Tributyltin (TBT) was previously used to prevent marine organism growth on ship and boat hulls, but has been banned in Australia since 2008.
In 2006, sampling by the Department of Environment and Conservation and Swan River Trust revealed high levels of TBT around yacht clubs and marinas on the Swan River.
Since then, the Trust has been working with yacht clubs and marinas to ensure there is no ongoing release of TBT to the river.