Links
Pressure-treated wood for raised bed construction in the Willamette Valley
extension.oregonstate.edu
This study showed that raised beds made from pressure-treated lumber do increase soil copper concentrations but only within 1 inch of the bed edge. The increase in copper was small — about 20 ppm above the level measured in the raised beds made from untreated lumber. This increase in soil copper concentration was minor, and even the highest copper concentrations seen within 1 inch of the bed material were well within natural range of copper levels for Willamette Valley soils.
This was (welcome) news to me.