MIDDLETON WELLFIELD IN CAMBRIDGE

Today we are going to look at one of the jewels in the Region of Waterloo's drinking water system. I indicated last year that the Middleton wellfield had to be the most expensive water produced throughout the tri cities and Townships. Two Annual Reports ago (2013) there was a $16 million upgrade using Advanced Oxidation Process (AOP) in order to reduce industrial contamination. Last year's Annual Report (2014) indicated an additional $200,000 in maintenance and upgrades to some of the wells and the same thing again has occurred in this year's Report (2015). Keep in mind these expenditures especially the $16 Million are to remove Trichloroethylene (TCE) an industrial cleaner and degreaser from the public's drinking water. And still yet the Region and City of Cambridge resist telling us who the culprits are. The most readily apparent are Canadian General Tower (CGT) next door with a hint of a former local drycleaner also being a possibility.

This "jewel" of a wellfield provides approximately 45% of Cambridge's drinking water. There is some good news despite a very long history of significant industrial contamination with a toxic chemical (TCE). The Region are doing at least two things to mitigate TCE contamination. They are spending literally millions of dollars to reduce the concentrations and keep them below the current Ontario Drinking Water Standard of 5 parts per billion (ppb). Keep in mind the drinking standard in Ontario was much higher a couple of decades ago however today there are U.S. jurisdictions with standards in the 3 ppb. range. The second thing the Region are doing is diluting this water. A decade ago well G15 which is located south of the Middleton wellfield was considered a separate water source. For the last many years it has been pumped into the Middleton reservoir either for convenience or for dilution. Hence the concentrations in treated water from the Middleton Wellfield last year were between 1.2 and 1.9 ppb. .

Frankly I had expected that the AOP system would have done better. The conclusion I am coming to is that the raw water from these wells prior to treatment may have rising TCE concentrations. This isn't likely due to an ongoing dissolved source of TCE but far more likely due to TCE as DNAPL. DNAPL or Dense Non-Aqueous Phase Liquid is essentially pure, undissolved TCE also known as free phase TCE, either stationery or slowly moving downhill under gravity. DNAPL can literally take decades to centuries to fully dissolve into groundwater. Either the TCE is dissolving faster than it was or it has flowed closer towards the pumping wells intake screens. This would occur as I mentioned under the influence of gravity as the free phase TCE moves downwards through the fractured bedrock aquifer closer to the intake screens of the five Middleton wells.

Good news would be the reduction in raw water bacteria levels. 2015 had zero E.Coli results and only 21 Total Coliform. This is an improvement. Turbidity and Chlorine levels are also better than they've been over the prior couple of years. Sodium unfortunately is still much too high at 141 mg/litre. Results greater than 20 mg/l are reported to the health department and M.O.E. every five years.

There are other inherent problems in the Region's Annual (drinking water) Reports but for me the most disappointing and potentially serious are the everchanging Method Detection Limits (MDLs). There is only one direction these should be going and that is downwards. In other words through scientific improvements in labratory testing we have and should continue to be able to test for and detect contaminants at lower and lower concentrations. Someone please explain to me why the reverse is happening with numerous contaminants in the Region of Waterloo's Annual Reports. The most striking example of this is Glyphosate otherwise known as "Roundup". This herbicide apparently is becoming ubiquitous in our groundwater due to its' use both in agriculture and residentially. A decade ago its' MDL was 10 ppb.. For the last many years the Region has been reporting Glyphosate concentrations as less than 25 ppb. (ie. < 25 ug/l). That is outrageous!

Indeed there are some contaminants whose MDLs have been reduced but there are yet others such as some chlorophenols with rising MDLs over the last several years. The most obvious interpretation of rising MDLs is simply that the reporting authority are attempting to hide increases in contaminants in our drinking water supply. As stated there are enough inherent problems with these reports already. Further deflection of water problems is not in the public interest but only serves the agenda of polluting industries and their political mouthpieces.