Methylgermanium in natural waters

Abstract

Biological methylation of metallic elements1 and the occurrence and cycling of organometals in the environment have been investigated in Japan during the 1950s and 1960s, where the ingestion of fish and shellfish contaminated with methylmercury compounds caused mercury poisoning2,3. Biomethylation ability has been demonstrated in bacteria, fungi and algae for As, Cd, Hg, Pb, Se, Sn, Te and Tl4–7. Naturally-occurring methylated species have been reported in estuaries and seawater for Sb8, As9, Ge10–13 and Sn14, although recent evidence suggests that some reports of methyltin species result from interferences by Ge and volatile sulphur compounds15. With the exception of Sb8, As9,12,16 and Ge11,12, there are no consistent estuarine or oceanic profiles for methylmetal compounds in the literature from which to judge their biogeochemical behaviour. Early investigations17–19 reported that methylgermanium species do not exist in the aquatic environment. Subsequently, we identified monomethylgermanium (MMGe) and dimethylgermanium (DMGe) in estuaries10,12, the Baltic Sea11 and the Bering and Sargasso seas13. We report here recent measurements of methylgermanium compounds in river water, estuaries, seawater and anoxic basins.