Julio sin plástico: ¿deberíamos preocuparnos por los microplásticos?

¿Qué son los microplásticos?

Plastics have entered every environment on earth as consumer products and industrial waste. Plastic pollution can do a lot of environmental harm and witnessing it - like seeing plastic bags in the ocean - can be emotive. But what about the tiny pieces we can't see when disposed plastic breaks down?   

Called microplastics, we now know that these disintegrated synthetic pieces - usually invisible to the naked eye - are all around us: in our tap water, our food, and the air in our homes. Thanks to recent research on human body tissues, we also know that microplastics have found their way into us. 

What we don't yet know is how toxic microplastics are to our bodies, and whether they can lead to health problems, as Professor Rotchell explains: "Cell-based and animal studies indicate that microplastics do cause negative biological effects, such as inflammation (internal swelling), oxidative stress (cell damage) and challenges to cellular barrier structures." 

It's thought that the chemicals in microplastics may have the power to disrupt the endocrine system - which releases hormones needed around the body for essential functions like growth, metabolism, and reproduction.  

"There has been a slight disconnect in between these studies and human tissue studies - the former usually involve bead-shaped microplastics, yet while we find fragments and fibres in the human tissues, we don't find beads," says the ecotoxicology specialist.  

"Whether these forms of microplastics negatively affect the human body is still unclear. We're starting to find correlations between their presence and negative health outcomes, such as irritable bowel and cardiovascular conditions, but the actual cause-and-effect mechanisms of how that damage might be occurring with the body is yet to be established." 

Here's a snapshot of the evidence for microplastics and human disease so far:  

• Heart problems - In 2024, researchers studied people with fatty plaque build up in their blood vessels. They detected microplastics in some people's plaque and found that these people were 4.5 times more likely to develop ataques cardíacos, accidente cerebrovascular, y muerte relacionada con el corazón que aquellos con placa libre de plástico¹.  

• Enfermedad inflamatoria intestinal (EII) - In 2022, researchers compared poo samples of people with IBD and healthy people. They found significantly more microplastics in the samples from people with IBD². 

• Endometriosis – In 2024, Professor Rotchell and her team discovered that larger microplastics in pee samples of women with endometriosis, en comparación con mujeres sin endometriosis³. Ella dice: "Necesitamos un estudio adicional para entender si existe un vínculo entre la presencia de microplásticos y la condición. Las partículas de microplásticos más grandes podrían llevar a respuestas de tipo inflamatorio, pero eso no ha sido investigado directamente aún y sería un gran experimento de seguimiento para realizar a continuación."

¿Dónde en el cuerpo?

There are also human tissue studies that don't directly link microplastics to disease, but raise concerns. For example:  

Microplastics in testicles: En 2024, los investigadores descubrieron 12 tipos de microplásticos en 23 testículos humanos⁴. The study sample was small but the findings highlight the need for more research on the effect of microplastics on sperm count and fertility.   

Microplastics in blood vessels: El estudio piloto de 2023 del profesor Rotchell fue el primero en encontrar microplásticos en los vasos sanguíneos humanos, apoyando la teoría de que pueden viajar a través de las venas hacia órganos importantes como los pulmones⁵. 

So just how are microplastics entering our bodies? Professor Rotchell explains that microplastics range in size - from a sesame seed at their largest, to the diameter of a hair invisible to the naked eye at the smaller end of the size range. 

These tiny particles are small enough to transfer and seep into all sorts of places - including several levels of our food chain.   

"These smaller plastics can be taken up by marine organisms which we then eat as seafood. Another source can be via plastic packaging particles that transfer into the foods that they contain," says the professor.   

Microplastics are also added to many synthetic fertilisers and pesticidas. Estos agroquímicos recubiertos de plástico se rocían directamente sobre los cultivos que comemos y se filtran en el suelo donde crecen nuevos cultivos⁶.

Microplásticos en la cadena alimentaria

• Alimentos - People may be eating an estimated 50,000 plastic particles every year⁷.  

• Agua - If you drink from water bottles, you could be consuming up to 90,000 extra microplastics annually - compared to the additional 4,000 microplastics per year from your tap water⁷. 

• Cerveza - A beer a day could amount to 520 particles each year⁸. 

From children's toys to cookware coating and fridge, door and window seals, plastic is used everywhere in the home. We don't know if these commonplace features affect us, but we do know that when plastic gradually breaks down into microplastics, these tiny particles can become airborne. 

"We may also inhale as well as ingest microplastics since they are floating in the indoor and outdoor air," says professor Rotchell. "We don't know much about the transport of microplastics in the outdoor and indoor air beyond knowing that they are present and at varying levels depending on location. Indoor studies have identified textile type microplastics, usually fibres, present - these could be from clothing and soft furnishings."  

Los científicos se sorprendieron al descubrir microplásticos en la cima de dos picos montañosos brumosos en Japón. No está claro cómo llegaron allí, pero es posible que este sea el primer informe de microplásticos en el aire en el agua de las nubes¹⁰.

This theory suggests that plastic litter in the ocean breaks down into microplastics and is then launched into the atmosphere through ocean spray. So-called 'plastic rainfall' has an alarming potential to contaminate vast areas of land - but there's a lot more we need to learn before this causes concern.   

Tackling microplastic pollution begins with your single-use plastics. These are things like disposable water bottles, shopping bags and plastic-coated coffee cups.   

Reduce, reuse, recycle  

Reduce lo que compras: Ask yourself if you really need something, or if you can repurpose something you already own, or buy secondhand to reduce plastic waste. 

Reutiliza artículos de plástico: Reuse plastic as you can or take it to a secondhand store where possible so it doesn't end up in landfill. 

Recycle: Understand what you can and can't recycle in your local area. You can also choose to buy recycled products to close the loop. 

The relationship between microplastics and el cambio climático appears to be cyclical. Global warming is expected to speed up the rate at which plastic products breakdown into microplastic particles¹¹. Al mismo tiempo, si los encontramos en grandes cantidades en la atmósfera superior, los investigadores temen que los microplásticos también puedan estar contribuyendo al problema del cambio climático¹⁰. 

Microplastics and climate change

Los microplásticos en la atmósfera superior están más cerca de la luz solar, lo que significa una mayor exposición a la radiación ultravioleta (UV). Esto podría causar que los microplásticos se descompongan y contribuyan a los gases de efecto invernadero. Más estudios como el realizado en los picos de las montañas japonesas podrían ayudarnos a comprender mejor si los microplásticos contribuyen al cambio climático¹⁰. 

Reducing our use of plastic in everyday life is one way to try and reduce the demand for plastic production. There are also other ways to reach policy makers.  

"As a scientist, my role is to conduct experiments to establish presence, and biological impacts, of contaminants such as microplastics in a robust manner," says professor Rotchell. "Then to communicate these findings to policy makers, regulators, and the public.

“Cuanta más evidencia produzcamos para ilustrar un impacto negativo de los microplásticos en la salud humana, más influirá esto en los responsables de políticas, reguladores y políticos para introducir prácticas de monitoreo, regulación o legislación."

1. Marfella et al: Microplásticos y nanoplásticos en ateromas y eventos cardiovasculares.

2. Yan et al: El análisis de microplásticos en heces humanas revela una correlación entre los microplásticos fecales y el estado de la enfermedad inflamatoria intestinal.  

3. Rotchell et al: Microplastics in human urine: characterisation using μFTIR and sampling challenges using healthy donors and endometriosis participants.  

4. Hu et al: Presencia de microplásticos en testículos de perros y humanos y su posible asociación con el conteo de espermatozoides y el peso de los testículos y el epidídimo.  

5. Rotchell et al: Detección de microplásticos en tejido de vena safena humana usando μFTIR: Un estudio piloto.    

6. Centro para el Derecho Ambiental Internacional: Sembrando un planeta de plástico: cómo los microplásticos en los agroquímicos están afectando nuestros suelos, nuestra comida y nuestro futuro.  

7. Cox et al: Consumo humano de microplásticos.  

8. Kosuth: Contaminación antropogénica del agua potable, la cerveza y la sal marina.  

9. Key et al: Influencia de los colorantes en la degradación ambiental de los desechos plásticos.  

10. Wang et al: Microplásticos hidrofílicos en el agua de las nubes a grandes altitudes y su papel en la formación de nubes.  

11. Haque y Fan: El destino de los microplásticos bajo la influencia del cambio climático.