Heavy metal pollution of soil, as demonstrated by , is associated with higher levels of these metals, lower levels of organic matter and nutrients, a decreased ability to retain water, and a decreased ability to exchange ions.High concentrations of heavy metals in soil negatively impact the soil biota by interfering with important microbial activities and lowering microbial activity and abundance . By changing the microbial population that oversees synthesising enzymes, these metals also have an indirect effect on the activity of soil enzymes .