Hi everyone!
In the final instalment of this 2-part series on toxic CECs, today’s post will endeavour to uncover some of the toxic truths about anti-fouling paints and their harmful effects on marine organisms such as crustaceans, whales, dolphins and even human communities.
Crustaceans
According to Roach (2019), TBT is especially toxic to crustaceans as its contamination can engender deformation and shell thickening in mature oysters, reducing rates of overall larval success. In dog whelks in particular, TBT contamination can cause female dog whelks to start developing male characteristics which may result in sterilisation and death. Moreover, it was observed that even minute amounts of TBT have culminated in abnormal growths in oysters and clams, slowing their reproduction and weaking their exterior shells.
Whales and Dolphins
Source: Turner (2010)
Roach (2019) further elucidates that TBTs have also entered into deep-water food chains, and have often been found in pelagics such as whales and dolphins as well. This is the case for whales such as humpbacks and blue whales who are placed at higher risks of ingesting TBTs due to more intense bio-concentration up in the food chain, as they feed on tiny organisms and krill. What is concerning is that filter-feeding whale calves that nurse on their mother’s milk are placed at greater vulnerability to TBT contamination as they are also feeding higher up food chains.
The ubiquity of TBT poisoning due to anti-fouling paint fragments is another cause for concern, especially in dolphin deaths. Roach (2019) posits that while dolphin die-offs may be frequently ascribed to bacteria, parasites and viral diseases, scientists recently discovered that the culprit of declines in the dolphin population is due to coastal water pollution. Not only is TBT extremely toxic, but it also constrains dolphins’ resilience in fighting infections and diseases. In fact, scientists discovered large concentrations of trace remnants of TBT in the brain, heart, liver, blubber and kidney of dolphins residing in coastal waters. Therefore, this led scientists to confirm that TBT was both a potent immune suppressor in marine mammals, and that coastal dolphins were more likely to be contaminated with TBT as opposed to other dolphin species in offshore waters. Thus, this leads Schubert (1997) to posit that the intensification of coastal shipping and greater use of anti-fouling paints on coastal boats has resulted in greater exposure (Schubert, 1997 as cited in Roach, 2019).
Dear reader, I hope that this post has jolted you to the realities of CECs, anti-fouling paints and the insidious effects of TBT, and the need to find an alternative that has minimal environmental impacts. If you’re not yet convinced, consider this – humans are constantly at risk of TBT contamination. In particular, shipyard workers repainting ships with anti-fouling paints are often exposed to TBT vapours and dust. This has culminated in adverse health effects such as breathing problems, skin irritation and liver and kidney damage with extended exposure.
References:
Roach, H., 2019. The Effects of Tributyltin on the Marine Environment. [online] ScienceBuzz. Available at: <https://www.sciencebuzz.com/the-effects-of-tributyltin-on-the-marine-environment/#:~:text=TBT%20is%20extremely%20toxic%20to,both%20oyster%20and%20scallop%20harvests.>
Turner, A., 2010. Marine pollution from antifouling paint particles. Marine Pollution Bulletin, 60(2), pp.159-171.