where, Md (mmol/kg) is the amount of the heavy metal
desorbed by KNO3, Ma (mmol/kg) is the amount of the
heavy metal adsorbed by the soils. The results of the
desorption percentage for Cu(II) and Pb(II) (Table 3) show
that all the desorption percentages are less than 100%,
which is consistent with the previous reports (Nriagu,
1980). This suggests that the heavy metal desorption from
the soils was incomplete and not fully reversible.