The effect of organic amendments on the phytoavailability of heavy metals in polluted soil

Four substances used for organic soil amendments to reduce immobilisation and thus the bioavailability of heavy metals in soils were tested in field stonepots rye culture. The bio-accumulation index (BI) was calculated to evaluate the mobility of heavy metals in the soil and their availability to plants. The (almost) total contents of Zn, Pb, Cd in soil after first year of growing plants on contaminated soil not changed significantly in soil with organic amendments. The contents of bioavailable forms of heavy metals were reduced in soil with organic amendments, and the degree of this reduction depended on the type of the organic amendment used. The phytoavailability of tested heavy metals was the lowest when a brown-carbon derived preparation (the Rekulter) was used as an amendment, as indicated by the lowest BI.