A search for an extracellular extractant of Hg for use in the sequential elution technique with Pseudoscleropodium purum

AbstractThe extraction efficiency of several metal cations (50 mM CoCl2, 20 mM NiCl2, 30 mM Pb(NO3)2 and 50 mM SrCl2) and chelating agents (30 mM dimercaprol, 10 mM EDTA and 50 mM D-penicillamine) was evaluated in order to determine the optimal extracellular extractant for extracting Hg from the moss Pseudoscleropodium purum, by the sequential elution technique (SET). Moss samples were incubated with a high concentration of Hg (40 μg L–1) for one hour, and after the intercellular fraction was removed, the samples were subjected to the SET with the above-mentioned extractants. The chelating agents dimercaprol and D-penicillamine displaced most extracellular Hg, probably because both contain -SH groups, which have a high affinity for Hg. Dimercaprol was chosen as the best extractant because it displaced up to 93% of the extracellular metal. This compound was then used to extract Hg in an industrial gradient of Hg contamination, and the concentration of extracellular Hg was calculated relative to the total a...