Investigations into mercury control across conventional scrubber systems have precipitated questions concerning (1) the initial speciation between oxidized and elemental forms of mercury in flue gas from coal-fired boilers and subsequently, (2) the effects of scrubber slurry composition and pH on the mercury forms. Mercury capture in scrubber slurry is highly dependent on its own form. Oxidized mercury is highly water-soluble and can be removed by scrubber slurry, whereas elemental mercury is not and passes through the scrubber to the stack. The objectives of this project are to determine whether scrubber solutions convert either form of mercury to another and whether mercury capture is affected by pH.