Elemental mercury (Hg-0) re-emissions from slurries and solutions were evaluated in a lab-scale simulated scrubber. Oxidized mercury (Hg2+) standard solution was injected into the simulated scrubber at a desired rate to simulate absorbing and dissolving of Hg2+ in the flue gas across wet flue gas desulfurization (WFGD) systems. PS analytical mercury analyzer was used to continuously determine Hg-0 re-emission concentrations in the carrier gas from the scrubber. Sulfite ion in the slurry of CaSO3 was validated to reduce Hg2+ to Hg-0, while no Hg-0 re-emission occurred from slurries of CaSO4 and CaO. Transitional metal ions with low chemical valence such as Fe2+, Pb2+, Ni2+, AsO2- and Cu+ were used to prepare solutions with concentration levels of mmol.L-1. Reduction reaction of Hg2+ to Hg-0 was observed from these solutions. Reduction capabilities for the different transitional metal ions in the solutions were: Pb2+>Cu+>Fe2+> AsO2->Ni2+.