Table of Contents
Introduction
Plastics are derived from petroleum products, that are not biodegradable. Some plastics will degrade from UV light and heat, but this process can take centuries. Most plastics are buoyant due to their density, which causes it to float on the surface of the water where it can easily be mistaken for food. Over the past 100 years plastic manufacturing has grown exponentially in production taking the place of metal in automobiles, paper and glass in packaging, and wood.
Think about all the uses for plastic, garbage bags, automotive parts, even kevlar. According to Jambeck et al (2015) “global plastic resin production reached 288 million metric tons in 2012, a 620% increase since 1975. The largest market is packaging that is materials designed for immediate disposal”. “In 1960 plastics made up less than 1% of the municipal solid waste by mass in the United States. By 2005 plastics made up 10% of solid waste by mass in 61 out of 105 countries with available data” (Jambeck, 2015).
Jambeck et al (2015) “calculated that 275 million metric tons of plastic waste was generated in 192 coastal countries in 2010, with 4.8 to 12.7 million metric tons entering the ocean. Population size and the quality of waste management systems largely determine which countries contribute the greatest mass of uncaptured waste available to become plastic marine debris”. Jambeck defined mismanaged waste as “material that is either littered or inadequately disposed”. “Inadequately disposed waste is not formally managed and includes disposal in dumps or open, uncontrolled landfills, where it is not fully contained. Mismanaged waste could eventually enter the ocean via inland waterways, wastewater outflows, and transport by wind or tides’ (Jambeck et al, 2015).
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Plastics unique properties make for a good product but if it is not properly recycled or it cannot be recycled, it can wreak havoc on the surrounding environment. One of the main issues with plastic in the ocean is that marine life ingests plastics which can contain harmful chemicals. This can be transferred through the food chain back to us. A calculation by Cauwenberghe & Janssen (2014) showed “European top consumers of mollusc will ingest up to 11,000 microplastics per year, while minor mollusc consumers still have a dietary exposure of 1800 microplastics year”.
His calculation was based on a study done by the European Food Safety Authority in 2011. Seltenrich (2015) states that “Studies have demonstrated plastics’ tendency to sorb (take up) persistent, bioaccumulative, and toxic substances, which are present in trace quantities in almost all water bodies”. “The constituents of plastics, as well as the chemicals and metals they sorb, can travel into the bodies of marine organisms upon consumption, where they may concentrate and climb the food chain, ultimately into humans” (Seltenrich, 2015).
According to Nordqvist (2017) “Bisphenol A (BPA) a chemical found in many hard plastics also an endocrine disruptor, can imitate the body’s hormones, and interfere with the production, secretion, transport, action, function, and elimination of natural hormones”. It has been linked with reproductive disorders, heart disease, fetal brain developmental issues, breast and prostate cancer, asthma, type 2 diabetes and body weight. “In a study in 2003 the free plus conjugated (total) urinary species of BPA were detected in 92.6% of persons ≥ 6 years of age in this sample of the U.S. population” (Calafat, 2007). So, what is happening is that plastic is making its way into our oceans which is then making its way into our bodies and having adverse effects.
How Plastic Reaches the Ocean
Dumping from sea vessels is one of the ways plastic has made its way into the ocean. Until the 1970s there were no laws prohibiting dumping. “The London Convention is an international treaty that created a global system to protect the marine environment from pollution caused by ocean dumping.
This Convention ensures that the few materials that are permitted for ocean disposal are carefully evaluated to make sure that they will not pose a danger to human health or the environment and that there are not more feasible alternatives for their reuse or disposal.”(1972 Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Convention), 2017). Now dumping is less of an issue but the damage has already been done. “In 1975, the estimated annual flux of litter of all materials to the ocean was 6.4 million tons [5.8 million metric tons], based only on discharges from ocean vessels, military operations, and ship casualties” (Jambeck et al, 2015).
A larger contributor to ocean pollution is mismanaged waste. Plastic that is improperly recycled is considered mismanaged waste. This waste can travel by wind, sewage, rivers and waterways eventually making its way into the ocean. When plastic makes its way into the ocean it will either wash up on shore, sink to the ocean floor, or follow the current into a gyre. Within the earth’s vast oceans there are five large gyres. “An ocean gyre is a large system of circular ocean currents formed by global wind patterns and forces created by Earth’s rotation” (National Geographic Society, 2012).
The Greater Pacific Garbage Patch is located between California and Hawaii in the North Pacific Subtropical Gyre. A study by the Ocean Cleanup on the North Pacific gyre (Lebreton et al, 2018) stated “Our model, calibrated with data from multi-vessel and aircraft surveys, predicted at least 79 (45–129) thousand tons of ocean plastic are floating inside an area of 1.6 million km2. Micro plastics accounted for 8% of the total mass but 94% of the estimated 1.8 (1.1–3.6) trillion pieces floating in the area”. The North Pacific Subtropical gyre now referred to as the Greater Pacific Garbage Patch is like a floating dump that was created by mismanaged waste we do not recycle properly.
Effect on the Environment
The effect plastic has on aquatic life should not be taken lightly. “Numerous autopsies have shown that ingested plastic and tar are the primary culprits of stress and non-natural death for sea turtles. Debris including fishing line, ropes, nets, six pack rings, Styrofoam, and plastic bags have been extracted from turtle digestive tracts” (Sigler, 2014). A study on leatherback turtles showed that after 1968 “of the 371 autopsies from that year and onwards, 37.2% revealed the presence of plastics” (Mrosovsky, 2009).
We can see an increasing rise of plastic consumption in these turtles. The x-axis is broken down into 5-year periods. The y-axis represents the % of turtles with plastic in their gut. The numbers on the scatter plot represent the number of turtles autopsied in any given 5-year period. For example, between 1975-1980 there were 8 autopsies performed on leatherback turtles and roughly 38% had consumed plastic. Before plastic manufacturing took place, you can see there was no plastic found in these animals until 1968.
As you can imagine fish also have problems mistaking food supply and ingesting plastic. In 2015 there was a study done on board a ship crossing the Northern Atlantic Ocean. Over a two-week period, they collected fish samples. A total of 280 were captured on the voyage. Out of the 280 fish caught, 233 samples were autopsied in search of plastic in their gut. “Overall 73% of fish contained plastics in their stomachs” (Morrison, 2018). The results were astonishing that ¾ of fish were found to have consumed plastic.
For each species of fish examined they show us the number of fish dissected, the number of fish with plastic, and the percentage of fish with plastic. For some species the percent of fish with plastic is as high as 100%. The average being 73% of fish containing plastic in their gut.
Birds are also heavily affected by plastic in the environment. the Midway Atoll, an island half way between Asia and North America, in the North Pacific gyre, is home to hundreds of thousands of Albatrosses. They search the surrounding ocean for food for their chicks unknowingly consuming plastic debris. “Of the 500,000 albatross chicks born here each year, about 200,000 die, mostly from dehydration or starvation. A two-year study funded by the U.S. Environmental Protection Agency showed that chicks that died from those causes had twice as much plastic in their stomachs as those that died for other reasons” (Weiss, 2006).
Research by Blight (1997) has shown that “autopsies in surface feeding birds reported of 353 anthropogenic items examined, 29% were industrial pellets and 71% were fragments of discarded products (‘user’ plastic), with user plastic making up 60% of total mass.” The population of these birds was focused around the eastern North Pacific.
“A piece of plastic found in an albatross stomach last year bore a serial number that was traced to a World War II seaplane shot down in 1944. Computer models re-creating the object’s odyssey showed it spent a decade in a gyre known as the Western Garbage Patch, just south of Japan, and then drifted 6,000 miles to the Eastern Garbage Patch off the West Coast of the U.S., where it spun in circles for the next 50 years” (Weiss, 2006). This goes to show you the longevity of the effects plastic can have on the environment.
Ocean Currents
Ocean currents largely determine where plastic debris can be found in the ocean. In order to maximize our efficiency in cleaning up the ocean we must understand how these currents work. The second law of thermodynamics states that heat moves towards the cold. This is how water circulates the entire globe. Ocean gyres form when the water circulating is deflected by the earth’s rotation, perpendicular to the winds direction. This causes the currents to flow in a circular motion.
Land masses also effect where a gyre will form. They can act as barriers forming the boundaries of each individual gyre. There are three main types of ocean gyres which is determined by their location and climate. Most gyres are subtropical, meaning they form between the equator and one of the poles. The flow of each gyre is determined by the direction of the current. Most gyres are stable and do not change direction for long periods of time. Ocean gyres form around stationary water. All of these properties of gyres create an area of high concentration of plastic debris known as garbage patches. Mismanaged waste makes its way out to sea and becomes trapped in these giant vortex’s driven by the wind and current.
Ocean Cleanup Nonprofit Organization
There is an estimated 80,000 tons of plastic in the Greater Pacific Garbage Patch(GPGP). The Ocean Cleanup group was founded in 2013 by Boyan Slat with a mission of ridding the ocean of plastic debris. In recent news Ocean Cleanup deployed SYSTEM 001, the latest technology in ocean clean-up equipment, to collect and recycle plastics from the North Pacific Subtropical gyre. Their goal is to clean up 50% of the GPGP in the next 5 years.
SYSTEM 001 is a 2,000ft boom that will float on the surface of the water corralling plastic debris with its 9ft skirt. “The system is propelled by the waves, current and wind. It will take on the shape of a U to capture debris in its 9ft deep skirt that is designed not to trap ocean creatures. Ships will periodically collect the garbage and recycle the plastic once on shore. It has been successfully tested and is currently embarking on a three-week journey to the GPGP where it will begin to collect plastic” (Ocean Cleanup, n.d.).
“SYSTEM 001 cost the 24-year-old founder and CEO of Ocean Cleanup Boyan Slat over $20 million which was largely funded by Silicon Valley philanthropists Marc & Lynne Benioff, as well as Peter Thiel and other supporters” (Ocean Cleanup, n.d.). To achieve his goal of cleaning 50% of the GPGP in five years Slat says they will need around 50 individual booms working simultaneously together. “After fleets of systems are deployed into every ocean gyre, combined with source reduction, The Ocean Cleanup projects to be able to remove 90% of ocean plastic by 2040” (Ocean Cleanup, 2018).
The Hawaii Wildlife Fund
Hawaii lies in the Northern Pacific Subtropic gyre. To the south lies the Northern Pacific Subpolar Gyre. Between the two is a convergence zone. Plastic debris are accumulating on either end of this convergence zone in what is called the eastern and western garbage patches. Due to the nature of the current plastic debris from the eastern patch are flowing west towards Hawaii.
Here, tons of plastic winds up on the shore line every year. Kamilo beach and Kahuku Beach have high concentrations of debris washing up on shore due to their location. This started happening around the 1980s. “Native Hawaiians once used the beach to collect large driftwood, which traveled to Kamilo from the American Pacific Northwest, to make dugout canoes. Today, old toothbrushes, shards of plastic and mounds of rope and fishing line pile up on the shore instead.” (Herreria, 2017).
The Hawaii Wildlife Fund is a non-profit organization dedicated to the conservation of Hawaii’s native wildlife. In 2003 they started organizing cleanups along the coastline. “HWF has cleaned more than 100 tons of marine debris from these remote beaches during the last four years.
This coastline is visited by endangered Hawaiian monk seals, humpback whales, and nested on by the endangered hawksbill turtle.” (WildHawaii, n.d.). The problem is the plastic is constantly making its way to the shore at a rate of 15-20 tons per year, because of this the HWF must constantly find volunteers to help clean up.
Ocean Conservancy
The Ocean Conservancy is another organization focused on protecting ocean wildlife. 30 years ago, they started a small beach cleanup event with 2,800 volunteers in Texas. Now that event is known as the international coastal cleanup where over 100 countries participate in beach and waterway cleanups. The Ocean Conservancy collects data from all the volunteers and publishes statistics every year.
“In 2017, nearly 800,000 volunteers collectively removed more than 20 million pieces of trash from beaches and waterways around the world” (Ocean Conservancy, 2018). “At our International Coastal Cleanups, volunteers have picked up more than half a million straws and stirrers, making straws one of the top ten items on our annual list. Straws pose a real danger to animals like sea turtles, albatross and fish who can eat them” (Ocean Conservancy, 2018).
Orange County California
Plastic debris were collected along the coastline of Orange County, California. Some of these beaches include Huntington Beach, Laguna Beach, Newport Beach, San Clemente, and Seal Beach. All of these are popular locations that invite heavy human traffic. Southern California has the highest coastal population in the country. This puts a lot of stress on the surrounding environment because of the increase in plastic that correlates to a high population.
43 beaches were surveyed, random locations selected, each site containing an area of 25 yards total Three or more people were chosen to walk on line and sieve the sand. All the trash and plastic were separated and sent to a lab to be identified. The data was then extrapolated to calculate the number of plastic items as well as the weight of all plastic debris found on the beaches. “More than 106 million items, weighing approximately 13 tons, were estimated to occur along the Orange County shoreline” (Moore, 2001).
“Three categories of plastics (pre-production plastic pellets, foamed plastics, and hard plastics) accounted for 99% of the total abundance and 51% of the total weight. Cigarette butts were fourth in abundance and accounted for less than 1% of the total abundance and weight” (Moore, 2001). Plastic pellets made up the abundance of materials collected. Plastic materials made up the top three contributors of the pollution in the sample data. Before this study was done the previous estimates for plastic in this area were based on the annual California Coastal Cleanup Day in 1998.
You can see the numbers are greater in the more recent study, and probably more accurate considering the scientific approach that was chosen. Also, during the 2001 study, scientist sifted through the sand collecting small plastic particles, whereas during a beach cleanup volunteers focus mostly on larger pieces.
