Excerpts from Recent Findings
"Contamination of Soil with Copper, Chromium, and Arsenic Under Decks Build From Pressure Treated Wood". By D.E. Stillwell and K.D Gorny. Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, PO Box 1106, New Haven, Connecticut 06504. Published in: Bulletin of Environmental Contamination and Toxicology. Vol. 58, No.1, pp 22-29. January 1997. Springer-Verlag, Life Science Journals, New York, NY.
Presented at American Chemical Society. Abstract of Papers S212. 114-ENVR Part 1. August 25, 1996.
"Presently, the most widely used wood preservative is chromated copper arsenate (CCA)"……Due to the massive amounts of CCA treated wood sold each year, the extent of dispersal of these additives from the wood could have a considerable environmental impact. The potential toxicity of Cu, Cr, and As to humans, animals, and plants is well documented. According to published studies in controlled laboratory settings, high percentages of CCA can be released from the wood by aqueous solutions. …Warner and Solomon (1990) also concluded that the acidity of aqueous solutions is a major factor in the leaching of CCA from treated lumber. In their study, the percent leached after 40 day immersions in buffered solutions between 3.5 - 5.5 ranged from 92-100% (Cu), 12-53% (Cr), and 32-68% (As). These findings imply that considerable amounts of Cu, Cr and As could leach from outdoor use of CCA treated wood since rainwater is acidic. The natural pH of rainwater ranges between 4.9-6.5 (Calvert 1983). In many regions worldwide, including the Northeastern US (where this study was conducted) anthropogenic atmospheric sulfur and nitrogen compounds have increased this acidity. The pH of "acid rain" has been measured between 4.1-4.5 in the Northeastern US (Calvert 1983).
In this field study, the Cu, Cr, and As content in soils under seven decks built with CCA treated wood was determined. The decks ranged in age from 4 months to 15 years. Decks are ideal for the study of the effects of weathering due to rain and solar radiation on the wood. The wood is above ground and the leachate from precipitation tends to flow directly to the soil below."
Results and Discussion:
"These results demonstrate that significant amounts of Cu, Cr, and As leaches from the wood and manifests itself in the soil. The average As (arsenic) content exceeds both regulatory limits by substantial amounts. Moreover, the As concentrations appear to be persistent with depth…Clearly, the arsenic levels pose a potential environmental problem."