--> --> Abstract: Aquifer Heterogeneity, Anthropogenic Effects and a RCRA Facility Investigation Case Study, by K. P. G. Svitana; #90926 (1999)

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SVITANA, KEVIN, P.G. , URS Greiner Woodward Clyde, Columbus, OH 43215

Abstract: Aquifer Heterogeneity, Anthropogenic Effects and a RCRA Facility Investigation Case Study

The importance of understanding anthropogenic effects and aquifer heterogeneity when assessing plume migration is discussed in this paper. The discussions are based on a RCRA Facility Investigation (RFI) completed at a 13-acre solvent recycling center in Central Ohio. The RFI was in response to a waste solvent release that occurred over a decade ago.

The data collected during the RFI indicated a shallow unconfined aquifer with a potentiometric surface sloping towards the northwest. Water sample analyses from monitoring wells indicated the highest concentration of solvents were northeast of the release point; no solvents were down gradient of the release. To understand why contaminants were not migrating in the direction of groundwater flow, additional assessment and investigation of site development history was completed.

Slug and pumping test data suggested that near surface sand layers were not laterally continuous. Slug tests indicated hydraulic conductivity's ranging from 1 x 10-3 to 1 x 10-6 centimeters/second, indicating heterogeneity of the subsurface soils.

The construction contractor who built the facility revealed that undocumented dewatering trenches were dug between foundations, tank cavities and storm sewers. Subsequent investigations conducted in the vicinity of the dewatering trenches revealed soil and groundwater had the highest concentrations of the released solvents. Hydraulic testing indicated that man-made conduits were the primary pathways of migration.

To prevent off site discharge of solvents, corrective measures to control ground water flow were developed that include a cut off wall and sumps, recovery wells, and a dual phase recovery system. Evaluation of the on-going remediation will be presented. 

AAPG Search and Discovery Article #90926©1999 AAPG Eastern Section Meeting, Indianapolis, Indiana