A remedial investigation/feasibility study has been undertaken at Oak Ridge National Laboratory (ORNL). Bechtel National, Inc. and partners CH2M Hill, Ogden Environmental and Energy Services, and PEER Consultants are contracted to Lockheed Martin Energy Systems, performing this work for ORNL`s Environmental Restoration (ER) Program. An on-site Close Support Laboratory (CSL) established at the ER Field Operations Facility has evolved into a laboratory where quality analytical screening results can be provided rapidly (e.g., within 24 hours of sampling). CSL capabilities include three basic areas: radiochemistry, chromatography, and wet chemistry. Radiochemical analyses include gamma spectroscopy, tritium and carbon-14 screens using liquid scintillation analysis, and gross alpha and beta counting. Cerenkov counting and crown-ether-based separation are the two rapid methods used for radiostrontium determination in water samples. By extending count times where appropriate, method detection limits can match those achieved by off-site contract laboratories. Volatile organic compounds are detected by means of gas chromatography using either headspace or purge and trap sample introduction (based on EPA 601/602). Ionic content of water samples is determined using ion chromatography and alkalinity measurement. Ion chromatography is used to quantify both anions (based on EPA 300) and cations. Wet chemistry procedures performed at the CSL include alkalinity, …