The answer to the question to Dr. John Cherry and Dr. Beth Parker (U. of Waterloo at the time) as to whether DNAPL should be left in place or removed from the Uniroyal Chemical (Chemtura) site was very clear. This question was posed to them by Susan Bryant, Pat McLean, Wilf Ruland (hydro G) and myself in January 2007. To the apparent horror and shock of the other three, the answer from both Profs was absolutely free phase DNAPL that is accessible should be removed in order to shorten by decades the cleanup time of the aquifers it is impacting. The return trip to Elmira by the four of us was very quiet and solemn. Only in hindsight did I realize that the intended purpose of the trip was to get the single holdout (myself) to reverse my position that the DNAPL should be removed sooner than later.
Now seventeen years later I am in the middle of reading a Master's degree thesis regarding DNAPLs and Natural Attenuation. This thesis has as usual been reviewed by many of the author's peers including Drs. Parker and Cherry! I personally have had a very dim view of Natural Attenuation over the decades from information provided to myself and other citizens that claimed that among other issues chlorinated solvents (DNAPLS) were highly resistant to bacteria/microbial breakdown in the subsurface. If you think about it chlorine in and of itself is an antibiotic used specifically to kill bacteria in drinking water hence it made sense that it would not succumb readily to bacterial breakdown itself.
This thesis is looking at TCE specific breakdown by both biotic and abiotic breakdown meaning by biological breakdown including bacteria and abiotic or chemical breakdown in the subsurface. This research and studies have been underway for years by a combined group from the University of Waterloo and the University of Guelph.
No comments:
Post a Comment