Sampling and analysis of mercury species in effluent gases derived from waste incineration

Mercury and its compounds are highly toxic. Therefore, the determination of mercury species present in flue gases from combustion sources is extremely important. Mercury is initially emitted from the combustion chamber as mercury vapour. However, as the combustion products cool the mercury vapour can react with a variety of other flue gas components to form a range of inorganic and possibly organic mercury species. The diversity of mercury compounds which could form means that a sampling and analysis procedure is needed which can determine the elemental, inorganic and organic mercury content of the flue gases. This would allow appropriate clean-up procedures to be employed and, if necessary, the modification of the process to eliminate the formation of particularly toxic mercury species. In this work a sampling train has been developed using model mercury compounds to efficiently trap elemental, inorganic and organic mercury from a hot gaseous environment. Chemical analysis of the sampling mediums was carried out by HPLC-UV to speciate between inorganic and organic mercury.