The impact of microplastics in the sea: the case of pellets in Galicia

We examine the nature of pellets, exploring their origin and assessing the environmental and human risks of these microplastics in the sea.
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In late 2023, an unusual event unfolded off the coast of Galicia, situated in northwestern Spain. Beaches in the region became inundated with millions of small plastic spheres, commonly referred to as pellets, causing concern among residents and authorities.

These pellets originated from a merchant ship that, while navigating off the Portuguese coast, lost six containers from its cargo. One of these containers held 1,050 sacks of the product, with each sack weighing 25 kilograms. This resulted in a total of 26.25 tons of microplastics released into the sea. The scale of this microplastic spill has led to it being dubbed a “white tide,” drawing parallels to the “black tide” resulting from the Prestige tanker tragedy off the Galician coast in 2002.

This article covers the following topics:


What are pellets, the microplastics released into the sea of Galicia?

In this specific scenario, the plastic pellets found along the Galician coast resemble lentils in size. These microplastics undergo transportation to factories where they are melted and utilized as raw materials to produce various plastic products, including packaging, toys, and bags.

Generally, pellets come in the form of small cylinders made from compressed materials. The most prevalent types include:

  • Wood pellets: Crafted from pressed sawdust and wood chips, primarily employed in pellet stoves to generate heat.
  • Biomass pellets: Derived from organic materials like vegetable waste, agricultural and forestry residues, or even animal droppings. Like wood pellets, they serve as a renewable energy source, with variable compositions based on source materials.
  • Plastic pellets: Unlike the others, these are not an energy source but a raw material. They can be composed of various plastics such as polyethylene, PVC, polypropylene, among others.

Crucially, while wood and biomass pellets are generally recognized as environmentally friendly due to their renewable origins, plastic pellets can pose environmental challenges if mishandled. Instances such as the discharge of microplastics into the sea, as discussed earlier, underscore these issues. Nevertheless, their role is pivotal in industry, and their utilization can mitigate the necessity for manufacturing new plastic, particularly when produced from recycled materials.


The danger of microplastics in the sea

The primary challenge posed by pellets stems from their size; once introduced into the environment, these diminutive plastic particles resist biodegradation and prove exceptionally challenging to extract or dispose of.

While a technical report from the Centro Tecnológico de Investigación Multisectorial (Cetim) in Spain asserts that “it is not a hazardous substance or mixture,” caution is advised. It also offers the following recommendation, “In case of spillage, do not inhale the dust and avoid contact with skin, eyes and clothing.”

The main problem with pellets is that, due to their size, once in the environment, these small plastic particles do not biodegrade and are very difficult to extract or dispose of.

Although a technical report prepared by the Centro Tecnológico de Investigación Multisectorial (Cetim) states that “it is not a hazardous substance or mixture”, it also recommends “in case of spillage, do not inhale the dust and avoid contact with skin, eyes and clothing”.


“These diminutive plastic particles resist biodegradation and prove exceptionally challenging to extract or dispose of.”


The Spanish Attorney General's Office, through its specialized environmental unit, has launched an investigation into the spill, noting that the materials “show signs of toxicity” and “are not biodegradable”.

Compounding the issue is the fact that these pellets, with their spherical shape and size, are often mistaken for food by marine wildlife, especially fish.

The ingestion of microplastics by these species triggers several problems, including:

  • The stomachs of marine species become filled with microplastics.
  • Consequently, they consume less nutritious food.
  • Possible intoxications can adversely affect their health.
  • This issue has repercussions throughout the food chain, extending to humans. Ingesting fish that have consumed microplastics leads to the presence of these particles in our bodies.

Humans already ingest up to more than 100,000 microplastic particles every day, which is roughly equivalent to the mass of a credit card per year, as we reported in this article. However, the impact of these microplastics on human health remains uncertain.



Environmental and ecosystem consequences

Meanwhile, an analysis published in the journal Proceedings of the Royal Society in 2020 underscores that terrestrial microplastic contamination has led to the decline of subterranean species, including mites, larvae, and other vital contributors to soil fertility.

Microplastics take a long time to decompose, but when they do, they release toxic substances that can infiltrate our groundwater and alter ecosystems. This process releases additives like phthalates and bisphenol A (BPA), capable of interfering with the hormonal systems of various organisms.

Furthermore, nano-sized particles possess the ability to traverse cellular barriers and highly selective membranes, inducing genetic and biochemical changes. While long-term consequences are still under investigation, there is existing evidence suggesting that nanoplastics can induce behavioral changes in fish by penetrating the blood-brain barrier, according to the Leibniz Institute for Freshwater Ecology and Inland Fisheries.

The presence of microplastics in our environment is a growing threat to both marine life and terrestrial ecosystems. Their capacity to infiltrate the food chain and potential toxicity entail significant, yet not entirely understood, risks.

The difficulty of eliminating these microplastics from the environment makes it essential to focus our efforts on preventing their production and disposal. A glimmer of hope resides in the text of the first international treaty currently under negotiation at the UN to curb global plastic production and combat pollution. Expected to be finalized by year-end, this treaty aims to establish concrete limitations on a material that, despite being nonexistent a few years ago, now pervades every corner of the planet.