Emissions of Metals, Chromium and Nickel Species, and Organics from MunicipalWastewater Sludge Incinerators. Volume 2. Site 5 Emission Test Report Hexavalent Chromium Method Evaluation

摘要

At Site 5, three candidate sampling methods and two candidate analytical methodsfor hexavalent chromium were assessed. The conversion of hexavalent chromium (Cr (+6)) to other valence states of chromium during sampling and sample storage was of primary concern. Method 5-type samples and impinger train samples were collected by PEI Associates, Inc. Dilution train samples were collected bySouthern Research Institute. Method 5-type train samples were analyzed by Technology Applications, Inc.'s (TAI) staff under contract to EPA's Environmental Monitoring Systems Laboratory (EMSL) in Cincinnati, Ohio. Dilution train samples, Method 5-type samples, and impinger train samples were analyzed by Entropy Environmentalists, Inc. TAI used an ion chromatograph with post column reaction (IC/PCR) and inductively coupled argon plasmography/mass spectrometry (ICP/MS) to analyze the Method 5-type samples. A stable chromium isotope (63CR(+6)) spiked onto the Method 5 filter prior to sample collection was used to assess conversion of Cr(+6). The samples analyzed by Entropy were collected using a dilution train on an 8.5 in X 11 in glass fiber filter, a Method 5-type sampling train on an 82 mm quartz fiber filter, and an impinger sampling train with an alkaline impinger reagent, and spiked with native hexavalent chromium and a radioactively-labeled chromium isotope (51Cr(+6)). The samples were analyzed for hexavalent chromium by IC/PCR and for the radioactive isotopes by scintillation (gamma) counting. EMSL has not released the TAI data. The preliminary method evaluation testing demonstrated that all sampling methods had problems with conversion of hexavalent chromium.