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Leland M. Humble The risk of introduction of pests or pathogens in association with wood used to package, support, or brace goods in transit varies with wood quality, condition, and degree of manufacturing. Nonmanufactured wood products (i.e., wood that has undergone only primary alteration, e.g., debarking, sawing, milling, etc.) generally pose a higher risk for such introductions than packing materials composed of manufactured wood (i.e., processed wood products, e.g., particle board, oriented strand board, plywood, etc.). Quarantine agencies around the world have adopted a variety of mitigation measures to ensure that exotic pests and pathogens are not introduced into their jurisdictions with the dunnage, crating, pallets, reels, or other wood packaging associated with imported commodities. The risk reduction options used by selected quarantine agencies are identified, and issues associated with determining the environmental impacts of these measures are discussed. Both permanent and nonpermanent methods (1) are used to treat in-service solid wood packing. Non-permanent treatments (e.g., fumigation) eliminate pests or pathogens potentially present in wood packaging prior to shipment or discovered during quarantine inspections. They give no protection against post-treatment reinfestation of the wood products. Permanent treatments eliminate pest or pathogen problems present at the time of treatment and prevent post-treatment reinfestation for the service life of the wood. Examples of currently approved treatments for wood packing materials across a range of jurisdictions are presented in Table 1. Two treatments are widely accepted, fumigation with methyl bromide (MB) and heat treatment with moisture reduction. Broader adoption of other treatments (e.g., chemical preservatives) may occur as the service life of wood packing shifts from single to multiple use as a consequence of the use of wood of higher quality and value in packaging. Direct environmental impacts may arise during preservice treatment of wood (e.g., during production of chemically preserved wood products), during the in-service treatment of wood packaging (e.g., quarantine fumigation of infested wood packaging), or as a consequence of the disposal of wood packing (e.g., at the end of its service life or when it doesn’t meet the quarantine standards of a jurisdiction). Evaluation of the environmental impacts of the treatments requires a detailed knowledge not only of the types of treatments and their environmental impacts, but also of the volumes of wood packing used and its fate after use for each of the treatment types. Of these factors, the environmental impacts of the compounds used to treat solid wood packing have received the most scrutiny. Fumigation followed by proper handling generally eliminates quarantine pest risk, while posing no direct risk to personnel involved in the treatment of nontarget species when properly applied. The efficacy of MB makes it the preferred fumigant for quarantine treatments. However, deleterious effects on the ozone layer resulting from the use of MB have been identified. It reacts chemically with ozone in the atmosphere and contributes to the depletion of the stratospheric ozone layer. Increased quarantine usage of MB for control of organisms associated with wood packing materials could further increase stratospheric ozone depletion should the fumigant be released to the atmosphere following treatment. Potentially significant increases in MB usage in China resulting from recent regulatory changes have been identified (8). The deleterious environmental effects resulting from atmospheric release of MB could be potentially mitigated through recovery of the fumigant after treatment (9). Alternative fumigants such as sulfluryl flouride or phosphene do not contribute to ozone depletion. However, the former is difficult to handle effectively and safely, while the latter works best in small, enclosed areas and is less efficient for larger treatments. For both alternatives, the duration of treatment for good penetration and efficacy is generally greater than that for MB. Progress toward alternatives to MB fumigation are documented at the EPA Methyl Bromide Phase Out Web Site (10). Environmental impacts of preservative treatments can result from release of compounds during the treatment process, during the in-service use of the packaging or following disposal. Impacts can be minimized through adherence to application and disposal protocols and safeguards to prevent adverse health or environmental effects during production, shipping, and handling processes. Large volumes of wood packing are generated each year. The EPA estimated that almost 6,300 thousand tons of wood packaging (excluding pallets) entered landfills in the United States in 1993. There is potential for increased environmental impacts associated with the disposal of treated wood packing should treatment of wood packing become more prevalent. Concerns and issues related to the safety and disposal of treated wood can be found at web sites identified below (11). All treatment options for wood packing pose some degree of environmental risk. The environmental hazards associated with a no-treatment option or those resulting from inadequate treatment of wood packing are readily apparent in the impacts of introduced species (e.g., Chestnut blight, Dutch elm disease, gypsy moth, or the Asian or brown spruce longhorned beetles) in jurisdictions around the world. Those associated with individual treatments have often been identified. However, the hazards associated with the application of these treatments to significantly larger volumes of wood packaging as a consequence of recent regulatory changes is not readily apparent. Any evaluation of the environmental impacts of treatments to mitigate the transfer of harmful organisms with solid wood packing must be considered in relation to the environmental impacts of introduction of the introduced organisms. Do the benefits of treatment outweigh the environmental risks? Table 1. Quarantine treatments for solid wood packing materials from selected international jurisdictions.
a Sulphuryl fluoride is not registered for use in New Zealand. It can be used only as a pre-export treatment. b Phosphine fumigation is allowed for use only on dry or nearly dry (not green) wood packaging. c permethrin only allowed. References Australian Quarantine Inspection Service. Cargo containers, quarantine aspects and procedures. (Dated 01 Dec. 2000) http://www.aqis.gov.au/docs/border/cargo.doc. Canadian Food
Inspection Agency Policy Directive D-98-08 (1st Revision, Effective
Date Jan. 24, 2000): Import requirements for wood dunnage, pallets,
crating or other wood packaging materials. http://www.cfia-acia.agr.ca/english/plaveg/protect/dir/ Canadian Food
Inspection Agency Policy Directive D-98-10 (3rd Revision, Effective
Date January 24, 2000): Import requirements for wood dunnage,
pallets, crating or other wood packaging materials originating in
China and Hong Kong special administrative region. http://www.cfia-acia.agr.ca/english/plaveg/protect/dir/ New Zealand Ministry
of Agriculture and Forestry. Summary of New Zealand's Import
Requirements for Wood and Forest Products. 03 August, 2000 http://www.maf.govt.nz/Standards/plants/forest/ Treatment Schedules for Solid Wood Packing Materials from the PPQ Treatment Manual http://www.aphis.usda.gov/oa/alb/Appendix2.pdf Solid Wood Packing Material from China A Summary of U.S. Entry Requirements According to 7CFR 319.40 http://www.aphis.usda.gov/oa/alb/swpmsum.html Import requirements for wood dunnage and other wood packing materials into a NAPPO member country. November 3, 1998. http://www.nappo.org/989-002_e.htm http://www.epa.gov/fedrgstr/EPA-GENERAL/1998/September/ Snyder, J.D. &
Leesch, J.G. Methyl bromide recovery (USDA-ARS TEKTRAN Dated
2000-08-02) http://www.nal.usda.gov/ttic/tektran/data/000011/38/ United States Environmental Protection Agency. Methyl Bromide Phase Out Web Site. http://www.epa.gov/ozone/strathome.html Disposal: The Achilles' Heel of CCA-Treated Wood (from Environmental Building News Vol. 6, No. 3. Mar. 1997) http://www.buildinggreen.com/features/tw/treated_wood.html; Treated Lumber http://www.urbanext.uiuc.edu/greenline/99v4/gl9904.02.html; Murdoch, C.W. 1992. Alternatives to petroleum-based biocides for protecting hardwood lumber and manufactured products. http://www.nal.usda.gov/ttic/industry/hrdwood4.htm; Chromated Copper Arsenicals (CCA) and Its Use as a Wood Preservative (Oct. 2000) http://www.epa.gov/pesticides/citizens/1file.htm
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