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Vessel Antifoulants:
Some history and new technologies...
A new approach to vessel antifouling in Australia (some current testing in Tasmania)
www.qwikskin.com/
Alternatives to toxic antifoulants (Denmark)
www.mst.dk
A new non-toxic antifouling paint (Denmark)
www.biolocus.com
Naturally occurring marine antifoulant research (European university research)
www.esmb.org
Links
Research and testing in the USA
www.poseidonsciences.com
History...
(Exerpt from Poseidon Newsletter)
Marine research demonstrates how fragile ocean ecosystems can be. Scientists working in this field have shown how readily chemicals, such as pesticides and industrial wastes, generated in the last 50 years of the chemical revolution threaten human health and earth biodiversity. Among these persistent organic chemical pollutants is tributyl tin (TBT), a toxic heavy metal incorporated in marine paints to prevent algae, oysters, mussels, barnacles, tube worms and other fouling organisms attaching themselves to the submerged portion of the ship hull. Biofouling impedes the movement of ships and assists corrosion.
The earliest recorded attempts by mariners to prevent fouling dates back to the 5th century BC. In 1625 William Beale was the first to file a patent for a paint composition containing iron powder, copper and cement. Further advances did not come about until after the Second World War with the chemical revolution producing a range of industrial chemicals for new industries.
TBT PROVIDED THE BREAKTHROUGH. A major breakthrough in antifouling technology occured in the 70's when paint companies began to use TBT as a toxicant. The development of self-polishing paints that continously released TBT revolutionised the ship coatings industry and permitted longer intervals between dry-docking. However, unbeknown to its original designers, the long-term performance of TBT-impregnated paints carried with a heavy environmental price. By the '80's and '90's, TBT was blamed for environmental damage in marine ecosystems to such an extent that the International Maritime Organization (IMO) of the United Nations passed a resolution, banning the application of TBT-containing paints by 2003, and enforcing a total ban on the presence of TBT on all ships by 2008.
This is a harbinger of hard times for the industry as different compounds are likely to be banned. The IMO Resolution and the Biocidal Products Directive of the European Union (EU) are recent examples of tighter regulatory control. In December 2000, 122 countries signed an international treaty that banned 12 of the most toxic persistent organic pollutants. This is a harbinger of hard times to come for the biocides industry, as different compounds are likely to be added to the list. Companies willing to take a long-term view will have to re-think how their R&D funds will be allocated and focus on identifying new biocides that will survive a more difficult regulatory environment.
BEYOND THE SHORT-TERM SOLUTIONS. The initial reaction of the coatings industry was to develop TBT-free antifoulings. Although this has led to innovations in formulation, such changes have only provided solutions to near-term needs. Many companies have optimised their coatings formulation by increasing the copper content of their paints or including biocides to augment the reduced efficiency of cuprous oxide alone. With these new developments came increases in cost, often to two or three times that of conventional TBT-based coatings. Zinc-and copper-based biocides are non-specific, retain toxic effects and will come under regulatory pressures. With silicone-based technologies, high price alone is not a deterrent to market entry. Such non-stick coating technologies use surfactants and oils, which are toxic to marine life, and are likely targets for future regulations.
Cuprous oxide is a toxicant and an essential component of coatings. Though necessary in trace amounts for normal cellular function, toxicity occurs when cells are overloaded with copper because there is no existing mechanism for cells to remove this heavy metal from their cytoplasm.
CUTTING OUT COPPER. In response to the elevated copper load in marinas, the recent working conference sponsored by the University of California Sea Grant in September recommended copper reduction programmes and advocated promoting alternative options to copper in antifouling paints. This conference is indicative of the move toward a pro-environment stance that may eventually lead to the eventual ban on copper in the years to come in the same way that TBT has now been banned. While it has taken over a decade to ban TBT, it is likely that regulatory control of other heavy metals, like copper, will move at faster pace.
The adoption of the Precautionary Principle as a guide to determine legislation against the continued use of chemical entities presents a new paradigm. This states that action should be taken against a chemical when there is sufficient evidence to prove that it threatens human and animal health, even in the absence of conclusive evidence. The search for compounds to replace TBT and other biocides has stricter requirement for safety than ever before.
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