Wood Treater Sites
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 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.
- Chromium VI
- Chemistry and Behavior
- Environmental Occurrence
- Detection and Site Characterization
- Treatment Technologies
- Direct and Multiphase Recovery
- In Situ Flushing
- In Situ Oxidation
- Permeable Reactive Barriers
- Soil Vapor Extraction and Air Sparging
- Source Area Excavation
- Thermal Processes: Ex Situ
- Thermal Processes: In Situ
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.
Proceedings: Environmental Impacts of Preservative-Treated Wood, 8-11 February 2004, Orlando, Florida
Florida Center for Environmental Solutions, Gainesville. 387 pp, 2004
The proceedings consist of presented papers and abstracts on the impacts of CCA wood-preserving compounds on environmental media and biota and human health, as well as disposal approaches and innovative remediation technologies applicable to treated wood waste.
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: