New directions in RCRA ground-water monitoring regulations

Abstract

ABSTRACT EPA soon expects to issue a Notice of Proposed Rulrakiking (NPRM) in the Federal Register concerning amendments to the ground-water nunitaring requirements Ear land-based hazardous waste treatment, storage, and disposal facilities (TSDFs) that are regulated under Subtitle C of the Resource Conservation and Recovery Act (RCRA)- TfcRi.-notice will propose amendments to the list of ground-water monitoring constituents for TSDFs, Appendix IX to Title 40, Code of Federal Regulations, Fart 264, (“Appendix IX”), and require that certain procedures be used in the design, installation, and operation of ground-water monitoring systems at TSDFs. The proposed changes to Appendix IX include the addition of a required list of detection monitoringj analytes (Appendix IX-A), the deletion or addition of several Appendix IX compounds due to analytical considerations, and a site-specific variance from the annual Appendix DC analysis requirement during compliance monitoring. The proposed standards for ground-water monitoring procedures will, be specified in revisions to Chapter Eleven of the U.S. EPA document SW-846, “Test Methods for Evaluating Solid Waste, Physical/Chemical Methods,” (Third Edition), or more generally referred to as “Chapter Eleven of SW-846.” Chapter Eleven of SW-846 specifies requirements concerning the characterization of site hydrogeology, placement of detection monitoring wells, monitoring well design and construction, and ground-water sampling and analysis programs. All hydrogeologic investigations and monitoring activities must comply with the methods and procedures required in Chapter Eleven of SW-846. The proposed requirements in Chapter Eleven of SW-846 represent EPA's establishment of qualitative:-, data quality objectives (DQOs) for the RCRA ground-water monitoring program. At the same time, EPA's Environmental Monitoring Systems Laboratory in Las Vegas, Nevada (EMSL-LV) is in the process of evaluating the efficacy of establishing quantitative DQOs for ground-water monitoring system performance. If appropriate, quantitative DQOs would allow EPA to determine the minmum number and location of monitoring wells required to achieve a specified probability of leak detection. This paper will summarize some of the methods that have been investigated to establish quantitative DQOs for RCRA ground-water monitoring.