FREE PHASE DNAPL vs. RESIDUAL DNAPL - LAST NIGHT"S CPAC DELEGATION

Today's posting is only going to cover one aspect of last night's Chemtura Public Advisory Committee. That would be my Delegation to CPAC in which I presented a couple of pages with illustrations of subsurface DNAPL. Dense Non Aqueous Phase Liquids have a density greater than one (hence they sink through groundwater), form a separate phase from water in the subsurface and only very slowly dissolve, sometimes over decades or even centuries. The two pages and illustrations came from a 2003 report written by Drs. John Cherry, Beth Parker and two other colleagues from the University of Waterloo. They clearly show how subsurface DNAPL weathers over time. It starts as trails (or tails) of residual DNAPL which follow pools of subsurface DNAPL known as free phase. These free phase pools can be only one or two pools sitting on a lower permeabilty surface such as a clay aquitard or they can be multiple pools dispersed downwards throughout the aquifer with tails of residual DNAPL connecting them. Over time moving groundwater slowly dissolves both residual and free phase however the residual being a much smaller quantity and with more surface area exposed and surrounded by groundwater, dissolves more quickly. Hence as the text and figures illustrate over time the residual trails (tails) disappear entirely leaving only the pools of free phase DNAPL behind.

The significance of this on the Chemtura (Uniroyal) site in Elmira, Ontario is huge. All parties back in 1993 agreed to a set of written DNAPL Principles which clearly state that free phase DNAPL when found must be removed. This only makes sense if the Chemtura site is ever going to be removed as a threat to the Elmira Aquifers. Chemtura's consultants since then have jumped through hoops and loops and contorted themselves and reality beyond belief in their attempt to show only residual DNAPL on their site versus free phase. To date our esteemed Ministry of the Environment have carefully kept themselves out of this argument with only occasional lapses. Their hydrogeologist in 2006 suggested in writing that free phase DNAPL from the Chemtura site has flowed off-site onto a neighbour's property, where of course it has grossly contaminated their groundwater.

More on the rest of the meeting tomorrow.