Authors: |
P.B. Bush, D.G. Neary, Charles K. McMahon, J.W. Taylor |
Year: |
1987 |
Type: |
Scientific Journal |
Station: |
Southern Research Station |
Source: |
Archives of Environmental Contamination and Toxicology. 16: 333-341. |
Abstract
Abstract. Potential exposure to pesticide residues resulting from burning wood treated with phenoxyand pyridine herbicides was assessed. Wood samples from trees treated with 2,4-D [2,4-dichlo-rophenoxy acetic acid], dicamba [3,6-dichloro-o-anisic acid], dichlorprop [2-(2,4-dichlorphenoxy) propionic acid], picloram [4-amino-3,5,dtrichloropico-linic acid], and triclopyr (3,5,6-trichloro-2-pyridinyl)oxy acetic acid contained variable amounts of parent compound residues at 4, 8, and 12 months after application. At the time of the latter sampling, residues of 2,4-D, dicamba, and picloram were ~2.1 mg/kg on a fresh weight basis. Mean residue concentrations of triclopyr and dichlorprop were somewhat higher at 3.5 and 13.0 mg/kg, respectively.In a laboratory experiment, samples with known amounts of herbicide residue were subjected to either slow or rapidly burning conditions in a tube furnace. During slow combustion, relatively stable compounds such as 2,4-D, dicamba, and dichlorprop were released in significant amounts. Rapid combustion greatly enhanced de-composition of 2,4-D, dicamba, dichlorprop, picloram, and triclopyr. A well-developed fire in a wood stove or fireplace, with active flaming combustion, where temperatures commonly reach 800- l,000C, should result in greater than 95% thermal decomposition of the herbicides examined in this study. Burning of herbicide-treated wood under smoldering conditions could result in very low levels of herbicide residue in ambient indoor air. However, the exposure levels are less than 0.3% of the threshold limit value for 2,4-D and triclopyr. The exposure is also more than 3 orders of magnitude lower than the established acceptable daily intakes for these products.
Citation
Bush, P.B.; Neary, D.G.; McMahon, Charles K.; Taylor, J.W. 1987. Suitability of hardwood treated with phenoxy and pyridine herbicides for firewood use. Archives of Environmental Contamination and Toxicology. 16: 333-341.