Residual metal content and metal distribution in chromium/copper-treated wood after field and laboratory leaching exposure

Laboratory and field leaching exposure tests were conducted to compare the residual metal content in EN 252 (50 x 5 x 2.5 cm(3)) pine sapwood stakes treated with commercial chromium- and copper-containing preservatives. Treated stakes were subjected to a series of laboratory leaching tests (CEN/TS 15119-1 and CEN/TS 15119-2) and field test exposure for 24 months. Metal content and distribution were determined prior to and after exposure. The remaining metals contents in the stakes in both laboratory tests were greater than that in field test stakes. In addition, during field test exposure metal migration occurred in the treated stakes which was not observed in the laboratory tests. Results are important in developing more realistic standard laboratory methods to evaluate the leaching behaviour of preservative components during in-service conditions.