Organotins: their analysis and assessment in the Elbe river system, Northern Germany

Organotins have been analyzed using a new derivatisation technique in wet sediments by ethylation with NaBEt₄ and a GC/AAS coupling for separation and detection. In this way the Sn(IV) and the monoalkylated compounds could also be analysed more easily than by the Grignard derivatisation method used by other authors. Organotins are present not only as expected in the harbours, shipyards and the pleasure boat areas but also in the river itself, upstream of these places. Ships are thus not the only sources. An organotin production plant on the banks of a tributary, the Mulde river, is characterised by high tetrabutyltin and lower tributyltin amounts along the river to its mouth over 350 km away. The concentrations are up to 14 mg tetrabutyltin (Sn)/kg sediment. The superimposed patterns are from ship antifouling paints, characterised by a high content of tributylin in different stages of degradation to di and monoalkylated compounds; this shows the bacterial degradation possibilities for organotins in the river. In general, organometallics are a contaminant of great concern in the Elbe river system.