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Competency Area 5: Soil pH and Liming

PO 43. Identify how biosolid application and soil pH affect heavy metal availability to plants.

In general, heavy metal availability is highest at low pH.  Thus, liming can decrease heavy metal availability; at low pH these heavy metals could become toxic.  Biosolids can contain heavy metals, while some biosolids might also be lime-stabilized, resulting in a pH increase upon application.