Tributyltin TBT

Hoch M, Alonso-Azcarate J, Lischick M (2003) Assessment of adsorption behaviour of dibutyltin (DBT) to clay-rich sediments in comparison to the highly toxic tributyltin (TBT). Environmental Pollution, 123(2) 217-227. 

Butyl- and phenyltin compounds, particularly the trialkylated forms are very toxic to marine life. The antifouling paints, mainly tributyltin (TBT) but also triphenyltin (TPhT) caused and continue to cause substantial damage because of their slow biodegradation and their accumulation in the biota, notwithstanding a substantial reduction in application through multi-national regulation). 

FIGURE 5. Tributyltin (TBT) and triphenyltin (TPT) levels in shortnecked clam collected in Tokyo Bay (1980-1987) (modified from Reference 65)... 

Dowson and coworkers studied partitioning and sorptive behavior of tributyltin (TBT) and its degradation products, dibutyltin (DBT) and monobutyltin (MBT) in the aquatic environment107. The determination of the sorptive behavior of TBT is necessary in order to understand its fate in freshwater and estuary environments. The results indicate that MBT and TBT in freshwater will be partitioned to a lesser extent towards the particulate phase, whereas DBT exhibits a 50 50 partitioning between the particulate and solution phases. In estuary waters, MBT will almost exclusively be adsorbed on the particulates, while TBT will be predominantly in the solid-phase fractions but 10-30% may remain in solution. DBT, in contrast, is solubilized in estuary waters. The order of adsorption to particulate matter for butyltins is MBT > TBT > DBT107. 

Bryan, G.W., P.E. Gibbs, G.R. Burt, and L.G. Hummerstone. 1987. The effects of tributyltin (TBT) accumulation on adult dog-whelks, Nucella lapillus long-term field and laboratory experiments. Jour. Mar. Biol. Assoc. U.K. 67 525-544. 

Two other examples of the behaviour of chemicals in sediments and the effects on benthic organisms will be reviewed here to illustrate the complexity of these problems. The first deals with silver and the second with tributyltin (TBT). 

To explain the working mechanisms of an antifouling paint we will here use the well-known tributyltin (TBT)-based paint. The reason for this is that this paint type has been thoroughly characterised over the years (Kiil et al., 2001, 2002a,b,c, 2003). Other modem antifouling paints appear to have similar working mechanisms (Yebra et al., 2004). 

In another set of experiments the effeet of exposure of field and cultured E. cordatum to tributyltin (TBT) spiked sediments was eompared. The results are presented in Fig 5. The meas ured eoneentrations of TBT in the spiked sediment after 14 days exposure ranged from 9.6 to 16,646 pg Sn/kg dry weight and eonsisted of 82 to 98 % of the nominal concentrations. TBT concentrations of 4,346 pg Sn/kg dry weight eaused 100% mortality in both field and cultured ii. cordatum. Cultured heart urehins are less sensitive to TBT spiked sediments than field urchins. Mortalities were observed at eoneentrations above 1,525 and 702 pg Sn/kg dw respectively for cultured and field E. cordatum. 

Choi, M., Choi, H., Moon, H. and Kim, G. (2009). Spatial and temporal distribution of tributyltin (TBT) in seawater, sediments and bivalves fiom coastal areas of Korea during 2001—2005, Environmental Monitoring and Assesse-ment. Volume 151,Numbers 1-4,301-310. 

An even more pronounced case involves the sorption of the two biocides, tributyltin (TBT) and triphenyltin (TPT) to AHA. Because of their very high toxicity toward... 

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