LIFE02 ENV/B/000341 Development of an integrated approach for ...

LIFE02 ENV/B/000341 

Development of an integrated approach for the 

removal of tributyltin (TBT) from waterways and 

harbors: 

Prevention, treatment and reuse of TBT 

contaminated sediments 

Task 3543 

State of the art on TBT alternatives 

Kurt Van Passen – Guido Van Meel – Gert Thues 

Antwerp Port Authority 

Entrepotkaai 1 

B-2000 Antwerpen 

1

Task 3543: State of the art on TBT alternatives 

Table of Contents 

Table of Contents_________________________________________________________ 2 

Executive Summary_______________________________________________________ 3 

A. Introduction___________________________________________________________ 4 

B. Main alternative tin-free antifoulants: Overview [1]___________________________ 6 

B.1. Types of coatings containing biocides or natural antifouling products as active 

materials ___________________________________________________________________ 6 

B.2 Types of active antifouling products _________________________________________ 7 

B.2.1 Copper _____________________________________________________________________ 7 

B.2.2 Organic booster biocides _______________________________________________________ 7 

B.2.3 Natural antifouling products_____________________________________________________ 7 

B.3 Fouling-release coatings ___________________________________________________ 7 

B.4 Electric current __________________________________________________________ 8 

B.4.1 Electrical disinfection__________________________________________________________ 8 

B.4.2 Electrolysis__________________________________________________________________ 8 

C. State of the Art ________________________________________________________ 9 

Overview___________________________________________________________________ 9 

C.1 Biocide containing antifouling _____________________________________________ 10 

C.1.1 Copper containing antifoulings _________________________________________________ 10 

C.1.1.1 Copper in the aquatic environment___________________________________________ 10 

C.1.1.2 Organic booster biocides __________________________________________________ 13 

C.1.1.3 Degradation and toxicity __________________________________________________ 15 

C.1.1.4 Evaluation______________________________________________________________ 15 

C.1.2 Metal free biocide containing antifoulings_________________________________________ 17 

C.2. Natural antifouling agents________________________________________________ 17 

C. 3 Non-toxic, fouling release coatings _________________________________________ 18 

C.3.1 Silicone coatings ____________________________________________________________ 18 

C.3.2 fluopolymer coating __________________________________________________________ 18 

C.3.3 Glass-flake paint_____________________________________________________________ 19 

C.4. Electroconductive coatings _______________________________________________ 19 

D. Survey of shipyards and ship owners about the use of TBT-containing antifouling 

and the use of alternatives_________________________________________________ 20 

D.1 Introduction____________________________________________________________ 20 

D.2 Results of the survey _____________________________________________________ 20 

D.2.1 Response __________________________________________________________________ 20 

D.2.2 Use of TBT-containing antifoulings _____________________________________________ 21 

D.2.3. Sediment characterisation by shipyards __________________________________________ 21 

D.2.4. TBT alternatives ____________________________________________________________ 21 

E. Final remarks ________________________________________________________ 24 

F. Reference List ________________________________________________________ 33 

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Executive Summary 

The task objective was to provide an overview of environmental friendly alternatives for 

antifouling paints containing TBT, considering their overall environmental impact, userfriendliness 

and risks related to it. 

A questionnaire to ship owners and shipyards concerning anti-fouling paints containing 

TBT and other alternatives has been elaborated by the Port of Antwerp. In the 

questionnaire the following topics were addressed: 

� The use of anti-fouling paints containing TBT and other alternatives; 

� Experience with TBT-free anti-fouling paints; 

� Reasons to use an alternative paint; 

� Decisions on the type of paint that is used; 

� Negative effects of -anti-fouling paints containing TBT. 

The questionnaire was sent in May 2003 to about 450 shipyards located in the EU and 

accessing countries, and 200 ship owners (worldwide). In September 2003 a reminder was 

sent to all shipyards and ship owners who had not answered the questionnaire until then. 

Both sectors (shipyards and ship owners) provided a representative level of response to the 

questionnaire (around 10%) and the awareness of the need to switch to TBT-free paints 

was clearly present. 

Moreover, both sectors are looking intensively for TBT-free alternatives that are best 

suited for each situation of use of the ships to be painted. 

In addition to the questionnaire, the Port of Antwerp performed a literature research and 

contacted paint producers in order to obtain a worldwide overview of environmental 

friendly alternatives for antifouling paints containing TBT, and the environmental impact 

of these alternatives. The following alternatives were detected 

� Copper Paints - the use of copper seems to be widespread, together with antifouling 

chemical booster. In depth studies are being published about the impact of copper on 

the maritime environment. As for the chemical booster components, broad 

investigations are being conducted in order to evaluate the environmental impact and 

by this proposing components with a limited impact in space and in time. 

� Silicone Paints - ship paint formula's offering only a very limited grip of the fouling 

agents on the ship's hull are also on the market. These paints are generally based on 

silicones and are totally free of any chemical active agent. The lower mechanical 

strength and resistance to damage, as well as the difficulties encountered to repair the 

damages are aspects of these paints that are currently under investigation. 

� Epoxy Paints - a paint containing small glass flakes in an epoxy matrix is giving very 

promising results and is completely neutral for the environment. 

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State of the art on TBT-antifouling paint alternatives 

A. Introduction 

Protective coatings for ships come in two categories: 1) anti-corrosive in order to protect 

the degradation of the steel hull and 2) antifouling in order to prevent the build-up of biofouling 

by organisms such as barnacles. 

Preventing corrosion can also be realised by the use of corrosion resistant steels or metals 

such as aluminium or by metallic coatings. All these alternatives are rather expensive. 

On top of the anticorrosive coatings comes the antifouling paint layer. Fouling of the ship 

increases the hull roughness and by this the force needed to propel the ship through water. 

In order to maintain the ship's speed more power is needed. It is estimated that, on average, 

fuel consumption increases 6% for every 100 µm increase in the average hull roughness 

caused by fouling organisms. Many antifouling systems have been used over the centuries 

from copper and lead sheathings to paint containing compounds of copper, lead, arsenic 

and mercury in the 20 th century. 

Organotins were first used in the mid-1960s. Research evidence of the damaging effect of 

tri-organotins such as tributyltin (TBT) on the reproduction and growth of various marine 

life forms has prompted action by many countries to regulate or ban their use in antifouling 

products. In this respect the European Parliament and Council have adopted Regulation EC 

782/2003 on the prohibition of organotin compounds on ships. The date of entry into force 

is 10 may 2003. 

However studies have indicated that even though regulations were effective in reducing 

TBT-levels, contamination of sediments by organotin compounds is still wide spread and 

has ecotoxicological consequences [19]. Toxicity to non-target aqueous organisms and the 

sorption behaviour to natural sediments have been investigated. The same kind of studies 

have been started in the late 1990s as meanwhile alternatives to organotin antifoulants 

such as copper and organic booster biocides have been used now since more than 10 years. 

4


Investigation and development of more environmentally friendly antifouling paints and 

systems has since then gone forward on several fronts. This search for economically and 

environmentally better antifoulants is still going on. But the world marine environment is 

still waiting for the development of products or systems proven to be completely safe in 

practice and in the long term. 

5


B. Main alternative tin-free antifoulants: Overview [1] 

B.1. Types of coatings containing biocides or natural antifouling products 

as active materials 

The active material is included in a paint layer and is released in the surrounding water. 

Three families of paint can be distinguished each showing a different process of release. 

B.1.1. Free association: Biocides are dispersed in a resinous matrix. The performance is 

only over a relatively short term as the release of the biocides is rather uncontrolled. 

B.1.2 Hydrative degradation: A low molecular weight water-sensitive polymer matrix 

slowly dissolves in seawater and releases the biocides while it is undergoing hydrative 

degradation. The biocide release rate decreases gradually in time. 

B.1.3. Ablative self polishing: The biocides are included in a paint film of methacrylate 

or acrylate copolymers. The paint film is eroded by moving seawater, constantly 

exposing a fresh surface layer of biocide carrying polymer. A controlled, uniform 

biocide release at a constant rate is performed. 

Figure 2. SEM (Scanning Electron Microscope) photograph (magnification 2000x) showing part of the cross 

section of a self-polishing antifouling paint (pigment volume concentration of 40 vol. %) that has been 

6


exposed to seawater for 47 days at 20 knots and 25 °C. The leached layer and the Cu2O particles in the 

unreacted paint film can be clearly seen. 

The latter coating type is the latest development and is more expensive but its antifouling 

action is superior to the two other types and has a longer effective life time. Next to the 

three paint families, three groups of active products can be included in the paint, either 

alone, either in combination. 

B.2 Types of active antifouling products 

B.2.1 Copper 

Copper metal, copper alloys and copper compounds are the main component of tin free 

antifoulants. These substances are able to form the cupric ion Cu 2+ which is biocidal and 

has an antifouling effect on many fouling organisms. 

B.2.2 Organic booster biocides 

Some of the common marine algae are tolerant to copper. To achieve protection against 

these tolerant species, organic biocides are used in conjunction with copper. 

B.2.3 Natural antifouling products 

Corals, sponges, starfishes, mussels, algae, marine plants and dolphins and other marine 

lives protect the surface of their bodies with antifouling substances without causing serious 

environmental problems. These natural antifoulants include not only toxins but also 

anaesthetics, growth-inhibiting, metamorphosis-inhibiting and repelling materials. 

B.3 Fouling-release coatings 

These "non-stick" coatings make the bond with the fouling organism so weak that it can be 

broken by the weight of the fouling or by the friction of the water around the ship in 

motion. The fouling can easily be removed by a water jet. 

7


B.4 Electric current 

B.4.1 Electrical disinfection 

Marine bacterial cells are killed by electrical current from a positive electrode at a low 

electric potential of around 1-1,5 V. Bacterial cell accumulation is prevented by applying 

an alternating potential between – 0,6 V and + 1,2 V. 

B.4.2 Electrolysis 

Electrolysis of seawater produces at the anode chlorine, hypochlorite and oxygen, all three 

with biocidal activities. Hypochlorite is easily decomposed by ultraviolet light in seawater 

to form chlorine ions. This system does not cause environmental problems. 

8


C. State of the Art 

Overview 

Testing is now going on since a few years, mostly organised together with either larger 

shipping companies, either the navy in different countries. The stakes are high as the tests 

are costly and time-consuming. TBT-containing antifoulings had reached a high 

performance level as they succeeded in eliminating very effectively the fouling and this 

during at least five years in most cases. This resulted in two very cost favourable 

consequences in the shipping business. For the first time: 

1. The smooth hull characteristics obtained by the last generation of TBTcontaining 

antifoulings reduced the costly fuel consumption by at least 5 

and even op to 30%; 

2. The time interval between two dry dockings for the removal of the fuelconsuming 

foulings could be extended to 60 months (5 years) or more. 

After this period of 5 years, dry docking is often also needed for mechanical 

overhaul and is economically accepted in the operational lifetime of the 

ship. 

The new, after-TBT-generation of antifoulings comes in two categories: 

1. The first category includes the biocide containing antifoulings. Within this 

first category distinction has to be made between copper containing 

antifoulings, which include always also booster biocides (1.1) and metal 

free antifoulings (1.2). The main points of concern are the toxic effects in 

the aquatic environment and in the sediments. Important parameters in this 

context are the velocity of degradation (half-life time) of the chemicals and 

their degradation products. 

2. The second category comprises non-toxic, fouling release coatings. These 

coatings are in a way so slippery or have such an impenetrable glassy 

structure that organisms have but an extremely weak grip on it. This weak 

bond can rather easily be broken, e.g. by the friction force of the water flow 

alongside the ship's hull or by mechanical cleaning (brushing, water jet, etc.) 

9


Finally, one can mention antifouling effects produced by electrolysis, but this seems not to 

be practical for commercially operating ships. 

From the beginning of the TBT Clean project, our team met an attitude of reticence when 

asking the paint industry full collaboration when trying to have an insight in the 

development of new antifoulings. Obviously a lot of costly research is being performed 

and the competition to bring forward the ideal alternative for TBT-antifoulings must be 

fierce. 

C.1 Biocide containing antifouling 

C.1.1 Copper containing antifoulings 

For owners of ships with aluminium hulls, the situation is urgent for the best available 

alternative, a copper based coating cannot be used: aluminium hulls are attacked by 

copper. [3]. Coatings containing copper metal, cuprious thiocyanate or cuprous oxide offer 

a well understood technology. But these copper coatings are likely a stopgap measure: the 

biocidal activity spectrum is very large. Moreover the background levels of copper in 

sediments in restricted water areas seems to rise, giving concern about the environment. 

C.1.1.1 Copper in the aquatic environment 

Some concerns about the occurrence of copper in the aquatic environment has arisen out of 

the assumption that further regulatory action on triorganotinbased antifouling products is 

likely to increase the use of copper-based products. 

In the UK, the Environmental Quality Standard (EQS) for copper in seawater is 5 µg l -1 

(expressed as an annual average). This is designed to protect all marine life and associated 

non-aquatic organisms (i.e. direct and indirect effects have been taken into account). 

However, the EQS refers to dissolved and not total copper, because copper forms insoluble 

complexes in seawater which effectively bind the copper and reduce its bioavailability. 

The UK EQS for copper is similar to those used in the USA and Denmark (2,9 µg l -1 , acute 

criterion), but less stringent than the Ecotoxicological Assessment Criterion recommended 

10


by the Oslo and Paris Commission (0.1 – 1.0 µg l -1 ), which is used as a guide to identify 

areas for further monitoring. 

Copper is an essential element, required for the normal growth of all plants and 

animals and occurs commonly in the environment. However, high concentrations can 

be deleterious to algae and other aquatic biota. Copper is not lipophilic and shows only 

a slight tendency for bioaccumulation. The most bioavailable, and thus the most toxic form 

of ionic, unbound copper, is the free hydrated ion, Cu(H2O)6 2+ . Copper speciation is 

governed by pH, salinity and the presence of dissolved organic matter. 

Copper toxicity to algae depend upon the individual species, their physiological and 

environment conditions and the chemical forms of metal in the medium. For example, 

Hydrilla verticillata (an aquatic macrophyte) exhibited indications of toxic stress in the 

presence of copper at low pH (4.5), while at high pH (9.5) toxicity was considerably 

reduced. Biological indicators differ widely with respect to copper sensitivity and a 

general decreasing order of sensitivity would be: micro-organisms > invertebrates > 

fish > bivalves > macrophytes. The presence of water-soluble ligands that bind copper 

reduces toxicity, probably by decreasing the concentration of free ionic copper. Binding of 

the cationic species with organic ligands results in the formation of anionic hydrophilic and 

kinetically inert copper chelates. 

Speciation studies carried out in coastal waters indicate that more than 99% of the 

total copper is strongly bound or chelated with organic ligands, leaving the 

concentration of free Cu 2+ at levels that are non-toxic to most organisms. In addition 

there is evidence that strong copper chelators are synthesized and excreted by microorganisms 

in response to gradual and potentially toxic increases in copper 

concentrations in the water column. 

However, the effects of some organic compounds (including booster biocides such as 

dithiocarbamates) and copper are additive, as lipophilic complexes are formed and 

synergistic effects have been observed. 

Short-term uptake experiments with the fungicides ziram and maneb using a coastal diatom 

demonstrated that these Zn and Mn complexes can be subsequently form lipophilic organic 

copper complexes in the environment that diffuse across the plasma membrane and into the 

11


cytosol of the cell. Intercellularly, copper is thought to dissociate from the transport ligand 

and complex intercellular ligands. On the basis of these results, it has been suggested that 

the presence of dithiocarbamate fungicides in surface water may inadvertently 

enhance the passive uptake of a variety of toxic heavy metals from the water into 

biota. 

A number of studies have tried to link changes in the environmental concentrations of 

copper with its use in antifouling paints. Monitoring of oysters in Arcachon bay (on the 

Atlantic coast of France) over the period 1979-1991 demonstrated an increase in the 

copper content of oysters (Crassostrea gigas) in the vicinity of marinas and mooring areas. 

This was attributed to the growing use of copper-based paints. In another study, monitoring 

and analysis were conducted in inshore Chesapeake Bay, including three boating marinas 

where leaching of copper from antifouling paints was found to be significant. It was 

demonstrated that all the stations yielded highest mean dissolved copper concentrations 

during August and September. Increasing copper concentrations were observed between 

the inner harbour and the exit channels on falling tides, followed by a decrease as the 

channel broadened into open waters. 

In general, copper concentrations above the EQS in water are expected to be causing a 

range of deleterious sublethal effects in several invertebrate phyla, and even lethal effects 

in early life stages. Of particular concern is the production of the readily absorbed lipidsoluble 

organic complexes with other compounds used in antifoulants (e.g. 

dithiocarbamates). However, in the UK, the Advisory Committee on Pesticides (ACP) 

has suggested that the contribution form antifouling products to the environmental 

loading of copper is not a cause for concern. Subsequently it has recommended that 

monitoring of copper in water an appropriate biota should continue and also be conducted 

in and around UK harbours and marinas to assess the risk to sediment-dwelling organisms. 

The Netherlands and Sweden on the other hand have expressed their concern. The use of 

copper in yacht paints is no longer allowed at the East coast of Sweden. 

A lot of information concerning problems with copper in harbours and data on exceeding 

the free copper limits are available from SPAWAR (Space and Naval Warefare Systems 

Center) website (http://www.spawar.navy.mil). Also information about Copper chemistry, 

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Toxicity Bioavailability and its relationship to regulation and marine environment is 

available from this website 

C.1.1.2 Organic booster biocides 

Copper containing paints include in many cases also organic biocides such as Irgarol, 

diuron, Sea-nine 211, dichlofluanid, chlorothalonil, zinc pyrithione, TCMS pyridine, 

TCMTB and zineb [4] [9]. The presence of these biocides was revealed in European 

coastal environment and in waters in Japan, United States, Singapore, Australia and 

Bermuda. 

Since these alternatives to TBT are also toxic, their contamination of the aquatic 

environment is a topic of increasing importance. [10] 

Although the physico-chemical properties of the compounds differ significantly and some 

are rapidly degraded, these compounds will also accumulate in marine sediments if 

introduced within paint particles. 

Organic booster biocides that have been used as active ingredients in antifouling products 

are shown in Table 1. Irgarol 1051 (Irgarol) is highly effective against freshwater and 

marine algae. It belongs to the s-triazine group of compounds which act as photosystem-II 

(PSII) inhibitors, with the inhibition of photosynthetic electron capture transport in 

chloroplasts as their biochemical mode of action. 

Diuron, one of the major urea herbicides in use since the 1950s, also inhibits 

photosynthesis. 

Although utilized in antifoulants, it is predominantly used on land for general weed control 

on non-crop areas. However, it bas been detected in saline coastal waters at concentrations 

higher than in fresh waters, suggesting that its use in antifouling products may be 

ofsignificance. 

Kathon 5287 is a highly effective, broad-spectrum biocide. It is an isothiazolone compound 

which is licensed for use as an active component in antifouling products in the UK and 

elsewhere. It was the first organic booster biocide to be registered for use by the USA- 

EPA. 

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Various other booster biocides are also used in antifouling applications: chlorothalonil, 

dichloftuanid, TCMTB, TCMS pyridine, zinc pyrithione and the dithiocarbamates thiram, 

ziram, zineb and maneb (TabIe 1). These are protective fungicides 

with a wide range of action against a number of organisms 

Occurrence 

Booster biocides were introduced into antifouling paint formulations only after restrictions 

were imposed on the use of organotins. Little or no monitoring of these biocides has been 

carried out, possibly as these compounds were not perceived to be an environmental 

problem. Their relatively recent introduction, limited usage and perceived lower toxicity in 

comparison with TBT may have been some of the factors reducing their priority as 

compounds of environmental concern. Lack of established analytical methodology may 

also have been a contributory factor. 

Limited monitoring data are available for IrgaroVS-38 whereas, among the other booster 

biocides, diuron, chlorothalonil, dichlofluanid and some of the dithiocarbamates have been 

studied in the marine environment, but not in the context of their use as antifouling 

products. Almost all of these compounds have agricultural uses (pesticides, fungicides, 

herbicides etc.). Therefore their presence in the aquatic and estuarine environments cannot 

be attributed solely to the use of antifoulants (Table 2). 

In an article by I.K. Konstantinou and T.A. Albanis [4] a world wide review on occurrence 

and effects of booster biocides is presented. The following paragraphs are small extracts of 

the review. 

Water samples collected from marinas, estuaries and coastal waters along the Southern UK 

coast and sediment samples from the Hamble estuary in the UK were analysed by Gough 

et al.37 Irgarol residues were present in most marine and estuarine samples, but were not 

detected in fresh waters. The highest concentrations were found in areas of high boating 

activity, particularly marinas and the estuary, indicating a correlation with its use in 

antifouling paints. Sediment contamination with Irgarol was found to he related to high 

concentrations in the water column. 

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In subsurface waters from the Mediterranean (Côte d'Azur) coastline, and substantial levels 

of Irgarol were detected in all marinas, with concentrations reaching 640 ng-1 .Toth et al., 

assessing the contamination of different compartments of Lake Geneva (water, sediments, 

zebra mussels, macrophytes and algae) over a period of nine months, found concentrations 

comparable with those observed by Tolosa et al. and Gough et al. In a more recent study, 

water samples taken from Plymouth Sound (UK) were analysed for Irgarol, which was 

detected at all sampling sites. The highest levels were found in close proximity to areas of 

high boat density, especially where water flow was restricted within marinas. The highest 

detected value was 127 ng l -1 at Sutton Harbour Marina. 

Of the other biocides, the impact of the agricultural uses of diuron was demonstrated by a 

survey detecting herbicide residues in water samples from draining streams and pumping 

stations of the agricultural area of Thessaloniki, Greece. Considerable amounts of diuron 

were found to be released form the agricultural fields and transferred through rivers, 

draining streams and pumping stations to the coast. In the UK, Environment Agency (EA) 

data show that one of the pesticides which most frequently exceeds the EQS of 1 mg l -1 in 

Controlled Waters is diuron, predominantly due to its use as a herbicide in agriculture, 

although some inputs are related to its use as an antifouling agent in paints. 

C.1.1.3 Degradation and toxicity 

There are many factors that influence the degradation and persistence of these biocides in 

the marine environment. These include their chemical and physical properties as well as 

ecosystem-specific parameters such as the nature and concentration of microbial 

populations, dissolved and suspend material, temperature, etc. 

C.1.1.4 Evaluation 

Environmentally sound shipboard management practices should be encouraged and 

policies to the use of booster biocides and copper antifoulants are expected. There is a 

belief that the use in antifoulants of copper in the first place and of longer lasting biocides 

(half life of more than a few hours) will ultimately be disallowed [5]. 

15


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C.1.2 Metal free biocide containing antifoulings 

New biocides have been developed which are announced as having very low impact on the 

environment. They are filed for registration at US EPA in April 2002 and a filing for 

registration as a new active in Europe under the Biocide Product Directive is planned this 

year (2004). Two complementary biocides are used in combination: an algaecide, 

bethoxazin and an anti-hard fouling (anti-barnacles) with the chemical name 3-cyano-4- 

bromo-5- trifluoromethyl. These biocides are registered as ECONEA 025 and ECONEA 

028 by Janssen Pharmaceutica (Plant and Material Protection Division), a member of the 

Johnson & Johnsen group of companies. 

The product ECONEA 028 is reported as having an extremely rapid degradation (half life 

time less than 1 hour in seawater) and a low ecotoxicity of degradation products [21]. 

C.2. Natural antifouling agents 

These substances may be expected to be used as new environmentally friendly antifouling 

agents. Especially those having high anaesthetic, repellent and settlement inhibition 

properties, without biocidal properties, are desired [1][6]. 

Many of the antifouling substances are found from marine animals, plants and microorganisms 

and also in terrestrial plants such as green tea, wasabi and oak tree leaf [1]. 

Future efforts are expected to focus on chemically synthesizing polymer analogues. 

17


C. 3 Non-toxic, fouling release coatings 

These coatings receive great attention among interested parties, as the bond between 

fouling and coating can be broken by the friction force of the water while the ship is in 

motion. Although most ships don't have the speed or extra power to dislodge fouling. 

C.3.1 Silicone coatings 

Silicone coatings are on the market. One provider (CMP – Chugoku Marine Paints – 

Japan) offers a first generation type for high activity and high speed vessels, and a second 

generation for slow coastal and low activity vessels. Both versions feature low slime build 

up and for the second generation type self cleaning starting from a speed of 10 knots. CMP 

stipulates moreover: "There have been limited full applications to coastal and deep-sea 

vessels. More practical experience is required before these products can be recommended 

to all vessels. However non-biocide, foul release coatings can provide a successful 

alternative for ship operators for up to a 5-year dry-docking period. 

It is recommended that these products are applied to areas protected from regular 

mechanical damage due to the reduced mechanical strength of silicone rubber in 

comparison to tin-free antifoulings. " [23] 

The challenge with silicones is to create a thick, relatively soft film with mechanical 

properties needed in marine environments and during ship operations [3]. The silicone 

coating exhibits nevertheless a high vulnerability for mechanical damage and a rather 

difficult repair procedure. 

C.3.2 fluopolymer coating 

An other fouling release coating type is the fluoropolymer coating. Highly fluorinated 

polymers create a smooth, low-energy surface, but they are relatively insoluble in coatings 

solvents and thus difficult to apply; they are also expensive [3]. 

Incorporating in one material the best properties of fluorinated and silicone coatings was 

pursued and a blend of fluorinated polyols and non-fluorinated polyisocyanites gave good 

testing results [3]. 

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C.3.3 Glass-flake paint 

Incorporating small glass flakes into a matrix of though carrier resins provides an 

exceptionally smooth finish, remaining stable for long periods of time in corrosive 

elements. The non-toxic coating has high level "non-stick" properties and is resistant to the 

destructive forces of heavy barnacle growth. Fouling is not totally prevented and 

maintenance of the hull is expected to be limited to an economically feasible level. 

Underwater maintenance equipment, developed for this purpose, is an integral part of the 

system. It is expected that the coating will probably last the life time of the ship without 

having to be renewed. The product is called ECOSPEED and is available through Subsea 

Industries (Antwerp-Belgium). [22] 

C.4. Electroconductive coatings 

Electroconductive coatings for seawater electrolysis resist fouling by substances 

generated by electrolysis reactions. The hull is first coated with an insulating paint; it is 

then coated with an electroconductive layer. 

The system has been investigated in application to aqueduct pipes for powerplants and to 

small ships [2][7]. The cost is still high in comparison with antifouling paints and is a 

serious handicap for a commercial breakthrough. 

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D. Survey of shipyards and ship owners about the use of TBT-containing 

antifouling and the use of alternatives 

D.1 Introduction 

A questionnaire was sent to a 668 companies (shipyards and owners) for completion (see 

annexe) during the second half of the year 2003. The answers (and the lack of answers) 

should show in how far these two players in the shipping industry are aware of: 

1) the negative effects of TBT-containing antifouling paints; 

2) the legal aspects of the TBT ban. Moreover the answers should give an idea of 

perception of the mentioned group when comparing aspects of effectiveness, cost 

and frequency of docking using either TBT antifouling of TBT-free antifouling. 

D.2 Results of the survey 

D.2.1 Response 

The questionnaire was sent to a total of 668 companies (shipyards and owners) for 

completion. 61 completed questionnaires were received, i.e. 9% on the total amount of sent 

questionnaires. Table 1 gives the response on this survey. 

Table 1: Geographical location of interrogated companies and their response. 

Type Location Number of 

questionnaires 

sent 

% of 

total 

Received 

Completed 

Questionnaires 

% of 

total 

Ships owner EU-member state 130 62% 18 14% 

Enlargement 5 2% 0 0% 

Not EU-member 

states 

75 36% 7 9% 

Total 210 100% 25 11% 

Shipyards EU-member state 309 67% 23 7% 

OWNERS + 

YARDS 

Enlargement 78 17% 4 5% 

Not EU-member 

states 

71 16% 9 13% 

Total 458 100% 36 8% 

Total 668 100% 61 9% 

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A response of 9 % can be considered large enough in order to detect larger trends in the 

behaviour and thinking of the targeted groups. 

D.2.2 Use of TBT-containing antifoulings 

Only a minority of companies is still using TBT-containing antifoulings (17% of the 

shipyards and 13% of the ships owners, 3 owners – 6 yards) 

The shipyards which still use TBT-containing antifouling are all localised outside the EU. 

Two of the ships owners who stated that they still use TBT-containing antifouling were 

localised in the EU which is very strange because use of TBT is not allowed in EU 

countries since January 1st 2003. Possibly they’ve chosen to do the maintenance of their 

vessels outside the EU. 

There were also a few of companies that were not aware of the negative effects of TBTcontaining 

antifouling paints. (16% of the shipyards and 4% of the ship owners who 

completed the questionnaire) 

D.2.3. Sediment characterisation by shipyards 

Nine or a quarter of the shipyards are measuring TBT-concentrations in their docks or have 

done this kind of measurements in the past. Only 2 of them were willing to share this info 

with us. 

Item 2.3 shows that shipyards are becoming aware of the problem of polluted sediments 

but are not yet sure how to cope with this problem. 

One shipyard situated at the Baltic Sea gives an extensive report on the results of a 

thorough analysis of the sediments in the neighbourhood of the yard. The content of TBT 

and TBT-related material is comparable to the results of the investigation on sediments in 

the port of Antwerp. 

D.2.4. TBT alternatives 

In the following tables there’s an overview from the findings from companies which are 

using TBT-free antifoulings. 

21


Table 2: Experience with TBT-free antifoulings 

Shipyards Ship owners Total 

As effective as TBT 39% 50% 43% 

Increase in maintenance cost 22% 54% 35% 

Vessels have to go to dry 

dock more often 

14% 0% 8% 

There is an increase in costs when a TBT-free antifouling is used but only in a few cases 

the frequency for dry docking has to increase. 

The motivation to use TBT-free antifoulings is very different. The main argument to 

change to TBT-free, environment-friendly anti-fouling for ships is EU-and IMOlegislation. 

This motivates approximately 50% of the shipyards and owners to stop using TBTantifoulings. 

Concern for the environment stimulates about 60% of the companies to start using 

alternatives for TBT. 

The answers on item 3 (Reasons to use TBT alternatives) show an awareness as well about 

the legal situation as about the environment. Both are expected to grow in time. 

In the answers on our questionnaires the shipyards and ships owners answered in many 

cases that they use alternative antifoulings. Table 3 gives an overview of the mentioned 

TBT-alternatives that are already used by shipyards and ships owners showing the 

predominance of copper based paints amongst the TBT-free alternatives. (not all returned 

questionnaires mentioned clearly an alternative). 

Table 3: Mentioned Alternatives which are used by shipyards and ship owners 

Alternatives Used by shipyards Used by ship owners 

Copper Based Paints 56% 29% 

Silicone Based 6% 13% 

Epoxy-based - 17% 

Use of no antifouling 3% 4% 

No specified tin free 

antifouling 

6% 4% 

22


The use of epoxy-based paint is mentioned by the ship owners operating in the Baltic Sea 

area. Navigation through icy waters in winter makes the use of epoxy-paints more 

interesting as the ice has a cleaning effect on the ship's hull. 

23


E. Final remarks 

It seems interesting to maintain a mutual feedback between users and legislators about the 

topic of TBT-free alternatives. This activity will of course happen through the well-known 

mechanisms of lobbying. A parallel circuit could be fed by the findings of the inspectors of 

the bureau's for registration and classification of shipping: a yearly report could be very 

helpful for the good understanding of the situation by the parties involved. Elements for 

this idea can be found in the article "Prohibition of organotin in antifouling systems: the 

classification societies' perspective" by H. Vold, Det Norske Veritas [18]. 

Amongst the lot of research actually being performed it is worthwhile mentioning the 

investigations about the effects of copper and biocides in antifouling on the marine 

environment together with searching the best methods of detection and evaluation of 

toxicity. References to this publications are to be found in the documents referred to in this 

reports. More recent papers: see [10, 11, 12, 13, 14, 15, 16, 17]. 

A nice insight in the economics of antifouling technology is given in an article "TBTantifouling 

paints: a company's experience" by C. Nygren of Wallenius Lines. [8]. Using 

fouling release paint instead of self polishing (SP) polymer paint (with biocides) reduces 

hull roughness together with fuel consumption. And this lower fuel cost could more than 

compensate the higher cost of the fouling release paint compared to the SP-paint. 

The questionnaires sent back by Wallenius and Wilhelmsen Lines confirm the policy of 

these companies towards a general use of fouling release paints. 

A comprehensive survey of the state of the art is to be found in the articles [1] and [2] and 

in the review "Antifouling technology – past, present and future steps towards efficient and 

environmentally friendly antifouling coatings [9]. 

This review closes with the following remarks: "While many commercial fouling-release 

systems are already available in the market, the development of an efficient product 

entirely based on natural biocides seems still far away in time. Again, the still incomplete 

understanding of the working mechanisms of these products may be slowing down the 

identification of truly interesting compounds. The latter has already caused a change from 

24


a blind and massive screening of organisms to a more rational study to determine which 

compounds have actually a role in deterring the growth of epibiota on marine organisms 

and to identify the common functional groups. Still, the broad-spectrum activity of these 

compounds is questioned by the huge diversity of organisms, behaviours and attachment 

mechanisms found in the oceans. Thus, some authors already state that no system entirely 

based on natural products will ever prevent the fouling of a surface totally. Unfortunately, 

some "external" factors (e.g. lack of industrial/academic interaction, slow testing times, 

costly and time-consuming environmental assessments, government registration and, more 

importantly, the existence of highly efficient toxic methods) may never allow scientists to 

prove that it is indeed possible to attain such a coating. On the other hand, fouling-release 

coatings already yield good results on fast-moving vessels. Further studies on the influence 

of the surface properties on the adhesion phenomena will orientate the search for a 

material, which could release the fouling organisms at lower speeds. This should be 

achieved at the same time that other problems, inherent in these systems, are solved. The 

next years will help to elucidate whether the goal will be achieved. 

25

ANNEX 1: Questionnaire SHIPYARDS 

Life02 ENV/B/341 

TBT CLEAN 

Introduction 

The European Commission has funded through the Life-Environment program a project 

called TBT CLEAN. This project is being carried out by the Antwerp Port Authority 

together with several partners. Within the framework of this study, the effects of 

Tributyltin (TBT) present in the bottom of navigation channels are being investigated, e.g. 

when the sediments are dredged. Moreover, existing and new cleaning techniques for 

dredged material polluted with TBT are evaluated. 

Survey 

Part of the survey also covers the comparison between TBT containing 

antifoulings and alternative marine paints. With this survey we would like to gather 

some practical information on the vessels you build or do the maintenance of. If 

you would like to get more information on the project or on the result of the 

questionnaire, please feel free to contact us: TBTclean@haven.antwerpen.be 

The filling in of the following questionnaire will only take a few minutes. 

1. What type of marine paints do you presently use for seagoing vessels? 

- TBT-containing anti-foulings Yes � No � 

- Alternative paints: 

� Copper based paints Yes � No � 

� Self-polishing paints Yes � No � 

- Other paints (please specify) 

- Don't know 

………………………………………… 

2. In case you presently use anti-fouling paints which do not contain TBT: 

- Do you consider these new paints as 

effective as TBT-containing anti-foulings? 

� 

Yes � No � 

- Have you experienced an increase in Yes � No � 

26


maintenance costs of vessels? 

- Do vessels have to go to dry dock more 

frequently than before 

- Other remarks (please specify): 


…………………………………………………………………………………………….. 

3. For which reason have you decided to use an alternative paint? 

- For environmental reasons Yes � No � 

- For company policy rules Yes � No � 

- Under pressure of IMO and EU 

legislation 

- For other reasons (please specify) 


…………………………………………………………………………………………….. 

4. Who takes the decision to use a specific ship's paint? 

- The shipowner Yes � No � 

- The shipyard Yes � No � 

5. Did you (or the shipowner) choose the new ship's paint 

- After a study of the different 

alternatives for anti-foulings? 

- Based on a suggestion from the 

shipyard? 



27


- On request from a paint 

manufacturer? 



…………………………………………………………………………………………….. 

5. Were you aware of the negative effects of TBT-containing anti-fouling paints? 


6. Do you carry out analyses about TBT concentrations in sediments in your 

docks? 


If so, are you willing to share this data with us, on condition that it will be used 

confidentially and on an aggregated level? 


If you would like to get a copy of the results of this survey, please mention your email 

address: 

………………………………………………………………………………….. 

Company: ……………………………………………………………… 

Number of vessels built / maintained in 2002 ……………………… 

Total Gross Tonnage of vessels built/maintained in 2002: ………. 

Name:………………………………………………………………….. 

Function: ………………………………………………………………. 

Address: ………………………………………………………………. 

Telephone: …………………………………………………………… 

Fax: …………………………………………………………………… 

Website: ………………………………………………………………… 

Thank you for your cooperation ! 

28


Contact us for more information: 

Antwerp Port Authority, attn. Mr. Guido Van Meel 



Tel. +32 (0)3 205.22.49 , Fax + 32 (0)3 205.20.21 

E-mail: TBTclean@haven.antwerpen.be 

Website: www.portofantwerp.be/tbtclean 

Fax the completed questionnaire 

to +32 (0) 3 205.20.21 

or e-mail: 

TBTclean@haven.antwerpen.be 

29

ANNEX 2: Questionnaire SHIPOWNERS 

Life02 ENV/B/341 

TBT CLEAN 

Introduction 

The European Commission has funded through the Life-Environment program a project 

called TBT CLEAN. This project is being carried out by the Antwerp Port Authority 

together with several partners. Within the framework of this study, the effects of 

Tributyltin (TBT) present in the bottom of navigation channels are being investigated, e.g. 

when the sediments are dredged. Moreover, existing and new cleaning techniques for 

dredged material polluted with TBT are evaluated. 

Survey 

Part of the survey also covers the comparison between TBT containing 

antifoulings and alternative marine paints. With this survey we would like to gather 

some practical information on the maintenance of your vessels. If you would like to 

get more information on the project or on the result of the questionnaire, please 

feel free to contact us: TBTclean@haven.Antwerpen.be 

The filling in of the following questionnaire will only take a few minutes. 

1. What type of marine paints do you presently use for your seagoing vessels? 

- TBT-containing anti-foulings Yes � No � 

- Alternative paints: 

� Copper based paints Yes � No � 

� Self-polishing paints Yes � No � 

- Other paints (please specify) 

- Don't know 

………………………………………… 

2. In case you presently use anti-fouling paints which do not contain TBT: 

- Do you consider these new paints as 

effective as TBT-containing anti-foulings? 

� 


- Have you experienced an increase in Yes � No � 

30


maintenance costs? 

- Do you have to go to dry dock more 

frequently than before 

- Other remarks (please specify): 


…………………………………………………………………………………………….. 

3. For which reason have you decided to use an alternative paint? 

- For environmental reasons Yes � No � 

- For company policy rules Yes � No � 

- Under pressure of IMO and EU 

legislation 



…………………………………………………………………………………………….. 

4. Did you choose the new ships' paint 

- After a study of the different 

alternatives for anti-foulings? 

- Based on a suggestion from the 

shipyard? 

- On request from a paint 

manufacturer? 





…………………………………………………………………………………………….. 

31


5. Were you aware of the negative effects of TBT-containing anti-fouling paints? 


If you would like to get a copy of the results of this survey, please fill in your e-mail 

address: ………………………………………………………………………………….. 

Company: …………………………………………………… 

Number of vessels: ………………………………………… 

Total Gross Tonnage: …………………………………….. 

Contact Person:……………………………………………… 

Function: ……………………………………………………… 

Address: ……………………………………………………… 

Telephone: …………………………………………………… 

Fax: …………………………………………………………… 

Website: ……………………………………………………… 

Contact us for more information: 

Antwerp Port Authority 

Mr. Guido Van Meel 



Tel. +32 (0)3 205.22.49 

Fax + 32 (0)3 205.20.21 

E-mail: TBTclean@haven.antwerpen.be 

Website: www.portofantwerp.be/tbtclean 

Thank you for your cooperation! 

Fax the completed questionnaire 

to +32 (0) 3 205.20.21 

or e-mail: 

TBTclean@haven.antwerpen.be 

32


F. Reference List 

[1] OMAE, I. 2003. General Aspects of Tin-Free Antifouling Paints. Chemical 

Reviews 103: 3431-3448 

[2] OMAE, I. 2003. Organotin Antifouling paints and their alternatives. Applied 

Organometallic Chemistry 17: 81-105 

[3] BRADY, R.F. 2003. Antifouling coatings without organotin. Journal of 

protective coatings and linings 20: 33-37 

[4] KONSTANTINOU, I.K., T.A. ALBANIS. 2003. Worldwide occurence and 

effects of antifouling paint booster biocides in the aquatic environment: a review. 

Environmental International 30: 235-248 

[5] 2002. FEATURES: ANTIFOULING: Is copper-based paint the next to be 

outlawed? Calls for a greater understanding of copper-biocide in antifouling 

systems are getting louder; also a new antifouling system that coats the hull with 

'fur'. Marine Engineers Review 12-17 

[6] 2004. Antifouling: A brief background on antifouling products and Poseidon's 

Antifouling Program. www.poseidonsciences.com 

[7] SANDROCK, S., E.-M. SCHARF, E. GÜNTHER, H.-G. NEUMANN, K. 

REITER and A. FRANZ. 2002. Bewuchsschtuz wird durch pH-Wert-Änderung 

steuerbar. Schiff und Hafen 54: 212-214 

[8] NYGREN, C. 2002. TBT-Free Antifouling Paints, One Company's Experience. 

Journal of protective coatings and linings 19: 44-50 

[9] YEBRA, D.M., S. KIIL, K. DAM-JOHANSEN. 2003 Review: Antifouling 

technology – past, present and future steps towards efficient and environmentally 

friendly antifouling coatings. Progress in Organic Coatings, Elsevier 

2003.06.001 

[10] VAN WEZEL, A.P., P. VLAARDINGEN. 2003. Environmental risk limits for 

antifouling substances. Aquatic Toxicology Elsevier 2003.11.003 

[11] VOULVOULIS, N., M. D. SCRIMSHWAW, J.N. LESTER. 2003. Comparative 

environmental assessment of biocides used in antifouling paints. Chemosphere 

47: 789-795 

[12] THOUVENIN, M., V. LANGLOIS, R. BRIANDET, J.Y. LANGLOIS, P.H. 

GUERIN, J.J. PERON, D. HARAS. 2003. Biofouling 19: 177-186 

33


[13] KIIL, S., K. DAM-JOHANSEN, C. E. WEINELL, M. S. PEDERSEN. 2002. 

Seawater-soluble pigments and their potential use in self-polishing antifouling 

paints: simulation-based screening tool. Progress in Organic Coatings, Elsevier 

45: 423-434 

[14] THOUVENIN, M., J.-J. PERON, CL CHARRETEUR, P. GUERIN, J.-Y. 

LANGLOIS, K. VALLEE-REHEL, 2002. A study of the biocide release from 

antifouling paints. Progress in Organic Coatings, Elsevier 44: 75-84 

[15] THOUVENIN, M., J.-J. PERON, CL CHARRETEUR, P. GUERIN, J.-Y. 

LANGLOIS, K. VALLEE-REHEL, 2002. Formulation and antifouling activity 

of marine paints: a study by a statistically based experiments plan. Progress in 

Organic Coatings, Elsevier 44: 85-92 

[16] LAMBROPOULOU, D. A., V. A. SAKKAS, T. A. ALBANIS. 2003. 

Determination of antifouling compounds in marine sediments by solid-phase 

microextraction coupled to gas chromatography-mass spectometry. Journal of 

chromatography A 1010: 1-8 

[17] OKAMURA, H. 2002. Photodegradation of the antifouling compounds Irgarol 

1051 and Durion released from a commercial antifouling paint. Chemosphere 

48: 43-50 

[18] VOLD, H. 2003. Prohibition of organotin in antifouling systems: the 

classification societies' perspective. 20: 30-32 

[19] VOULVOULIS, N., M. D. SCRIMSHWAW, J.N. LESTER. 1999. Review. 

Alternative Antifouling Biocides. Applied Organometallic Chemistry 13: 135- 

143 

[20] KIIL, S., C. E. WEINELL, M. S. PEDERSEN, K. DAM-JOHANSEN, 2002. 

Mathematical modelling of a self-polishing antifouling paint exposed to 

seawater: a paramater study. Institute of Chemical Engineers 80: 45-52 

[21] Metal free biocide ECONEA 028 Janssen Pharmaceutica NV, Plant and 

Material Division, Turnhoutseweg 30, B-2340 BEERSE, Belgium, 

www.janssenpharmaceutica.be/pmp 

[22] Ecospeed Subsea Industries, Noorderlaan 9, haven 29B, B-2030 Antwerpen, 

Belgium, www.hydrex.be 

[23] Chugoku Marine Paints Lino building, 1-1, Uchisaiwaicho 2-chome, Chiyodaku, 

Tokyo, 100-0011 Japan, www.cmp.co.jp 

34

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