Today let us first begin with understanding what anti-fouling paints are. Anti-fouling paint is a concoction of heavy metals and biocides. It is a particular kind of coating applied as the outer layer to the hull of a ship or boat, it stops marine life adhering to and grow on ocean steel constructions such as boats and ships as it increases resistance in water which leads to more fuel consumption, extra emission of carbon dioxide and in the long run may also worsen the working of the engine.
Marine pollution is a much-belittled problem that we humans have been overlooking since time immemorial. Marine pollution happens when damaging effects result from the entry into the ocean of chemicals, particles, industrial, agricultural, and residential waste, noise, or the spread of invasive organisms. The International Convention for the Prevention of Pollution from Ships is the main global resolution covering the prevention of pollution of the marine environment by ships from operational or accidental causes.
MARPOL is a short form of marine pollution, it was implemented on 2 November 1973 at International Maritime Organization and has been amending itself throughout the years. The International Convention for the Prevention of Pollution from Ships (MARPOL) has been dealing with various issues such as prevention of pollution by sewage from ships, prevention of pollution by garbage from ships, prevention of pollution by harmful substances carried by sea in packaged form, prevention of air pollution from ships which are given in the form of different annexes to try to curtail marine pollution to a larger magnitude.
One of the annexes discussed by the International Convention for the Prevention of Pollution from Ships is “Regulation for prevention of pollution by anti-fouling paints from ships”.
Anti-fouling paint is a concoction of heavy metals and biocides. It is a particular kind of coating applied as the outer layer to the hull of a ship or boat, it stops marine life adhering to and grow on ocean steel constructions such as boats and ships as it increases resistance in water which leads to more fuel consumption, extra emission of carbon dioxide and in the long run may also worsen the working of the engine. Therefore, the smooth coating of the anti-foulant paint ensures maintenance of the submerged portion of the ship, under the prerequisite that guarantees the normal speed of a ship, reduces oil consumption to the greatest extent and prolongs the working life of the coating, reduces unnecessary expenditures for maintenance.
In the Era of Sails, sailing vessels suffered brutally from the growth of barnacles and weeds on the hull, called “fouling”. Thin sheets of copper were used and after many years the use of Muntz metal came into practice, Muntz metal were nailed onto the hull in an attempt to prevent marine growth.
Historically, copper sheets were red, leading to ship bottoms still being painted red till today.
The use of biocides in the anti-fouling paint industry, nevertheless, has proved to be detrimental as it has toxic effects on the marine environment. Anti-fouling paints are designed in such a way that they wear away easily so that fresh biocides are always brought to the surface of the coating which will prevent marine growth. The chemicals and heavy metals from the anti-fouling paint that have worn of starts to accumulate in the seabed. The poisonous substances enter the marine life which then enters into the food chain. Organic booster biocides are used as an alternative of tributyltin (TBT) which is banned. generally copper metal oxides and organic biocides are used as replacement.
Biocides are chemical substances that can deter or kill the microorganisms responsible for biofouling. The rapid expansion of the anti-fouling paint industry is having a substantial influence on the marine ecosystems. As the industry multiplies, it requires the use of additional anti-foulant compounds (biocides) to eliminate the microorganisms.
The biocides that are generally used in antifouling paints comprise of chlorothalonil, dichlofluanid, DCOIT (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one), Diuron, Irgarol 1051, TCMS pyridine (2,3,3,6-tetrachloro-4-methylsulfonyl pyridine), zinc pyrithione and Zineb.
It is seen that there are many types of risks associated with the use of biocides in the marine field. Predators and beings may consume the fish that contain these toxins. It also hinders in the growth of aquatic life and is destroying it gradually. Ship owners usually prefer the strongest anti-fouling paint they can get hold of so that the condition of the ship is not hampered totally disregarding the repercussions it may cause on the environment. The scale at which this is taking place may give the impression of small and insignificant but we are totally misjudging the situation and inviting further problems for all the breathing creatures dwelling on this beautiful planet.
FACT: Commercial shipping releases around 1 million tons of biocides into the ocean every year. In some areas manual under water cleaning of anti-fouling paint from the keel of the ship is allowed. This process is extremely harmful to the environment as several biocides and heavy chemicals get released in the into the water then and there. Marine companies claim that they filter all the harmful chemicals from the water but only a small portion of these chemicals are filtered out and around 80% of the chemicals get mixed up in the water.
Anti-fouling paint manufacturers use the most powerful and potent chemicals and biocides that the law will allow. Investigation on natural product antifoulants (NPA) is going on for the last two decades. NPAs are much better and advantageous over toxic biocides which are used today as they are less toxic, effective at low concentrations, safe for the marine environment, and is effective for its anti-fouling property.
The aquatic fouling organisms in seawater are used by various marine lives such as corals, sponges, marine plants, dolphins, etc., which prevent the surface of their bodies with anti-fouling substances without causing serious environmental problems.
Therefore, NPAs are expected to be used as an environmentally friendly anti-fouling paint. Many NPAs have been tried and tested for their potential industrial application also consisting of halogenated furanones, triterpenoids. After exhaustive studies and trial runs the data which has emerged is very promising as a natural anti-foulant.
In today’s world there are many safe alternatives which are not only less harmful but also cheap. I am sure that we humans will take care of the environment and will protect what is ours today for our future generation tomorrow and will find more and more ways to make not only the shipping industry the most environmental approachable industry but also for other fields and industries by keeping the similar devotion and commitment for our mother nature.
“The only thing we know about the future is that it will be different”
Peter Drucker
Authored By:- Cdt. Yash Katoch, TMI
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