Organotin compounds

OTC, organostannic compounds; formula: R(n)SnX(4-n)

Class of organometallic compounds of tin

Organotin compounds occur naturally as methyl-compounds. All other organotin compounds result from anthropogenic activities.
Mono- and Dibutyltin compounds are used as stabilizers in PVC production and as catalysts for silicones and polyurethane foams. Triorganotin compounds are effective biocides and are used, e.g., as pesticides, antifouling agents, wood preservatives, disinfectants and as preservatives for materials such as textiles, leather, synthetics, adhesives and paints. Octyltin compounds are also used as PVC stabilisers mainly in food packaging, whereas tetraorganotin compounds are needed for the synthesis of tri-, di-, und monoorganotin compounds.

Organotin compounds may enter the environment during production, uses (e.g. leaching of mono- and diorganotin compounds from PVC pipes) and application (e.g. triorganotin compounds in antifouling agents, biocides etc.).

Under anaerobic conditions these compounds are persistent. They have a high potential for bioaccumulation which is, however, highly dependent on the respective biota species.

The toxicity of organotin compounds depends on nature and number of the alcyl- and aryl-substitutes. Basically, the toxicity ranks as follows: Mono- < Di- << Tri- >> Tetra-organotin compounds.

Since 2003, antifouling agents containing tributyltin compounds are banned in the EU. Since 2006, marketing of biocides containing tributyltin- and triphenyltin-compounds is banned.

Substances

Tributyltin Organometallic compound of tin with three butyl groups
Triphenyltin Organometallic compound of tin with three phenyl groups

Specimen

Bream Bioindicator in rivers and lakes
Blue mussel One of the most important edible mussel species common in the North and Baltic Sea
Eelpout As the only viviparous fish in German nearshore waters, it is a bioindicator in nearshore coastal marine ecosystems.

Sampling area

Saarländischer Verdichtungsraum Important, old-industrialised conurbation in Germany.
Bornhöveder Seengebiet Main water divide between the North- and Baltic Sea
Rhein Longest river in Germany
NP Vorpommersche Boddenlandschaft National Park in the largest brackish water (Bodden) habitat of the world.
BR/NP Wattenmeere National park in the world largest connected sand and mud flats.
Elbe Fourth largest river basin in Central Europe
Verdichtungsraum Halle-Leipzig Region in the chemical triangle of Central Germany

Sampling period

1985 - 2006