CONCLUSIONS - doerc160014

ERDC TN-DOER-C16

July 2000

CONCLUSIONS: A leachate screening protocol is being developed that considers the entire

leachate pathway from the dredged material (source) through the CDF, foundation (vadose zone),

and the saturated zone to the receptors. The protocol is based on the theoretical considerations

presented in this technical note. The approach taken consists of three steps:

1) Evaluate the source strength for its potential to generate pore water with unacceptable levels

of contaminants and identify the contaminants of concern (those that may pose a leachate

problem) based on equilibrium partitioning between the dredged material solids and the pore

water. Screening values for unacceptable concentrations would be based on the receptors.

2) Evaluate the attenuation by adsorption/retardation of contaminants of concern in the CDF

and vadose zone and determine which contaminants may pose a leachate problem beyond

the vadose zone. For screening, relationships among the controlling factors in the CDF and

vadose zone and the attenuation of leachate concentration will be developed using the

HELPQ model.

3) Evaluate the diffusion (dilution) of the remaining contaminants of concern in the saturated

zone between the CDF and the receptor. For screening, relationships among the controlling

factors in the saturated zone and the attenuation of leachate concentration will be developed

using the MEPAS model and the GMS.

POINTS OF CONTACT: For additional information, contact the author, Dr. Paul R. Schroeder,

(601-634-3709, schroep@wes.army.mil) or the Program Manager of the Dredging Operations and

Environmental Research Program, Dr. Robert M. Engler, (601-634-3624, englerr@wes.army.mil).

This technical note should be cited as follows:

Schroeder, P. R. (2000). "Leachate screening considerations," DOER Technical Notes

Collection (ERDC TN-DOER-C16), U.S. Army Engineer Research and Development

Center, Vicksburg, MS. www.wes.army.mil/el/dots/doer

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