Copper distribution in soil leached from full scale decking boards during one year
IRG/WP 10-50265
F G Evans
The distribution of copper in the soil under exposed decking boards after one year has been analysed. The decking boards were impregnated with copper HDO, copper quat and copper triazoles. The decking boards were pine sapwood and pressure treated in a full cell process, fixed by heating and then dried. The samples were not surface treated. Each decking sample of five boards (0.25 m2) was placed on a frame of untreated spruce, 10 cm above the soil surface. In addition to the three treated samples, there was one untreated as a reference. After one year of exposure, the samples were removed and soil samples in different depths were taken. These were later boiled in de-ionised water and nitric acid (pH=2). The solutions were analysed for copper. Only the surface samples (0-2 cm) had elevated copper content compared to the back ground level. The copper fixes hard to the soil and only small amounts of copper will be washed out by rain.
Keywords: copper preservative, copper HDO, copper quat, copper triazole, leaching, full scale, soil distribution