Tributyltin canned | WWF
Tributyltin canned

Posted on 17 September 2008

A milestone in the protection of the oceans was reached today as a global ban on tributyltin (TBT) - one of the most toxic chemicals deliberately released into the sea - entered into force.
A milestone in the protection of the oceans was reached today as a global ban on tributyltin (TBT) - one of the most toxic chemicals deliberately released into the sea - entered into force.

The International Convention on the Control of Harmful Antifouling Systems for Ships obliges its signatories to ensure that no vessels using hull paint containing TBT and other so-called organotin chemicals go under their flag or call at their ports.

"This is a tremendous victory for the marine environment, but one that is long overdue. It has been over forty years since TBT's negative effects were first identified and seven years since the legislation to ban organotins was agreed, yet we have only now achieved a global ban," says Dr. Simon Walmsley, Director of WWF-UK's Marine Programme.

Take-up of the agreement has been slow, with many of the large shipping states having yet to sign and implement the agreement into their national legislation. Whereas WWF is applauding the commitment of the 34 states that have ratified the agreement so far, the conservation organization urges all 168 member states of the International Maritime Organization (IMO) to ratify as soon as possible.

TBT is often used in marine antifouling paint, as it swiftly kills organisms such as barnacles, algae and mussels which naturally attach themselves to hard surfaces, including ship hulls, thus reducing the drag effect and lowering fuel consumption.

The problem is that TBT leaks out from the paint and into the surrounding water, affecting marine life and seeping into the food chain where it accumulates and eventually reaches humans through fish consumption.

Heard of sea snails changing sex, or oysters seeing their shell being deformed? These are but two known adverse TBT effects on marine species. The decline of commercially harvested oysters along the Atlantic coast of France and the UK has been attributed to TBT contamination. TBT has also been found far from shipping lanes in albatrosses, whales and fish.

But we have probably only begun to see the long term effects of TBT and other organotins on marine ecosystems, as the poison is stored in sediments for many years and can re-enter the food chain when the sea bottom is stirred up by passing vessels in ports and shallow areas, or even by storms and dredging activities.

“TBT belongs not in the sea but in the poison cupboard, and this agreement will help put it firmly back there,” says Stephan Lutter, International Policy Officer with WWF Germany.

WWF has been lobbying for the ban of TBT for more than a decade. At the end of the 1990’s, WWF, together with some leading shipping companies and paint manufacturers, initiated the 2003 Group, whose members voluntarily banned the use of TBT on their vessels and developed toxics-free alternatives.

Scandinavian Wallenius Wilhelmsen Logistics (WWL) banned the use of TBT in hull paint on all vessels in 2000.

“There are better alternatives which balance the need for antifouling with environmental stewardship. It is our responsibility to use them,” says Melanie Moore, WWL’s Global Head of Environment.

WWF continues to advocate for all vessels to apply biocide-free non-toxic alternatives.

Fore more information: Stephan Lutter, stephan.lutter@wwf.de and Jessica Battle jbattle@wwfint.org
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TBT has been shown to cause sex changes in dog whelks.
© Gordon Fletcher