ALL OTHER THINGS BEING EQUAL : ECONOMICS & HYDROGEOLGY

As in economics, hydrogeology cause and effect is difficult to determine sometimes due to confounding factors. Recently I have been examining concentrations of DNAPL chemicals over time in Chemtura's former operating pond area (south-west). The trends are literally all over the place as the following examples will show.

Shallow Aquifer Pumping Well U+500 Mercaptobenzothiazole (MBT) was 11,000 ppb in 2000 and 12,000 ppb in 2001. Last month (Jan. 2014) the concentration was 14,000 ppb.

Pumping well U+560 MBT was 10,000 ppb in 2001, 4,700 ppb in 2002, 4,350 in 2012 and finally 7,700 ppb in Jan. 2014.

Monitoring well OW74-6 had MBT at 3000 ppb in 1991, 5,900 ppb in 1994, 44,000 ppb in 2000, 8,700 ppb in 2004 and finally 9,700 ppb in 2006.

These wells have all been under the influence of hydraulic containment of the shallow aquifer since 1997. There are indeed many wells in the south-west operating ponds whose concentrations have significantly decreased while others go up and down over many years. Both carboxin and chlorobenzene also are in wells in the operating ponds which have not shown expected decreases due to either dissolution over time or the pump and treat "remediation". I expect that an honest examination by unbiased professionals could most probably determine precisely which wells have nearby sources of free phase DNAPL versus those whose concentrations show a decreasing trend due to the complete dissolution of nearby residual DNAPL. To date we the public have had no such unbiased and honest examination.