Welcome to Boating School!
While researching on this week’s theme, it reminded me a lot of the boats Spongebob drove in Bikini Bottom…
See the red bottom of the boat? That’s antifouling (AF) paint, which is actually pollutive.
Last week, we learnt about the pollutive aspects of cruise ships in the context of tourism (e.g. fecal waste and chemicals). This week, we’ll be exploring pollution generated by boat maintenance. More specifically, heavy metal pollution by antifouling paint for biofouling prevention on boats.
Biofouling and antifouling (AF) paint
Biofouling refers to the accumulation of undesirable biological material such as barnacles on the surfaces of submerged boats (Lagerström, Norling & Eklund, 2016; Bighiu, Eriksson-Wiklund & Eklund, 2017).
The presence of such organisms are undesirable as they impede the boat’s ability to maneuver through waters which increases fuel consumption by up to 40% (Eklund & Eklund, 2014). If you need a visual representation on how biofouling occurs, check out the short video (till 0.55 min) below!
This means that as long as a boat is used, boat maintenance must be carried out to prevent biofouling. The process includes sandpapering and scraping the boat hull, then coating it with antifouling (AF) paint to prevent the growth of undesirable organisms (Eklund & Eklund, 2014).
The problem? Heavy metal pollution.
Antifouling paint is considered toxic since heavy metals are used, where copper (Cu) and zinc (Zn) are the most abundant. Cu is used extensively as cuprous oxide (Cu₂O) acting as a base material and primary active ingredient since it prevents barnacles well (Wang et al., 2008; Bighiu, Eriksson-Wiklund & Eklund, 2017). Zn is found as zinc oxide (ZnO) or in combination with Cu (Lagerström, Norling & Eklund, 2016) as a binder (Eklund & Eklund, 2014) in the paint. Since heavy metals are used in large quantities, antifouling paint results in heavy metal pollution which poses problems on soils, aquatic organisms and human health. For instance, a study by Bighiu, Eriksson-Wiklund and Eklund (2017) found high concentrations of Cu (up to 28,000 mg copper/kg dw) and Zn (up to 171,000 mg zinc/kg dw) in biofouling waste, exceeding guidelines in Sweden by 140 and 340 times respectively!
Links to consumerism
Perhaps less of a concern in Singapore, heavy metal pollution from antifouling paint is worrying in the Nordic countries (such as Finland, Denmark and Sweden) whose boats account for half of the amount of recreational boats in Europe (Eklund & Eklund, 2014). Sweden – which has one of the highest recreational boat densities globally of eight boats per adult (Sjöhistoriska, 2016) – houses 1 million boats, accounting for half of the total in the Baltic Sea (Bighiu et al., 2017). Once an elitist activity, recreational boating is now immensely popular among locals and tourists alike with no sign of fading (Sjöhistoriska, 2016). In 1929, mass production popularised recreational boats in Sweden since the affordable prices empowered more people to own boats (Sjöhistoriska, 2016).
Not just recreational boats, the consumerist culture has contributed to ballooning numbers of ships – from oil tankers to transport oil to fuel our vehicles and everyday activities, to container ships to facilitate the booming transboundary trade of goods. According to the United Nations Conference on Trade and Development (UNCTAD), there were 1,861,852 of such ships in 2017, which was a 3.15% increase from the previous year. Imagine the sheer amount of antifouling paint used… In fact, it is estimated that 30,000 tons of antifouling paint is consumed annually by commercial ships alone (Wang et al., 2008)!
Hmm makes me wonder how serious the problem of antifouling paint is…
Next “lesson”, join us as we explore the effects of heavy metal pollution on soils!
References:
Bighiu, M.A., Eriksson-Wiklund, A. & Eklund, B. (2017). Biofouling of leisure boats as a source of metal pollution. Environmental Science and Pollution Research. 24(1), 997-1006. Available from: 10.1007/s11356-016-7883-7.
Eklund, B. & Eklund, D. (2014). Pleasure boatyard soils are often highly contaminated. Environmental Management. 53(5), 930-946. Available from: 10.1007/s00267-014-0249-3.
Lagerström, M., Norling, M. & Eklund, B. (2016). Metal contamination at recreational boatyards linked to the use of antifouling paints—investigation of soil and sediment with a field portable XRF. Environmental Science and Pollution Research. 23(10), 10146–10157. Available from: 10.1007/s11356-016-6241-0.
Sjöhistoriska (2016). The history of the pleasure boat. Available from: https://www.sjohistoriska.se/en/ships-boats–networks/the-history-of-the-pleasure-boat [Accessed 30 August 2020].
United Nations Conference on Trade and Development (2017). Review of maritime transport 2017. Available from: https://unctad.org/en/PublicationChapters/rmt2017ch2_en.pdf [Accessed 30 August 2020].
Wang, J.L., Wang, F.Q., Yu, J. Zhuang, Y., Zhou, X.F., Zhang, X.B. & Peng, B.X. (2008). A survey analysis of heavy metals bio-accumulation in internal organs of sea shell animals affected by the sustainable pollution of antifouling paints used for ships anchored at some domestic maritime spaces.中国科学通报:英文版 53(16), 2471-2475. Available from: 10.1007/s11434-008-0355-9.
Images:
News Wheel (2017). The 5 best “SpongeBob SquarePants” boating school episodes. Available from: https://thenewswheel.com/the-5-best-spongebob-squarepants-boating-school-episodes/ [Accessed 30 August 2020].
Pinterest (n.d.). Watch Spongebob. Available from: https://www.pinterest.com/pin/431853051745085900/ [Accessed 30 August 2020].
Richards, N. (2018). Changes to biofouling regulations in New Zealand. Available from: https://www.sail-world.com/news/202672/Changes-to-NZ-Biofouling-Regulations [Accessed 30 August 2020].
Ships Business (n.d.). Effective use of anti-fouling paints in marine environment. Available from: http://shipsbusiness.com/anti-fouling-paints.html [Accessed 30 August 2020].