NEW RESEARCH: Maritime Routes Are Choking Oceans with Plastic Pellets.

Welcome to Suits & Tides, the sustainability newsletter with more knowledge than microplastics in the ocean! In this episode, we uncover the hidden threat of plastic pellets, tiny “nurdles” leaking from ships into our seas, creating one of the most persistent forms of marine pollution.

When you think of marine plastic pollution, you probably think of bottles, shopping bags, abandoned fishing nets. But, there’s something far more sinister that is not talked about enough: plastic pellets or nurdles.

These are tiny resin beads, about the size of a lentil. Pellets or nurdles are essentially the feedstocks or raw materials from which almost every plastic product is born. They’re super light, durable, and produced by the billions. 

If nurdles are so perfect (operationally), what is the ‘sinister’ element all about then? When they leak into the environment (land, inland waterways, oceans), they become one of the most persistent and widespread forms of microplastic pollution on Earth.

A recent study published in Marine Pollution Bulletin (Köppel et al., 2025) takes a deep dive into how plastic pellets are lost during maritime transport, revealing a complex chain of events that connects routine shipping operations to large-scale environmental leakage and damage. 

This study's findings are intended to serve as a call to action for the maritime industry, urging a re-evaluation of current practices in managing a frequently underestimated source of marine plastic pollution.

Nurdles are Terrifying... 

At first glance, a nurdle doesn’t seem particularly threatening. It’s small, smooth, and inert. But their sheer scale and behavior in the marine environment make them profoundly damaging.

Each year, an estimated 446,000 tonnes of plastic pellets leak into the ocean, making them the second-largest source of microplastics. They travel vast distances with ocean currents, wash up on beaches around the world, and persist for centuries. Once released, they cannot simply be “cleaned up.”

Marine organisms mistake these pellets for food, leading to internal injuries, starvation, and in many cases, death. Even more insidiously, nurdles act as sponges for toxic chemicals like persistent organic pollutants (POPs), concentrating them and transporting them through marine food webs, all the way up to human diets.

What makes pellet pollution especially frustrating is that it is almost entirely preventable. Unlike single-use plastics discarded by consumers, pellets are industrial products handled in controlled environments. 

So why are they still ending up in our oceans?

The Overlooked Role of Maritime Transport…

Most discussions about pellet loss focus on land-based sources like factories, warehouses, and transport depots. Yet the study reveals that maritime shipping itself is a significant but poorly understood contributor to pellet marine leakage.

We’ve seen the consequences before. In October 2017, a severe storm in Durban Harbour, South Africa, caused a shipping container to spill an estimated 49 tonnes (around 2 billion nurdles) into the ocean. These tiny plastic pellets quickly spread along the KwaZulu-Natal coastline, contaminating beaches, estuaries, and marine habitats.

But it’s not only catastrophic accidents that matter. Pellets also leak gradually during everyday maritime operations - spilled during loading, escaping from poorly sealed containers, or lost when a container falls overboard in rough seas. These losses often go unnoticed, unreported, and unaddressed, yet collectively they create a steady, chronic stream of microplastic pollution.

How Do Pellets End Up in the Sea?...

The research identifies four main ways pellets are lost at sea, each connected to a different kind of operational failure or accident:

i) Leaking containers: Sometimes packaging isn’t sealed properly, or the containers themselves are compromised. During long voyages, vibration and shifting cargo can cause pellets to slowly escape.

ii) Damaged containers: Rough seas, improper handling, or accidents can rupture containers, spilling their contents directly into the ocean.

iii) Containers lost overboard: A single shipping container can hold tens of billions of pellets. When storms or poor stowage lead to containers falling into the sea, the pellets inside disperse rapidly.

iv) Total vessel loss: Catastrophic events like fires, collisions, or sinkings release entire cargo holds in a matter of hours.

What’s worth noting is how avoidable these pathways really are. Better packaging, stricter container handling standards, improved stowage planning, and real-time monitoring could dramatically reduce these risks.

Recovery of Nurdles Is Nearly Impossible…

Once pellets are in the ocean, they’re almost impossible to recover or cleanup. Their small size and buoyancy mean they spread quickly over large areas. By the time they wash ashore, they’re often mixed with sand, seaweed, and debris, making removal painstaking and expensive.

Cleanup after a major spill can take years, cost millions of dollars, and still fail to recover more than half of the pellets released. In this case, prevention is the only viable solution.

A Major Regulatory Blind Spot…

Perhaps the most troubling revelation in the study is the policy vacuum surrounding pellet transport by sea.

Unlike oil or other hazardous cargo, plastic pellets are not classified as dangerous goods under international shipping law. This means there are no mandatory safety requirements for their packaging or stowage. Even more concerning, there’s no requirement for shipping companies to report pellet losses, whether from accidents or operational leaks.

As a result, data on pellet spills is scarce and fragmented. Industry, insurers, regulators, and environmental organisations each hold pieces of the puzzle, but there’s no comprehensive global record of how much is being lost, or where.

The International Maritime Organisation only began formally discussing pellet pollution in 2021, prompted by nations dealing with spill disasters. And, if we’ve learned anything about the pace of regulatory shifts from all of the “progress” in forming an international plastics treaty, it’s that it’s super annoying, redtaped to the gills, and it can take not years, but decades. 

READ MORE: From INC-5 to 2025: Will We Ever See a Global Plastic Treaty?

What the Study Gets Right, and What’s Missing…

The paper’s greatest strength lies in its transdisciplinary approach. It doesn’t just rely on academic literature; it draws in voices from the shipping industry, NGOs, policymakers, and insurers. This makes its findings both richer and more realistic. The use of cause-consequence diagrams is a clever way to show how small operational failures cascade into major pollution events.

But the study also highlights just how little we know. Without mandatory reporting, much of its analysis relies on expert opinion and anecdotal evidence. It calls for better regulations and spill response measures but stops short of detailing exactly what those might look like in practice.

In other words, it maps the problem clearly but leaves the next step - how we fix it - as an open challenge.

What We Feel Needs to Happen Next…

If there’s one message to take from this research, it’s that maritime pellet pollution is both preventable and neglected. To change that, we need:

• Clear international rules for pellet transport, including robust packaging standards and proper container stowage protocols.

• Mandatory reporting of pellet losses, so we can build an accurate picture of the problem.

• Better spill response systems, with predefined cleanup plans for ports and coastal areas.

• Collaboration across the plastics supply chain, from manufacturers to shippers to insurers, to share data and best practices.

Above all, we need to recognize that as global plastic production continues to rise, projected to double by 2045, the risks will only grow.

A Wake-Up Call for the Shipping Industry

This study is more than just an academic exercise. It’s a wake-up call. Plastic pellets might be small, but their impact is enormous, and the maritime sector can no longer treat them as just another inert commodity.

Without stronger safeguards, every voyage that carries pellets is a potential spill waiting to happen. And once those nurdles are in the ocean, there’s no bringing them back.

But, this is a solvable problem. Unlike the diffuse plastic waste created by consumers and organisations, pellet transport happens in a controlled supply chain. With the right policies, industry standards, and accountability mechanisms, we could drastically cut pellet pollution at sea.

At Seven Clean Seas, we build and operate certified plastic recovery and circularity projects in heavily impacted regions. That’s why we work with businesses, policymakers, and local communities to tackle plastic pollution at its source - whether on land or at sea. Organisations across the world fund our operations through the purchase of plastic credits - and we’ve been able to remove 5.5 million kg+ of plastic from the environment and we’ve been able to generate fair and formal employment for 106+ waste collection crew members.

And, much like what the shipping industry needs to focus on, we believe funding recovery solutions and prioritising plastic leakage prevention are clear long-term solutions. 

From reducing The Economist’s global plastic footprint by over 50% in just three years, to supporting the FIFA World Cup in achieving an 88% landfill waste diversion rate to profiling and reducing plastic waste onboard Berge Bulk’s vessels  - we partner with some of the world’s leading organisations to measure and reduce plastic footprint volumes. Our expertise enables us to embed plastic reduction and circularity into even the most complex global supply chains.

DHL, MOL, Berge Bulk, Scorpa Pranedya and many many more - the maritime industry loves Seven Clean Seas. 

Do you? 

Drop us an email at hello@sevencleanseas.com TODAY.

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