Download IV. Overview of previous studies of overload with antifouling paints in

Analysis of Compounds from Antifouling Paints in Croatian Part of
Adriatic Sea
Astrid Zekić, Renato Ivče, Đani Mohović
University of Rijeka, Faculty of Maritime Studies, Studentska ulica 2, Rijeka, Croatia
[email protected]
Abstract - Marine pollution by antifouling paints is becoming a
serious environmental problem due to anthropogenic activities.
Antifouling paints have a very harmful efect not only on marine
organisms but also, through the food chain, on humans. Although
the ban on tributyltin (TBT) has resulted in significant changes
in the paint industry, its adverse effects are still present. This
paper investigates the degree of pollution by antifouling paints.
Previous studies confirmed contamination by organic compounds
as a result of their long-term use in antifouling paints. Given that
there has been no continuous monitoring of harmful antifouling
systems at the national level, the authors point to the necessity of
its implementation.
Keywords - Antifouling; Pollution; Organotin tributyltin
I.
INTRODUCTION
Croatia has about has total 1244 islands, islets, cliffs and
reefs scattered all along its coastline, which is the main reason
why it has been attracting a large number of leisure boats. Boat
owners have problems with fouling organisms attached to
underwater parts of boat hulls. Marine biofouling can be
defined as a natural process of undesirable attachment and
accumulation of microorganisms, plants and animals on
underwater surfaces. Attaching organisms create friction that
decrease the boat’s speed, manoeuvrability, and also increase
fuel consumption.
Antifouling coatings are used in maritime transport to
control the growth of organisms such as algae and barnacles
on underwater parts of boat hulls. Generally, antifouling paints
can be divided into traditional and alternative antifouling
coatings. Traditional antifouling coatings slowly release toxic
elements from the paint applied on the underwater hull. While
such coatings are very effective as they discourage the growth
of fouling organisms, the toxic elements also slowly leak in
the surrounding water and eventually fall to the sediment.
Such marine biofouling can be reduced or eliminated, but
unfortunately the release of hazardous substances also causes
serious problems to the environment. Alternative antifouling
coatings can generally be classified as biocide antifouling
coatings and non-biocide antifouling coatings. Biocide
antifouling coatings slowly release toxic substances such as
zinc, fluorine, chlorine and various organic biocides. Nonbiocide coatings contain silicon or have ceramic or epoxy
basis, which may produce a slick surface thus making it
difficult for organisms to attach [1].
One of the most effective antifouling paints was developed
in the 1960s, with the organotin tributyltin (TBT) as main
toxic component. It has been proven to cause serious problems
to the environment. Copper-based antifouling paint is
currently dominated on the market and its ions at low
concentration may have influence on the health of animals and
plants through the enrichment effect of food chain, causing
damage to the ecological balance [1].
The toxicity of antifouling paints decades and attention has
generally focused on the active substances. The toxicity of
antifouling coatings has been debated during the last 30 years
[2]. Focused studies have shown that toxic elements from
antifouling coatings remain in the water and bottom sediment,
killing sea-life, harming the environment and entering the food
chain. A study conducted in the UK estimated that commercial
vessel and pleasure boats are the single largest source of
metals like copper and zinc in coastal areas, and also
significant concentrations of irgarol and dichlofluanid have
been detected in waters and sediments in marinas and mooring
areas. Conducted research has shown that oysters located in
the vicinity of marinas and mooring areas had significant
copper content. Focused studies in Sweden have shown that
especially at the time of launching pleasure boats (May–June),
high concentrations of copper and irgarol have been measured
in the archipelago of Stockholm [3].
Organotin tributyltin (TBT) has been globally banned for
all sizes of ships by the International Convention on the
Control of Harmful Anti-fouling Systems on Ships (AFS)
Convention of the International Maritime Organization (IMO),
but TBT and its degradation products, dibutyltin (DBT) and
monobutyltin (MBT), are still observed in high concentrations
in sediments at marinas, harbours and estuaries [4].
Being a significant tourist destination in the Mediterranean,
especially during the summer season, Croatia has been
attracting a large number of pleasure boats. These boats,
together with boats owned by the local residents and merchant
(passengers and cargo) ships, have been leaching significant
concentrations of toxic elements from antifouling paints which
have accumulated in the sea and the sediment. The main
objective of this paper is to present the amounts of
contaminants accumulated in some areas and to point to
establish continuous monitoring of harmful antifouling
systems.
II.
MARINE BIOFOULING, TERM
Marine biofouling, settlement and growth of sedentary and
semi-sedentary organisms at artificially sunken structures in
the water, is a grave technical and economic problem [5]. It is
a very dynamic process which can be affected by sea currents,
mechanical damage, sea salinity, the amount of light,
temperature, pollution and the availability of nutrients. Marine
biofouling communities which can be found on immersed
hulls are a special problem as they reduce the smoothness of
the hull, thus increasing its resistance to passage through
water. Fouled ships use more fuel to achieve necessary speed,
which creates additional pollution of the atmosphere.
The protective method used to prevent marine biofouling
on vessels is applying antifouling paint. The application of
antifouling paint must satisfy two basic criteria:


Rejection of colonisation by micro- and macroorganisms
Keeping the surface as smooth as possible
Other desirable characteristics of antifouling paints include
their low persistency, low toxicity for sea organisms, poor
water-solubility, a broad spectrum of impact, acceptable price,
easy application and low bioaccumulation. Vessels are
normally coated once a year and in contact with water, the
coating gradually dissolves and its active components infiltrate
in the marine environment. The rate of dissolution varies from
paint to paint, depending on the method of using the active
components, pH, temperature, sea salinity, current velocity
and the speed of the vessel. Released biocides are venomous
for the marine environment and for people.
Biocide coatings which contain stannyne are the most
harmful. The toxic effects of tributyltin (TBT) can be seen
already at concentrations of one nanogram per litre. The
European Water Framework Directive lists TBT among the
major pollutants and its application is forbidden in the EU
countries.
Among the coatings that started being used after the ban
on the use of TBT, those containing copper oxide and zinc
oxide prevail, although Directive 67/548/EEC categorized
them as dangerous for the environment. Toxic components
that are soluble in water may spread their toxic effect into the
surrounding environment [6].
The biggest problem of contamination by antifouling
paints lies in the fact that it is the ecosystems of enclosed and
shallow seas that are the most exposed to it. Antifouling paints
enter the water tower and remain there for some time. Sea
tides, wind, local currents, adsorption of suspended particles
and gravitational sedimentation are the most powerful
mechanisms of their removal from the water column [7].
However, in seas like the Adriatic Sea, the exchange of water
with the open sea is poor, which favours marine sediment
deposition. The problem is only amplified with nautical
tourism, which is one of the most profitable selective forms of
tourist offer and which, considering the market, can be
expected to lead to an increase in vessel mooring. Although
the vessels individually do not represent a threat to the
environment, the cumulative effect of a larger number of
vessels found in confined waters represents a major source of
contamination and other forms of degradation of the marine
environment [8].
III.
LEGISLATION
Marine environment protection imposes the necessity of
legal regulation of activities related to the sea. Due to the
threat that antifouling paints present to the environment and
human health, their application in Croatia must comply with
the following regulations:

International Convention on the Control of Harmful
Antifouling Systems on Ships - AFS Convention,
2001.
The Convention was adopted with a view to prohibiting
and/or restricting the use of harmful antifouling systems on
ships, which comprise coatings, paints, surface treatments or
agents. Moreover, the Convention establishes a mechanism for
preventing the potential future use of other harmful substances
in antifouling systems. Appendix 1 of the Convention lists
systems whose use has been prohibited or whose application
has been limited. At present, these are systems containing
organic tin compounds, usually tributyltin – TBT, whose
harmful effects on marine organisms have been proven.
However, the list is not exhaustive and will be supplemented
as needed. The Convention entered into force on 17th
September 2008.
The AFS Convention has been implemented in the EU
which prohibits using harmful organotins, thus tributyltin and
other harmful components, in antifouling paints on ships.
Based on the adopted Convention and EC Regulations, and
due to the harmful effects of some antifouling systems, special
measures were introduced to control and prohibit entry into
the Croatian ports to ships using harmful substances in
antifouling paint and, moreover, the use of these systems is
prohibited on ships of Croatian nationality [9]. Restriction of
application of harmful substances in antifouling coatings in
the EU is regulated by:

Regulation (EC) No. 782/2003 adopted by the
European Parliament and the Council on 14 April
2003, banning the use of TBT and other harmful
components in antifouling coatings
Since January 2008, EU member states have been
required to prohibit and/or restrict the use of harmful
antifouling systems on ships flying EU countries flag, as well
as ships not entitled to fly their flag but which operate under
their authority, and all ships that enter in EU ports, shipyards
or offshore terminals. Ships of less than 24 metres in length
are not required to have special examination or declaration.
These ships include mainly recreational craft and fishing
vessels, and are adequately covered by the provisions of
Directive 76/769/EEC relating to restrictions on the marketing
and use of certain substances and preparations in antifouling
paints. The Croatian government, within the Mediterranean
strategy, has adopted

Mediterranean Strategy for Sustainable Development:
A Framework for Environmental Sustainability and
Shared Prosperity (UNEP(DEC/MED IG. 16/7))
An integral part of the Mediterranean Strategy for
Sustainable Development is the requirement to improve the
quality of coastal waters. The issue of toxicity of antifouling
paints has been addressed in:

Sustainable Development Strategy of the Republic of
Croatia
This Strategy comprises a plan to solve the problem of
toxicity of antifouling paints [10]. Prevention of possible
transfer of harmful marine aquatic organisms and pathogens
through marine fouling has been regulated by:

Port's Rules and Regulations and rules and
regulations on other parts of internal waters and the
territorial sea of the Republic of Croatia
Cleaning, scraping and painting of freeboard and
underwater parts of ship hulls have been prohibited in port and
at anchorage. Such activities may be carried out in the
shipyards, while in ports they should be approved by the
relevant port authority [12]. The concentration of TBT
substances in the water has been regulated by:

Location
Sveti Ivan
The Maritime Code
Maritime objects are required to take measures to prevent
the transmission of harmful marine aquatic organisms and
pathogens through fouling [11]. The maintenance of freeboard
and underwater parts of ship hulls is regulated by:

TABLE I.
Ploče
Vranjic
Martinska
Bakar
Rijeka
Lim bay
CONCENTRATIONS OF ORGANOTIN COMPOUNDS IN MUSSELS
2010. (µg Sn/kg)
MBT=42.5
DBT=5
ƩBuT=82
TBT=34.5
MBT=.9
DBT=63.2
ƩBuT=203.8
TBT=103.7
MBT=130.3
DBT=102.2
ƩBuT=330.4
TBT=97.9
MBT=137.9
DBT=49.2
ƩBuT=234.9
TBT=47.8
MBT=124.3
DBT=106.6
ƩBuT=354.8
TBT=123.9
MBT=96.3
DBT=94.1
ƩBuT=276.2
TBT=85.8
MBT=230.9
DBT=86.5
ƩBuT=383.7
TBT=66.3
2013. (µg Sn/kg)
MBT=11.4
DBT=0
ƩBuT=31.9
TBT=20.5
MBT=25.4
DBT=3.6
ƩBuT=57.8
TBT=28.8
MBT=58
DBT=15.4
ƩBuT=185.4
TBT=112
MBT=24.7
DBT=11.5
ƩBuT=68.9
TBT=32.7
MBT=25.1
DBT=13
ƩBuT=85
TBT=46.9
MBT=35.1
DBT=8.2
ƩBuT=79.7
TBT=36.4
MBT=21.4
DBT=0
ƩBuT=55.2
TBT=33.8
Regulation on Hazardous Substances in Water
This Regulation prescribes the maximum allowable
concentration (MAC) of tributyltin compounds in the waters
[13]. To date, no continuous monitoring of harmful elements
in antifouling paints has been carried out on national level.
This is due to: discrepancies in the mode and location of
sampling, ill-defined tasks for workers who will perform
sampling, and insufficient number of specialists who will
perform the analysis and interpret the results, which has led to
an improper assessment of the sea condition.
The new Environment Protection Act recognised the
National List of Indicators (NLI) as a key document for
drafting reports on the state of the environment at the national
level. Control of harmful elements in antifouling systems is
expected to become a reality shortly. The data will be
provided by the Ministry of the Sea, Transport and
Infrastructure and also by the Oceanographic and Fisheries
Institute, each within their respective jurisdiction.
IV.
OVERVIEW OF PREVIOUS STUDIES OF OVERLOAD WITH
ANTIFOULING PAINTS IN THE CROATIAN PART OF THE ADRIATIC
In spite of its few areas with increased contamination (Gulf
of Rijeka, Gulf of Bakar, the zone of Zadar, Šibenik, Split
with the Gulf of Kaštela, embouchure of the Neretva), the
Adriatic Sea along the coast of Croatia is not a highly
contaminated sea. In the past few years, several studies were
carried out to establish the degree of its contamination.
In 2010, research conducted at 15 locations along the
Adriatic coast investigated the concentrations of TBT and its
degradation products DBT and MBT found in mussels. Table
1 shows the results of measurements at the seven locations
where this was carried out also in 2013. The total
concentration of butyltin compounds (∑BuT = TBT + DBT +
MBT) indicates the amount of TBT that has been released into
the environment [14].
In 2010, the respective concentrations of organotin
compounds found at the locations shown in the table were as
follows: TBT: 34.5-123.9; DBT: 5-106.6; MBT: 36.9-230.9.
The total butyltin compounds concentration (ΣBuT) range was
82-383.7 µg Sn/kg, average 233.22 µg Sn/kg.
In 2013, the concentrations of organotin compounds were:
TBT: 20.5-112; DBT: 3.6-15.4; MBT: 11.4-35.1. The total
butyltin compounds concentration (ΣBuT) range was 31.9185.4 mg Sn/kg, average 80.55 µg Sn/kg.
In 2013, a new location, Marina Rovinj, was included and
it showed the greatest overload of all locations investigated in
2013. The concentrations of organotin compounds found
amounted to 119.2 for TBT; 83.7 for DBT and 150.9 for
MBT, the total concentration of butyltin compounds (ΣBuT)
being 353.8 µg Sn/kg. The results of analysis in sea sediment
samples from marinas are shown in Fig. 1.
The Adriatic project was designed for the purpose of
protection and preservation of the quality of the sea, and for
creating conditions for safe economic development in
accordance with the requirements of environmental protection,
and the preservation and improvement of the achieved level of
this protection. The results of analysis are shown in Table I.
Figure 1. Concentration of butyltin products at surface sediment in marinas,
2009.
These concentrations were the highest in marinas, a little
lower in ports, and the lowest in farms. This proves that
pollution by organotin compounds is widespread along the
Adriatic coast. Sea sediments, which are the final repository of
heavy metals but also a source of contamination of water and
wildlife, represent an issue apart.
Many countries have introduced Cu regulations. Sweden
has limited emissions on copper-bearing coatings in the Baltic
to 200 µg/cm²/14-day, while the Netherlands bans cleaning or
scrubbing copper-bearing antifouling coatings altogether. That
the Cu problem is big is best illustrated by data from the USA.
The estimates for total annual copper loadings from all
discharges within a contiguous zone (<12 nm) is 121 675
kg/year; vessels hull coating leachate is responsible for 78%
(93 929 kg/year) [15].
The results of the studies assessing the concentration of
toxic elements in sediments near areas where ships are
serviced along the Gulf of Kvarner and its islands were
presented at the 2nd Scientific Symposium of Natural History
Research in the Region of Rijeka in 2006. Concentrations of
copper, zinc and lead, found in high levels in antifouling
paints, were measured in Punat Bay. The results, expressed in
ppm, were as follows:





sediment depth 0-2 cm: Cu-46.4; Zn-167.1; Pb-43.4
sediment depth 2-4 cm: Cu-32.9; Zn-143.91; Pb-99.4
sediment depth 4-6 cm: Cu-25.1; Zn-61.7; Pb-25.5
sediment depth 6-8 cm: Cu-23.3; Zn-54.9; Pb-25.1
sediment depth 8-10 cm: Cu-24.3; Zn-55.91; Pb-14.3
Changes in the sea environment due to contamination by
vessels can permanently endanger the quality of the sea. For
this reason, the above-mentioned causes of pollution must be
monitored, controlled and sanctioned in accordance with
positive regulations of the Republic of Croatia.
In order to achieve comprehensive protection, systematic
planning of human activities that must be in harmony with the
environment is required. The state of the environment in
Croatia is also important for the broader European and global
context, so indicators of environmental pollution by
antifouling paints could serve as the basis for international
reporting to, for instance, the European Commission, the
European Environment Agency or the United Nations.
Given that that the damage caused by pollution cannot be
removed completely, it is necessary to put in place preventive
measures to obstruct its occurrence in the first place. Raising
the ecological awareness of all the participants in nautical
tourism and also of the society as a whole could positively
affect the protection of the ocean ecosystem, which is the basis
of sustainable development, particularly important in this
century.
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The highest concentrations were present in the first two
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Given that heavy metals are not degradable, their
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concentrations of copper, zinc and lead.
[5]
Another point worth mentioning is the problems caused by
sport ports, especially during the preparation of boats for the
season. The fact that sports ports present a significant source
of pollution is due to relaxed understanding and lax
application of regulations, and tolerance on the part of those
responsible for enforcement of relevant regulations in them.
V.
CONCLUSION
Vessel protection is based on continuous release of
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the sea environment, they settle on the existing sediments.
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harbours. However, although use of TBT has been prohibited,
its presence has been proven at 15 locations along the Adriatic
coast.
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