Heavy metal mobility in biosolids-amended glaciated soils.

Abstract

The mobility of heavy metals from one-time application of biosolids (i.e., compost, pellet, and cement kiln dust stabilized biosolids) onto glaciated soils (Paxton soil) was studied because previous work on metal leachate characteristics from different biosolids is limited for glaciated soils. Two types of batch tests were performed: first, a pH-edge adsorption study to evaluate the effect of pH on heavy metal adsorption to Paxton soil and, second, a pH-edge leaching study to evaluate the effect of pH on the leaching potential of heavy metals from biosolids-amended Paxton soil. Finally, a semicontinuous soil column study was performed to assess the mobility of heavy metals from biosolids-amended Paxton soil. The pH-edge leaching results showed that the leaching potential of heavy metals was lower with the compost product. Desorption concentrations for arsenic, chromium, and lead were found to be greatest in the cement kiln dust stabilized product whereas cadmium, copper, and nickel were present at the greatest concentrations in the pellets. The total organic carbon results measured during the pH-edge leaching study indicated that there is a minimum leachable concentration in the pH range of 4 to 5 for all three biosolids. Overall, the column studies indicated that heavy metals were not readily leached from the three biosolids-amended Paxton soils. The results from this study suggest that a one-time land application of these biosolids will not adversely affect groundwater quality.