It Only Takes Six Hours for Billions of Plastic Nanoparticles to Accumulate in Sea Scallops

In roughly six hours — the time it takes to fly directly from Washington, D.C. to San Francisco or binge watch the entire first season of “The Good Place” — billions of nanoplastic particles can accumulate in a sea scallop’s muscles, gills, kidneys and other organs.

An international group of researchers observed this surprisingly speedy process, newly detailed in Environmental Science & Technology, during a laboratory experiment that mimicked pollution conditions seen in actual oceans. As Lacy Schley reports for Discover, the scientists mixed a nanoplastic of their own creation—a doctored version of the polymer polystyrene, which serves as a main ingredient in Styrofoam—with the scallop’s main food source, algae. The final ratio of water to plastic was 15 micrograms per liter, a level is comparable to those recorded in marine environments, writes Clive Cookson of The Financial Times.

Next, the researchers released the hungry mollusks, which had been starved for two days to ensure ample appetite, into the tainted water. At the six-hour mark, the team used a special imaging technique to detect the amount of synthetic nanoplastics built-up in the scallops’ bodies. Needless to say, the results were disheartening, with billions of 24- and 250-nanometer particles circulating throughout the creatures’ systems.

Nanoplastics and their slightly larger microplastic counterparts lurk in all corners of the world: beer, table salt, the air, tap and bottled water, and even human stool. But the highest concentrations of these pesky particles are found in the oceans, which the study’s authors say contain 51 trillion plastic fragments—and counting.

This report marks the first time scientists have shown just how quickly (and thoroughly) marine organisms can absorb nanoparticles, according to Inverse’s Sarah Sloat. The 250-nanometer particles largely settled in the scallops’ intestines, while the 24-nanometer pieces spread throughout the kidneys, gills and muscles.

Moving the mollusks into plastic-free water tanks enabled their systems to filter out the particles, but the process was far slower than the initial uptake. As Laura Parker notes for National Geographic, it took 14 days for the smaller nanoplastics to disappear and 48 days for all of the larger ones to disperse.

The implications of widespread plastic pollution are little-understood. Scientists know that small filter feeders such as mollusks, barnacles and mussels readily absorb nanoplastics, sending suspect particles up the food chain to fish and humans. What we don’t know, however, is how these tiny pieces of plastic affect different organisms.

Study co-author Richard Thompson, head of the University of Plymouth’s International Marine Litter Research Unit, tells The Financial Times’ Cookson that humans are almost certainly ingesting nanoplastics. But, he adds, “We have very little idea of what they are doing inside our bodies.”

Speaking with Newsweek’s Kashmira Gander, Steve Ormerod, an ecologist at Cardiff University’s Water Research Institute who was not involved in the study, says the research underscores the need to investigate contamination more widely and “move from describing the presence of plastics to understanding effects and risks to consumers.”

Until then, perhaps it’s enough to note that nanoplastics are far more ubiquitous than you might think. Researchers have yet to identify tangible health risks associated with the particles, but the thought of minute plastics floating around one’s innards is certainly unnerving in and of itself.

Meilan Solly | | READ MORE

Meilan Solly is Smithsonian magazine's senior associate digital editor, history.