ABSTRACT
A number of metals and metalloids may undergo methylation under environmental conditions through chemical or biological processes or, in some cases, through a mixed biological and chemical process involving more than one metal. The possibility of biomethylation of lead under environmental conditions was first discussed in 1975. The element lead is a member of Group IVA in the periodic table. It is relatively highly polarizable. Arsenic, selenium, and tellurium have long been known to undergo biological methylation. Some forms of lead seem certain to undergo methylation under environmental conditions. Whether the methylation is a biological process or a purely chemical reaction is, however, under debate. Monomethyllead is very labile, however, and any reaction product, if formed, would decompose rapidly in aqueous solution. A number of metals and metalloids can be methylated under environmental conditions. Trimethyllead can be methylated into tetramethyllead in the laboratory under simulated environmental conditions, abiotically and, as it seems, also microbially.
