Plastiglomerates: Plastic Rocks, A New Form of Pollution

Plastiglomerates: Nasty Plastic Rocks Polluting Beaches and Oceans

As if there aren't enough problems with plastic pollution in the oceans, a new threat has emerged. By now, you are probably aware that nanoplastics are showing up everywhere, from food, water, rain, in humans, everywhere. But now a new form of plastic pollution has appeared, and it is beyond weird: plastic rocks, formed in nature from man-made plastic waste has appeared in bizarre rocks found on the shorelines of 11 countries and 5 continents. There is even a book about them, Plastiglomerate by Tim Cresswell, June 8, 2020.

What are Plastiglomerates and how are they formed?

An article in Environmental Science & Technology describes how rocks made from artificial nanoplastics (and microplastics, MPs) in the oceans. Both are associated with cardiovascular and respiratory diseases in humans. Hard evidence of causation is, as yet, absent, but the association is causing concern.

Plastic debris sticks onto rocks and other debris, like wood, typically after flooding events. Analysis shows these to be low-density polyethylene (LDPE) or polypropylene (PP) films that stick onto quartz-containing rocks.  It appears to be a chemical bonding between plastic and rock. They believe the chemical binding is caused by sunlight irradiation, which oxidized the plastic.

The first documented instance of Plastiglomerates was in Hawaii in 2014 when natural sedimentary grains and organic debris combined with melted plastic during a campfire on the beach.

Dr. Deyi Hou, Tsinghua University, China says in Newsweek:

"Molten plastic, sand grains, clasts from rock, coral, shells, and wood debris were held together after campfire burning on Kamilo Beach, Hawaii, USA,. Since then, they have been frequently found on beaches, both on islands and mainland coastlines. They can result from waves crashing against intertidal rocks, causing ocean plastic to become physically adhered to the rock surface.”

Where are they showing up?

As noted in the introduction, pastiglomerates arwe rocks being found on the shorelines of 11 countries and 5 continents, first along the shoreline of Hawaii in 2014. Geologist Patricia Corcoran of the University of Western Ontario in London, Canada, and Charles Moore, captain of the oceanographic research vessel Alguita, were the first researchers to identify plastiglomerates on Kamilo Beach, Hawaii. Waste on Kamilo Beach prior to cleanup efforts was 8 to 10 feet (2.4 to 3.0 m) high in some places. This firsthand account is horrifying. Written by a young mom who is also a  PhD marine environmental toxicologist, Jennifer Lynch describes the waste from Asia that washes up on the formerly pristine Hawaiian beaches. Dr. Lynch has a Ph.D. in marine environmental toxicology from Duke University and has worked for the NIST Chemical Sciences Division for over 20 years. Here's a snippet from the story, which is well worth reading:

...from tiny specks to large objects made of colorful plastic and become increasingly motivated—and defeated—by the next piece of garbage just a step in front of me. I grumble under my breath about each piece I find. Here’s a white triangular fragment, here’s a black tube used in oyster aquaculture from across the Pacific Ocean, here’s a hagfish trap, a highly weathered bottle cap, a junk-food wrapper, a toothbrush, 10 cigarette butts, the corner of a foam takeout container and more fragments of hard plastic, nets, line, and foam...

What harm do plastiglomerates cause?

Scientists fear the plastic can lower microbial diversity and shed microplastics, as well as harm health and other life.

What can be and is being done about Plastiglomerates ?

Beyond the questions of how they are formed and what hazards they pose, is the question of how to safely and cost-effectively remove nanoplastics in the ocean waters. The University of Missouri is conducting promising research on a method  of removing the nanoplastics from sea water, while leaving clean water behind.

See "Scientists achieve more than 98% efficiency in removing nanoplastics from water", University of Missouri,  Eric Stann.

 

What can you do to help?

It is not hopeless... and you can help! Here's how:

1. Create less plastic waste.
2. Dispose of plastic waste properly.
3. Join a cleanup effort: There are community-based cleanup efforts. For example, in Hawaii,
   the Hawaiʻi Wildlife Fund, Imi Pono No Ka 'Aina, Hawaii Rainbow Gatherings, "CITO" geocachers, Sierra Club Hawaii and Beach Environmental Awareness Campaign Hawaiʻi.
   In other areas,
   Here's a guide to organizing a beach cleanup

References:

Some references are incorporated into the text above, by the links to the sources. Below are additional references.

1. "Brazilian researchers find 'terrifying' plastic rocks on remote island".
   CNN. Reuters. 16 March 2023
2. "Plastiglomerates from uncontrolled burning of plastic waste on Indonesian beaches contain high contents of organic pollutants"
   Scientific American, 27 June 2023
   This study reports on plastiglomerate and other new forms of plastic pollution in the tropical marine continent of Indonesia. Twenty-five samples were collected from an island beach in the Java Sea where plastiglomerate, plasticrusts, and pyroplastic were formed by the uncontrolled burning of plastic waste. The most common plastic types were polyethylene and polypropylene (PE/PP),
3. "First record of plastiglomerates, pyroplastics, and plasticrusts in South America"
   Science of The Total Environment, Volume 833, 10 August 2022, 155179
   Plastiglomerates, plasticrusts, and pyroplastics were found in beaches of Peru. A new formation pathway for plasticrusts was reported. Pyroplastics may consist of different polymer blends, such as HDPE and PA.