Toxic Ship Paint Pollutes Mediterranean Sea

ATHENS, Greece, September 5, 2000 (ENS) - Paint used to protect ships from algae and barnacle growth is polluting the Mediterranean Sea off the coast of Greece, according to research commissioned by the environmental group Greenpeace.

Tests carried out on sediment taken from Piraeus and Thessaloniki harbors and the sea close to popular swimming beaches around Salamina island found high levels of toxic tributyl tin (TBT) and other organotin compounds.


Thessaloniki harbor. (Photo courtesy University of Thessaloniki)
In sufficient amounts TBT can cause headaches, vertigo, eye irritation, psycho-neurological disturbance, vomiting, urine retention and skin burns in humans. But only trace amounts poison molluscs such as clams, oysters, and mussels. Molluscs and other bivalves filter clean water so even tiny amounts of TBT build inside them.

TBT disrupts the immune and endocrine systems of marine shellfish, leading to the development of male sex characteristics in females, an effect known as imposex. It has been detected in the tissues of marine mammals, such as seals, sea otters and water birds and shellfish around the world.

A recent submission by the governments of Italy, the Netherlands, Portugal and Spain to the International Maritime Organization (IMO) reported numerous examples of imposex in marine species off the coasts of southwestern Spain, Sicily and Portugal. It said that imposex is common in whelks in the North Sea and had recently been found to be disrupting the hormones of snails.

A problem that has long plagued engineers is how to manufacture paint for the hulls of ships that will keep barnacles and other organisms off of the hulls while being environmentally friendly and cost effective.

Until the early 1980s TBT was thought to be the answer. But when scientists discovered TBT leaches from such paint, certain countries, including France, Australia and the United States, banned its use on boats.

Since TBT is still widely used on other nations' ocean going vessels, trace amounts of TBT are found in almost all the world's harbors.

sea snails

The common littoral snail known as Nucella fails to develop sex organs even at low concentrations of TBT according to the Norwegian Institute for Water Rsearch. (Photo by Are Pedersen, courtesy Norwegian Institute for Water Rsearch)
In the Greek harbors surveyed in the Greenpeace study, levels are high enough to potentially threaten human health.

In the sediments from Kynosoura, an area where paint is sand blasted from ships in the open sea, levels of TBT were as high as 89,600 micrograms per kilogram - 1.8 million times higher than the provisional limit set by the OSPAR convention in 1997.

OSPAR is the intergovernmental organization that regulates marine pollution in the northeast Atlantic, from Gibraltar to the Arctic.

"These poisons are wreaking havoc in the marine environment and could pose a threat to human health," Stelios Psomas, executive director of Greenpeace Greece said in Athens today. "It's clear they are leaching directly from ship paint into waters just meters from popular swimming areas. They must be banned immediately."

Last year, following increased concern about TBT, the International Maritime Organization passed a resolution calling for a complete phaseout of the use of organotins, especially TBT, in ship paints by 2003 and for TBT-free alternatives to be used.

But the European Commission recently rejected draft proposals by Belgium for a national ban on all organotin anti-fouling paints for use on ships.

"The European Commission and other governmental bodies should support initiatives to ban these toxic pollutants and encourage the shipping industry to use biocide free paints," said Psomas. "While progress towards a ban is obstructed, these hazardous chemicals continue to poison our seas."

Last week, a Greenpeace study found that eight inflatable beach bathing items made of soft polyvinyl chloride (PVC) contain the TBT and another toxic organotin compound dibutyl tin (DBT). And in May, Greenpeace found TBT in various brands of babies' diapers.

Organotin compounds are used in high concentrations as stabilizers in numerous PVC articles. Last week's results from tests commissioned by Greenpeace on inflatable water wings, beach balls and air mattresses revealed that many contain between 0.9 and 26.2 micrograms of TBT per kilogram and up to 1,470 micrograms of DBT.


Dog whelks researched in ORTEP's study "The Value of Imposex as an Indicator of TBT." (Photo courtesy Organotin Environmental Program - ORTEP)
Such concentrations are not likely to cause acute damage to human health but the long term hazards concern some scientists.

This year, the Swedish National Chemicals Inspectorate (KemI) warned the Swedish government that, "The total human exposure to organotin compounds as a group gives rise to concern."

"It is doubtful whether the estimated safety margin is sufficient to protect humans from potential detrimental effects on the immune system," said KemI.

According to the World Health Organization, TBT is one of the most toxic substances knowingly released into the environment today.

In its defense, the European Council of Vinyl Manufacturers points out organotin compounds for stabilizing PVC have been in commercial use for more than 40 years. "Typical exposure levels are so low that any risks to health are considered to be negligible," said the ECVM's "European Industry Position Paper On PVC And Stabilizers."