Small volumes of a commercial timber preservative containing approximately
60% w/w chromated copper arsenic (CCA) were applied to 15-cm-deep, undistur
bed soil monolith lysimeters containing the surface horizon of a mildly aci
dic, sandy loam soil extracted from within the forestry plantation region o
f south-west Victoria. The collected leachate and samples of the core profi
les were analysed by inductively coupled plasma emission spectroscopy (ICP-
ES) for a total of 28 elements, including the active ingredients of the pre
servative, copper, chromium, and arsenic.
After application of CCA, of the metals studied, only the concentrations of
arsenic, calcium, chromium, sodium, and potassium in the leachate differed
from background concentrations during the irrigation of the cores. Copper
concentrations in all leachate remained at background levels throughout the
experiment. Up to 36% of the applied dose of chromium was detected in the
leachate, with breakthrough at 15 cm soil depth occurring within 20 days of
preservative application. Up to 13% of the applied dose of arsenic was det
ected in the leachate collected at 15 cm depth, although in this case break
through was not observed until 25 days after preservative application. The
applied copper was immobilised in the top 4 cm of the soil. Elevated concen
trations of arsenic and chromium were found in the top 6 cm of the soil pro
file.