Abstract:
The incidence of treated wood in a recycling stream was assessed at a recycling center in western Oregon. Chromated copper arsenate (CCA) was the predominant treatment present in the material, ranging from 0 to 2 percent of the material present at any given time. Treated wood was present at 38 of the 41 sampling times, and the average amount of treated wood in the waste stream was 0.98 percent (volume basis). The material from this site is typically used for hog fuel; calculations of total CCA components in the resulting ash suggested that As, Cu, and Cr levels in the ash (assuming all metal in the wood wound up in the ash) would be approximately 9,900, 6,600, and 11,000 ppm, respectively. These values exceed the current State of Oregon limits for the land application of ash; however, this waste stream represents a relatively small fraction of the overall material being burned. As a result, it is likely that there is considerable dilution in the resulting ash, although these contaminants would pose a disposal issue if treated wood residues increase in the recycling stream.
