Searching for manganese pollution from MMT anti-knock gasoline additives in snow from central Greenland

Mn has been measured in snow core samples dated from 1967 to 1989 collected in central Greenland. Observed concentrations range from 16 to 236 pg g(-1 ). A large fraction of Mn in Greenland snow is found to originate from rock and soil dust. The different possible natural sources for 'excess' Mn abov e that contributed from rock and soil dust include volcanoes, natural veget ation fires and continental biogenic emissions. They could explain part of the observed excess. At least part of it is, however, probably related to a nthropogenic inputs, especially from North America. Aside from industrial s ources, MMT (methyl-cyclopentadienyl manganese tricarbonyl) anti-knock gaso line additives are good candidates, but our data do not allow to clearly id entify their influence. Unambiguous identification will require the direct determination of organo-Mn compounds in comprehensive series of Greenland s now samples with sub-seasonal resolution using highly sensitive speciation techniques. (C) 1998 Elsevier Science B.V. All rights reserved.