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Microplastics found embedded in tissues of whales and dolphins

In a disturbing study on ocean microplastics, researchers discovered microplastics — microscopic plastic particles — embedded in the fats and lungs of whales, dolphins, and ultimately two-thirds of the marine mammals examined.

This significant finding indicates that microplastics can move beyond the digestive tract, embedding themselves within animal tissues.

The research, soon to be published in the Oct. 15 edition of Environmental Pollution, made its preliminary appearance online just recently. The potential ramifications of these embedded microplastics in whales, dolphins and other marine mammals remain unknown. However, previous research has linked plastics to hormone disruption and other endocrine-related issues.

Greg Merrill Jr. is a fifth-year graduate student at Duke University Marine Lab who helmed the research. He commented, “This is an extra burden on top of everything else they face: climate change, pollution, noise, and now they’re not only ingesting plastic and contending with the big pieces in their stomachs, they’re also being internalized.” He highlighted the alarming notion that “some proportion of their mass is now plastic.”

Locating microplastics in whales

The study’s data was derived from tissue samples taken from 32 marine mammals, either stranded or subsistence-harvested, spanning from 2000 to 2021 across Alaska, California, and North Carolina. Twelve species, including a bearded seal that also tested positive for plastic in its tissues, are represented.

Since plastics exhibit an affinity for fats due to their lipophilic nature, they’re believed to be easily attracted to several fat-based structures in marine mammals.

These include blubber, the melon (a sound-producing structure) found on the foreheads of toothed whales, and the fat pads along their lower jaw which focus sound into their ears. The researchers analyzed these specific fats, as well as lung tissues, and uncovered plastics in all of them.

Types of microplastics found in whales

To provide some perspective, the plastic particles identified ranged between 198 to 537 microns in size. For comparison, a human hair is roughly 100 microns in diameter. Beyond the potential chemical hazards posed by these plastics, Merrill also noted their physical dangers posed when microplastics become embedded in whales. He explained how these tiny particles can tear and wear down tissues.

“Now that we know plastic is in these tissues, we’re looking at what the metabolic impact might be,” Merrill added. His upcoming research will explore the toxicological effects of these plastic particles, using cell lines developed from biopsied whale tissue.

When it comes to the types of plastics found, polyester fibers, often released from laundry machines, were predominant. Polyethylene, a primary component of beverage containers, was also frequently detected. Interestingly, blue plastic emerged as the most commonly found color in all tissue types.

Some plastics found were over 20 years old

A 2022 study published in Nature Communications offered a startling estimate. Given the known concentrations of microplastics off California’s Pacific Coast, a filter-feeding blue whale could be consuming up to 95 pounds of plastic waste daily. According to Merrill, marine predators such as whales and dolphins may also be accumulating plastics from their prey.

Merrill posited, “We haven’t done the math, but most of the microplastics probably do pass through the gut and get defecated. But some proportion of it is ending up in the animals’ tissues.”

He concluded with a somber reflection on the pervasiveness of ocean plastics. “Some of these samples date back to 2001. Like, this has been happening for at least 20 years.”

More about microplastics

Microplastics have invaded every corner of our planet, from the deepest oceans to the highest mountain peaks.

These minuscule particles, smaller than 5 millimeters, pose a significant threat to our ecosystems and potentially our health. But what are microplastics and why should we care?

What Are Microplastics?

Microplastics are tiny fragments of plastic that originate from various sources. They can be primary microplastics, designed small for products like facial scrubs or industrial processes.

Alternatively, they can be secondary microplastics, resulting from the breakdown of larger plastic items, such as bottles and bags.

Where Do They Come From?

Consumer products

Some personal care products contain microbeads, tiny plastic spheres used for exfoliation. Though many countries ban these beads, they remain a significant source of primary microplastics.

Wear and tear

Everyday activities, such as washing synthetic clothing or driving, release microplastics. Car tires, for instance, shed tiny particles as they wear down.

Plastic Breakdown

Larger plastic items degrade over time. Sunlight, waves, and other natural processes break them into smaller and smaller pieces, ultimately creating microplastics.

Why Are They a Concern?

Environmental impact

Microplastics absorb toxins from surrounding environments, becoming poison pills. Many marine animals mistake these particles for food. When ingested, these toxins enter their systems, often leading to starvation, injury, or death.

Human health

Seafood lovers may consume microplastics without realizing. The health implications remain unclear, but the presence of foreign, potentially toxic substances in our food chain undoubtedly raises concerns.


Their small size means they easily travel. Winds and water currents carry microplastics to the most remote regions. They have even been found in Arctic ice cores.

What Can We Do?

Reduce plastic use

The simplest way to combat microplastic pollution is to reduce our plastic consumption. Opt for reusable products and avoid single-use plastics.

Support bans

Advocate for bans on products containing microbeads or other primary microplastics.

Proper disposal

Ensure plastic waste goes to appropriate facilities. Proper recycling or disposal prevents plastics from entering natural environments.

Innovative solutions

Support organizations and companies developing solutions to remove microplastics from water or develop biodegradable alternatives.

Microplastics represent a pressing environmental challenge. Their tiny size belies their vast impact. By understanding the problem and taking collective action, we can work towards a cleaner, safer world for all.

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