Wood Treater Sites
Overview
Valence state: The combining capacity of an atom or radical determined by the number of electrons that it will lose, add, or share when it reacts with other atoms.
Source: The American Heritage™ Dictionary of the English Language, Fourth Edition
Copyright © 2000 by Houghton Mifflin Company.
free product: A NAPL found in the subsurface in sufficient quantity that it can be partially recovered by pumping or gravity drain.
aerobic: Direct aerobic metabolism involves microbial reactions that require oxygen to go forward. The bacteria uses a carbon substrate as the electron donor and oxygen as the electron acceptor. Degradation of contaminants that are susceptible to aerobic degradation but not anaerobic often ceases in the vicinity of the source zone because of oxygen depletion. This can sometimes be reversed by adding oxygen in the form of air (air sparging, bioventing), ozone, or slow oxygen release compound (e.g., ORC(r)).
Aerobic dechlorination may also occur via cometabolism where the dechlorination is incidental to the metabolic activities of the organisms. In this case, contaminants are degraded by microbial enzymes that are metabolizing other organic substrates. Cometabolic dechlorination does not appear to produce energy for the organism. At pilot- or full-scale treatment, cometabolic and direct dechlorination may be indistinguishable, and both processes may contribute to contaminant removal. For aerobic cometabolism to occur there must be sufficient oxygen and a suitable substrate which allows the microbe to produce the appropriate enzyme. These conditions may be present naturally but often in the presence of a source area oxygen and a substrate such as methane or propane will need to be introduced.
Adapted from US. EPA 2006 Engineering Issue: In Situ and Ex Situ Biodegradation Technologies for Remediation of Contaminated Sites
anaerobic: Direct anaerobic metabolism involves microbial reactions occurring in the absence of oxygen and encompasses many processes, including fermentation, methanogenesis, reductive dechlorination, sulfate-reducing activities, and denitrification. Depending on the contaminant of concern, a subset of these activities may be cultivated. In anaerobic metabolism, nitrate, sulfate, carbon dioxide, oxidized metals, or organic compounds may replace oxygen as the electron acceptor.
Anaerobic dechlorination also may occur via cometabolism where the dechlorination is incidental to the metabolic activities of the organisms. In this case, contaminants are degraded by microbial enzymes that are metabolizing other organic substrates. Cometabolic dechlorination does not appear to produce energy for the organism. At pilot- or full-scale treatment, cometabolic and direct dechlorination may be indistinguishable, and both processes may contribute to contaminant removal.
Quoted from US. EPA 2006 Engineering Issue: In Situ and Ex Situ Biodegradation Technologies for Remediation of Contaminated Sites
architecture: "Architecture" refers to the physical distribution of the contaminant in the subsurface. Residuals that take the form of long thin ganglia or small dispersed globules provide a larger surface area that will dissolve much faster than if the same amount of liquid were concentrated in a competent pool.
Sources: For purposes of this discussion, a DNAPL source zone includes the zone that encompasses the entire subsurface volume in which DNAPL is present either at residual saturation or as "pools" of accumulation above confining units. In addition, the DNAPL source zone includes regions that have come into contact with DNAPL that may be storing contaminant mass as a result of diffusion of DNAPL into the soil or rock matrix.
source zone: For purposes of this discussion, a DNAPL source zone includes the zone that encompasses the entire subsurface volume in which DNAPL is present either at residual saturation or as "pools" of accumulation above confining units. In addition, the DNAPL source zone includes regions that have come into contact with DNAPL that may be storing contaminant mass as a result of diffusion of DNAPL into the soil or rock matrix.
focal ulceration: The process or fact of a localized area being eroded away.
metaplasia of the glandular stomach: A change of cells to a form that does not normally occur in the tissue in which it is found.
hyperplasia of the glandular stomach: A condition in which there is an increase in the number of normal cells in a tissue or organ.
histiocytic: Degenerative.
duodenum: First part of the small intestine.
microcytic: Any abnormally small cell.
squamous cell papillomas: A small solid benign tumor with a clear-cut border that projects above the surrounding tissue.
squamous cell carcinomas: Cancer that begins in squamous cells-thin, flat cells that look under the microscope like fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of hollow organs of the body, and the passages of the respiratory and digestive tracts. Squamous cell carcinomas may arise in any of these tissues.
jejunum: The middle portion of the small intestine, between duodenum and ileum. It represents about 2/5 of the remaining portion of the small intestine below duodenum.
ileum: The distal and narrowest portion of the small intestine.
squamous: Flat cells that look like fish scales.
metaplasia: A condition in which there is a change of one adult cell type to another similar adult cell type.
ossification: The process of creating bone, that is of transforming cartilage (or fibrous tissue) into bone.
clastogenesis: Any process resulting in the breakage of chromosomes.
neoplastic: Abnormal and uncontrolled growth of cells.
ulceration: The process or fact of being eroded away.
leucocytosis: An elevation of the total number of white cells in blood.
neutrophils: A type of white blood cell.
chromodulin: A small protein that binds four trivalent chromium ions.
biomagnification: The increased accumulation and concentration of a contaminant at higher levels of the food chain; organisms higher on the food chain will have larger amounts of contaminants than those lower on the food chain, because the contaminants are not eliminated or broken down into other chemicals within the organisms.
exencephaly: Cerebral tissue herniation through a congenital or acquired defect in the skull.
everted viscera: Rotated body organs in the chest cavity.
To Be Considered: Documents, such as federal or state guidances, that are not legally binding but may be relevant to the topic in question.
gaining: A gaining surface water body is one where groundwater flows into it.
losing: A surface water body is losing when there is a permeable sediment bed that is not in contact with the groundwater allowing the surface water to seep through it.
fluvial: Of or pertaining to flow in rivers and streams.
lacustrine: Of or pertaining to a lake as in lacustrine sediments—sediments at the bottom of a lake.
lipid: Any class of fats that are insoluble in water.
lipophilic: Able to dissolve in lipids—in this case fatty tissue.
organelles: A part of a cell such as mitochondrion, vacuole, or chloroplast that plays a specific role in how the cell functions and membranes.
RfD: The RfD is an estimate of a daily exposure of the human population (including sensitive sub-groups) to a substance that is likely to be without "the appreciable risk of deleterious effects during a lifetime." An RfD is expressed in units of mg/kg-day.
autonomic: That part of the nervous system that controls non-conscious actions such as heart rate, perspiration and digestion.
ataxia: Lack of muscle coordination.
funnel-and-gate configuration: A system where low-permeability walls (the funnel) placed in the saturated zone direct contaminated ground-water toward a permeable treatment zone (the gate)
References: ATSDR (Agency for Toxic Substances and Disease Registry). 2015. Draft Toxicological Profile for Perfluoroalkyls. 574 pp.
EFSA (European Food Safety Authority). 2008. Opinion of the scientific panel on contaminants in the food chain on perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) and their salts. EFSA Journal 653:1-131.
Hekster, F.M., R.W.P.M. Laane, and P. de Voogt. 2003. Environmental and toxicity effects of perfluoroalkylated substances. Reviews of Environmental Contamination and Toxicology 179:99-121.
Higgins, C. and R. Luthy. 2006. Sorption of perfluorinated surfactants on sediments. Environmental Science & Technology 40(23):7251-7256.
HSDB (Hazardous Substances Data Bank). 2012 Update. Perfluorooctanoic acid.
Kaiser, M.A., B.S. Larsen, C-P.C. Kao, and R.C. Buck. 2005. Vapor pressures of perfluorooctanoic, -nonanoic, -decanoic, -undecanoic, and -dodecanoic acids. Journal of Chemical and Engineering Data 50(6):1841-1843.
Kauck, E.A. and A.R. Diesslin. 1951. Some properties of perfluorocarboxylic acids. Industrial and Engineering Chemical Research 43(10):2332-2334.
Lewis, R.J., Sr., ed. 2004. Sax's Dangerous Properties of Industrial Materials. 11th ed. Wiley-Interscience, Hoboken, NJ. V3:2860.
Lide, D.R. 2007. CRC Handbook of Chemistry and Physics. 88th ed. CRC Press, Boca Raton, FL. 3-412.
SRC (Syracuse Research Corporation). 2016. PHYSPROP Database. SRC Scientific Databases,
Accessed May 2016.
UNEP (United Nations Environmental Program). 2015. Proposal to List Pentadecafluorooctanoic Acid (CAS No: 335-67-1, PFOA, Perfluorooctanoic Acid), Its Salts and PFOA-Related Compounds in Annexes A, B and/or C to the Stockholm Convention on Persistent Organic Pollutants. UNEP/POPS/POPRC.11/5.
USEPA (U.S. Environmental Protection Agency). 2016. Drinking Water Health Advisory for Perfluorooctanoic Acid (PFOA).#pdfsmall# Office of Water, EPA 822-R-16-005, 103 pp
Historically, wood preserving typically has involved treating the wood under pressure with the preservative chemicals chromated copper arsenate (CCA), creosote, or pentachlorophenol (PCP), usually dissolved in some suitable solvent. Wood treater activities often left behind widespread soil, sediment, sludge, and water contamination at the site.
Chromated Copper Arsenate
Chromated copper arsenate (CCA) is a chemical wood preservative containing chromium, copper, and arsenic. This mixture commonly contains chromium(VI) (hexavalent chromium) as chromic acid, arsenic(V) (pentavalent arsenic) as arsenic pentoxide, and copper(II) (divalent copper) as cupric oxide, often in an aqueous solution or concentrate. The copper serves as the primary fungicide, the arsenic serves as a fungicide and insecticide, and chromium fixes the copper and arsenic in the wood. CCA has been used in pressure-treated wood since the 1940s to protect wood from rotting due to decay-causing insects and microbial agents. Since the 1970s, the majority of the wood used in outdoor residential settings has been CCA-treated wood. Since December 31, 2003, EPA has classified CCA as a restricted-use product, and pressure-treated wood containing CCA is no longer being produced for use in most residential settings, including decks and playsets. More information on CCA and its use as wood preservative is available from EPA's Office of Pesticides.
Creosote
Creosote is a wood preservative used for commercial purposes only (i.e., telephone poles and railroad ties). This compound is manufactured by the distillation of coal tar and is composed of numerous chemicals with varying physical characteristics. Polycyclic aromatic hydrocarbons (PAHs) are its primary constituents. Exposure to PAHs may cause harmful health effects. The Agency for Toxic Substances and Disease Registry has a toxicological profile for PAHs. More information on creosote and its use as a wood preservative is available from EPA's Office of Pesticides.
CLU-IN contains resource areas that are relevant to remediation of environmental contamination by CCA and creosote. The focus areas for arsenic and hexavalent chromium as individual contaminants offer collected resources organized in sections to address the chemistry, occurrence, toxicology, detection, and treatment of those contaminants in the environment. Similar sections for creosote were developed as a subset of the dense non-aqueous phase liquids (DNAPLs) focus area.
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Additional Information
Presumptive Remedies for Soils, Sediments, and Sludges at Wood Treater Sites
The purpose of this directive is to provide guidance on selecting a presumptive remedy or combination of presumptive remedies for wood treater sites with soils, sediments, and sludges that are contaminated primarily with creosote, pentachlorophenol, and/or chromated copper arsenate. This guidance describes the contaminants generally found at wood treater sites; presents the presumptive remedies for contaminated soils, sediments, and sludges at wood treater sites; describes the presumptive remedy process concerning the site characterization and technology screening steps; and outlines the data that should be used to select a presumptive remedy. This directive is designed to assist Superfund site managers (i.e., Remedial Project Managers (RPMs) and On-Scene Coordinators (OSCs)) in selecting remedies for wood treater sites. To ensure a full understanding of wood treater site characterization and remedy selection, site managers should refer to the FS/ROD analysis, which is summarized in Appendix A of this document, and the documents cited as references at the end of this document.
Technology Innovation News Survey (TINS)
Information on wood treating chemicals also is available in the form of abstracts collected since 1997 within the TINS archive database. See the results of the following searches:
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