EFFECTS OF LONG-TERM BIOSOLIDS APPLICATIONS ON PHYTOAVAILABILITY OF SOIL CADMIUM AND ZINC

Collect soils and bioassay phytoavailability of Cd, Zn and Cu in soils unamended or long-term biosolids amended soils with pH made equal, to characterize changes in the metal binding equilibria of the paired soils, in relation to properties of the biosolids or soils. Evaluate changes in Fe or Mn oxides or humics which could cause observed changes in metal uptake. Collect soils from Pb contaminated sites to evaluate the effect of phosphate and biosolids.