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Lookup NU author(s): Emeritus Professor Stewart Evans
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Effective antifouling brings enormous economic benefits to the shipping industry. There are also indirect environmental benefits. Ships with clean hulls use less fuel, reducing emissions of 'greenhouse' and 'acid rain' gases, and they also provide less opportunity for 'invasive' species to hitch-hike across the world's oceans. The use of tributyltin (TBT), first in free association paints and then in self-polishing copolymers (TBT SPC), were breakthroughs for the paint industry-they are the most efficient antifoulants ever devised. Unfortunately, TBT leaches from the paints into the water column and caused harm to some non-target organisms, particularly during the period when it was used solely in free association paints. The best-documented impacts are on cultivated oysters Crassostrea gigas in west France and dogwhelks Nucella lapillus in Britain, but similar impacts were described worldwide. The use of TBT-based antifoulants was regulated in several countries during the 1980s and early 1990s. In most cases, their use was prohibited on small vessels (<25 m in length) which were believed to be the main cause of contamination in coastal waters. These regulations have been effective in reducing ambient levels of TBT in the water column, sediments (although less so) and in the tissues of marine organisms. Open waters are now largely free of contamination at biologically harmful levels but commercial harbours, especially those with dry docks, are still hot-spots of contamination. Nevertheless, even in these cases, impacts are localised. The International Maritime Organisation is likely to ban the use of TBT-based paints altogether in the near future but there is a danger that this measure will be introduced prematurely. The ban should not be enforced until alternative antifoulants are available which perform as well as TBT-based coatings on economic and environmental cost-benefit analyses.
Author(s): Evans SM
Editor(s): Sheppard, C
Publication type: Book Chapter
Publication status: Published
Book Title: Seas at the millennium - an environmental evaluation
Year: 2000
Volume: 3
Pages: 247-256
Print publication date: 01/01/2000
Series Title: Global issues and processes
Publisher: Pergamon
Place Published: New York, Oxford
Library holdings: Search Newcastle University Library for this item
ISBN: 0080432077
