Arsenic treated wood

Arsenically treated wood. Discarded arsenically treated wood or wood products that are hazardous only because they exhibit certain toxic characteristics (e.g., contain harmful concentrations of metal or pesticide constituents), are excluded from the definition of hazardous waste. Once such treated wood is used, it may be disposed of by the user (commercial or residential) without being subject to hazardous waste regulation. This exclusion is based on the fact that the use of such wood products on the land is similar to the common disposal method, which is landfilling. This exclusion applies only to end-users and not to manufacturers. 

In air, most arsenic particulates consist of inorganic arsenic compounds, often as As+3. Burning of coal and arsenic-treated wood, and smelting of metals are major sources of atmospheric arsenic contamination (i.e., >1 pg/m3). In general, atmospheric arsenic levels are higher in winter, due to increased use of coal for heating (Pershagen and Vahter 1979). 

The toxicity of chronic exposure to arsenic is well established and the best recommendation is to avoid arsenic exposure. The most common home exposure is from contaminated drinking water and arsenic-treated lumber. Certain areas of the country have higher levels of arsenic in water. The EPA has lowered arsenic drinking water standards, but water providers have until 2006 to meet the new standards. Avoid inhalation of sawdust from arsenic-treated lumber or inhalation of smoke from burning arsenic-treated wood. And of course always wash your hands. This is particularly important if a young child is playing on arsenic-treated wood. 

Nico, P.S., Ruby, M.V., Lowney, Y.W. and Holm, S.E. (2006) Chemical speciation and bioaccessibility of arsenic and chromium in chromated copper arsenate-treated wood and soils. Environmental Science and Technology, 40(1), 402-8. 

Dubey, B., Solo-Gabriele, H.M. and Townsend, T.G. (2007) Quantities of arsenic-treated wood in demolition debris generated by hurricane Katrina. Environmental Science and Technology, 41(5), 1533-36. 

Mercury, arsenic and cadmium are metals, which are volatile at low tenq>eratures (356.88, 614 and 767 °C respectively). Such metals must be captured at the exit of the gas after the condensation columns. Arsenic appears in treatments like CCA. It was shown that CCA (Copper, Chromium, Arsenic) treated wood could be pyrolysed with a negligible release of copper and chromium and a minimal release of arsenic (76,84 % of arsenic was found in the pyrolysis residues) at a reactor tenq)erature of 350 °C during 20 minutes, using a nitrogen at a flow rate of 5 Nm /h. [5]... 

Figure 6 shows that the increase in zinc and copper content in the charcoal is due to their concentration in this product. The pyrolytic liquids content in these two metals is very variable. But the majority of zinc and copper is found in the charcoal as well as for nickel, lead and chromium. The same conclusion was observed for CCB (Copper, Chromium, Arsenic) treated wood [2]. 

Helsen L. and Van den Buick E, (2000) Kinetics of the low-temperature pyrolysis of chromated copper arsenate-treated wood. J. Anal. Appl. Pyrolysis, 53, 51-79. 

Helsen L, and Van den Buick E. (2(XK)) Metal Behaviour During the Low-Temperature Pyrolysis of Chromated Copper Arsenate Treated Wood Waste, accepted for publication in Environ. Sci. TechnoL. 

If you use arsenic-treated wood in home projects, you should wear dust masks, gloves, and protective clothing to decrease exposure to sawdust. 

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