Identification of Non-Target List Analytes in Complex Environmental Samples
Identification of non-target list compounds, including pharmaceuticals and personal care products that enter the environment.
EPA method target lists are limited to several hundred analytes. But a significant fraction of the 2800 high production volume (>10^6 lbs/yr) chemicals) and at least 88,000 chemicals used in commerce, their byproducts, and their transformation products could have toxicological effects on humans and ecosystems. Most of these chemicals are not found in mass spectral libraries and standards can only be made available after they have been identified in environmental samples. Only a small minority of the compounds are identifiable using conventional mass spectrometry. Special mass spectrometric techniques have been developed to aid in the identification. Such identification is needed to obtain standards for quantitative measurement and to begin an assessment of potential health and ecological effects.
Project: Outcomes 1. A higher incidence of childhood cancer in a population believed exposed to municipal well water that contained several unidentified isomers: Identified acrylonitrile:styrene (2:1) adducts, so toxicological tests could be performed. 2. Confirmed for NEIC the source of tar-like contamination at a Superfund site in West Virginia, elemental compositions were determined for 51 compounds: most were benzothiazole derivatives used in rubber and dye industries, confirmed a dye plant as the source. 3. Assisted Region in identifying brominated water disinfection byproducts: dibrominated anabolic steroid found, probably related to cattle feed lot. Compounds were identified in well water extracts from a site near Orlando, Florida: chlorinated compounds associated with pesticide manufacture were found in shallow well samples, while sulfur containing compounds from anaerobic bacterial metabolism predominated in deeper well samples. 4. Well water extracts were collected to confirm successful remediation of a superfund site: dozens of monochloro and dichloro thio- and dithio-phosphates were identified. 5. Study with NEIC of compounds formed by a Mg producing plant in UT: heavily chlorinated PAHs and certain heavily chlorinated nitrogen containing compounds were found. Also with NEIC, a study of identification of unknowns not in MS libraries using MS and IR techniques: identified products of a drug synthesis. 7. Compounds were identified above a pollutant plume that potentially could be used for drinking water during droughts: 42 compounds were identified and 43 compounds were tentatively identified, mostly as halogenated phenols. In FY07 an ion correlation program developed to deconvolute composite mass spectra based on exact masses and relative isotopic abundances and applicable to less expensive time-of-flight (TOF) mass spectrometers will be automated. Applications to HPLC/TOFMS and GC/TOFMS will provide ion compositions for precursor and product ion. The software will be transferable to EPA labs with this type of mass spectrometer.
Andrew Grange at email@example.com