BIOFOULING : THE SEARCH FOR

GREEN ANTIFOULING ALTERNATIVES

Elisheba Muturi December 1’06

Biofouling defined

Biological fouling (Biofouling) is the undesirable attachment of microorganisms, plants and animals to artificial surfaces submerged under water

Microfoulers: tiny organisms such as bacteria Macrofoulers: barnacles, zebra mussels

Biofouling effects

Affects shipping, offshore, oil and gas, water treatment, fishing industries

Ship hulls: reduce efficiency, corrode, cause drag (50% of marine transport costs)

Ship heating and cooling systems Fishing equipment, mesh cages (80% of pearl

industry costs)

Zebra mussels infestations in pipes

Antifouling technologies

Antifouling technologies refer to the means of combating biofouling:

Hull cleaning with harsh chemicals Mechanical removal Application of anti-fouling coatings to

submerged surfaces

Environmental impact The most effective anti-fouling coatings are

organotins: contain tin eg. tributyltin (TBT). TBT is very effective but toxic to non-target

organisms: imposex in whelks Compounds persist and could enter the food

chain Mechanical removal results in transfer of

invasive species

In November 1999, IMO adopted … International Convention on the Control of Harmful Anti-fouling Systems on Ships

… 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 2008

.

The search for green alternatives

Research into natural products antifoulants and non-toxic alternatives: Foul release coatings; non-stick surfaces Biological control methods

predation Marine bioactive compounds from sponges etc.

Mechanical or electrochemical deterrents: pulse power devices, cathodic, vibration

Cross-disciplinary

Marine and fresh water biology Oceanography Toxicology Water pollution Environmental Engineering Environmental chemistry Shipping Aquaculture

Key databases Environmental Sciences

Environmental Sciences & Pollution Management ASFA Oceanic Abstracts EnviroNetBase E-book collection

Biology Biosis Previews Zoological Record

Databases…

Chemical Chemical Abstracts SciFinder Scholar

General Web of Science GrayLit

Lay sources

Clare, Anthony Natural ways to barnish barnacles, New Scientist , 1995

Stanczak, Marianne Biofouling: It's Not Just Barnacles Anymore (CSA Discovery Guide)

Scientific journals

CSA controlled vocabulary

CSA controlled vocabulary

CSA Search strategy

((natural or non?toxic or "non toxic" or alternative? or biocide?free or "biocide free" or ((Tributyltin or TBT) NEAR alternative*) or (environment* (sound or friend* or benign)) or DE= ((biological control) or (pollution prevention) or (water pollution prevention) or (water pollution control)))) and ((DE= ((antifouling substances) or (fouling control) or (antifoulants))))

Web of Science articles

Web of Science subject areas

Key authors

Key researchers

• Research Groups affiliated to Academic Institutions – Biofouling Research Group, Russian

• Individual researchers

– Canada Centre for Marine Biofouling and Bio-Innovation, U of Calgary

– University of New South Wales Centre for Marine Biofouling and Bio-Innovation

Impact of alternatives Positive

Research into more efficient antifoulants for industry

Reduced transfer of alien species Much better for the environment

Negative Non-stick surfaces not effective in slow vessels:

increase in fouling Uneven regulation may lead to black market

Barriers to alternatives

No alternative with global approval; no commercial applications available

Long-term toxicity of alternatives unknown Higher costs of foul-release coatings Poor disposal of toxic coatings

Stakeholders

Government agencies at national and international level

Transportation authorities: International Maritime Organization

Environmental agencies such as World Wide fund, UNEP

Shipping companies, aquaculture industry Paint manufacturers