4.1. Plastic Danger: a new continent

Today marine litter is recognized as one of the major problems for marine environment. Marine litter includes all anthropogenic material that has been entered the marine environment by intentional or unintentional actions of humans. The composition of marine litter varies between locations, but usually most of the litter consists of plastic (more than 90%).

Plastic is an important material for the economy used widely in many areas including catering and packaging. Annually the global plastic production is more than 400 million tonnes and only 9% of this is recycled, some landfilled but still a significant amount leaks into water bodies and finally ends up in oceans. It is estimated that more than 150 million tonnes of plastics have accumulated in the world’s oceans, while 4.6-12.7 million tonnes are added every year. It is broadly assumed that approximately 80% of marine litter is land-based delivered through rivers.

The presence of plastic in the sea is a serious danger, not only for marine organisms and their habitats, but also for humans. Types of different plastic litter in the sea vary in their chemical composition and physical characteristics. Based on these characteristics and size of plastic litter fragments, it can be found on six distinct compartments of the sea: sea surface, water column, shorelines, seafloor, sea ice and biota.

Floating litter that we initially encounter on the sea surface, creates navigation problems and is a serious problem for marine organisms that can swallow some parts and/or get entangled.
According to some estimates, 49 of 115 species of marine mammals are at risk of trapping or ingesting marine litter. Sea turtles can mistake plastic bags for a jellyfish and swallow it. This often ends up with blockage of the digestive tract and the consequent suffocation of the animal. Every year in the world about 100,000 marine mammals and an unspecified number of sea turtles are still killed by plastic in the sea. Out of 312 species of marine birds, 111 are known for ingesting plastic waste. Between 700,000 and one million marine birds are killed every year by suffocation or entangling.

Eventually, most of the litter ends up on the bottom of the sea, continuing its disruptive action by smothering marine organisms they cover on the seafloor. Especially sessile organisms are vulnerable to smothering since they are immobile and cannot move to a more suitable location when their habitat changes. Studies in the Mediterranean have shown that the most prominent plastic categories on the seafloor include plastic bags and beverage bottles, general food packing material and fishing-related litter such as fishing line and nets.

The concentrations of various toxic substances and additives, such as BPA, PBDEs and phthalates are often high in marine plastics. The harmful chemicals associated with plastics can be divided into three categories: ingredients of the plastic material, byproducts of manufacturing and chemicals absorbed from the environment. UV-radiation and thermal energy induces weathering and causes plastic to fragment into small pieces called microplastics that can easily enter in the food chains in the sea. Therefore, it is assumed that plastic litter may serve as a pathway for hazardous chemicals to marine organisms. In general, hazardous chemicals can enter marine organisms and food webs via the surrounding environment and diet. Through food chains thee chemicals and microplastics fragments can also be ingested by humans.

Due to the massive presence of plastic material in the seas, large vortices have been created such as the Pacific Plastic Vortex, whose extension is estimated to reach a few million square kilometers. Unfortunately, these “islands” have been identified in almost all the seas and oceans. About 500 tons of plastic waste floats in the Mediterranean. During the monitoring from 2002 to 2006, among the 12 most recurring types of waste found on the Mediterranean beaches, plastic bottles account for 9.8% of the total, whilst plastic bags account for 8.5% of the total.

All these facts are telling us that is time to act and start changing some of our habits!

4.1.1 Try to define marine litter!

Marine litter is one of the most worrying and discussed problems of these years. It consists in the huge amount of humans' scraps that hasn't been recycled in a proper way and ended up in the sea.
Of this litter, the most significant part is the plastic, produced in tonnes (more than 40 million) every year, for the global commerce. While its use started between the 30s and the 40s of the twentieth century, its disposal systems are quite recent. The fact that makes plastic a possible danger is that it's used to produce disposable things and so they soon become matters of waste, which, by the negligence of people or by their real aim, can cause troubles to the balance of the aquatic system. At the moment, more than 150 million tonnes are estimated to be located in the oceans, and they're likely to increase in the next years.
A lot of marine mammals risk every day to get trapped, entangle, ingest and suffocate in plastic packaging, an example is the one of the sea turtle which confuses plastic bags with jellyfishes. For this reason, every year, about 100.000 of them die.
Other scraps come from the drains of the aquatic vehicles. The pollution of the water causes a lower quality of life of the organisms living in the oceans. We must remember that also the numerous "plastic islands" can be obstacles and a danger for the navigation of humans... We are putting at big risk our own life and the biodiversity of our world. The first places of the list of the most polluting countries are occupied by China and other Asian countries. Fortunately, a lot of organizations have been founded to take care of this problem.

4.1.2 Where does the plastic come from into the sea?

At last count in 2017, there were at least 8.3 billion tons of plastic in the world, especially in our oceans. Researchers are looking for ways to collect and remove this plastic present in the sea using a variety of technologies, or at least catching the trash at the source, it would be a better solution to this problem.
The data from the Science Advances study speak for themselves: world production of resins and plastic fibers rose from 2 million tons in 1950 to 380 in 2015.
Over 8300 million tons produced in 65 years have made plastic one of the industrial symbols, with cement and steel, of the "Anthropocene" era, essentially the geological era in which we live in this period.
It is such an important part of our everyday life that it's hard to think of an object that doesn't contain polymers or it is composed of plastic.
In fact, plastic is the longest-kept synthetic product, it degrades completely only in hundreds of years.
It is therefore logical that, if not burned or recycled correctly, it will end up in the environment, favoring the alteration of too delicate ecosystems.
In the end, abusive landfills and lack of purifiers are mainly responsible for the accumulation of waste at sea. In the Mediterranean sea, however, an important source of waste is recreational, tourist and professional fishing. Children's toys, umbrella tips, sachets of ice cream or candies, bottles of suntan lotion come from seaside tourism; baits, fishing lines, and bait boxes are recreational fishermen's waste, while nets and nets for mussels come from professional fishing. It is impossible to know who left the thousands of bottles, bottles, bags, cigarette butts that plague our beaches.
One thing, however, is certain: most of the waste on our coasts is of Italian and often local origin, as shown by the writings found on many objects found on the beach.
But to diminish the plastic in the ocean it must start from our common sense and love for the foresight of our planet.

4.1.3 Name 6 compartments of the sea where plastics can be found!

Anthropogenic litter, especially plastic, has been increasing in oceans over the last decades: every year, 8 million metric tons of plastic debris (which by definition are waste that can vary in size from large containers, fishing nets to microscopic plastic pellets or even particles) is discarded, everywhere, polluting lands, rivers, coasts, beaches, and oceans.
Plastic debris can be nowadays found on six distinct compartments:
-sea surface;
-water column;
-coastlines;
-seafloor;
-sea ice;
-biota.
In the water column, plastic debris can be found both floating at the surface than submerged in the deepest waters.
The seabed and the sediment, from the shallow coast to the floor of abyssal plains, are home to plastic materials.
Recent studies have also discovered that so much plastic is now stored in Arctic sea ice, which then moves and melts, that it has become a significant system for transporting plastic particles around the region.
In addition, marine organisms can ingest debris of various sizes, turning biota into another “storage compartment” for accumulation of this substance within the marine environment. In nature plastics have been detected, for example, in marine mammals, seabirds, fishes, bivalves and other invertebrates. And when animals ingest plastic, it can cause life-threatening problems, including reduced
fitness, nutrient uptake and feeding efficiency—all vital for survival. Part of the ocean’s plastic load is hence
distributed in the biota even though the extent of this is still unclear and needs more research.

4.1.4 Floating plastics in the sea as a threat to sea animals

Wherever we look, at home, on the street or at work, we cannot fail to notice the omnipresence of plastic, to the point that it seems impossible to imagine a world without this material. His birth is very recent: large-scale plastic production dates back only to the fifties. According to some research, since then about nine billion tons of virgin plastics have been produced. Most of these were collected in landfills or thrown into marine environments. Another research conducted by a team of Australian and British experts in 2015 reported that 90% of seabirds worldwide have plastic residues in their intestines. It is also expected that, if the consumption of plastic will not decrease, by 2050 99% of the birds will have ingested plastic. This problem also involves many other marine animals that injure themselves with plastic residues or that ingest these materials (confusing them with food) compromising their health. Even sea turtles are in danger. These ancient reptiles exchange plastic waste for jellyfish and swallow them, going towards death. A 2015 video shot in Costa Rica shows an adult turtle that has swallowed a straw. Nathan Robinson, of the organization for the protection of sea turtles The Leatherback Trust, explained that, when the turtle tried to regurgitate the plastic, it came out of his nose and not of his mouth. Being a phenomenon so recent, the actual consequences of plastic on marine animals are not yet clear. New research by Loggerhead Marinelife Center and University of Georgia suggests that plastic ingestion poses a risk especially for young sea turtles. In fact, it is thought to prevent their development by jeopardizing entire populations. "If the level of mortality we observed in sea turtles also occurs for other organisms such as plankton, fish and crustaceans, then we will see a complete interruption in our ocean life cycle," explained Branson W. Ritchie, co- author of the study.

4.1.5 Plastics at the bottom of the sea � change of habitats

Thousands of tonnes of waste invade the sea every year, dangerously altering the ecosystem balances and marine biodiversity.
Plastic is a difficult enemy to fight, it has now become food of many species. For example, each small piece of plastic can be colonized by algae or microorganisms.
At this rate, new and dangerous ecosystems can be created, putting many animals at risk.
The most widespread plastic comes from the companies that produce a lot.
In addition, most waste is made up of bottles, bags and disposable items.
They promote pollution because they are thrown immediately after their use, which lasts very little.
This plastic creates real islands that float in the various oceans.
One of the most important and dangerous floating islands of waste is the Pacific trash Vortex.
Large pieces of plastic injuring, strangle and often cause the deaths of animals such as sea turtles and seabirds.
The most dangerous are the microplastics; they, entering the food chain, threaten an even greater number of animal species and put human health at risk too.
Moreover, the floating plastic is a real sponge that absorbs marine contaminants, such as pesticides and phthalates, which then releases in the stomach of organisms that ingest it.
In fact, the plastic produces serious damage that alter the reproductive system.
Finally, we can say that marine habitats will change for the worse if the man does not act quickly.
The presence of plastic is a serious threat also for important economic sectors, especially fishing and tourism.

4.1.6 What is microplastics and how does it emerge?

With microplastics we refer to small particles of plastic material generally smaller than one millimeter.
Microplastics come from a variety of sources, including from larger plastic debris that degrades into smaller and smaller pieces.
In addition, microbeads, a type of microplastic, are very tiny pieces of manufactured polyethylene plastic that are added as exfoliants to health and beauty products, such as some cleansers and toothpastes.
There are currently two categories of microplastic: the primary that is produced as a direct result of the human use of these materials and secondary as a result of fragmentation resulting from the breaking of larger portions that create the great Pacific garbage patch.
Plastic does not break for many years, and can be ingested in the body of many organisms.
Microplastic pollution is in the food chain affecting not only marine life but also foods such as sea salt, beer and honey.
A study by Orb Media ( anon-profit journalism organization) has shown that water coming out of taps around the world contains microscopic plastic fibres and the United States has been identified as the country with the highest contamination rate.
Microplastics are a serious threat to marine life, which they exchange for food. Controlling the introduction of these plastics into the environment therefore means safeguarding the marine fauna. Many marine animals such as seagulls or seals have ingested microplastics, affecting their health.
So, the microplastics are still a huge problem. You can help keep plastic out of the ocean. Remember: Reduce. Reuse. Recycle

4.1.7 Harmful chemicals in marine plastics

Plastics, which in oceans typically degrade within a year, can fragment into micro and nanoplastics in a shorter time, thus facilitating their absorption by the marine biota along the entire food chain. In the process, toxic chemicals such as bisphenol A and polystyrene can leach into waters from some plastics. These polymers may contain chemical additives and contaminants, so they could introduce potential risks to marine ecosystems, biodiversity and food availability. Plankton, fish, and ultimately the human race, through the food chain, ingest these highly toxic carcinogens and chemicals. Consuming the fish that contain these toxins can cause an increase in cancer, immune disorders, and birth defects.
Plastic chemicals can change the behavior of sea creatures and leave them vulnerable to attack; it has been found in seas all over the world, with pieces that can be seen everywhere from the ice of the Arctic sea to the bottom of the Mariana Trench.
Often its harmful effects are evident, particularly when whales die after suffocating on plastic bags or turtles have tangled in abandoned fishing nets.
Without strong and immediate preventive measures, environmental impacts and economic costs are destined to worsen, even in the short term. Continuous increases in the production and consumption of plastics, combined with expensive uses, inefficient waste collection infrastructures and inadequate waste management facilities, especially in developing countries, also ensure that the objectives already established for the marine litter reduction represents a huge challenge, and it is unlikely to be met without a fundamental rethinking of the ways in which we consume plastics.

4.1.8 Plastics in the sea as a threat to humans

The plastic thrown into the sea causes serious damage to the world.
There are some beaches or shores of rivers covered in plastic transported there by sea currents. What worsens the situation is that the complete degradation of the plastic takes place only after hundreds of years and only 20% of the plastic produced has been recycled or incinerated.
Plastic, besides being very dangerous for the marine ecosystem, is also very dangerous for humans because it contains some chemicals that can be harmful to humans through skin absorption, causing dermatitis in contact with human skin. In fact if we filtered all the salty waters of the world, we would find that in each square kilometre there are about 46,000 micro particles of plastic in suspension.
The effects on the human organism of many of these substances are not yet known. In the world there aren't more areas untouched by plastic and very often we talk about "plastic islands". These are gigantic accumulations of waste that gather in the middle of vast sub-tropical currents.
Even mussels, tuna or swordfish can contain plastic and then be harmful to the man who eats them. The plastic materials can release a part of the substances they are made of, among them are Bisphenol A and Phthalates, two substances that according to several doctors and food experts are extremely harmful to human health. In fact plastic and its additives are not only around us, but also within us. They are present in our blood and urine in measurable quantities, ingested with the food we eat, with the water we drink or from other substances.

4.1.9 Pacific Plastic Vortex

The Pacific Plastic Vortex, known as the Great Pacific Garbage Patch, is a huge amount of floating plastic, betweent the 135th and 155th West meridian, and between the 35th and 42nd parallel North in the Pacific Ocean.
Its extension is from 700.000 to more than 10 millions square kilometers, and it has been created since the 80s because of the action of the ocean current, called North Pacific Subtropical Gyre.
Despite the floating trash of biological origin are submitted by biodegradation, the trash int he Pacific Ocean is composed mostly by plastic, photodegradable.
Unlike organic debris, which biodegrades, plastic disintegrates into ever smaller pieces while remaining a polymer (without changing chemically). This process continues down to the molecular level. In other words, it means plastic gets smaller but not absorbed by the environment. Some plastics decompose within a year of entering the water, releasing potentially toxic chemicals such as biosphenol A, PCBs adn derivates of polystyrene.
As the plastic flotsam photodegrades into smaller and smaller pieces, it concentrates in the upper water column. As it disintegrates, the pieces become small enough to be ingested by aquatic organisms that reside near the ocean's surface. Plastic may become concentrated in neuston, thereby entering the food chain.
Considering the total of 1.5 million Laysan albatrosses (a large seabird) that inhabit the North Pacific coasts, a giant amount of them were found with plastic in their gastrointestinental tract. Approximately one-third of their chicks die, and many of those deaths are from plastic unwittingly fed to them by their parents. Twenty tons of plastic debris washes up on Midway every year with five tons ending up in the bellies of albatross chicks. Turtles, whales, fishes may eat dangeorus substances while looking for food, and it will come back to us thanks to our omnivorous diet.