NHSG research update: Microplastics on N.H. beaches

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On a recent steamy July morning, while most beach-goers were setting up their blankets and coolers for a day by the ocean, Gabby Bradt sifted through the hot sand in search of microplastics — pieces of plastic smaller than a button. 

This summer, Bradt, a NHSG/UNHCE commercial fisheries specialist, is working with intern Kelsey Cowen, an undergraduate majoring in physics at Mount Holyoke College, to make adjustments to microplastics sampling methods that have been used since October 2013 in the Granite State.

Bradt received NHSG development funds to conduct a pilot-scale study of the prevalence of microplastics on N.H. beaches during the past year. With help from a cadre of volunteers, many of whom are UNH Marine Docents or Coastal Research Volunteers, 12 beaches were sampled for the tiny bits of plastic.

Despite volunteer enthusiasm and interest, the sampling process turned out to be very time-consuming and didn’t seem to reflect the true abundance of microplastics. “I’d set up a square sampling quadrat in the sand and immediately outside of it, there were so many pieces of plastic, cigarettes, films and foams, but very few showed up inside the quadrat,” Bradt said. This happened so regularly that Bradt decided it was time to try another sampling method for comparison.

The sampling methodology that Bradt and Cowen are currently testing is based on recommendations from NOAA’s Marine Debris Program intended to help standardize the various microplastics sampling efforts that exist nationwide. The duo is sampling microplastics at three locations this summer — Hampton Beach, North Hampton Beach and Jenness Beach — to determine if the new methods are in fact easier and more accurate.

Preliminary results from the first round of sampling in Oct. 2013 and April 2014 have shed some light on the types of microplastics found on N.H. beaches. Thus far, Bradt has calculated that 76% of the samples were foam while 15% were plastic fragments between 1-5mm in size. In addition to comparing results from the two sampling methodologies, Bradt has some other thoughts about ways to improve the research in the future.

“After working on this project for almost a year, it seems that it would work better as a monthly monitoring program on fewer beaches — maybe five instead of 12 — to really make sense of what’s happening with microplastics on N.H. beaches,” Bradt said.

two women set up quadrat based on GPS coordinates

Gabby Bradt searches for GPS coordinates to ensure the microplastics quadrat is in the correct location. Intern Kelsey Cowen records data in the background.

Two women search through sand for small pieces of plastic.

Kelsey Cowen (L) and Gabby Bradt (R) take samples of the top layer of sand and debris in their quadrat.

close-up of blue tiny piece of plastic in sieve.

After sifting the sample, Kelsey finds a tiny piece of blue plastic.

Find out more about this research in our previous story and video about microplastics.


Rebecca Zeiber, N.H. Sea Grant Science Writer