Biomass, root penetration and heavy metal uptake in birch in a soil cover over copper tailings.
A study of naturally colonizing Betula pubescens and B. pendula on 10-yr-old soil cover up to 1 m deep on a 32-ha tailing near Garpenberg, Sweden. The covering soil was contaminated by upward transport of heavy metals. Even with 1 m depth of soil cover, fine roots of birch (mostly <4 yr old) had penetrated the spoil. Leaf content of Zn, Pb and Cd were higher than, and of Cu similar to, published values for uncontaminated soil. Leaf concentrations of Pb and Cd were correlated with soil concentrations, of Cu with above- and below-ground biomass, and of Zn mainly with soil pH. Depth of soil cover affected leaf concentrations of Zn and Cd.