To prepare the final concentration of 1 lg Hg g1, the mine
soil sample (1.76 lg Hg g1) was mixed with control soil. For the
other two concentrations, the mine sample was fortified with a
mercury nitrate solution [Hg(NO3)2: 50 g L1] to adjust Hg concentration
levels to 5 ± 0.08 and 10 ± 0.09 lg Hg g1.