Session 7 – The TBT Ban:  What next?

Tributyltin or TBT is the overly efficient biocide ingredient in the hull paint on much of today's commercial fleet.  Banned on small vessels in the 1980's due to its' detrimental effects on certain non-targeted organisms, TBT is still considered to be the most effective antifoulant available.  Members of the International Maritime Organization (IMO), the U.N. branch responsible for marine environmental regulations, are suggesting a full ban on the use of TBT on ships after Jan. 01, 2003.  ENSUS 2000 session #7 debated the TBT proposal and alternative antifoulants to TBT paints, such as tin-free self polishing copolymers (tin-free SPCs).

Protection of the marine environment: a joint responsibility

Although today's topic focused upon the variety of issues in the current tributyltin (TBT) debate, an underlying theme was immediately apparent.  The question arose as to "who is involved in the regulatory decision making process and are all parties properly informed ?"   Is the voice of science and scientists involved?  Are shippers' concerns being addressed?  Has the general public been made aware of all the issues?  The topic of TBT may be inherently controversial because certain participants in this debate believe their voice is under-represented by regulators looking into banning TBT.

Dr. Stewart Evans, Conference Chair, opened the day's events by citing this theme in his discussion on our joint responsibility in protecting the marine environment.  He challenged the logic in banning TBT citing the benefits of the antifoulant such as:

• Reduced fuel consumption on ships, yielding lower atmospheric pollution.
• Reduced chances of invasions of exotic species.
• The reduction in TBT in open ocean and coastal waters.

Clearly Evans succeeded in setting a tone of challenge and debate among the delegates.

Return to Top of Page

A voice for the community in environmental planning processes

Andy Birchenough of Newcastle University calmed the masses somewhat with an engaging presentation on a program designed to allow members of the community to participate in science testing and reporting.  The group was asked to repeat the tests of a controversial 1993 North Sea report claiming populations of marine snails along the North Sea coast were in danger of extinction due to TBT.

Birchenough had the team members, composed half of citizens without professional training and half of qualified scientists, go into the field to count the numbers of dogwhelks and bring samples back to the lab for tests on the sterility of females.  The group was shown how to detect differing levels of imposex, a biological test that assists in the detection of TBT in the snails.

The scientist/citizen team found no sterile populations, and no breeding impairment.  More importantly, Birchenough had the public group's data verified by the scientists and he found the results could be taken seriously.

One positive result was the media and journal attention that the study received.  The participants had their results published in journals such as NewScientist, and The Marine Pollution Bulletin , thanks greatly to the community group's participation.  Birchenough even suggested that perhaps the attention was greater due to the citizen groups' involvement.

Now, says Birchenough, many people are calling to request to be included in future studies.  The University is planning another similar project involving biodiversity.

He said that their work demonstrates how non-specialists can meaningfully contribute to the environmental planning process.  As long as the quality control component of scientific verification is included, decent scientific information is the result.

Other sessions reviewed in brief by CQD Journal include:

Risk assessment of TBT in the marine environment

Mary Sue Brancato of Parametrix, Inc. discussed TBT risk assessment studies performed for fish, birds, mammals and humans.  Results showed:

• Risks continue to decline over time as TBT levels decline in the environment.
• No risks are posed from TBT to birds, mammals or humans based on the most recent data.

Return to Top of Page

Session 7.2:  Finding solutions and learning lessons

Biocides and the precautionary principle: how do we evaluate the long-term impacts?

John Toll of Parametrix Inc. illustrated how the IMO's Marine Environmental Protection Committee failed to follow the precautionary approach in their adoption of measures to enact the TBT ban of 2003.  According to Toll:

• The precautionary approach takes cost effective measures into consideration to reduce uncertainties until one alternative dominates.
• TBT SPC is clearly not dominated by any available alternative paint or hull covering.
• To evaluate cost effectiveness, a comparison of alternatives is necessary.
• MEPC 45's process for proposing amendments to biocides other than TBT does not view alternatives against each other;  it evaluates each one individually.
• You cannot compare cost effectiveness without comparing alternatives.

Toll suggested the strong need for a comparative risk assessment of available alternative antifoulants.  He made detailed suggestions on how to properly assess the risk of TBT alternatives, beyond those outlined in current MEPC guidelines.

Monitoring of selected biocides utilized in antifouling paints as alternatives to TBT

Nick Voulvoulis described tests performed by the Imperial College of Science, UK to measure and assess the levels of popular biocides from alternative antifouling paints such as diuron, Irgarol 1051, chlorothalonil and dichlofluanid.  Levels were tested in the water column and in sediments from an estuary with a marina and high populations of small boats.  Voulvoulis said:

• Most of the biocide levels in the water do not indicate a risk.
• Certain biocides showed unexpectedly high levels in sediments.
• The biocides in sediments present a potential problem since they are designed to degrade.  If they are accumulating in the environment, will they become available to the marine biota?

Voulvoulis strongly felt his tests show the need to investigate further if the biocides in the sediments cause risks, or if the quantity in the water column is higher then previously measured.

Return to Top of Page

Evans worried that the time for performance tests was too short.  Ship owners want five years performance on their hulls and TBT will be banned in less then three years.

Return to Top of Page

Issue	Preferred improvement
Fuel quantity	new ship hull design, better engine design
NOx	better engine or scrubbers
Ballast treatment	treat with peroxide
Antifouling	use approved alternative
Waste	use separators, sewage systems

 

In a feasibility study Jantzen compared the "environmental sound" big ship against the "environmentally sound" small ship as well as current non-environmentally pure ships.

He found:

• The environmentally sound ship operates better than current ships and saves operational costs for owners.
• Two smaller environmentally sound ships are more fuel efficient and have a better value/cost ratio then one big ship.  This goes against currently accepted theory that bigger ships are better and cheaper.

He concludes that policy and public pressure on the environmental performance of shippers will increase in the future.  Shippers must be aware of the availability of cost-effective options to comply with demands.

Oil Spill characteristics and novel ideas in oil boom curtain design

J. Allen-Jones departed from his submitted text on global organizations associated with oil spill response, suggesting that delegates read his paper if they are interested.  Instead, he discussed a new design concept he and colleagues are working on for an oil spill curtain boom.

Allen-Jones points out that the technology for cleaning up oil spills on water is old and inefficient.  Spill teams must still use booms and barricades or chemical dispersants.  The average quantity of oil recovered in a major slick is about 3%.

Curtain booms are a type of boom hauled by boats to enclose the slick and keep it from spreading.  Allen-Jones says they are inoperable in wind conditions above force 5 and if the current of the water is above 1 knot.

However, Allen-Jones is devising a curtain boom system that works in tandem to separate the oil slick and make it easier to pump out.  The oil spill flows over the top of one curtain boom that serves to separate the oil better.  Another larger curtain boom is 100 yds or so behind the first creating a "lagoon."  Allen-Jones says his lagoon concept makes it much easier for pumps in boats to suck up the oil.

Risks of marine transport of dangerous goods and implications for the environment

Joanne Ellis of SSPA discussed work she performed with the Chalmers University of Technology in Sweden in chemical spills.  Their work on probability and consequences helps define economic risk definitions in the case of chemical spills in Swedish waters.

Chemical spills are less frequent than oil spills, however depending on the cargo they can pose great risk.  Ellis noted the IMO has been regulating dangerous goods carried by sea since 1965.

Ellis helps the Swedish coast guard determine the environmental and economic costs associated with cleaning up a chemical accident.  Her model is based on environmental consequence data such as clean-up costs, compensation costs, treatment costs and environmental economic evaluations.

Past chemical spills and the clean–up methods include:

• Frank Michael – dry bulk carrier grounded releasing 1,100 tons of fertilizer.  Ellis determined spill clean-up would have cost USD 3.5 million.  The authorities decided not to take actions as the environmental benefits of action may not be worth the costs.
   
• Martina – chemical tanker sank with 600 tons of hydrochloric acid in March 2000.  The HCL posed a risk in the tanks, however Ellis determined it was not a marine pollutant and the authorities released the cargo into the Baltic Sea without incident.

Session 7.4:  The Way Ahead
Effective antifouling: how does this influence invasive species?
Marine Coatings Board Concept Paper

Return to Top of Page

Legal Disclaimers and Policy Statements

This page last updated by Miller Associates: Thursday, June 05, 2003