THE DNAPL PLOT SLOWLY THICKENS

I have been continuing my data search for DNAPL chemicals while currently focusing on Mercaptobenzothiazole (MBT). I am also focusing on the former operating ponds namely RPW 5, 6, 7 & 8 which are on Chemtura's south-west corner. I have checked through the monthly Progress Reports from 2007 to December 2013 and the pickings have been slim. While Jeff Merriman of Chemtura advised myself, CPAC and the public that Chemtura were publishing DNAPL concentrations from the Upper Aquifer pumping wells each month; it turns out that what he meant was slightly different. First of all there are four Base/Nuetral Extractable DNAPL chemicals involved from a grand total of two of the nine pumping wells and the time frame is all of 2013 (12 results) and only eight months of 2012. The previous four years have exactly zero MBT results published however each January Progress Report (except 2011) has the results of Aniline and Benzothiazole (BT) for the Upper Aquifer pumping wells.

January 2007 has a much more extensive listing of DNAPL chemicals in both the pumping wells as well as a few of the operating pond monitoring wells. While the results are mostly from 2006 sampling there are four results for MBT in January 2007. All of these results I am incorporating into one Table covering 1990 through until the end of 2013. The very early 90's results come from a Morrison-Beatty DNAPL Report and the mid 90's until 2004 are from Conestoga Rovers October 2005 DNAPL Status Report. I will be doing the same for other DNAPL chemicals besides MBT. I will also be checking through the Annual Monitoring Reports to see what if anything I can find there for DNAPL results. In the past I've been very disappointed due to their focus on only three contaminant groundwater results namely Ammonia, NDMA and Chlorobenzene.

The results to date for but one DNAPL chemical are conclusive. The MBT results for two pumping wells (U+500 & U+560) have shown decreases since pumping started in 1997 but quite frankly they are not impressive. They are still well above the 1% solubility screening. Other monitoring wells also show decreases albeit again modest ones. A big problem is data gaps and that is due to Chemtura/CRA sucessful lobbying of the Ministry of the Environment. The persistence of MBT concentrations well above 1% solubility over a ten to twenty year time period, in multiple wells, speaks volumes as to the presence of free phase DNAPL beneath the operating ponds. The M.O.E. identified it in the November 1991 Control Order and all the wishful thinking and bogus DNAPL Investigations since have not removed it.