By – Capt. Raj
• Anti-fouling paints are used to coat the bottoms of ships to prevent sealife such as algae and molluscs attaching themselves to the hull – thereby slowing down the ship and increasing fuel consumption.
• The new Convention defines “anti-fouling systems” as “a coating, paint,
surface treatment, surface or device that is used on a ship to control or prevent attachment of unwanted organisms”.
• In the early days of sailing ships, lime and later arsenic were used to coat
ships’ hulls, until the modern chemicals industry, developed effective antifouling paints using metallic compounds.
• These compounds slowly “leach” into the seawater, killing barnacles and
other marine life that has attached to the ship. But the studies have
shown that these compounds persist in the water, killing sea life, harming
the environment and possibly entering the food chain.
• One of the most effective anti-fouling paints, developed in the 1960s,
contains the organotin tributyltin (TBT), which has been proven to cause
deformations in oysters and sex changes in whelks.
• The adoption of the new Convention marked the successful outcome of the task set by Chapter 17 of Agenda 21 developed by the 1992 Rio Conference on Environment and Development. Chapter 17 called on States to take measures to reduce pollution caused by organotin compounds used in anti-fouling systems.
• The harmful environmental effects of organotin compounds were recognized by
IMO in 1989. In 1990 IMO’s Marine Environment Protection Committee (MEPC)
adopted a resolution which recommended that Governments adopt measures to
eliminate the use of anti-fouling paint containing TBT on non-aluminium hulled
vessels of less than 25 metres in length and eliminate the use of anti-fouling paints
with a leaching rate of more than four microgrammes of TBT per day.
• In November 1999, IMO adopted an Assembly resolution that called on the MEPC to develop an instrument, legally binding throughout the world, to address the harmful effects of anti-fouling systems used on ships. The resolution called for a global
prohibition on the application of organotin compounds which act as biocides in anti-fouling systems on ships by 1 January 2003, and a complete prohibition by 1 January
• This instrument was later adopted as the International Convention on the Control of
Harmful Anti-fouling Systems on Ships.