Citation:

ACREE, S. D., R. G. FORD, AND R. R. ROSS. IMPACTS OF DRILLING ADDITIVES ON DATA OBTAINED FROM HYDROGEOLOGIC CHARACTERIZATION WELLS AT LOS ALAMOS NATIONAL LABORATORY. Presented at Northern New Mexico Citizens' Action Board, Santa Fe, NM, November 30, 2005.

Impact/Purpose:

To inform the public.

Description:

Personnel at the EPA Ground Water and Ecosystems Restoration Division (GWERD) were requested by EPA Region 6 to evaluate the impacts of well drilling practices at the Los Alamos National Laboratory (LANL). The focus of this review involved analysis of the impacts of bentonite- and organic polymer-based additives used during the drilling of regional aquifer wells installed to characterize the hydrogeologic setting. The posed questions centered on the capability of existing wells to provide representative ground-water samples for all site-related contaminants. Following review of well installation records and water chemistry data provided by LANL, it was concluded that intrusion of bentonite and organic-based drilling additives into the aquifer adjacent to well screens posed a potential problem for monitoring the transport of reactive contaminants of concern. For organic-based additives, the primary impact could be attributed to microbial degradation of the drilling fluid components leading to alteration of aquifer mineralogy via iron- and sulfate-reduction. In general, both drilling additives introduce new reactive solid phases within the screened interval that may retard contaminant transport relative to un-impacted zones that the screened interval is intended to sample. Recommendations were made regarding determination of the extent of impacts. Notice: This is an abstract of a proposed presentation and does not necessarily reflect EPA

Record Details: