CHEMTURA'S DNAPL BOTTOM LINE

The Elmira site is what is known as a mature site. Dumping into lined/unlined ponds, pits and lagoons ended mostly in the 70's and completely in the 80's. Any residual (ie. pore spaces versus pools) DNAPL whether by normal groundwater flow or even enhanced flow due to pump and treat should have been dissolved long ago. All that is left is free phase DNAPL residing in the subsurface in hopefully only small pools.

As the residual DNAPL dissolves away there will be more wells whose concentrations decrease significantly again with or without pump and treat. Wells downgradient of free phase DNAPL however will not have significantly decreasing concentrations unless they are under the influence of a pump and treat system. In that case the faster groundwater velocity makes for less contact time with the free phase DNAPL and hence lower concentrations. There are other factors however including dilution from greater rainfall ie. higher levels of groundwater. The other issue is "rebound". As soon as pumping stops or decreases back up come the concentrations. Hence when you see concentrations greater than 1% of solubility rising and falling over time, while pumping is underway, then you can conclude that either water volume is increasing/decreasing from rainfall or the pumping rates are rising and falling or both.

This is the story with Chemtura's south-west area of the former operating ponds. The sheer numbers of dissolved chemicals in the groundwater has also greatly reduced the solubility of individual chemicals. Therefore effective solubilities are what count when determining 1% solubility. Our authorities and local chemical company have gotten away with their factually fictional stories for the last quarter century.