Student survey says: Microplastics found even at new Pohoiki beach

  • Nicolas Vanderzyl doing field research at Chalk’s Beach, Hilo. (UH-Hilo photo/by Jeremiah Storie)

  • Plastic debris in sand at Kamilo Point beach, Hawaii Island. (UH-Hilo/photo by Gabriella Levine)

POHOIKI — Even newly formed beaches aren’t free of oceanborne waste, as a study of the new beach at Pohoiki proves.

A University of Hawaii at Hilo student surveyed three Big Island beaches last year to compare the concentration of microplastic waste fragments at each as a senior thesis project.

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“The question was, this was a brand-new beach, so I was curious to see how many microplastics there were,” said Nic Vanderzyl, currently an environmental educator with the Hawaii Wildlife Fund. “I wasn’t really expecting to find that much plastic at Pohoiki at all.”

But Vanderzyl discovered that while Pohoiki had a lesser microplastic concentration than the other two beaches — Hilo Bay and Hapuna Beach — it still had significantly more plastic than he had initially expected.

Vanderzyl said the concentration of microplastic fragments at the newly formed beach was approximately 20 fragments per a 50 gram handful of sand. Compared to the 52 fragments and 70 fragments per 50 grams at Hilo Bay and Hapuna Beach, respectively, the concentration was surprisingly high for such a young beach.

“Microplastics tend to accumulate more in sand than in the water column,” Vanderzyl said. Therefore, when the lava from the Kilauea eruption dredged up sand from the ocean floor as the Pohoiki beach formed, it also dredged up thousands of minuscule pieces of plastic waste.

The plastic particles found at Pohoiki were predominantly fiber particles, Vanderzyl said, fragments torn from synthetic fabrics such as polyester. Many of the fibers showed signs of substantial degradation, indicating that they were older fragments that have existed for some time.

All three sites had high amounts of plastic fibers, but also other categories of plastics referred to as “fragments” and “nurdles.” The former are “secondary microplastics,” pieces broken off of deteriorating larger plastic items; the latter, which Vanderzyl assured is a real word, are grains of raw plastic that would be processed into consumer products.

“That’s part of the problem with microplastics,” Vanderzyl said. “They break apart in the ocean and create more.”

Where the Pohoiki beach differs from the other two beaches is the distribution of the plastic. Vanderzyl said microplastics tend to be found in higher concentrations at the backshore areas of the beach — “where people generally hang out, put up umbrellas, put down towels” — rather than in the sands below the high tide marks.

However, Vanderzyl found no significant difference in plastic concentration at different sample elevations at the Pohoiki site, likely because of its relative youth.

Vanderzyl said he wants to visit the Pohoiki beach again in December, one year after his initial survey of the site, to see how the plastic concentration has changed.

While Vanderzyl said his findings will hopefully have pragmatic results — people cleaning beaches of plastic may decide to concentrate toward the backshores of beaches, where the most plastic can be found — he said the greater problem of eliminating microplastics will require a societal shift in the way we consume products.

“Sometimes I’ll see something I want at a store and I reach over to it, and I realize it’s packaged in plastic,” Vanderzyl said. “And I think, ‘is it worth getting to eat these delicious Oreos when the plastic they’re in is going to go into a landfill basically forever?’”

Vanderzyl said he hopes people can move beyond simple pushes toward transitioning to compostable plastics and eliminating single-use plastic products and instead focus their energy on simply not buying products that use plastic in their manufacture or packaging.

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“We can’t sit here and expect things to change on their own,” Vanderzyl said. “There needs to be a lot more hoopla.”

Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.

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