Ecosystems Research Division

Biographical Information

Name: John Washington
Title: Research Chemist

Contact Information:

phone (office & labs):
706 355 8227

fax:
706 355 8202

email:
washington.john@epa.gov

mail:
United States Environmental Protection Agency
National Exposure Research Laboratory
Ecosystems Research Division
960 College Station Road
Athens, GA 30605-2700

Education:

Expertise:

Generally geochemistry, soil chemistry, applied physical chemistry and transport through porous-media. Particular experience in perfluorinated compounds analyses, nitrogen chemistry, redox controls and characterization in natural systems, volatile organic compounds, elemental mobility, and natural radiochemistry.Analytically, LC/MS/MS, GC/MS, variety of other GC detectors, IC, and various spectrometric, fluorescent and phosphorescent methods.

Recent & Current Research:

Synthetic Fluorochemical Compounds:

Since the 1950s, fluorotelomers and fluorotelomer-based polymer products (FBPPs) have been commercially produced and applied to consumer products to impart anti-wetting and anti-staining properties. Treating carpeting, upholstery, clothing, fast-food containers and cookware among other products, today fluorotelomers and FBPPs are ubiquitously distributed in modern societies world-wide.

In the early 2000s, pioneering research confirmed the wide distribution on the global scale of perfluorinated octanoic sulfonate (PFOS) and perfluorinated carboxylic acids (PFCAs), including perfluorinated octanoic acid (PFOA), in ecosystems, biota and humans. Specific sources of these perfluorinated compounds in the environment remain uncertain, but hypotheses that have yet to be evaluated include releases from manufacturing and waste sites, leaching of residual perfluorinated chemicals (PFCs) from FBPPs, and breakdown of FBPPs themselves.

Given the intensive use of FBPPs in the consumer products of modern societies, and this documentation of the widespread occurrence of PFCAs in environmental and biologic materials, the USEPA is keenly interested in better defining the sources and distribution of PFCs in the environment. Analysis of these compounds at very low concentrations in complex environmental media presents daunting analytical challenges that we are addressing with advanced analytical equipment including LC/MS/MS (Waters Acquity UPLC/Quattro Premier XE MS/MS and Varian 230 HPLC/1200L MS/MS) and GC/MS (Agilent 6890N GC/5975 Inert MSD EI/CI).

Controls on, and Forms of, Nitrogen in the Environment:

Denitrification in Oxic Environments: we are conducting a series of lab experiments in which we have established that nitrate can be reduced in the presence of dissolved oxygen under conditions that are environmentally relevant. Since sources of excess nitrate generally are at or near the land surface, and recharge from precipitation is saturated with atmospheric concentrations of oxygen, whether denitrification takes place in the presence of oxygen is an important factor controlling its environmental fate. We are in the final stages of a series of experiments designed to quantify nitrate reduction rate as a function of oxygen concentration.

Forms of Nitrogen in Subsurface Waters: there are multiple species of nitrogen, e.g., nitrate, nitrite, nitrous oxide, ammonium, urea, organic nitrogen, and bio-availability varies between species. Lidia Samarkina of ERD, Athens, and I have quantified nitrogen speciation is several subsurface settings and are modeling redox controls on this speciation. This work is published in Geochimica et Cosmochimica Acta.

Controls on Denitrification in Wetland Settings: Serving as an Adjunct Assistant Professor of Geology in the Department of Geology at the University of Georgia, I am collaborating with doctoral student Kathy Schroer and Professor Valentine Nzengung. With fellow ERD scientists Caroline Stevens, BT Thomas and we are monitoring changes in nitrogen speciation in the field, and performing tracer studies to elucidate controls on nitrogen speciation at the wetland scale.

Controls on Nitrogen Speciation in Agricultural Steams and Ponds: working with Earl Hayter of ERD, Athens, we are monitoring nitrogen concentrations and speciation in an agricultural stream and farm pond to elucidate controls in these settings. Our work so far suggests that farm ponds can play a major role in reducing excess agricultural nitrogen.

Controls on Redox State in Environmental Systems:

Working with USDA/ARS (Campbell Center in Watkinsville, GA) researchers Dinku Endale and Steven Norris, we monitored an agricultural spring for two years and sampled several other locations, and analyzed these samples for about twenty redox-sensitive solutes to develop our understanding of how best to characterize oxidation state and modes of control on oxidation state using extensive thermodynamic and kinetic modeling. Because nitrogen has several oxidation states, this work is highly relevant to our understanding of its environmental fate. This work is published in Geochimica et Cosmochimica Acta.

Selected Publications:

Washington, J.W., W.M. Henderson, J.J. Ellington, T.M. Jenkins, J.J. Evans. 2008. Analysis of Perfluorinated Carboxylic Acids in Soils II: Optimization of Chromatography and Extraction. Journal of Chromatography A. accepted.

Washington, J.W., J.J. Ellington, T.M. Jenkins, J.J. Evans. 2007. Analysis of Perfluorinated Carboxylic Acids in Soils: Detection & Quantitation Issues at Low Concentrations. Journal of Chromatography A. 1154. 111-120

Henderson, W.M., E.J. Weber, S.E. Duirk, J.W. Washington, M.A. Smith. 2006. Quantification of Fluorotelomer-Based Chemicals in Mammalian Matrices by Monitoring Perfluoroalkyl Chain Fragments with GC/MS. Journal of Chromatography B. 846. 155-161.

Washington, J.W., R.M. Thomas, D.M. Endale, K.L. Schroer, L.P. Samarkina. 2006. Groundwater N Speciation and Redox Control on Organic N Mineralization. Geochimica et Cosmochimica Acta. 70. 3533-3548.

Washington, J.W., D.M. Endale, L.P. Samarkina, K.E. Chappell. 2004. Kinetic Control of Oxidation State at Thermodynamically Buffered Potentials in Subsurface Waters. Geochimica et Cosmochimica Acta. 68. 23. 4831-4842.

Garcia-Luque, E., J.M. Forja, A. Gomez-Parra, J.W. Washington. 2004. Nutrient Reactivity in Guadal Quivir Estuary ( SW Spain ) using Simulation Techniques. in Modeling Nutrient Loads and Response in River and Estuarine Systems. a NATO/CCMS pilot study.

Washington, J.W., L.P. Samarkina. 2004. Control of [NO3-] Flowing from Aquifers to Surface-Water Bodies by Fe2+ in Humid, Subtropical Climates. in Modeling Nutrient Loads and Response in River and Estuarine Systems. a NATO/CCMS pilot study.

Washington, J.W., B.A. Cameron. 2001. Evaluating Degradation Rates of Chlorinated Organics in the Environment Using Analytical Models. Environmental Toxicology and Chemistry. 20. 1909-1915.

Washington, J.W. 2000. The Possible Role of Volcanic Aquifers in Prebiologic Genesis of Organic Compounds and RNA. Origins of Life and Evolution of the Biosphere. 30. 53-79.

Greeman, D.A., A.W. Rose, J.W. Washington, R.R. Dobos, E.J. Ciolkosz. 1999. Geochemistry of Radium in Soils of the Eastern United States. Applied Geochemistry. 14. 365-385.

Washington, J.W. 1996. Gas Partitioning of Dissolved Volatile Organic Compounds: Principles, Temperature Effects and Literature Review. Ground Water. 34. 709-718.

Washington, J.W. 1995. Hydrolysis Rates of Dissolved Volatile Organic Compounds: Principles, Temperature Effects and Literature Review. Ground Water. 33. 415-424.

Washington, J.W., A.W. Rose, E.J. Ciolkosz, R.R. Dobos. 1994. Gaseous Diffusion and Permeability in Four Soil Profiles in Central Pennsylvania. Soil Science. 157. 65-76.

Washington, J.W., A.W. Rose. 1992. Temporal Variability of Radon Concentration in the Interstitial Gas of Soils in Pennsylvania. Journal of Geophys. Research. 97. B6. 9145-9159.

Washington, J.W., A.W. Rose. 1990. Regional and Temporal Relations of Radon in Soil Gas to Soil Temperature and Moisture. Geophysical Research Letters. 17. 829-832.