Warming Seas and Microplastics Are Harming Sardines—And Us

March 23, 2025 / activist360

Infographic showing how feeding behavior and temperature affect plastic fibre ingestion in European sardines (Sardina pilchardus). Sardines that use filter-feeding ingest more plastic fibres, expel them faster, and have a lower condition index compared to particulate-feeding sardines. Warmer temperatures (19°C) increase plastic fibre ingestion and speed up intestinal transit time.

Feeding behavior and warming seas influence plastic fibre ingestion in sardines. Sardines that filter-feed ingest significantly more plastic fibres than those that eat larger particles (particulate-feeding). Warmer water temperatures (19°C) lead to faster digestion but also more plastic consumption. Filter-feeding sardines show lower health scores, highlighting the combined stress of microplastic pollution and climate change. (Source: Rodriguez-Romeu et al., 2024)

Sardines may be small, but they play a big role in the ocean—and on our dinner plates. These little fish are a key food source for larger marine animals like dolphins and tuna, and millions of people around the world eat them, too. They’re also packed with nutrients and are considered one of the most sustainable seafood choices out there.

But sardines are in trouble. In the Mediterranean Sea, their population has dropped sharply in recent decades. And scientists are discovering that two major forces—warming ocean temperatures and plastic pollution—are teaming up to make life even harder for these essential fish.

What’s harming sardines may be a warning sign for us all.

The Hidden Threat: Plastic Fibres in the Ocean

Microplastics are tiny pieces of plastic that break down from larger items like bottles, bags, and packaging. But not all microplastics are the same. A specific type called plastic fibres is even more common in the ocean—and more likely to be eaten by fish.

Plastic fibres are tiny thread-like pieces that come from clothing, fishing gear, and other waste. They’re too small to see with the naked eye but can float in the water, where fish easily mistake them for food. In fact, up to 91% of microplastics in ocean water are fibres, making them the most common type of plastic pollution in the sea.

The Experiment: What Scientists Found

To better understand how sardines interact with plastic fibres, scientists designed a unique experiment. They took wild sardines and placed them in tanks that mimicked ocean conditions. The tanks contained a realistic amount of plastic fibres—five fibres per liter of water, similar to what’s found in polluted areas of the sea.

They fed the sardines in two different ways:

Particulate-feeding: Fish were given large food pellets, which they eat one by one.
Filter-feeding: Fish were given tiny particles, similar to how they naturally eat plankton by filtering water through their gills.

The scientists also tested two water temperatures:

16°C, which reflects current Mediterranean conditions.
19°C, which represents a possible future scenario as oceans warm due to climate change.

Startling Results: What Happened to the Sardines

The results were clear—and concerning.

Sardines that fed by filter-feeding accidentally ate about eight times more plastic fibres than those eating larger particles. On average:

Filter-feeders ingested 4.95 fibres per fish
Particulate-feeders ingested only 0.6 fibres per fish

Temperature also made a difference. At warmer temperatures (19°C):

Sardines expelled plastic fibres faster, likely due to faster digestion.
But they also ingested more plastic, probably because their metabolism increased and they needed more food.

Another discovery: Plastic fibres stayed in the sardines’ digestive system longer than real food. Half the food was gone in about 12–14 hours, but it took 23–25 hours to get rid of just half the plastic fibres.

The Health Impact on Sardines

Over the course of the experiment, filter-feeding sardines didn’t just eat more plastic—they also got weaker.

They lost more weight and had lower body condition scores compared to those eating larger particles.
Their stomachs were less full, which suggests they ate less food overall and didn’t get enough energy.

Interestingly, the plastic alone wasn’t what made them unhealthy. Instead, it was the combination of filter-feeding and warmer water that seemed to hurt them most. Warmer oceans can lead to smaller plankton, which makes filter-feeding more common—and that leads to more plastic being ingested.

Why This Matters for Climate and Human Health

The health of sardines isn’t just a fish problem—it’s an ocean problem and a human problem.

Here’s why this matters:

Warming oceans = smaller plankton
Smaller plankton = more filter-feeding by fish
More filter-feeding = more plastic consumed

If sardine populations continue to shrink:

Predators like tuna, dolphins, and seabirds could lose a key food source.
People who depend on sardines for protein or income may struggle.
Ocean ecosystems could become unbalanced.

These changes don’t happen in isolation. Climate change and plastic pollution often work together, creating stress that marine life—and people—may not be able to overcome.

What Can We Do?

The good news is that small changes on land can protect life in the sea. Here are a few steps anyone can take:

Choose clothes made from natural fibers (like cotton or wool). Washing synthetic clothes sheds plastic fibres into the water.
Reduce plastic packaging by using reusable bags, bottles, and containers.
Support ocean cleanup efforts and organizations that study microplastics.
Advocate for climate action, including clean energy and reduced carbon emissions, to help slow ocean warming.
Hold your local, state, and national elected officials accountable for taking climate action and protecting our water, air, and health.

A Call to Protect What Connects Us All

Sardines may not get much attention, but they’re part of a delicate chain that connects us all. When small creatures suffer, the effects can ripple through the food web—and onto our plates.

The choices we make on land ripple into the sea—and into our future.

By staying informed, reducing plastic use, and supporting climate action, we can help protect the ocean, our food systems, and the health of generations to come.

Source: Rodriguez-Romeu, O., Constenla, M., Soler-Membrives, A., Dutto, G., Saraux, C., & Schull, Q. (2024). Sardines in hot water: Unravelling plastic fibre ingestion and feeding behaviour effects. Environmental Pollution, 363, 125035. https://linkinghub.elsevier.com/retrieve/pii/S0269749124017500

Microplastics in Our Brains

March 16, 2025 / activist360

A conceptual illustration depicting human cognition, featuring a vintage anatomical drawing of a brain within a simple silhouette of a head.

What You Need to Know and How to Reduce Your Exposure

Did you know that tiny plastic particles—called microplastics—are in our food, water, and even the air we breathe? Every day, we are unknowingly consuming and inhaling microplastics. Scientists have now discovered something even more concerning: microplastics are making their way into human brains, and their levels are increasing.

This raises an important question: What does this mean for our health, and what can we do about it? While we may not be able to eliminate microplastics entirely, there are simple steps we can take to reduce our exposure and protect our health. In this article, we’ll break down what microplastics are, how they enter our bodies, the potential health risks, and practical ways to reduce our exposure.

What Are Microplastics?

Microplastics are tiny plastic particles, smaller than 5mm, that come from broken-down plastic waste, synthetic clothing, industrial processes, and food packaging. Because plastic never fully biodegrades, these particles remain in the environment indefinitely, breaking down into even smaller pieces over time.

Common Sources of Microplastics

Microplastics are found in everyday items, including:

Bottled water: Contains significantly more microplastics than tap water.
Seafood: Marine animals ingest microplastics from polluted oceans.
Processed foods: Particularly those packaged in plastic.
Tea bags: Some brands use plastic-based tea bags that release billions of plastic particles into hot water.
Air: Microplastics are floating around in household dust and city pollution.

Since we eat, drink, and breathe microplastics daily, it’s important to understand how they enter our bodies and what harm they may cause.

How Do Microplastics Get into the Human Body?

Microplastics make their way into our bodies through three primary routes:

Eating and Drinking

Bottled water drinkers ingest up to 90,000 microplastic particles per year, compared to 4,000 for tap water drinkers (Cox et al., 2019).
Seafood, processed foods, and canned goods can contain microplastics due to contamination during production and packaging.
Heating food in plastic containers releases billions of plastic particles into the food.

Breathing

Airborne microplastics are present in the air we breathe at home, in offices, and outdoors, particularly in urban areas. Additionally, synthetic clothing sheds plastic fibers into the air when it is washed or worn, further contributing to the inhalation of these particles.

Household Exposure

Cooking and storing food in plastic can cause microplastics to leach into the food we eat. Similarly, plastic tea bags and coffee pods release billions of tiny plastic particles into hot liquids, increasing overall exposure.

Because these tiny particles are everywhere, scientists are now studying how they affect our health—especially our brains.

Are Microplastics Harmful to Our Health?

While research is still ongoing, several studies have raised serious concerns about microplastics in the human body. Here’s what scientists have found so far:

Microplastics in the Brain

A recent study found microplastics in human brain tissue, with levels 3–5 times higher in people with dementia (Nihart et al., 2025). Scientists are unsure whether dementia weakens the brain’s defense, allowing more plastic in, or if microplastics contribute to cognitive decline.

Heart Disease Risk

A study found that people with plastic particles in their arteries had a higher risk of heart attacks and strokes (Marfella et al., 2024).

Gut Health Concerns

People with inflammatory bowel disease (IBD) had 1.5 times more microplastics in their stool compared to healthy individuals (Yan et al., 2022). Microplastics may disrupt gut bacteria and contribute to inflammation.

Other Potential Effects

Scientists suspect microplastics may also contribute to:

Hormone disruption: some plastics contain chemicals that interfere with the endocrine system.
Lung irritation: from inhaling airborne microplastics.
Long-term health risks: still being studied.

Since avoiding microplastics completely is impossible, the next best step is reducing exposure where we can.

Easy Ways to Reduce Microplastic Exposure

While plastic is everywhere, simple daily changes can significantly lower the amount of microplastics we ingest and inhale.

Switch to Tap Water: Drinking tap water instead of bottled water can reduce microplastic intake by over 90%. Use a water filter if concerned about contaminants.
Avoid Heating Food in Plastic: Use glass or stainless steel containers instead of plastic. Never microwave food in plastic containers.
Choose Fresh or Frozen Foods Over Canned: Canned foods can release chemicals like BPA, which is linked to hormone disruption. Opt for fresh, frozen, or glass-packaged alternatives.
Use Cloth or Metal Tea Strainers: Avoid plastic tea bags—opt for loose-leaf tea with a stainless steel infuser.
Improve Air Quality: Use a HEPA air filter at home to remove airborne microplastics. Vacuum regularly to reduce plastic dust indoors.

These small changes can make a big difference in reducing everyday exposure.

Can Microplastics Be Removed from the Body?

Right now, scientists don’t know if microplastics can be fully removed from the human body, but some early research suggests:

Sweating may help: Some studies suggest that sweating (through exercise or sauna use) can help excrete plastic-related chemicals like BPA.
Healthy lifestyle choices: Staying hydrated, eating fiber-rich foods, and regular exercise may help the body naturally eliminate toxins.
Long-term exposure reduction: The best strategy is reducing intake in the first place.

More research is needed, but reducing microplastic exposure now is the safest approach.

Small Changes Make a Big Difference

Microplastics are everywhere, and while we can’t avoid them completely, we can take practical steps to limit exposure and protect our health. By making the choices we suggested above, you can help protect your health while also reducing plastic pollution in the environment.

It’s crucial to hold local, state, and national elected officials accountable for policies that protect your health and the well-being of your loved ones. Be mindful of who you vote for, and once they are in office, advocate for strong regulations that reduce plastic pollution and safeguard public health. Your voice matters—demand action.

Sources: Nihart et al., 2025 – Study on microplastics in the human brain (Nature Medicine). Marfella et al., 2024 – Microplastics and heart disease (New England Journal of Medicine). Cox et al., 2019 – Microplastic consumption (Environmental Science & Technology).

Microplastics in Our Brains?!? What Scientists Have Discovered About Plastic Pollution and Human Health

February 9, 2025 / activist360

Comparison of microplastic accumulation in human organs—brain has 10x more than liver and kidney, visualized with sugar in glass jars.

Microplastic Concentrations in Human Organs: Brain samples contained 7–30 times higher MNP concentrations than liver or kidney tissues. Median MNP concentration in the brain (2024 samples): 4,917 µg/g (range: 4,026–5,608 µg/g). Median MNP concentration in the liver (2024 samples): 433 µg/g. Median MNP concentration in the kidney (2024 samples): 404 µg/g.

Why Should We Care?

Plastic pollution is everywhere. Scientists have found microplastics in our food, drinking water, and even the air we breathe. But a new study has revealed something even more alarming—microplastics are accumulating in human brains!

Researchers found that brain samples contained up to 30 times more microplastics than other organs, raising concerns about long-term health risks. Even more shocking, people with dementia had five times the amount of microplastics compared to those without the disease.

What does this mean for our health? Let’s break it down.

What Did Scientists Find?

A team of researchers studied liver, kidney, and brain samples from people who had passed away. Using advanced technology, they found:

All organs contained microplastics, but the brain had the highest levels—even more than the liver and kidneys, which naturally filter toxins.
The most common type of plastic found was polyethylene (PE)—used in plastic bags, food packaging, and containers.
The average microplastic concentration in the brain was 4,917 µg per gram of tissue—compared to 433 µg/g in the liver and 404 µg/g in the kidneys.

To put the quantity of microplastic concentration into perspective, imagine you’re filling three jars with sugar to represent the amount of microplastics in different organs:

The kidney jar gets a small teaspoon (404 µg/g).
The liver jar gets about the same—just over a teaspoon (433 µg/g).
But the brain jar? You dump in more than 10 times that amount—nearly half a cup (4,917 µg/g)!

Now picture that sugar as tiny plastic shards instead of something sweet. Your brain—one of the most protected organs in your body—is absorbing these particles at a dramatically higher rate than the liver or kidneys, which are designed to filter out waste.

While other organs process and remove toxins, the brain seems to be holding onto plastic, potentially for life. Scientists still don’t know exactly what that means for long-term health, but they do know the levels are rising quickly, and that’s a cause for concern.

This is the first time scientists have confirmed that microplastics are accumulating in the human brain—a place that should be well-protected from foreign substances.

Why Is This a Big Deal?

Plastic doesn’t belong in our bodies, let alone inside our brains! Scientists are especially worried because:

Microplastics in the brain may contribute to neurological diseases. In people diagnosed with dementia, microplastic levels were over 26,000 µg per gram of brain tissue—more than five times higher than in non-dementia cases. These tiny plastics were found inside blood vessel walls and immune cells, suggesting they might be affecting brain function.

Microplastics can bypass the brain’s defense system. The blood-brain barrier normally protects the brain from harmful substances. This study suggests nanoplastics (as small as 100–200 nanometers) may be slipping through, raising concerns about how they could impact brain health over time.

While scientists haven’t proven that microplastics cause diseases like dementia, the fact that they are accumulating in the brain demands more research.

How Do Microplastics Get into Our Bodies?

You may not realize it, but we consume and inhale plastic particles every day. Here’s how they might be reaching our brains:

Breathing in tiny plastic particles from dust, air pollution, and synthetic fabrics.
Eating plastic-contaminated food—studies have found microplastics in seafood, salt, fruits, and vegetables.
Drinking bottled water, which contains nearly double the amount of microplastics as tap water.
Absorption through the bloodstream—scientists believe that some nanoplastics are small enough to pass through protective barriers in our bodies.

Once inside, these plastics don’t just disappear. They may stay trapped in organs like the liver, kidneys, and brain for years.

Has This Problem Gotten Worse?

Yes—dramatically. Scientists compared brain samples from 2016 and 2024 and found that:

Microplastic levels in the brain have increased by nearly 50% in just 8 years.
Similar increases were found in the liver and kidney, suggesting we are all being exposed to more plastic than ever before.
Older brain samples (1997–2013) contained far fewer microplastics than recent ones, proving this is a rapidly growing problem.

With plastic production and pollution continuing to rise, scientists predict that microplastic exposure will only get worse unless major changes are made.

What Can We Do About It?

While the full health effects of microplastics are still unknown, reducing exposure is a smart move. Here’s how:

Use fewer plastics: Switch to reusable bags, glass or metal water bottles, and cloth grocery bags.
Filter your water: Some high-quality filters can remove microplastics from drinking water.
Limit processed foods: Fresh, whole foods are less likely to contain microplastics than packaged and processed foods.
Ventilate your home: Indoor air contains plastic particles from synthetic fabrics and household dust—keeping air clean can reduce inhalation.
Support policies to reduce plastic pollution: Push for laws that limit plastic waste and promote better recycling solutions.

Summing Up

Microplastics are inside our brains, and their levels are rising at an alarming rate. Scientists don’t yet know the full impact on human health, but the findings from this study suggest a need for urgent action. While research continues, the best thing we can do is reduce plastic exposure and push for solutions to stop plastic pollution at its source.

The next time you drink from a plastic bottle or open a plastic-wrapped snack, remember—some of that plastic may never leave your body.

Would you like to see a future where our brains stay plastic-free? At activist360, we sure would!

Nihart, A. J., Garcia, M. A., El Hayek, E., Liu, R., Olewine, M., Kingston, J. D., Castillo, E. F., Gullapalli, R. R., Howard, T., Bleske, B., Scott, J., Gonzalez-Estrella, J., Gross, J. M., Spilde, M., Adolphi, N. L., Gallego, D. F., Jarrell, H. S., Dvorscak, G., Zuluaga-Ruiz, M. E., … & Campen, M. J. (2024). Bioaccumulation of microplastics in decedent human brains. Nature Medicine. https://www.nature.com/articles/s41591-024-03453-1?error=cookies_not_supported&code=79978c49-7500-4963-807e-3de1d60b6782