Mixed waste landfill corrective measures study final report Sandia National Laboratories, Albuquerque, New Mexico.

Abstract

The Mixed Waste Landfill occupies 2.6 acres in the north-central portion of Technical Area 3 at Sandia National Laboratories, Albuquerque, New Mexico. The landfill accepted low-level radioactive and mixed waste from March 1959 to December 1988 This report represents the Corrective Measures Study that has been conducted for the Mixed Waste Landfill. The purpose of the study was to identify, develop, and evaluate corrective measures alternatives and recommend the corrective measure(s) to be taken at the site. Based upon detailed evaluation and risk assessment using guidance provided by the U.S. Environmental Protection Agency and the New Mexico Environment Department, the U.S. Department of Energy and Sandia National Laboratories recommend that a vegetative soil cover be deployed as the preferred corrective measure for the Mixed Waste Landfill.The cover would be of sufficient thickness to store precipitation, minimize infiltration and deep percolation, support a healthy vegetative community, and perform with minimal maintenance by emulating the natural analogue ecosystem. There would be no intrusive remedial activities at the site and therefore no potential for exposure to the waste. This alternative poses minimal risk to site workers implementing institutional controls associated with long-term environmental monitoring as well as routine maintenance and surveillance of the site. This final report represents the CMS that has been conducted for the MWL at SNL/NM. The purpose of the CMS was to identify, develop, and evaluate corrective measures alternatives and recommend the corrective measure(s) to be taken at the MWL. The DOE and SNL/NM implemented a streamlined approach to remedy selection. The CMS establishes corrective action objectives for the MWL that are designed to protect human health and the environment and identifies corrective measures alternatives that will achieve the corrective action objectives.In establishing corrective measures objectives and alternatives for the CMS, it was assumed that institutional controls (ICs) would be maintained at the MWL for the next 100 years. ICs are implicit in all proposed alternatives and include environmental monitoring, site surveillance and AL/3-04/WP/SNL04:r5485.doc 840857.04.04 03/04/04 2:34 PM 14 maintenance, and access controls. Corrective action objectives are based upon occupational (site worker), public health, and environmental exposure criteria; U.S. Environmental Protection Agency (EPA) guidance; and applicable state and federal regulations. Corrective action objectives developed for the MWL are designed to protect human health and the environment and take into consideration source areas, pathways, and receptors. The corrective action objectives developed for the MWL consist of the following: 1) minimize exposure to site workers, the public, and wildlife; 2) limit migration of contaminants to groundwater such that regulatory limits are not exceeded; 3) minimize biological intrusion into buried waste and any resulting release and redistribution ...