Quantitative analysis of small-plastic debris on beaches on Marrowstone Island and two nearby beaches in the Puget Sound waters of Washington.
Members of the Eighth Grade Science Class at The Bush School, Seattle WA 98112, USA
Abstract
Nineteen samples of plastic beach debris from eight locations throughout north Puget Sound were analyzed. At each collection site, around 40 ml of debris samples and sand were collected and later sorted by categories pertaining to type and size. Although plastic debris was found on all collection sites, the most debris collected in one sample was found on Irondale beach. Microplastic (plastics smaller than 1mm), was also found in 73% of the 19 samples and a total of 42 pieces of plastic were collected from the eight beaches. 50% of plastics found were fragments (plastics greater than1mm), and 17% percent of the plastics were bottle caps. The analysis confirms the presence of plastics in Puget Sound. This debris is common in the region of Marrowstone Island and affects the environment.
Introduction
Tidal currents flow from the Straight of Juan de Fuca through Admiralty Inlet and into Puget Sound bringing water, plastic, and other debris from the Pacific Ocean into Puget Sound. Similarly, an outgoing tidal current brings water, plastic, and other debris from the Tacoma/Seattle area back out to the Pacific Ocean. Since Admiralty Inlet lies to the north and to the east of Marrowstone Island, many of these tidal currents also bring plastic and other debris to the shores of Marrowstone Island (Features of Puget Sound). Plastic and debris enters the Pacific Ocean from the land of surrounding countries and states as well as from transportation from international industries. Much of this plastic and debris from the Pacific Ocean builds up on the Hawaiian islands. Similarly, plastic and debris from the Seattle/Tacoma area as well as from the Pacific Ocean builds up on Marrowstone Island beaches and on nearby beaches. The plastic pollution affects the wildlife and the surrounding environment.
Most of the plastic items found in the nineteen samples on or near Marrowstone Island were small items such as foam pieces, pellets, push-pins, and even microplastic (plastic less than 1 mm in diameter). Most of these items are not recyclable. While some of this debris is litter left on the beach by visitors to the beach, it is likely that many of these products washed up on the beach from the Puget Sound waters. The plastic debris could have entered the water by falling off transportation ships or by being swept up by rain water and carried down storm drains.
Many of these plastic items and the smaller plastic debris can be, and are ingested by the wildlife on the islands or surrounding waterways. In Puget Sound there are whales which end up eating these plastic fragments and becoming sick from plastic intake. Research has shown that many animals that eat plastic also face nutritional loss, some internal injuries, blockage in the internal organs and starvation (Baird, R.W., Hooker, S.K and Blight, L.K., Burger, A.E and Hirschi and Mallory). Various types of plastics were found in different types of fish and birds (Pierce). The plankton that live in the ocean can also ingest the small particles of plastic. Many of the fish and larger aquatic animals eat plankton so this could also be very unhealthy for many of the sea animals (McDermid). The prevalence of plastic in these small samples taken from beaches in Puget Sound helps us understand why plastics are affecting the health of Puget Sound ecosystems.
Materials and Methods
Nineteen samples of sand and debris were collected from Marrowstone Island and two nearby locations. There were samples from the following locations: Point North, Mystery Bay, East Beach (8 samples), West Beach, Marrowstone Point (2 samples), Point East (3 samples), Indian Island, and Irondale Beach. (See the map below where arrows mark the locations where samples were taken.)
Samples were collected at each location by Mr. Ron Hirschi at the first spot where he saw plastic in the sand at the high tide line. The samples were taken at the high tide mark with a sideways scoop horizontally. Each sample was approximately 40 ml in volume due to the fact that some had slightly more debris than others.
Mr. Hirschi brought the samples to The Bush School where it was handed out to Eighth Grade students. The samples were sent through a series of sorting:
Visual collection: First students collected the large pieces of plastic with their hands. They counted those to see how many large pieces of plastic made it to Marrowstone Island and nearby beaches.
Sifter: Then the samples were sifted with a testing sieve that had two mm holes. This was to take out all small pieces that may be hiding in the sand and be able to identify plastics.
Wet sort: Then the remaining sand was put through a wet sort. A wet sort is where you put the sand in a plastic container that contains two inches of water. All plastic floated to the top. This also showed us the microplastic.
Microscope: Finally students took all the unusual plastics or pieces of debris and looked at them under a microscope to determine their identity.
The data table below shows the results of this sorting process for each of the nineteen samples from beaches on or near Marrowstone Island and also shows the results for the one sample from Hawaii.
Results
Our class found that fourteen of the nineteen samples contained microplastic (plastic smaller them 1 mm in diameter) and we found 42 pieces of plastic (significantly larger than microplastic) in the nineteen samples. Comparing this to the sample in Hawaii, we discovered that this was a small amount. The one sample from Papaa Bay, Kauai had 31 pieces of plastic in the sand and debris sample. In the nineteen samples (not counting Hawaii) we found 21 fragments and 21 pieces of larger, identifiable plastic. We identified these larger pieces of plastic and grouped them into categories including: bottle caps, pellets, pen parts, and shotgun shells. In total we found 21 fragments, 7 bottle caps, no pellets, 2 pen parts, and 1 shotgun shell. (See the data table for more details about our results.)
These nineteen samples were all gathered from different areas on Marrowstone Island (Point North, Mystery Bay, East Beach, Marrowstone Point, Point East) or nearby on Irondale Beach and Government Cut on Indian Island. Although there were a lot of pieces of debris in these small samples, there are many more in the sample from Hawaii. In the sample from Hawaii, there were 31 total plastic pieces.
Discussion
In the nineteen samples that were collected at or near Marrowstone Island there was a large number of fragments. There was a large number of bottle caps found (7 caps) and there was also a large amount of microplastic found in the samples. There were many large, recognizable pieces of plastic including: a balloon, bottle caps, a lighter, toys, a pin, and a rope. Compared to Hawaii, the individual samples of approximately 40 ml of debris and sand collected on Marrowstone Island had fewer total pieces of plastic. This could be due to the location of Marrowstone Island.
Marrowstone Island is located in the Admiralty Inlet, near the straits of Juan de Fuca that run off into the Pacific Ocean. This could explain why it might get items that had fallen off shipping boats on their way from places in Asia to the U.S. and other countries with industrial needs. There also are strong currents that lead from the Pacific into Puget Sound and flow near Marrowstone Island which causes the island to collect large amounts of trash and other rubbish from overseas on its beaches. Marrowstone Island is fairly close to other land forms which causes plastic to be trapped between these land forms. This also made it useful to have samples from neighboring beaches like Irondale Beach and the Indian Island Government Cut which both presented similar features as the samples from Marrowstone Islands. Marrowstone and Indian Island have a ‘U-shape’ which causes plastic to get trapped in the long crescent shape. The plastic fragments have resulted in many harmful effects on the ecosystem.
The harmful effects include diminished food consumptions, internal injury, loss of nutrition, starvation, intestinal blockage and death of the native animals. Plastic also has a large effect on marine life and the Puget Sound as a whole. A main cause of death in marine creatures is due to this debris. An animal will consume plastic debris because the debris will appear like fish or something other that they would eat or a normal basis. This can and most likely will kill the animals as plastic can’t be digested especially in large proportions for most animals. There are many toxins in and related to plastic that will result in diseases of the animals. Animals can also become caught in larger amounts of plastic and then will not be able to consume other foods leading to starvation. There have been many cases of animals dying from plastic ingestion (Baird, R.W., Hooker, S.K and Blight, L.K., Burger, A.E and Hirschi and Mallory). If one species becomes extinct or endangered, other creatures that live closely with that species will be affected as well.
The amount of plastic debris in the Marrowstone samples is less than the amount of debris found in the Hawaiian islands, but it is still very noticeably negative. Our research shows that there is a significant amount of plastic pieces and microplastic on and near Marrowstone Island.
These pieces of microplastic were found in nearly all the collection sites and they help give us an understanding of the prevalence of plastic pollution in the Puget Sound and in the Pacific Ocean. The Pacific is a highway for trade, a resource, many ecosystems, and more recently in history, a dump. At the rate at which plastic is making its way into the ocean (14 billion Pounds a year) (
www.whoi.edu), it shows that we must do something before all life in the ocean is hindered by pollution. This data we were given is incredibly minute in the large scale of beaches and islands in the ocean, but it serves as a representation of what is, and what will further come to be. We must act now to stop plastic pollution before it is too late.
Acknowledgements
Our class room study was made possible by samples collected by Ron Hirschi and his dedication to making the world a better place. We want to thank our teacher, Ms. Gimelli Hemme, for helping us in the study of the plastics and sands and answering our questions. Additionally, we want to thank Ron Hirschi for sending our paper to his colleagues to review and we want to thank Goffinet McLaren, George Matsumoto, Wes Nicholson, Patricia Pierce, and Jason Schmid for taking time to review our paper and give us feedback. Finally, we want to recognize Brandon, Brooke, Camille, Cole, Deahna, Ellis, Erik, Greyson, Hal, Kaeley, Kellen, Kevin, Jackson H, Isabel M, Libbie, Maddi, Matheus, Ruby, and Sophia for their work making edits to the paper.
References
Baird, R.W., Hooker, S.K. 2000. Ingestion of plastic and unusual prey by a juvenile harbour porpoise. Marine Pollution Bulletin 40, 719-720.
Blight, L.K., Burger, A.E.1997. Occurence of plastic particles in seabirds from the eastern North Pacific. Marine Pollution Bulletin 35, 323-325.
Hirschi, Ron. 2012. Obstruction and starvation associated with entanglement and partial ingestion in an adult harbor seal. Unpublished Field Notes, Marrowstone Island, Washington State.
Mallory, et al., 2006. Marine plastic debris in northern fulmars from Davis Strait, Nunavut, Canada. Marine Pollution Bulleting 52, 813-815.
McDermid, K. J., & McMullen, T. L. (2004). Quantitative analysis of small-plastic debris on beaches in the Hawaiian archipelago. Retrieved April 2012, from Science Direct: http://www.sciencedirect.com/science/article/pii/S0025326X0300482X
Pierce, et al. 2004. Obstruction and starvation associated with plastic ingestion in a northern gannet and a greater shearwater. Marine Ornithology 32: 187-189.
Plastics in Our Oceans." Home : Woods Hole Oceanographic Institution. Web. 04 May 2012. .