By:
Tom Nordlie (352) 392-1773 x 277Source(s):
Jacob Huffman jakehuff@aol.com, (352) 846-0850
Tim Townsend ttown@eng.ufl.edu, (352) 392-0846
GAINESVILLE, Fla.—As the federal government and the lumber industry move to phase out most uses of pressure-treated wood laced with arsenic compounds, University of Florida researchers say their 50-year-old test site will show how much of the carcinogenic chemical leaches out of the wood into the ground and whether it’s safe to dispose of treated wood in unlined landfills.
“Large quantities of wood treated with chromated copper arsenate, or CCA, have been used in Florida and the nation to stop decay and termite damage, and now landfill managers want to know what will happen to the wood preservative chemicals in landfills,” said Jake Huffman, professor emeritus with UF’s School of Forest Resources and Conservation. “We expect definitive results by June.”
Plots of wooden stakes and posts installed nearly a half-century ago at UF’s Austin Cary Memorial Forest near Gainesville will help provide answers. “The media have reported on many short-term leaching studies, but there is little long-term research data on the issue,” he said.
Huffman is the leader of the wood preservation testing area at the forest, used since the late 1930s to test CCA and other wood preservatives in Florida’s warm, humid climate and sandy soils. He said the UF forest is one of three research sites in the nation; others are at Oregon State University in Corvallis and at a U.S. Department of Agriculture facility in Gulfport, Mississippi.
“At most commercial locations where pressure-treated wood has been used, few records on leaching have been kept,” he said. “But we have kept detailed records on how much CCA was put in each piece of wood at the test site, and we make regular inspections to measure what is happening to the wood.
“To assure accurate results, the test site has not been altered or disturbed for decades. We also keep the area free of human activity that could affect test results.”
Huffman is working on the project with Jeffrey Morrell, professor at Oregon State University’s forest products department, and they recently visited the UF test site to collect wood and soil samples. Some samples were from plots Huffman established in 1954 and 1957 to test early CCA formulations. Morrell has participated in the UF wood preservative study since 2000.
“The early CCA formulations were more mobile — more likely to leach from the wood into the soil than CCA formulations being used today,” Huffman said. “They also contained higher concentrations of arsenicals, so our findings should represent a worst-case scenario.
“Since we know how much preservative was in the wood to begin with, we can determine if any has leached out into the soil. If it has, we want to know where it went and whether the amount is a cause for concern.”
Morrell is analyzing samples from UF test plots for arsenic, copper and chromium, the active ingredients in CCA. The results will be submitted to a peer-reviewed scientific journal this summer.
Huffman and Morrell are being assisted by a technical awareness group that includes Nicholas Comerford, UF professor of soil and water science, James Healey, operations manager for Koppers Industries wood treatment facility in Gainesville, and Tor Schultz, forest products professor at Mississippi State University. The group will review findings made by Huffman and Morrell.
Funded by UF’s Institute of Food and Agricultural Sciences and the Florida Center for Solid and Hazardous Waste Management, the project is scheduled to end in June. Additional funding may be sought to continue research on landfill disposal of treated wood.
“Landfill managers have questions about proper disposal of CCA-treated wood, and this project is one step toward finding long-term answers,” Huffman said.
At present, Florida law allows CCA-treated wood to be placed in unlined landfills, but proposed legislation could change that, said Tim Townsend, assistant professor of environmental engineering at UF. The legislation would require CCA-treated wood to be placed in lined landfills to prevent chemicals from entering the soil or groundwater.
Townsend said the treated-wood industry has reached an agreement with the federal Environmental Protection Agency to phase out most forms of CCA-treated wood by the end of 2003.
“Even after the phase-out, disposal of CCA-treated wood will remain a controversial issue, particularly in Florida where it’s been so important to the construction industry for so long,” Huffman said.
CCA is the nation’s most popular wood preservative, used on more than six billion board-feet of lumber annually. It also eliminates the need to cut an estimated 226 million trees each year in the U.S., Huffman said.
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NOTE: Additional information about this project can be found at the following Web site: http://www.sfrc.ufl.edu/woodresearch/index.htm
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