TITLE: Fate of CCA⁽¹⁾-Treated Wood

COMPLETION DATE: March 31, 2001

PRINCIPAL INVESTIGATOR: Helena Solo-Gabriele, Assistant Professor

AFFILIATION: University of Miami, Dept. of Civil, Arch., & Environ. Engineering

ASSOCIATE INVESTIGATOR: Timothy Townsend, Assistant Professor

AFFILIATION: University of Florida, Dept. of Environ. Engrg. Sci., Solid & Haz Waste Prog.

______________________________________________________________________________

OBJECTIVES: This project will assess the ultimate fate of the metals within wood treated with preservative chemicals. The fate of these metals will be evaluated for wood treated with alternative chemicals (ACQ, CBA, CC, and CDDC) through TCLP and SPLP tests (phase I). Furthermore, arsenic species will be analyzed on leachates collected from landfills (phase II). The specie of the metals is of importance given that it dictates the relative mobility and toxicity of the metal.
 

METHODOLOGY: Leaching of ACQ-, CBA-, CC-, and CDDC-treated wood will be evaluated using EPA standard TCLP and SPLP procedures. Arsenic species will be determined using appropriate methods (Method 3500-As Standard Methods 1995; Pongratz 1998; and others) which are based upon the conversion of arsenic to arsine gas. Different species are converted under different environmental conditions. The arsine gas generated is then quantified by a detector.
 

RATIONALE: A major import of metals, in particular arsenic, into the State of Florida is associated with CCA-treated wood manufacture. Upon disposal, the majority of CCA-treated wood is either disposed in unlined construction and demolition (C&D) landfills, or recycled as mulch or wood fuel. As a result, a considerable amount of arsenic can be potentially released into the Florida environment. The impacts of CCA-treated wood can be lessened through waste minimization, i.e. use of alternative chemicals, and by evaluating the ultimate fate of the metals in CCA so that appropriate disposal management strategies can be implemented.
 

ACCOMPLISHMENTS: Dr. Solo-Gabriele and Dr. Townsend have worked on CCA-treated wood projects for the Center for the past three years. They have presented their research results at many conferences, have published their work in peer-reviewed journals, and collectively have graduated 4 masters students on Center sponsored CCA projects and have 2 masters and 2 Ph.D. students currently working on the existing Center project.
 
 

Arsenic is brought into the State of Florida primarily for the production of CCA-treated wood. Upon disposal, the majority of CCA-treated wood is either disposed in unlined construction and demolition (C&D) landfills, or recycled as mulch or wood fuel. As a result, a considerable amount of arsenic can be potentially released into the Florida environment. Currently, roughly 1,400 tons of arsenic per year are imported into the State for the production of CCA-treated wood. If these 1,400 tons were to impact the upper 1 inch of Florida soil, the background arsenic concentration of this upper 1 inch layer would increase by 0.2 mg/kg. This is very significant given that this computation was performed on only 1 year's CCA-treated wood production and that the Florida Department of Environmental Protection's (FDEP) residential clean-up target level is 0.8 mg/kg. If cumulative arsenic disposal quantities are considered, arsenic associated with CCA-treated wood production through 1999 represents a potential increase of 4 mg/kg in the upper 1 inch of Florida soils. It is important to note that it will take roughly another 25 to 40 years for the ultimate disposal of the CCA-treated wood produced today.

One manner by which the importation of arsenic can be significantly reduced is for user's of CCA-treated wood products to switch to a non-arsenical treated wood product or to another structural material. During last year's study, four feasible "waterborne" alternative chemicals were identified for treating wood products up to a retention value of 0.40 pounds per cubic foot (pcf). The 0.40 pcf corresponds to lumber, timbers, and plywood in ground contact. These alternative chemicals include: ammoniacal copper quat (ACQ) produced by Chemical Specialities Inc., copper boron azole (CBA) produced by Hickson Corp., copper citrate (CC) produced by Osmose Inc., and copper dimethyldithiocarbamate (CDDC) produced by Kodiak Inc.⁽²⁾ For applications requiring higher CCA retention levels, such as that needed for freshwater and marine docks, wood treated with oilborne preservatives or alternative structural materials including plastic lumber products represent a potential alternative to CCA-treated wood.
 
 

The overall goal of this study is to reduce the impacts of CCA-treated wood within the Florida environment by evaluating alternatives to the use of CCA (phase I) and by assessing the ultimate fate of the arsenic within the CCA chemical (phase II). First and foremost considered through this project is waste minimization by evaluating wood treated with alternative wood preservatives. Wood treated with alternative wood preservatives will be evaluated using the toxicity characteristic leaching procedure (TCLP) and the synthetic precipitation leaching procedure (SPLP). The purpose of the TCLP and SPLP is to determine the potential impact of wood treated with alternative wood preservatives upon disposal by simulating the leaching of chemicals under landfill and rainfall conditions, respectively. Furthermore, it is important to note that the environmental impacts of the arsenic contained in CCA-treated wood depends upon the particular form of the metals (i.e. species of the metals). The specie of the metal dictates its mobility and toxicity characteristics. Leachate samples will be collected from landfills that are fitted with liners. Samples will also be collected from groundwater monitoring wells around construction and demolition landfills. Arsenic will be analyzed in both the +3 and +5 oxidation state.
 
 

Phase I: Leaching of Alternative-Chemical Treated-Wood Products

This task will explore the leaching characteristics of alternative-chemical treated-wood products that contain no arsenic. A set of four alternative chemicals have been identified for potential substitution with CCA. These alternatives include ammoniacal copper quat (ACQ), copper boron azole (CBA), copper citrate (CC), and copper dimethyldithiocarbamate (CDDC). Leaching will be evaluated by conducting TCLP and SPLP tests. Metals concentrations and organics associated with each alternative chemical will be quantified during experimentation. TAG members have emphasized that the type of raw wood utilized will have a significant effect on the leaching characteristics of treated wood. In order to minimize the effects of different batches of raw wood, the research team intends to purchase 10 foot long 2 x 4's of untreated wood that are as homogeneous as possible. The purchase of the raw wood will follow the recommendations of a timber inspector, Don Keaf, that was recommended to the research team. Once purchased, this wood will be sent to each alternative chemical manufacturer for treatment. Currently the CDDC manufacturing plant is non-operational; a batch of CDDC-treated wood was obtained prior to their closing. If the plant opens in the near future, the raw wood samples will be be also sent to this facility. Once the treated wood is received by the alternative-chemical manufacturers, the retention levels will be checked.
 

Phase II: Arsenic Speciation of Landfill Leachate
 

Metal speciation is of importance given that the mobility and toxicity of these metals are governed by their oxidation state in the environment. Landfill leachate samples will be obtained from landfills fitted with liners. Samples will also be collected from monitoring wells in the vicinity of construction and demolition landfills. Samples from the lysimeters will be analyzed for total arsenic, As(V), and As(III) using appropriate methods (Method 3500-As Standard Methods 1995; Pongratz 1998; and others). The analytical methods involve converting dissolved arsenic to arsines. Chemical conditions are controlled such that only one arsenic specie is converted at a time, thus permitting for separate measurements of As(III) and As(V). The arsine gas is then measured in an appropriate detector.
 
 

Phase I, Leaching of CCA-treated Wood and Alternative-Chemical Treated-Wood Products.

Dr. T. Townsend will be the key faculty member. Dr. H. Solo-Gabriele will be responsible for purchasing the untreated wood and having it treated. She will then provide the treated wood Dr. Townsend for further processing and TCLP and SPLP analysis.

Phase II, Arsenic Speciation of Landfill Leachate.

Dr. H. Solo-Gabriele will be responsible for As speciation. She will coordinate her efforts with Dr. Townsend who is currently conducting a separate study which focuses on chromium speciation.
 
 

Wood needed for the leaching studies (phase I) will be purchased in April 2000. Once purchased the untreated wood samples will be sent to each chemical manufacturer for treatment. TCLP and SPLP analysis will likely begin in June 2000.

Equipment needed for the arsenic species analysis (phase II) will be ordered in April 2000. We anticipate that the analytical methods for arsenic will be running by June 2000. A student exchange is planned for August 2000 by which graduate students from each University will work together on the metal speciation and leaching tasks. The student exchange is considered important in order to foster a greater sense of team-work among each University.

There are plans to attend four conferences at a minimum. The two conferences, the national conference of the American Wood Preservers' Association and the International Conference on Wood Preservation will be held in May 2000. The research team has also been invited to speak at the Solid Waste Information Exchange Workshop (SWIX) and Recycle Florida Today (RFT) both which will be held in Tampa, FL during June 2000. Technical Advisory Group (TAG) meetings will be held three times during the course of the project. Monthly reports will be submitted to the Center at the beginning of each month and a final technical report will be submitted during March 2001.
 

Project Duration: April 1, 2000 to March 30, 2001
 

2000

2001

A

M

J

J

A

S

O

N

D

J

F

M

Phase I: Alternative Chemical Leaching

X

Phase II: Arsenic Speciation

X

AWPA, IRG, RFT, SWIX Conferences

X

X

TAG Meetings

X

X

X

Monthly Reports to FCSHWM

X

X

X

X

X

X

X

X

X

X

X

X

Draft & Submit Final Tech. Report

X

 

Leaching data (TCLP and SPLP) will be available for alternative-chemical treated wood products. This data will include copper analysis and the analysis for the co-biocides. Arsenic metal species will be quantified from landfill leachates and from leachates collected from monitoring wells near C&D landfills.
 
 

The results from leaching tests can be used to assess proper disposal options for the alternative-chemical treated wood products. Results can be used to determine whether the alternative-chemical treated wood products should be disposed in unlined or lined landfills or whether such material should be used for mulch. Results from the arsenic speciation analysis will be used to evaluate the potential impacts of CCA-treated wood upon landfill disposal. This is of importance because a significant amount of wood waste is disposed in unlined C&D landfills.
 
 

Technology transfer to interested parties is considered essential to the successful completion of the research. These communications are viewed as a means of expediting the progress of the research by avoiding unnecessary duplication of efforts, by facilitating information gathering, and by obtaining inputs, suggestions, and comments that will direct the research along a productive course.

The transfer of information to interested parties will occur at four levels. The first level is the transfer of information between the PI and the co-PI, located at the University of Miami, and the co-PI, located at the University of Florida. During the day-to-day execution of the research the PIs will communicate via email, fax, and telephone. The PI will copy the co-PI s (and vice versa) on any written correspondence and documentation generated during the execution of the research and the PIs will meet at least three times during the course of project. Furthermore, the PI and co-PIs are organizing a summer exchange for our graduate students to further facilitate technology transfer and foster a sense of teamwork between each University. The exchange will center around the metal speciation work. Given that the lysimeters are located at the University of Florida, it is likely that the exchange will likely occur at U.Florida over a period of four to five days.

The second level of technology transfer is the detailed communication that is provided by the PIs to the FCSHWM. This communication will take the form of monthly progress reports and, if necessary, more frequent contact with the program director via e-mail, telephone, or other forms of communication.

The third level of technology transfer will occur through our TAG meetings which are scheduled to occur at least three times during the course of the research project. These research meetings will serve as an effective means of communicating interim progress to interested parties outside the FCSHWM. All TAG members will be sent copies of the meeting agenda and minutes. Furthermore, prior to each meeting TAG members will be contacted to request agenda items and to remind them of meeting dates and times. A technical advisory group has already been formed as part of Drs. Solo-Gabriele's and Townsend's earlier research projects on CCA-treated wood. Members of the existing TAG will be invited to participate on the TAG for this research project. Other members will be added as needed to provide their expertise and to review different components of the research project. It is also important to note that earlier TAG meetings have been very successful; the last of which held in December 1999 had roughly 50 participants. To facilitate participation of TAG members, meeting locations will be distributed throughout Florida. During the next project year meetings will be held in Miami, Gainesville, and one other location.

The fourth level of communication will occur with the community at large. This level of communication will take the form of distributing the final technical report to interested parties, maintaining a web page for the project (See http://www.ccaresearch.org) and our participation at solid waste and wood preservation conferences. The PI plans to participate at the American Wood Preservers' Association research symposium to be held in San Fransisco, CA and the International Research Group on Wood Preservation conference to be held in Kona, Hawaii. Both these conferences will be held in May 2000. Furthermore, the Pis have been invited to speak at the Recycle Florida Today Conference and at a local Solid Waste Information Exchange (SWIX) Conference. Both of these local conferences will be held in Tampa, Florida in June 2000. Other conferences considered include those sponsored by the Solid Waste Assoc. of North America (SWANA) and the Department of Energy, biomass energy programs. The next Bioenergy Conference is scheduled for October 2000 in Buffalo, NY. Another inherent goal of the PIs is to develop publishable manuscripts to further facilitate the distribution of results to the research community. Results from the first year have been published in two scholarly journals. These journals are Waste Management and Research and Environmental Engineering Science. A manuscript for the second year study has been submitted to Waste Management and Research.
 
 

Leaching Studies: Leaching tests have been conducted by the wood treatment industry in order to standardize CCA and alternative chemicals. However, the types of leaching tests are very different than the standard TCLP and SPLP tests used to evaluate disposal options for various wastes. TCLP has been conducted on CCA-treated wood and wood ash through studies conducted by C.T. Donovan and Associates of Connecticut (C.T. Donovan & Assoc. 1995; Fehrs 1996). Other than these, there is no known work evaluating TCLP and SPLP of CCA-treated wood or of alternative-chemical treated wood.

Arsenic Speciation: A considerable amount of research has been conducted on arsenic speciation in aquatic environments (Ahmann et al. 1997; Jackson and Miller 1999 and others). However, none of the studies evaluated the species of metals leached from landfills. The proposed project is unique in this sense.
 
 

Another topic recommended by the researchers' technical advisory group for further study was to evaluate treatment and recycling options for CCA-treated wood ash, which was a topic of the year 2 study. The results from the year 2 study were promising and showed that citric acid was capable of removing almost 100% of the arsenic from the ash. Coupling this solvent along with a surfactant and/or ultrasonic methods has been recommended to further enhance the removal of CCA from the ash.

Principal Investigator Co-Principal Investigator

Helena Solo-Gabriele, Ph.D Timothy Townsend, Ph.D

Assistant Professor Assistant Professor

University of Miami University of Florida

Dept. of Civil, Arch. & Environ. Engrg. Dept.of Environ.Engrg.Science

P.O. Box 248294 333 New Engineering Bldg.

Coral Gables, FL 33124-0630 Gainesville, FL 32611-6450

305/284-3489 or 305/284-3391 352/392-0846

Fax: 305/284-3492 Fax: 352/392-3076

Email: hmsolo@miami.edu Email: ttown@eng.ufl.edu
 
 

David Dee, Attorney Landers & Parsons 310 West College Avenue P.O. Box 271, Tallahassee, FL 32302 (850)681-0311, Fax: (850)224-5595 ddee@landersandparsons.com	Mr. Dee is currently a member of the TAG. He was asked to serve when we sought representation from the sugar industry which owns two large wood cogeneration plants in Florida. He has been active in the TAG since he became a member in 1998.
Keith D. Drescher, Environ. Specialist Florida Power & Light 2455 Port West Blvd., Bldg. A West Palm Beach, FL 33407 (561)845-4968, Fax: (561)845-3308 keith_drescher@email.fpl.com	Mr. Drescher's company is an end-user of CCA-treated utility poles. He has considerable experience with issues that face industrial end-users including recycling and liability. Mr. Drescher has been instrumental in getting FPL support for this project.
Ram Tewari, Ph.D., P.E., Project Mngr. Broward County Commission Solid Waste Operations Division 201 S. Andrews Ave., Ft Lauderdale, FL 33301 (954)765-4202 x254 or (954)680-0087 x224 Fax:(954 )765-4237 rtewari@co.broward.fl.us	Dr. Tewari is a project manager for one of the largest public solid waste facilities in Florida. He has considerable experience in incineration and landfill issues. He is currently an active TAG member who provides regular feedback concerning the direction of the project.

mobilization of arsenic from sediments of the Aberjona Watershed." Environ. Sci. Technol. 31(10): 2923-2930.

American Public Health Association. 1995. Standard Methods for the Examination of Water and

Wastewater, 19^th ed. American Public Health Association, Inc., Washington, D.C.

Cooper, P.A., 1993. "Disposal of treated wood removed from service: the issues."

Proceedings of the Carolinas-Chesapeake Section of the Forest Products Society. Presented

at the May 13, 1993 meeting on Environmental Considerations in the Use of Pressure-

TreatedWood Products. Published by the Forest Products Society, Madison, WI.

C.T. Donovan Associates, 1995. Air Emissions and Ash Disposal at Wood-burning Facilities.

C.T. Donovan Associates, Inc., Burlington, VT.

Fehrs, J.E. and Donovan, C.T. 1996. "Ash from the combustion of treated wood: characteristics

and management options." Proceedings of the Second Biomass Conference of the Americas:

Energy, Environment, Agriculture, and Industry, p. 120-129.

Jackson, B.P., and W.P. Miller, 1999. "Soluble arsenic and selenium species in fly ash/organic

waste-amended soils using ion chromatography - inductively couple plasma mass spectrometry." Environ. Sci. Technol. 33(2): 270-275.

Pongratz, R. 1998. "Arsenic speciation in environmental samples of contaminated soil." The

Science of the Total Environment, 224: 133-141.

Solo-Gabriele, H. and T. Townsend. 1999. "Disposal practices and management alternatives for

CCA-treated wood waste." Waste Management Research. 17: 378-379.

1.

¹ CCA stands for chromated copper arsenate. CCA is the most common wood preservative used in Florida.

2. Kodiak Inc. is currently selling it's wood treatment facility.