Abstract: Remedial Investigation Field Techniques Applied in Fractured Carbonate Terrain, Upstate New York

S. R. Choiniere, V. Bryant, G. W. Cross

Roughly 30,000 gallons of trichloroethylene were spilled in a 1970 derailment in LeRoy, NY. Spilled TCE rapidly penetrated the thin overburden and reached a highly fractured and locally dissolved bedrock aquifer. Migration through the aquifer has been extraordinarily fast, creating a contaminant plume that now extends nearly four miles. Investigation of this plume involved use of geophysical techniques, some of which are not widely employed in the environmental field. Ground penetrating radar helped resolve the importance of "pop-up" structures exposed on the otherwise nearly flat-lying bedrock surface. Gamma logging helped define stratigraphy of a 200-foot section reaching from the Onondaga to the Syracuse Formations, allowing the use of expensive bedrock coring to be mi imized. Caliper and video logging identified zones of jointing and bedding plane dissolution. Combined with real-time analytical screening, the geophysical results guided the placement of wells and depths of well screens in 55 borings in a five-square-mile area.

AAPG Search and Discovery Article #90954©1995 AAPG Eastern Section, Schenectady, New York