Tuesday, August 9, 2011

GROUNDWATER MONITORING VERSUS SOIL SAMPLING

There is considerably more wiggle room when working with concentrations of dissolved chemicals in groundwater versus chemical concentrations in soil. Groundwater is constantly flowing, albeit slowly, but nevertheless it is possible to have a source of contaminants literally hundreds of yards away or more from a monitoring well with dissolved chemicals in it. With a soil sample however, what you get is indicative of the level of contamination in the soil, right there. Certainly over time precipitation can aid in dissolving and diluting soil contamination. Various consultants like to brag about "natural attenuation". This also includes microbial and bacterial breakdown of chemical contaminants. Possible but oh so slow. If you know the direction of groundwater flow you can also determine, especially via shallow wells whether a groundwater monitoring well is picking up nearby contamination or not. For example if the well is downgradient from a service station and it has high levels of toluene and xylenes then you are picking up evidence of leaking fuel tanks immediately upgradient.

In Elmira I would estimate that we the public have been given literally 1,000 groundwater results for evry soil sample. I am including Chemtura, Yara and the two Varnicolor sites. It is my expectation that many more soil samples have been taken but simply not shared with John Q. Public and for a very good (bad) reason. The soil samples would immediately identify source areas of contamination. The last few years I've become aware of multiple soil samples contaminated with NDMA and Chlorobenzene existing not only at shallow depths but even 100 feet below the surface. It is much more difficult to fudge and hide your source areas with soil testing than with groundwater testing, which is precisely why here in Elmira we have so little published soil testing.

The smaller companies pollution existed for decades in the shadow of the big fish in town namely Uniroyal/Chemtura. After the drinking wells were finally shut down the government made a sweetheart deal with Uniroyal for them to take all the blame.

No comments:

Post a Comment