Monday, June 5, 2017


Well done Anam Latiff and the Waterloo Region Record. Today's story on the front page of the Local Section is titled "Ministry looks at new options for Northstar site". The description of the planned new remediation methods is clear and straightforward and educational for the public. The focus on the health issues caused by vapour intrusion from Trichloroethylene (TCE) in the groundwater is excellent as this is the primary exposure route causing major health damage and eventual death in some residents of the area.

A couple of additional points need to be made including that Northstar filed for bankruptcy hence I don't believe that any money ended up going to the residents of the Bishop St. community whether for pain and suffering or for their direct health costs. Secondly the neighbouring company also responsible for groundwater pollution was at one point General Electric but it was also known as Borg-Warner and perhaps initially as Rozell.

This second location put both TCE and TCA (1,1,1 Trichloroethane) into the groundwater. My notes from several years back indicate that Northstar was responsible for 3/4 of the TCE in the groundwater whereas Rozell/GE was responsible for all of the TCA.

Another significant point is that both TCE and TCA are DNAPL chemicals. This means that they can gravity flow away from the initial discharge to the ground and slowly sink through the earth until they come to a lower permeabilty zone. Here they can sit literally for decades and longer, very slowly dissolving into the groundwater as it flows by.

The concentrations eight years ago certainly indicated the presence of DNAPL TCA and TCE around the Rozell/GE site. In that case I have to ask exactly where the proposed two new remediation methods are going to take place. If done immediately downgradient of the Northstar site it will reduce but never eliminate the overall TCE plumes and it won't do anything for the TCA plume from Rozell unless it is downgradient of that site. Maps of these proposed strategies, if they haven't already been made availble to the nearby residents, need to be released immediately for their study. Similar to Elmira we have two (or more) sources very close together. It is far too easy to blame one and underestimate the effects of the other(s).

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