As the International Maritime Organisation (IMO) (1) meets to deliberate the use of organotin paints (2) in London this week (2-6 November 1998), disturbing evidence of their effects are coming from around the world. Sea otters are dying off the coast of America. Dolphins, whales, sea lions, sea birds and fish are being contaminated in the Atlantic and Pacific oceans. The poison affecting them all is tributyltin (TBT), considered to be one of the most toxic chemicals deliberately released into the marine environment.WWF has monitored the effects of TBT on marine biodiversity and is alarmed at the new reports from America. Dr Sian Pullen, Head of the WWF-UK Marine Programme, said: The use of organotins in antifouling paints should be banned as soon as possible. The toxic effects of these chemicals on marine wildlife has been reported for over twenty years and now we are seeing sea otters dying, dolphins and seals livers are being poisoned by this highly toxic substance. The only way forward lies in a world-wide ban on the use of organotins in antifouling paints by 2001 and the development of environmentally friendly alternatives.
A joint programme in Germany between WWF, ship owners, paint manufacturers, government and academic bodies (3), has been evaluating alternative biocide free paints and have just had the first results back which show clear evidence that organotin and biocide free paints do work. By 2001 a range of alternatives to TBT-based paints will be well established making this ban a realistic proposition for the IMO.
TBT is being used in antifouling paints applied to ships hulls to stop marine creatures sticking to the bottom of them. The TBT from the paint migrates into the surrounding sea water and accumulates in sediments around harbours and along shipping lanes. This is then ingested by marine invertebrates and gets in to the food chain.
TBT continues to pose a threat to marine wildlife, not only to their food base, but directly to their health and reproductive success by interfering with sex organ development (4). TBT also attacks the thymus gland , suppressing the immune system, reducing the animals ability to fight infection and making them more susceptible to disease.-Ends- For more information please contact David Cowdrey, Press Officer, WWF-UK on 01483 412386 Dr Sian Pullen, Head of WWF-UK Marine programme on 01483 412519 Dr Patricia Cameron, Marine Pollution Prevention Officer, WWF-Germany on 0049 421 658 4616 Notes to Editors
1) The International Maritime Organisation is the UN body responsible for regulating shipping activity internationally. An opportunity exists this week for countries worldwide to agree an IMO Resolution endorsing a global ban on organotin use in antifouling paints by 2001.
2) Organotins are a family of chemicals including tributyltin (TBT). They are highly toxic and are used in antifouling paints.
3) WWF-Germany is working with three environmental Ministries, nine ships, nine paint manufacturers, seven dockyards and two research institutions investigating biocide-free alternative technologies for antifouling. Each ship is cleaned and an alternative paint applied (several per hull). The ships then operate on a normal basis. The vessels are inspected by scientists every two months. The aim is to assess which alternatives can be recommended as effective substitutes to organotin antifouling paints. A number of existing ecological alternatives are being tested - self-polishing, antifouling paints without biocides; non-toxic, non-stick coatings to prevent settling, and hard coatings in combination with special cleaning procedures. Other methods include electro-chemical methods and self-polishing antifouling paints with biogenic biocides.
4) Imposex is the condition seen in female dogwhelks exposed to TBT. Exposure results in the development of a penis which blocks the oviduct. When the females become egg bound, it tears apart the dogwhelk resulting in the death.
5) WWF can provide a list of contact details for some of the companies which produce non-TBT based paints.Scientific Papers Kurunthacalam Kannan, Keerthi S. Guruge, Nancy J Thomas and John P Giesy. Butyltin residues in Southern Sea Otters found dead along California Coastal Waters Environ. Sci. Technol. 1998, 32 1169-1175. Henderson, Shirley. Sea otter decline, Marine Pollution Bulletin, 1989, 36 page 565. WWF Fact sheet, Organotin compounds, October 1993. Marine Update 21: Marine Pollution by Triorganotins, May 1995. (The above press release was issued by WWF UK)