Microplastic pollution stands as an increasing threat to both our environment and the intricate balance of marine life. With millions of tons of plastic waste infiltrating our oceans annually, it’s clear that a significant problem has taken root.

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Among the numerous sources of microplastic pollution, the paint industry, emerges as a major contributor, shedding an estimated 1.9 million tons per year into our oceans and waterways. These minute particles – a byproduct of coating application is released through processes such as wear and tear or removal. Surprisingly, the coating application phase alone accounts for approximately 13% of this total loss, equating to a staggering 356 kt annually. (1)

 

Recognizing the scale of this challenge, a collaborative effort involving government policymakers, paint manufacturers, coating contractors, asset owners and other important stakeholders in the paint sector is underway to tackle microplastic pollution. As we set sail towards a more sustainable horizon, it’s only natural to unravel the impact of microplastic pollution originating from the maritime industry and chart a course towards cleaner seas.

The predominant constituent within organic coatings are polymers. The utilization of organic coatings can lead to the emission of microplastics. For instance, non-applied water-based paints that are inadequately disposed of might release polymer particles into the environment. Furthermore, the weathering of organic coatings contributes to the formation of particles, adding to the microplastic concern.

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So what are microplastics?

By definition, microplastics are small plastic pieces less than five millimeters long which can be harmful to our ocean and aquatic life. There are two types of microplastics: primary and secondary. Since the microplastic definition does have a lower size limit, plastics in the nano-size range (<100 nm) are also included in the microplastic definition.

 

Primary microplastics refers to plastic particles that are intentionally manufactured at that size, such as nurdles and cosmetic microbeads. Secondary microplastics result from the breakdown of larger items, such as the weathering of plastic litter and paint layers, as well as car tyres.

 

Microplastics derived from paints have been detected in the aquatic environment as well as in aquatic species. A report in 2019 showed that 16.7% of the sampled fish contained participles in the form of microplastics in the gastrointestinal tract. While in 2018, another study concluded that 55% of the plastic fragments found in sampled fish species derived from paint fragments of vessels. (2)

 

In the maritime industry, a wide range of coating materials with pigments are used for different functionalities. The main functionalities are corrosion protection and anti-fouling.

 

Depending on the kind of functionality different coatings are used, these have different compositions and hence the toxicity of the release of these materials to the environment is strongly depending on their composition.

 

Blasting

Under the protection of coatings, a vessel can operate for a service lifetime of 20 to 30 years. However, coating degradation and rusting of the vessel surfaces occur during marine transportation, which requires the ship to be docked for repair and maintenance at intervals of 3-5 years. During ship maintenance, foreign matter on the ship coating surfaces such as grease, salt, attached marine organisms and slimes are usually washed down with high-pressure water, followed by the removal of rust and coatings via spot or full blast cleaning. (3)

A lot of the blasting methods share the same challenges when it comes to waste management. For instance, dry abrasive blasting, even though it is economical and efficient, produces a large amount of dusting emission and abrasive blasting media, which contain paint chips. In contrast, wet abrasive blasting methods generates a smaller quantity but usually more hazardous solid paint waste. Moreover, due to vessel size, blasting typically occurs in open dry docks, introducing containment and environmental challenges. (2)

 

Coating application

The current coating application method are also far from perfect. For instance, when using a roller for painting application, the roller will distribute the paint depending on the applied pressure. It also results in an uneven coating thickness and poor-quality finishes. Consequently, painters may compensate for uneven application by adding more paint to the missed pots or insufficient coverage. Too much paint on the roller ends can result in splatters as the painter rolls them across the surface.

 

Although coating with a spray gun is more efficient in terms of speed and coverage, it still generates a significant amount of paint waste because it produces a large volume of paint in a short amount of time, often more than what is required to cover the surface. But then, what happens to the paint particles that do not make it to the asset’s surface? The paint mist or overspray could drift away with the wind and contaminate nearby water bodies.

 

And just like blasting, the coating application process for a vessel is often carried out in dry dock as well. Regulations and monitoring, for example by harbour masters, should prevent the release of waste to the environment. In cases where maintenance is performed while at sea, monitoring waste management practices is more complex. These maintenance activities are, however, limited. (2)

 

Wear and Tear during lifetime

Wear and Tear losses happen onboard while the boat is in service and is a direct result of ultraviolet (UV) radiation, heat, microbial activity, and mechanical stress from wave and wind energy. (4)

 

Different parts of a ship demand distinct types of coatings. For instance, ship hulls, constantly immersed in seawater, are typically coated with primers and antifouling paints that can reduce drag. Conversely, areas not submerged, like decks and superstructures, require different paint types, primarily focused on corrosion prevention.

 

While no specific distinction was made between emissions and paint types, antifouling paints are often associated with higher emissions. Over time, some of these paints wear off, releasing their contents into the aquatic environment. Consequently, antifouling paints have already been identified as contributors to aquatic water pollution. (2)

 

End of Life

In contrast to popular belief, only 29% of the leakage from the marine coating is actually related to the Wear and tear phase. The most significant losses actually stemmed from ship dismantling process, which accounted for a total of 34% (End of life). As this process takes place in Ship Graveyards on the beaches of India, Bangladesh, Pakistan, China and a small part in Turkey, it is not a surprise that more than half of the total marine paint leakage (51%) happens in Asia – Pacific regions. (1)

 

The Ripple Effect: Ecological and Human Implications

According to research conducted by EA, marine paint accounts for 7% of the global paint demand, amounting to a staggering number of 3.7 Mt. It was also reported that 66% of the total paint used in the marine sector would eventually end up in the environment, including 911 kt of plastic. And of this plastic, 816 kt will leak into ocean and waterways. 65% of the total leakage will be in the form of microplastics. (1)

 

The consequences of microplastics in marine coatings are far-reaching, threatening both the balance of the ecosystem and the human’s life. In a scientific study published in March 2018, it was reported that fish who were exposed to microplastics reproduced less. Unfortunately, their offspring who were not directly exposed to microplastic particles also had fewer young. This suggested that the effects after ingesting microplastics can linger into the next generations. (5)

 

For humans, a study in 2019 showed that an average person could be digesting approximately 5 grams of plastic every week, which is the equivalent weight of a credit card. (6)

 

 

Ingested paint microplastic particles can physically damage organs and leach hazardous chemicals – from the hormone-disrupting bisphenol (BPA) to pesticides – that can compromise immune function and stymie growth and reproduction. Dangerously, the microplastics will not only be contained in the ocean. Both microplastic particles and those chemicals will accumulate further up the food chain, not only stopping at the fish that we eat and water that we drink. They can potentially impact the whole ecosystem, including the health of the soils in which we grow our crops.

 

Charting a Sustainable Course: Preventing Microplastics in Marine Coatings

In the wake of escalating environmental concerns, it is crucial for policymakers as well as coating contractors, asset owners and paint manufacturers to take the steering wheel and help us sail into a more sustainable future.

 

In this endeavour, key stakeholders are actively embracing cutting-edge technologies to revolutionize surface preparation and maintenance practices within the maritime sector.

 

For blasting processes, coating contractors and assets owners have been leaning towards the adoption of surface blasting robots. Their precision and control minimize abrasive material and paint chip wastage. Equipped with closed-system solutions, they contain all debris, preventing microplastics from entering the environment. By collecting and containing waste, they also facilitate a more responsible disposal processes, reducing the environmental impact.

The maritime sector is also exploring the use of underwater drones, designed to inspect and remove algae from hulls without disturbing fouling coatings, thus reducing potential paint microplastic particles leaking in the ocean. Moreover, the industry is transitioning away from biocides containing harmful compounds in favour of environmentally friendly, biocide-free paint formulas that prolong vessel repaint intervals, reducing dry dock time and the need for repeated blasting and recoating.

 

Several companies are ambitiously developing anti-fouling paint formulas that would eliminate the release of microplastics from ocean-going ships, further underscoring the industry’s commitment to a sustainable and eco-conscious future.

 

In addition to research and development activities from active players in the coating industry, governmental bodies and policymakers are also working on stricter regulations governing the use of microplastics in marine coating and waste management guidelines.

 

 

A brighter horizon ahead

The detrimental impact of microplastics in the maritime industry calls for immediate and unified action. By steering the maritime industry towards sustainable practices and embracing innovative solutions, we can safeguard our oceans and preserve the intricate balance of marine ecosystems. As conscious captains of our planet, it is our responsibility to rise above this threat and pave the way for a future where marine coatings protect without compromising the environment.

 

Together, we have the power to rewrite the narrative, transforming the seas into thriving hubs of life and vitality, untouched by the looming dangers of microplastic contamination. The journey might be tendinous, but it will worth the effort and it is definitely a necessary one for our future generations.

 

Are you ready to take on this challenge with us?

There have been numerous educational initiatives and collaboration partnerships that foster collaboration between industry leaders, researchers and environmental organizations to drive innovation and collectively address the microplastics challenges from paint.

Reference

(1) https://www.e-a.earth/plastic-paints-the-environment/

(2) https://rivm.openrepository.com/handle/10029/624865

(3) https://www.sciencedirect.com/science/article/pii/S030147972101776X#bib80

(4) https://www.frontiersin.org/articles/10.3389/fmars.2022.1074654/full

(5) https://www.scientificamerican.com/article/from-fish-to-humans-a-microplastic-invasion-may-be-taking-a-toll/
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(6) https://www.newcastle.edu.au/newsroom/featured/plastic-ingestion-by-people-could-be-equating-to-a-credit-card-a-week