Sub-samples were further ground with an agate grinder to pass
through a 0.15-mm nylon sieve, which were then used to determine selected
heavy metals, soil organic matter, and total phosphorus. The concentrations
of heavy metals (Cd, Pb, Cu and Zn) in soil, as well as such
selected soil properties as pH, organic matter, and particle size distribution
were determined according to the methods described by Li et al.
[19].