The previous posters have described the difficult chemistry
associated with removing inorganic S from material, and Stribling raises the
interesting question of whether all inorganic S be considered a "contaminant"
and removed. I am using S isotopes as tracers of food webs, so what I am
really interested in is "what is the isotopic signature of the biologically
available S in plant or animal tissue?"  So, my next question is, do animals
assimilate inorganic S from their food into biomass? (my assumption has been
it is little or none) Maybe not an "Isogeochem" question, but just to put the
issue of organic vs. inorganic S into the context of the ecological question.

Carolyn Currin