Accumulation of heavy metals in the soil due to annual dressings with sewage sludge.

In a long term field experiment 0, 6, 12 or 18 tonnes/ha/yr of sewage sludge (dry matter basis) were applied to permanent grassland. Sludge application markedly increased the contents of Cd, Pb, Zn, Cu, Ni, Cr, Mo, to a depth of 15-25 cm, but Co, Mn and Fe contents were increased only in the surface 5 cm of soil. (Abstract retrieved from CAB Abstracts by CABI’s permission