Comments on measuring PCBs released from springs

February 27, 2002

Mr. Alcamo:

I wanted to express some concern for a recent submittal from your contractor Tetra Tech EM, Inc., that uses data from another contractor, Earth Tech to calculate PCB releases from Neal's Landfill one of the Bloomington Project's Superfund sites. I specifically refer to the report dated February 13, 2001 titled Estimate of Polvchlorinated Biphenvl Mass Discharged to Conard's Branch Neal's Landfill. Monroe County. Imliana. A copy of the first page is attached. The approach used in this calculation is not justified by the nature of the data and can only produce erroneous and misleading results.

The calculation attempts to estimate PCB transported from the site by spring water based on flow alone. An assumption is made that PCB concentrations are linearly correlated with water flow, and that PCB concentrations are relatively constant. This is incorrect. PCBs are released from the site despite the consolidation and capping to a quite different extent and form over a range of flow conditions. Greater attention to the details of the relation of PCB content to suspended solids levels, variable concentrations in the water, and the change of PCB concentrations over the flow events. Frequently there appears to be a "flushing" phenomenon of elevated PCB levels early in an increased flow regime that does not persist over the flow event. Further, there is little evidence that one flow event is representative of all flow events.

I have attached some data from a Lemon Lane Landfill spring to show the nonlinear nature. Simply by being able to generate a straight line that passes through a "cloud" of data points, does not justify assuming a linear x-y response. This is particularly true if it is clear that the supposed "dependent" variable is clearly changing over time, or if the correlation coefficient, such as R2, does not show a significant correlation. A more correct "integration" or summation of "non-formula" related data can be done by summing areas of quadrangles under the curve. A consultant should be able to provide this. Accurate data are needed to design a treatment facility, or to assess environmental impact. Accurate data comes from correctly designed experiments and accurate analyses.

Let me point out first that it is this poor data that may be at fault for the "surprising" performance failure of the granular activated carbon (GAC) units at the Water Treatment Facility at Illinois Central Spring noted in the December 2001 report. Inaccurate loading of loading of filter presses, tanks, and GAC will cause premature, surprising overloads and interrupts. It is so much easier to go into a project having expended the necessary investigation finds at the proper time, rather than to have to reengineer later. Having to add new tanks and components to a system that was supposed to handle 25 year storm events, yet which cannot manage base flow treatment needs without discharging untreated water, as is occurring, indicates a poor understanding of the problem and a poor management of public resources.

Sincerely,

Joseph G. Hailer
Environmental Geochemistry & Quality Assurance
650 Dittemore Road
Bloomington, IN 47404