contamination in the Bedrock aquifer which I find strange. Afterall Chlorobenzene will migrate vertically very fast as a DNAPL chemical as its'density is greater than that of water. It also will migrate vertically in the dissolved phase exactly as NDMA, Ammonia and lots of other chemical contaminants and solvents. Very strange.

There are no pumping wells with their wellscreens into the Bedrock Aquifer. Yes there are three with their wellscreens into the Municipal Lower Aquifer (ML) situated above the Bedrock Aquifer. Even if the aquitard between the Municipal Lower Aquifer and the Bedrock Aquifer (BR) is thin or absent it is still miles beyond wishful thinking to seriously believe that those pumping wells could hydraulically contain the entire Bedrock Aquifer to depth. They very well may capture some of the groundwater in the higher or surface fractures of the BR but that's it. This may well be the issue which Dr. Jackson subtly was implying to Alan Deal (CRA/GHD) last Thursday.

There are many more problems and errors in CRA/GHDs Conceptual Hydrogeologic Model. For example they have given short shrift to both the presence of various aquifers on the east side of their site as well as to "windows" through the aquitards as well as areas where the aquitards thin dramatically. Yes Chemtura have very self-serving reasons for these "errors" and they are in regards to their lack of shallow hydraulic containment and eastwards flow of contaminants onto their neighbour's property.