GC–MS Analysis of Marine Organotin Pollution

The ban on organotins (OTs) has not led to a significant reduction in marine pollution according to research published by the Polish Academy of Sciences (1). Researchers found unacceptable levels of harmful organotins in the muscle and liver tissues of fish species collected in the Southern Baltic Sea coastal zone exceeding the good environmental status (GES) boundaries.

Organotins have for decades been used in anti-fouling coatings intended to prevent the settlement and growth of aquatic organisms on structures such as ship hulls, fish cages, and oil rig supports. However, a spate of studies highlighting the toxic effects of OTs on the wider marine environment led to a reassessment of their use. In particular, OTs such as tributylin (TBT) and triphenyltin (TPhT) were found to disrupt the endocrine system of organisms, resulting in sterility and species extinction (2,3).

After considerable legislative debate the International Convention on the Control of Harmful Anti-fouling Systems on Ships (AFS Convention) came into force on the 17th September 2008 globally (4), European Union (EU) flagged ships and ports complied with the convention requirements starting July 2003 (5). The convention aimed to ban the application of organotin anti-fouling paints on ships in the hope of reducing OTs contamination levels.

To assess the success of this ban researchers collected fish samples from three different marine environments along the Baltic Sea. The Gulf of Gdańsk, known for large international seaports, marine traffic, and large scale shipyard acitivty, the Vistule Lagoon, dominated by freshwater flora and fauna with fishing harbours and marinas, and the Szczecin Lagoon a key point in the Odra River estuary which acts as a ‘biological filter’ for river waters and the city of Szczecin.

Muscle and liver tissues from the fish species were subjected to sonication extraction, followed by derivatization. Samples were purified before extracts were injected into a gas chromatographic system coupled with a mass spectrometric detector (GC–MS). Organotin concentrations were determined on the basis of response factors derived from daily repeated injections of a standard mixture of derivatized compounds (CHIRON).

Results indicated that in the six to seven years since the total ban was fully implemented concentrations of butyltins (BTs) in fish muscles and livers have remained high in comparison to pre-ban concentrations, TBT samples exceeded GES boundaries recommended in the HELCOM (Baltic Marine Environment Protection Commission) CORESET for TBT in seafood.

The presence of OTs isn’t surprising as they are known to reside in sediments for years and not degrade (6,7), however, these results highlight the importance of continued studies into the subject and the authors recommend that OTs continue to be monitored in marine environments because of the threat butyltins can pose to marine life.

References

1. Filipkowska et al., Mar. Pollut. Bull. (In Press) http://dx.doi.org/10.1016/j.marpolbul.2016.06.052
2. C. Alzieu, Ocean Coast. Manag. 40, 23–36 (1998).
3. M. Hoch, Appl. Geochem. 16, 719–743 (2001).
4. International Maritime Organization (IMO), International Convention on the Control of Harmful Anti-fouling Systems on Ships (2001).
5. European Union (EU), Off. J. Eur. UnionL115/1 (2003).
6. P.H. Dowson, J.M.Bubb and J.N. Lester, Estuar. Coast. Shelf Sci. 42, 551–562 (1996).
7. I. Takahashi et al., Mar. Environ. Res.57, 397–414 (2004).