Microplastics are fragments of any type of

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...

less than in length, according to the U.S.

National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...

(NOAA) and the European Chemicals Agency. They cause

pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...

by entering natural

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

s from a variety of sources, including

cosmetics Cosmetics are constituted mixtures of chemical compounds derived from either natural sources, or synthetically created ones. Cosmetics have various purposes. Those designed for personal care and skin care can be used to cleanse or protect ...

clothing Clothing (also known as clothes, apparel, and attire) are items worn on the body. Typically, clothing is made of fabrics or textiles, but over time it has included garments made from animal skin and other thin sheets of materials and natural ...

, food packaging, and industrial processes. The term ''macroplastics'' is used to differentiate microplastics from larger plastic waste, such as plastic bottles. Two classifications of microplastics are currently recognized. Primary microplastics include any plastic fragments or particles that are already 5.0 mm in size or less before entering the environment. These include microfibers from clothing, microbeads, and plastic pellets (also known as nurdles). Secondary microplastics arise from the degradation (breakdown) of larger plastic products through natural weathering processes after entering the environment. Such sources of secondary microplastics include water and soda bottles, fishing nets, plastic bags, microwave containers, tea bags and tire wear. Both types are recognized to persist in the environment at high levels, particularly in aquatic and

marine ecosystem Marine ecosystems are the largest of Earth's aquatic ecosystems and exist in waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the sur ...

s, where they cause

water pollution Water pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. ...

. 35% of all ocean microplastics come from textiles/clothing, primarily due to the erosion of polyester, acrylic, or nylon-based clothing, often during the washing process. However, microplastics also accumulate in the air and terrestrial ecosystems. Because plastics degrade slowly (often over hundreds to thousands of years), microplastics have a high probability of ingestion, incorporation into, and accumulation in the bodies and tissues of many organisms. The toxic chemicals that come from both the ocean and runoff can also

biomagnify Biomagnification, also known as bioamplification or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain. This increase can occur as a ...

up the food chain. In terrestrial ecosystems, microplastics have been demonstrated to reduce the viability of soil ecosystems and reduce weight of earthworms. The cycle and movement of microplastics in the environment are not fully known, but research is currently underway to investigate the phenomenon. Deep layer ocean sediment surveys in China (2020) show the presence of plastics in deposition layers far older than the invention of plastics, leading to suspected underestimation of microplastics in surface sample ocean surveys. * Microplastics have also been found in the high mountains, at great distances from their source. Microplastics have also been found in human blood, though their effects are largely unknown.

Classification

The term "microplastics" was introduced in 2004 by Professor Richard Thompson, a marine biologist at the

University of Plymouth The University of Plymouth is a public research university based predominantly in Plymouth, England, where the main campus is located, but the university has campuses and affiliated colleges across South West England. With students, it is the ...

in the United Kingdom. Microplastics are common in our world today. In 2014, it was estimated that there are between 15 and 51 trillion individual pieces of microplastic in the world's oceans, which was estimated to weigh between 93,000 and 236,000 metric tons.

Primary microplastics

Primary microplastics are small pieces of plastic that are purposefully manufactured. They are usually used in facial cleansers and

, or in air blasting technology. In some cases, their use in medicine as vectors for drugs was reported. Microplastic "scrubbers", used in

exfoliating Exfoliation is the removal of dead skin cells and built-up dirt from the skin's surface. The term comes from the Latin word ''exfoliare'' (to strip off leaves). This is a regular practice within the cosmetic industry, both for its outcome of pro ...

hand cleansers and facial scrubs, have replaced traditionally used natural ingredients, including ground almond shells, oatmeal, and pumice. Primary microplastics have also been produced for use in air blasting technology. This process involves blasting acrylic,

melamine Melamine is an organic compound with the formula C3H6N6. This white solid is a trimer of cyanamide, with a 1,3,5-triazine skeleton. Like cyanamide, it contains 67% nitrogen by mass, and its derivatives have fire retardant properties due t ...

, or polyester microplastic scrubbers at machinery, engines, and boat hulls to remove rust and paint. As these scrubbers are used repeatedly until they diminish in size and their cutting power is lost, they often become contaminated with heavy metals such as

cadmium Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of ...

, chromium, and

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...

. Although many companies have committed to reducing the production of microbeads, there are still many bioplastic microbeads that also have a long degradation life cycle similar to normal plastic.

Secondary microplastics

Secondary plastics are small pieces of plastic derived from the breakdown of larger plastic debris, both at sea and on land. Over time, a culmination of physical, biological, and chemphotodegradation, including photo-oxidation caused by sunlight exposure, can reduce the structural integrity of plastic debris to a size that is eventually undetectable to the naked eye. This process of breaking down large plastic material into much smaller pieces is known as fragmentation. It is considered that microplastics might further degrade to be smaller in size, although the smallest microplastic reportedly detected in the oceans at present is 1.6 micrometres (6.3×10⁻⁵ in) in diameter. The prevalence of microplastics with uneven shapes suggests that fragmentation is a key source.

Other sources: as a by-product/dust emission during wear and tear

There are countless sources of both primary and secondary microplastics. Microplastic fibers enter the environment from the

washing Washing is a method of cleaning, usually with water and soap or detergent. Washing and then rinsing both body and clothing is an essential part of good hygiene and health. Often people use soaps and detergents to assist in the emulsification o ...

of synthetic clothing. Tires, composed partly of synthetic

styrene-butadiene Styrene-butadiene or styrene-butadiene rubber (SBR) describe families of synthetic rubbers derived from styrene and butadiene (the version developed by Goodyear is called Neolite). These materials have good abrasion resistance and good aging st ...

rubber, will erode into tiny plastic and rubber particles as they are used. Furthermore, 2.0-5.0 mm plastic pellets, used to create other plastic products, often enter ecosystems due to spillages and other accidents. A

Norwegian Environment Agency The Norwegian Environment Agency ( no, Miljødirektoratet) was created on 1 July 2013 through a merger of the Norwegian Directorate for Nature Management and the Norwegian Climate and Pollution Agency.Sundt, Peter, and Schulze, Per-Erik: "Sources of microplastic-pollution to the marine environment", "Mepex for the Norwegian Environment Agency", 2015 states it would be beneficial to classify these sources as primary, as long as microplastics from these sources are added from human society since the "start of the pipe", and their emissions are inherently a result of human material and product use and not secondary defragmentation in the nature.

Nanoplastics

Depending on the definition used, nanoplastics are less than 1 μm (i.e. 1000 nm) or less than 100 nm in size. Speculations over nanoplastics in the environment range from it being a temporary byproduct during the fragmentation of microplastics to it being an invisible environmental threat at potentially high and continuously rising concentrations. The presence of nanoplastics in the North Atlantic Subtropical Gyre has been confirmed and recent developments in Raman spectroscopy coupled with optical tweezers (Raman Tweezers) as well as nano-fourier-transform infrared spectroscopy (nano- FTIR) or atomic force infrared ( AFM-IR) are promising answers in the near future regarding the nanoplastic quantity in the environment. Fluorescence could represent a unique tool for the identification and quantification of nanoplastics, since it allows the development of fast, easy, cheap, and sensitive methods. Nanoplastics are thought to be a risk to environmental and human health. Due to their small size, nanoplastics can cross cellular membranes and affect the functioning of cells. Nanoplastics are lipophilic and models show that polyethylene nanoplastics can be incorporated into the hydrophobic core of lipid bilayers. Nanoplastics are also shown to cross the epithelial membrane of fish accumulating in various organs including the gallbladder, pancreas, and the brain. Little is known on adverse health effects of nanoplastics in organisms including humans. In zebrafish, polystyrene nanoplastics can induce a stress response pathway altering glucose and cortisol levels, which is potentially tied to behavioral changes in stress phases. In Daphnia, polystyrene nanoplastic can be ingested by the freshwater cladoceran Daphnia pulex and affect its growth and reproduction as well as induce stress defense, including the ROS production and MAPK-HIF-1/NF-κB-mediated antioxidant system.

Sources

Most micro

plastic pollution Plastic pollution is the accumulation of plastic objects and particles (e.g. plastic bottles, bags and microbeads) in the Earth's environment that adversely affects humans, wildlife and their habitat. Plastics that act as pollutants are catego ...

comes from textiles, tires and city dust which account for over 80% of all microplastic in the environment. The existence of microplastics in the environment is often established through aquatic studies. These include taking

plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...

samples, analyzing sandy and muddy

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...

s, observing

vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...

and

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

consumption, and evaluating chemical

pollutant A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. These can be both naturally forming (i.e. minerals or extracted compounds like o ...

interactions. Through such methods, it has been shown that there are microplastics from multiple sources in the environment. Microplastics could contribute up to 30% of the Great Pacific Garbage Patch polluting the world's oceans and, in many developed countries, are a bigger source of

marine plastic pollution Marine plastic pollution (or plastic pollution in the ocean) is a type of marine pollution by plastics, ranging in size from large original material such as bottles and bags, down to microplastics formed from the fragmentation of plastic material ...

than the visible larger pieces of marine litter, according to a 2017 IUCN report.

Car and truck tires

Wear and tear from tires significantly contributes to the flow of (micro-)plastics into the environment. Estimates of emissions of microplastics to the environment in Denmark are between per year. Secondary microplastics (e.g. from car and truck tires or footwear) are more important than primary microplastics by two orders of magnitude. The formation of microplastics from the degradation of larger plastics in the environment is not accounted for in the study. The estimated per capita emission ranges from 0.23 to 4.7 kg/year, with a global average of 0.81 kg/year. The emissions from car tires (wear reaching 100%) are substantially higher than those of other sources of microplastics, e.g., airplane tires (2%), artificial turf (wear 12–50%), brakes (wear 8%), and road markings (wear 5%). In the case of road markings, recent field study indicated that they were protected by a layer of glass beads and their contribution was only between 0.1 and 4.3 g/person/year, which would constitute approximately 0.7% of all of the secondary microplastics emissions; this value agrees with some emissions estimates. Emissions and pathways depend on local factors like road type or sewage systems. The relative contribution of tire wear and tear to the total global amount of plastics ending up in our oceans is estimated to be 5–10%. In air, 3–7% of the particulate matter (PM_2.5) is estimated to consist of tire wear and tear, indicating that it may contribute to the global health burden of air pollution which has been projected by the World Health Organization (WHO) at 3 million deaths in 2012. Pollution from tire wear and tear also enters the food chain, but further research is needed to assess human health risks.

Clothing

Studies have shown that many synthetic fibers, such as polyester, nylon, acrylics, and

spandex Spandex, Lycra, or elastane is a synthetic fiber known for its exceptional elasticity. It is a polyether-polyurea copolymer that was invented in 1958 by chemist Joseph Shivers at DuPont's Benger Laboratory in Waynesboro, Virginia, US. The g ...

, can be shed from clothing and persist in the environment.Grossman, Elizabeth: "How Microplastics from Your Fleece Could End up on Your Plate", "Civil Eats", January 15, 2015 Each garment in a load of laundry can shed more than 1,900 fibers of microplastics, with fleeces releasing the highest percentage of fibers, over 170% more than other garments. For an average wash load of , over 700,000 fibers could be released per wash.

Washing machine A washing machine (laundry machine, clothes washer, washer, or simply wash) is a home appliance used to wash laundry. The term is mostly applied to machines that use water as opposed to dry cleaning (which uses alternative cleaning fluids and ...

manufacturers have also reviewed research into whether washing machine filters can reduce the amount of microfiber fibers that need to be treated by

sewage treatment Sewage treatment (or domestic wastewater treatment, municipal wastewater treatment) is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable for discharge to the surrounding e ...

facilities. These microfibers have been found to persist throughout the food chain from zooplankton to larger animals such as whales. The primary fiber that persist throughout the textile industry is polyester which is a cheap cotton alternative that can be easily manufactured. However, these types of fibers contribute greatly to the persistence to microplastics in terrestrial, aerial, and marine ecosystems. The process of washing clothes causes garments to lose an average of over 100 fibers per liter of water. This has been linked with health effects possibly caused by the release of

monomer In chemistry, a monomer ( ; '' mono-'', "one" + ''-mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization. Classification ...

s, dispersive dyes, mordants, and

plasticizer A plasticizer ( UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture. Plasticiz ...

s from manufacturing. The occurrence of these types of fibers in households has been shown to represent 33% of all fibers in indoor environments. Textile fibers have been studied in both indoor and outdoor environments to determine the average human exposure. The indoor concentration was found to be 1.0–60.0 fibers/m³, whereas the outdoor concentration was much lower at 0.3–1.5 fibers/m³. The deposition rate indoors was 1586–11,130 fibers per day/m³ which accumulates to around 190-670 fibers/mg of dust. The largest concern with these concentrations is that it increases exposure to children and the elderly, which can cause adverse health effects.

Cosmetics industry

Some companies have replaced natural

ingredients with microplastics, usually in the form of "

microbead Microbeads are manufactured solid plastic particles of less than one millimeter in their largest dimension. They are most frequently made of polyethylene but can be of other petrochemical plastics such as polypropylene and polystyrene. They are u ...

s" or "micro-exfoliates". These products are typically composed of

polyethylene Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including b ...

, a common component of plastics, but they can also be manufactured from

polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins a ...

, polyethylene terephthalate (PET), and

nylon Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from pe ...

. They are often found in face washes, hand soaps, and other personal care products; the beads are usually washed into the sewage system immediately after use. Their small size prevents them from fully being retained by preliminary treatment screens at wastewater plants, thereby allowing some to enter rivers and oceans. In fact, wastewater treatment plants only remove an average of 95–99.9% of microbeads because of their small design . This leaves an average of 0–7 microbeads per litre being discharged. Considering that one treatment plant discharges 160 trillion liters of water per day, around 8 trillion microbeads are released into waterways every day. This number does not account for the sewage sludge that is reused as fertilizer after the waste water treatment that has been known to still contain these microbeads. Although many companies have committed to phasing out the use of microbeads in their products, according to research, there are at least 80 different facial scrub products that are still being sold with microbeads as a main component. This contributes to the 80 metric tons of microbead discharge per year by the United Kingdom alone, which not only has a negative impact upon the wildlife and food chain, but also upon levels of toxicity, as microbeads have been proven to absorb dangerous chemicals such as pesticides and

polycyclic aromatic hydrocarbon A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. ...

s. The restriction proposal by the European Chemicals Agency (ECHA) and reports by the United Nations Environment Programme ( UNEP) and TAUW suggest that there are more than 500 microplastic ingredients that are widely used in cosmetics and personal care products. Even when microbeads are removed from cosmetic products, there are still harmful products being sold with plastics in them. For example, acrylates copolymers cause toxic effects for waterways and animals if they are polluted. Acrylate copolymers also can emit styrene monomers when used in body products which increases a person's chances of cancer. Countries like New Zealand which have banned microbeads often pass over other polymers such as acrylates copolymer, which can be just as toxic to people and the environment.

Fishing industry

Recreational Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for enjoyment, amusement, or pleasur ...

and

commercial fishing Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...

, marine vessels, and marine industries are all sources of plastic that can directly enter the marine environment, posing a risk to biota both as macroplastics, and as secondary microplastics following long-term degradation. Marine debris observed on beaches also arises from beaching of materials carried on inshore and ocean currents. Fishing gear is a form of plastic debris with a marine source. Discarded or lost fishing gear, including plastic monofilament line and nylon netting (sometimes called

ghost net Ghost nets are fishing nets that have been abandoned, lost or otherwise discarded in the ocean. These nets, often nearly invisible in the dim light, can be left tangled on a rocky reef or drifting in the open sea. They can entangle fish, dol ...

s), is typically neutrally

buoyant Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pr ...

and can, therefore, drift at variable depths within the oceans. Various countries have reported that microplastics from the industry and other sources have been accumulating in different types of seafood. In

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

, 55% of all fish species had evidence of manufactured debris similar to America which reported 67%. However, the majority of debris in Indonesia was plastic, while in North America the majority was synthetic fibers found in clothing and some types of nets. The implication from the fact that fish are being contaminated with microplastic is that those plastics and their chemicals will bioaccumulate in the food chain. One study analyzed the plastic-derived chemical called

polybrominated diphenyl ethers Polybrominated diphenyl ethers or PBDEs, are a class of organobromine compounds that are used as flame retardants. Like other brominated flame retardants, PBDEs have been used in a wide array of products, including building materials, electronics, ...

(PBDEs) in the stomachs of short-tailed shearwaters. It found that one-fourth of the birds had higher-brominated congeners that are not naturally found in their prey. However, the PBDE got into the birds' systems through plastic that was found in the stomachs of the birds. It is therefore not just the plastics that are being transferred through the food chain but the chemicals from the plastics as well.

Manufacturing

The manufacture of plastic products uses granules and small

resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on n ...

pellets as their raw material. In the United States, production increased from 2.9 million pellets in 1960 to 21.7 million pellets in 1987. In 2019, plastic world production was 368 million tonnes; 51% were produced in Asia. China, the world's largest producer, created 31% of the world total. Through accidental spillage during land or sea transport, inappropriate use as packing materials, and direct outflow from processing plants, these raw materials can enter

aquatic ecosystem An aquatic ecosystem is an ecosystem formed by surrounding a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms that are dependent on each other and on their environment. The t ...

s. In an assessment of

Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...

waters using an 80 µm mesh, KIMO Sweden found typical microplastic concentrations of 150–2,400 microplastics per m³; in a harbor adjacent to a plastic production facility, the concentration was 102,000 per m³. Many industrial sites in which convenient raw plastics are frequently used are located near bodies of water. If spilled during production, these materials may enter the surrounding environment, polluting waterways. "More recently, Operation Cleansweep, a joint initiative of the

American Chemistry Council American Chemistry Council (ACC), formerly known as the Manufacturing Chemists' Association (at its founding in 1872) and then as the Chemical Manufacturers' Association (from 1978 until 2000), is an industry trade association for American chemic ...

and

Society of the Plastics Industry Founded in 1937, the Society of the Plastics Industry, Inc. was a professional society representing individuals in the plastics industry. In 2010, the organization began doing business as SPI: The Plastics Industry Trade Association, before changi ...

, is aiming for industries to commit to zero pellet loss during their operations". Overall, there is a significant lack of research aimed at specific industries and companies that contribute to microplastics pollution.

Packaging and shipping

Shipping Freight transport, also referred as ''Freight Forwarding'', is the physical process of transporting commodities and merchandise goods and cargo. The term shipping originally referred to transport by sea but in American English, it has been ...

has significantly contributed to marine pollution. Some statistics indicate that in 1970, commercial shipping fleets around the world dumped over 23,000 tons of plastic waste into the marine environment. In 1988, an international agreement (

MARPOL 73/78 The International Convention for the Prevention of Pollution from Ships, 1973 as modified by the Protocol of 1978, or "MARPOL 73/78" is one of the most important international marine environmental conventions. MARPOL 73/78, MARPOL is an amalg ...

, Annex V) prohibited the dumping of waste from ships into the marine environment. In the United States, the Marine Plastic Pollution Research and Control Act of 1987 prohibits discharge of plastics in the sea, including from naval vessels. However, shipping remains a dominant source of

, having contributed around 6.5 million tons of plastic in the early 1990s. Research has shown that approximately 10% of the plastic found on the beaches in

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...

are nurdles. In one incident on July 24, 2012, 150 tonnes of nurdles and other raw plastic material spilled from a shipping vessel off the coast near

Hong Kong Hong Kong ( (US) or (UK); , ), officially the Hong Kong Special Administrative Region of the People's Republic of China (abbr. Hong Kong SAR or HKSAR), is a city and special administrative region of China on the eastern Pearl River Delta i ...

after a major storm. This waste from the Chinese company Sinopec was reported to have piled up in large quantities on beaches. While this is a large incident of spillage, researchers speculate that smaller accidents also occur and further contribute to marine microplastic pollution.

Personal protective equipment

Face masks

Since the emergence of the

COVID-19 pandemic The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identi ...

, the usage of medical face masks has sharply increased to reach approximately 89 million masks each . Single use face masks are made from polymers, such as polypropylene, polyurethane, polyacrylonitrile, polystyrene, polycarbonate, polyethylene, or polyester. The increase in production, consumption, and littering of face masks was added to the list of environmental challenges, due to the addition of plastic particles waste in the environment. After degrading, disposable face masks could break down into smaller size particles (under 5mm) emerging a new source of microplastic. A report made in February 2020 by Oceans Asia, an organization committed to advocacy and research on marine pollution, confirms "the presence of face masks of different types and colors in an ocean in Hong Kong".

Plastics

Bottled water

In one study, 93% of the bottled water from 11 different brands showed microplastic contamination. Per liter, researchers found an average of 325 microplastic particles. Of the tested brands, Nestlé Pure Life and Gerolsteiner bottles contained the most microplastic with 930 and 807 microplastic particles per liter (MPP/L), respectively. San Pellegrino products showed the least quantity of microplastic densities. Compared to water from taps, water from plastic bottles contained twice as much microplastic. Some of the contamination likely comes from the process of bottling and packaging the water.

Baby bottles

In 2020 researchers reported that

infant feeding bottles with contemporary preparation procedures were found to cause microplastics exposure to infants ranging from 14,600 to 4,550,000 particles per capita per day in 48 regions. Microplastics release is higher with warmer liquids and similar with other polypropylene products such as lunchboxes. Unexpectedly, silicone rubber baby bottle nipples degrade over time from repeated steam sterilization, shedding micro- and nano-sized particles of silicone rubber, researchers found in 2021. They estimated that, using such heat-degraded nipples for a year, a baby will ingest more than 660,000 particles.

Single-use plastic products

Common single-use plastic products – such as paper coffee cups that are lined with a thin plastic film inside – release trillions of microplastic-nanoparticles per liter into water during normal use. Single-use plastic products enter aquatic environments and "Local and statewide policies that reduce single-use plastics were identified as effective legislative actions that communities can take to address plastic pollution".

Sewage treatment plants

Sewage treatment Sewage treatment (or domestic wastewater treatment, municipal wastewater treatment) is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable for discharge to the surrounding e ...

plants, also known as wastewater treatment plants (WWTPs), remove contaminants from wastewater, primarily from household sewage, using various physical, chemical, and biological processes. Most plants in developed countries have both primary and

secondary treatment Secondary treatment is the removal of biodegradable organic matter (in solution or suspension) from sewage or similar kinds of wastewater. The aim is to achieve a certain degree of effluent quality in a sewage treatment plant suitable for the inte ...

stages. In the primary stage of treatment, physical processes are employed to remove oils, sand, and other large solids using conventional filters, clarifiers, and settling tanks. Secondary treatment uses biological processes involving

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

and protozoa to break down organic matter. Common secondary technologies are

activated sludge The activated sludge process is a type of biological wastewater treatment process for treating sewage or industrial wastewaters using aeration and a biological floc composed of bacteria and protozoa. It uses air (or oxygen) and microorganism ...

systems,

trickling filter A trickling filter is a type of wastewater treatment system. It consists of a fixed bed of rocks, coke, gravel, slag, polyurethane foam, sphagnum peat moss, ceramic, or plastic media over which sewage or other wastewater flows downward and c ...

s, and

constructed wetland A constructed wetland is an artificial wetland to treat sewage, greywater, stormwater runoff or industrial wastewater. It may also be designed for land reclamation after mining, or as a mitigation step for natural areas lost to land development ...

s. The optional tertiary treatment stage may include processes for nutrient removal (

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

and

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

) and

disinfection A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than st ...

. Microplastics have been detected in both the primary and secondary treatment stages of the plants. A groundbreaking 1998 study suggested that microplastic fibers would be a persistent indicator of sewage sludges and wastewater treatment plant outfalls. A study estimated that about one particle per liter of microplastics are being released back into the environment, with a removal efficiency of about 99.9%. A 2016 study showed that most microplastics are actually removed during the primary treatment stage where solid skimming and sludge settling are used. When these treatment facilities are functioning properly, the contribution of microplastics into oceans and surface water environments from WWTPs is not disproportionately large. Sewage sludge is used for soil fertilizer in some countries, which exposes plastics in the sludge to the weather, sunlight, and other biological factors, causing fragmentation. As a result, microplastics from these biosolids often end up in storm drains and eventually into bodies of water. In addition, some studies show that microplastics do pass through filtration processes at some WWTPs. According to a study from the UK, samples taken from sewage sludge disposal sites on the coasts of six continents contained an average one particle of microplastic per liter. A significant amount of these particles was of clothing fibers from washing machine effluent.

Effects on the environment

According to a comprehensive review of scientific evidence published by the

European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been de ...

Scientific Advice Mechanism The Scientific Advice Mechanism is a service created by the European Commission which provides independent science advice directly to European Commissioners to inform their decision-making. The Mechanism consists of two parts: the Group of Chief ...

in 2019, microplastics are now present in every part of the environment. While there is no evidence of widespread ecological risk from microplastic pollution yet, risks are likely to become widespread within a century if pollution continues at its current rate. Participants at the 2008 International Research Workshop on the Occurrence, Effects and Fate of Microplastic Marine Debris at the

University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattl ...

at Tacoma concluded that microplastics are a problem in the marine environment, based on: * the documented occurrence of microplastics in the marine environment, * the long residence times of these particles (and, therefore, their likely buildup in the future), and * their demonstrated ingestion by marine organisms. So far, research has mainly focused on larger plastic items. Widely recognized problems facing marine life are entanglement, ingestion, suffocation and general debilitation often leading to death and/or strandings. This causes serious public concern. In contrast, microplastics are not as conspicuous, being less than 5 mm, and are usually invisible to the naked eye. Particles of this size are available to a much broader range of species, enter the food chain at the bottom, become embedded in animal tissue, and are then undetectable by unaided visual inspection. Furthermore, consequences of plastic degradation and pollution release over long term have mostly been overlooked. The large amounts of plastic currently in the environment, exposed to degradation, but that has many more years of decay and release of toxic compounds to follow is referred to as ''toxicity debt''. Microplastics have been detected not just in marine but also in freshwater systems including marshes, streams, ponds, lakes, and rivers in (Europe, North America, South America, Asia and Australia). Samples collected across 29

Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lak ...

tributaries from six states in the United States were found to contain plastic particles, 98% of which were microplastics ranging in size from 0.355mm to 4.75mm.

Biological integration into organisms

Microplastics can become embedded in animals' tissue through ingestion or respiration. Various annelid species, such as deposit-feeding

lugworm The lugworm or sandworm (''Arenicola marina'') is a large marine worm of the phylum Annelida. Its coiled castings are a familiar sight on a beach at low tide but the animal itself is rarely seen except by those who, from curiosity or to use as f ...

s (''Arenicola marina''), have been shown to have microplastics embedded in their gastrointestinal tracts. Many

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

s, like the shore crab ''

Carcinus maenas ''Carcinus maenas'' is a common littoral crab. It is known by different names around the world. In the British Isles, it is generally referred to as the shore crab, or green shore crab. In North America and South Africa, it bears the name europ ...

'', have been seen to integrate microplastics into both their respiratory and digestive tracts. * Plastic particles are often mistaken by fish for food which can block their digestive tracts sending incorrect feeding signals to the brains of the animals. New research revealed, however, that fish ingest microplastics inadvertently rather than intentionally. Some coral such as Pocillopora verrucosa have also been found to ingest microplastics. It can take up to 14 days for microplastics to pass through an animal (as compared to a normal digestion period of 2 days), but enmeshment of the particles in animals' gills can prevent elimination entirely. When microplastic-laden animals are consumed by predators, the microplastics are then incorporated into the bodies of higher trophic-level feeders. For example, scientists have reported plastic accumulation in the stomachs of

lantern fish Lanternfishes (or myctophids, from the Greek μυκτήρ ''myktḗr'', "nose" and ''ophis'', "serpent") are small mesopelagic fish of the large family Myctophidae. One of two families in the order Myctophiformes, the Myctophidae are represente ...

which are small filter feeders and are the main prey for commercial fish like

tuna A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max len ...

and swordfish. Microplastics also absorb chemical pollutants that can be transferred into the organism's tissues. Small animals are at risk of reduced food intake due to false satiation and resulting starvation or other physical harm from the microplastics. A study done at the Argentinean coastline of the Rio de la Plata

estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...

, found the presence of microplastics in the guts of 11 species of coastal freshwater fish. These 11 species of fish represented four different feeding habits: detritivore,

planktivore A planktivore is an aquatic organism that feeds on planktonic food, including zooplankton and phytoplankton. Planktivorous organisms encompass a range of some of the planet's smallest to largest multicellular animals in both the present day and i ...

, omnivore and ichthyophagous. This study is one of the few so far to show the ingestion of microplastics by freshwater organisms.

Bottom feeder A bottom feeder is an aquatic animal that feeds on or near the bottom of a body of water. Biologists often use the terms ''benthos''—particularly for invertebrates such as shellfish, crabs, crayfish, sea anemones, starfish, snails, bristlewo ...

s, such as benthic sea cucumbers, who are non-selective scavengers that feed on debris on the ocean floor, ingest large amounts of sediment. It has been shown that four species of sea cucumber (''Thyonella gemmate'', '' Holothuria floridana'', ''H. grisea'' and ''

Cucumaria frondosa The orange-footed sea cucumber (''Cucumaria frondosa'') is the largest sea cucumber in New England, United States. It is one of the most abundant and widespread species of holothurians within the North Atlantic Ocean and the Barents Sea (Russia), ...

'') ingested between 2- and 20-fold more PVC fragments and between 2- and 138-fold more nylon line fragments (as much as 517 fibers per organism) based on plastic-to-sand grain ratios from each sediment treatment. These results suggest that individuals may be selectively ingesting plastic particles. This contradicts the accepted indiscriminate feeding strategy of sea cucumbers, and may occur in all presumed non-selective feeders when presented with microplastics. Bivalves, important aquatic filter feeders, have also been shown to ingest microplastics and nanoplastics. Upon exposure to microplastics, bivalve filtration ability decreases. Multiple cascading effects occur as a result, such as immunotoxicity and neurotoxicity. Decreased immune function occurs due to reduced

phagocytosis Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is ...

and

NF-κB Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a protein complex that controls transcription of DNA, cytokine production and cell survival. NF-κB is found in almost all animal cell types and is involved in cellular ...

gene activity. Impaired neurological function is a result of the inhibition of ChE and suppression of neurotransmitter regulatory enzymes. When exposed to microplastics, bivalves also experience

oxidative stress Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage. Disturbances in the normal ...

, indicating an impaired ability to detoxify compounds within the body, which can ultimately damage DNA. Bivalve gametes and larvae are also impaired when exposed to microplastics. Rates of developmental arrest, and developmental malformities increase, while rates of fertilization decrease. When bivalves have been exposed to microplastics as well as other pollutants such as

POPs Pops may refer to: Name or nickname * Pops, an informal term of address for a father or elder * Pops (nickname), a list of people * Pops (Muppet), a Muppets character * Pops (Johnny Bravo), a character from the Cartoon Network animated television ...

, mercury or

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...

s in lab settings, toxic effects were shown to be aggravated. Not only fish and free-living organisms can ingest microplastics.

Scleractinian corals Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by an oral disc in which a mo ...

, which are primary reef-builders, have been shown to ingest microplastics under laboratory conditions. While the effects of ingestion on these corals has not been studied, corals can easily become stressed and bleach. Microplastics have been shown to stick to the exterior of the corals after exposure in the laboratory. The adherence to the outside of corals can potentially be harmful, because corals cannot handle sediment or any particulate matter on their exterior and slough it off by secreting mucus, expending energy in the process, increasing the likelihood of mortality. Marine biologists in 2017 discovered that three-quarters of the underwater

seagrass Seagrasses are the only flowering plants which grow in marine environments. There are about 60 species of fully marine seagrasses which belong to four families (Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae), all in the or ...

in the Turneffe Atoll off the coast of Belize had microplastic fibers, shards, and beads stuck to it. The plastic pieces had been overgrown by

epibiont An epibiont (from the Ancient Greek meaning "living on top of") is an organism that lives on the surface of another living organism, called the basibiont ("living underneath"). The interaction between the two organisms is called epibiosis. An ep ...

s (organisms that naturally stick themselves to seagrass). Seagrass is part of the barrier reef ecosystem and is fed on by parrotfish, which in turn are eaten by humans. These findings, published in ''Marine Pollution Bulletin,'' may be "the first discovery of microplastics on aquatic vascular plants... ndonly the second discovery of microplastics on marine plant life anywhere in the world." It is not just aquatic animals which may be harmed. Microplastics can stunt the growth of terrestrial plants and earthworms. In 2019, the first European records of microplastic items in amphibians' stomach content was reported in specimens of the common European newt ''( Triturus carnifex)''. This also represented the first evidence for

Caudata The Caudata are a group of amphibians containing the extant salamanders (Urodela) and all extinct species of amphibians more closely related to salamanders than to frogs. They are typically characterized by a superficially lizard-like appearance ...

worldwide, highlighting that the emerging issue of plastics is a threat even in remote high-altitude environments. Zooplankton ingest microplastics beads (1.7–30.6 μm) and excrete fecal matter contaminated with microplastics. Along with ingestion, the microplastics stick to the appendages and exoskeleton of the zooplankton. Zooplankton, among other marine organisms, consume microplastics because they emit similar infochemicals, notably dimethyl sulfide, just as phytoplankton do. Plastics such as

high-density polyethylene High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a thermoplastic polymer produced from the monomer ethylene. It is sometimes called "alkathene" or "polythene" when used for HDPE pipes. With a high strength-to-density ratio, ...

(HDPE),

low-density polyethylene Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene. It was the first grade of polyethylene, produced in 1933 by Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. Its ...

(LDPE), and

(PP) produce dimethyl sulfide odors. These types of plastics are commonly found in plastic bags, food storage containers, and bottle caps. Green and red filaments of plastics are found in the planktonic organisms and in seaweeds. Not only do animals and plants ingest microplastics, some microbes also live on the surface of microplastics. This community of microbes form a slimy

biofilm A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular ...

which, according to a 2019 study, has a unique structure and possesses a special risk, because microplastic biofilms have been proven to provide a novel habitat for colonization that increases overlap between different species, thus spreading

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

s and antibiotic resistant genes through

horizontal gene transfer Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between unicellular and/or multicellular organisms other than by the ("vertical") transmission of DNA from parent to offspring (reproduction). H ...

. Then, due to rapid movement through waterways, these pathogens can be moved very quickly from their origin to another location where a specific pathogen may not be naturally present, spreading the potential disease.

Humans

According to a comprehensive review of scientific evidence published by the

in 2019, "little is known with respect to the human health risks of nano- and microplastics, and what is known is surrounded by considerable uncertainty". The authors of the review identify the main limitations as the quality or methodology of the research to date. Since "the poison is in the dose", the review concludes that "there is a need to understand the potential modes of toxicity for different size-shape-type NMP combinations in carefully selected human models, before robust conclusions about 'real' human risks can be made". Mean/median intake of microplastics in humans are at levels considered to be safe in humans; however, some individuals may sometimes exceed these limits; the effects, if any, of this is unknown. It is unknown whether and to what degree microplastics

bioaccumulate Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated ...

in humans. Research reported in 2022 identified, for the first time, the presence of polymers in human blood in 17 of 22 healthy volunteers. The mean of the sum quantifiable concentration of plastic particles was 1.6 mg/L. The stated purpose of the study was to develop a sampling and analytic method that could be used to detect plastics in human blood. A recent sub-chronic study investigated methacrylate-based polymer beads (> 10 μm) in food for therapeutic purposes and it found no sign of polymer beads' bioaccumulation in mice organs apart from gastrointestinal tract. The microplastics ingested by fish and crustaceans can be subsequently consumed by humans as the end of the

food chain A food chain is a linear network of links in a food web starting from producer organisms (such as grass or algae which produce their own food via photosynthesis) and ending at an apex predator species (like grizzly bears or killer whales), de ...

. Microplastics are found in air, water, and food that humans eat, especially seafood; however, the degree of absorption and retention is unclear. However, ingestion of microplastics via food may be relatively minor; for example, while mussels are known to accumulate microplastics, humans are predicted to be exposed to more microplastics in household dust than by consuming mussels. There are three main areas of potential concern with microplastics: the plastics themselves may have some effect on human physiology, microplastics might complex with heavy metals or other chemical compounds in the environment and act as a vector for bringing them into the body, and it is possible that microplastics might serve as vectors for pathogens. It is as yet unknown if exposure to microplastics at the levels found in the environment represent a "real" risk to humans; research into the subject is ongoing.

Persistent organic pollutants and Emerging organic contaminants

Plastic particles may highly concentrate and transport synthetic organic compounds (e.g.

persistent organic pollutants Persistent organic pollutants (POPs), sometimes known as "forever chemicals", are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. They are toxic chemicals that adversel ...

and emerging organic contaminants), commonly present in the environment and ambient seawater, on their surface through

adsorption Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the ''adsorbate'' on the surface of the ''adsorbent''. This process differs from absorption, in which ...

. Microplastics can act as carriers for the transfer of POPs from the environment to organisms. Recent articles have also shown that microplastics can sorb emerging organic chemicals such as pharmaceuticals and personal care products. The sorption potential is affected by water matrix, pH, ionic strength and aging of microparticles. Additives added to plastics during manufacture may leach out upon ingestion, potentially causing serious harm to the organism.

Endocrine disruption Endocrine disruptors, sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds are chemicals that can interfere with endocrine (or hormonal) systems. These disruptions can cause ca ...

by plastic additives may affect the

reproductive health Sexual and reproductive health (SRH) is a field of research, healthcare, and social activism that explores the health of an individual's reproductive system and sexual wellbeing during all stages of their life. The term can also be further de ...

of humans and wildlife alike. Plastics, polymers derived from mineral oils, are virtually

non-biodegradable Biodegradable waste includes any organic matter in waste which can be broken down into carbon dioxide, water, methane or simple organic molecules by micro-organisms and other living things by composting, aerobic digestion, anaerobic digestion ...

. However, renewable natural polymers are now in development which can be used for the production of biodegradable materials similar to those derived from oil-based polymers.

Where microplastics can be found

Steve Allen of Dalhousie University in Canada, main author of a study that found microplastics in high mountains, said "Plastic leaving the ocean into the air that high – it shows there is no eventual sink for this plastic. It's just moving around and around in an indefinite cycle."

Air

Airborne microplastics have been detected in the atmosphere, as well as indoors and outdoors. In 2019 a study found microplastic to be atmospherically transported to remote areas on the wind. A 2017 study found indoor airborne microfiber concentrations between 1.0 and 60.0 microfibers per cubic meter (33% of which were found to be microplastics). Another study looked at microplastic in the street dust of

Tehran Tehran (; fa, تهران ) is the largest city in Tehran Province and the capital of Iran. With a population of around 9 million in the city and around 16 million in the larger metropolitan area of Greater Tehran, Tehran is the most popul ...

and found 2,649 particles of microplastic within 10 samples of street dust, with ranging samples concentrations from 83 particle – 605 particles (±10) per 30.0 g of street dust. Microplastics and microfibers were also found in snow samples, and high up in "clean" air in high mountains at vast distances from their source. However, much like freshwater ecosystems and soil, more studies are needed to understand the full impact and significance of airborne microplastics.

Water

Oceans

Ice cores

Kelly et al. found 96 microplastic particles from 14 different types of polymers in an ice core sampled in 2009 from east

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest cont ...

Plastic pollution Plastic pollution is the accumulation of plastic objects and particles (e.g. plastic bottles, bags and microbeads) in the Earth's environment that adversely affects humans, wildlife and their habitat. Plastics that act as pollutants are catego ...

has previously been recorded in Antarctic surface waters and sediments as well as in Arctic sea ice, but this is thought to be the first time plastic has been found in Antarctic sea ice. Relatively large particle sizes suggest local pollution sources.

Freshwater

Microplastics have been widely detected in the world's aquatic environments. The first study on microplastics in

freshwater ecosystem Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes, ponds, rivers, streams, springs, bogs, and wetlands. They can be contrasted with marine ecosystems, which have a larger salt content. Freshwater habitats ...

s was published in 2011 that found an average of 37.8 fragments per square meter of Lake Huron sediment samples. Additionally, studies have found MP (microplastic) to be present in all of the

with an average concentration of 43,000 MP particle km⁻². Microplastics have also been detected in freshwater ecosystems outside of the United States. In Canada, a three-year study found a mean microplastic concentration of 193,420 particles km⁻² in

Lake Winnipeg Lake Winnipeg (french: Lac Winnipeg, oj, ᐑᓂᐸᑲᒥᐠᓴᑯ˙ᑯᐣ, italics=no, Weenipagamiksaguygun) is a very large, relatively shallow lake in North America, in the province of Manitoba, Canada. Its southern end is about north of t ...

. None of the microplastics detected were micro-pellets or beads and most were fibers resulting from the breakdown of larger particles, synthetic textiles, or atmospheric fallout. The highest concentration of microplastic ever discovered in a studied freshwater ecosystem was recorded in the Rhine river at 4000 MP particles kg⁻¹.

Soil

A substantial portion of microplastics are expected to end up in the world's

soil Soil, also commonly referred to as earth or dirt Dirt is an unclean matter, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty. Common types of dirt include: * Debri ...

, yet very little research has been conducted on microplastics in soil outside of aquatic environments. In wetland environments microplastic concentrations have been found to exhibit a negative correlation with vegetation cover and stem density. There exists some speculation that fibrous secondary microplastics from washing machines could end up in soil through the failure of water treatment plants to completely filter out all of the microplastic fibers. Furthermore, geophagous soil fauna, such as earthworms, mites, and collembolans could contribute to the amount of secondary microplastic present in soil by converting consumed plastic debris into microplastic via digestive processes. Further research, however, is needed. There is concrete data linking the use of organic waste materials to synthetic fibers being found in the soil; but most studies on plastics in soil merely report its presence and do not mention origin or quantity. Controlled studies on fiber-containing land-applied wastewater sludges (biosolids) applied to soil reported semiquantitative recoveries of the fibers a number of years after application.

Human body

Microplastics find their way into the food we eat, the water we drink and even the air we breathe. By some estimates, people consume more than 50,000 plastic particles per year – and many more if inhalation is considered. Microplastics were found in every human tissue studied by graduate students at Arizona State University. A study published in March, 2022, revealed that Microplastics have also been found in 80% of 22 anonymous blood samples, meaning they can be transported around the human body and raising the question of whether they can be transported to the brain. In December 2020, microplastic particles were found in the placentas of unborn babies for the first time. In June 2022, microplastic particles were found in breastmilk for the first time. Plastic pollution is having the greatest impacts on the world’s poorest and most vulnerable populations. Segments of these populations predominantly work in the informal waste sector and/or live in the vicinities of open dumpsites.

Prevention

Treatment

Some researchers have proposed incinerating plastics to use as energy, which is known as energy recovery. As opposed to losing the energy from plastics into the atmosphere in landfills, this process turns some of the plastics back into energy that can be used. However, as opposed to recycling, this method does not diminish the amount of plastic material that is produced. Therefore, recycling plastics is considered a more efficient solution.

Biodegradation Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegrada ...

is another possible solution to large amounts of microplastic waste. In this process, microorganisms consume and decompose synthetic polymers by means of enzymes. These plastics can then be used in the form of energy and as a source of

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

once broken down. The microbes could potentially be used to treat sewage wastewater, which would decrease the amount of microplastics that pass through into the surrounding environments.

Filtering

Stormwater or wastewater collection systems can capture many microplastics which are transported to treatment plants, the captured microplastics become part of the sludge produced by the plants. This sludge is often used as farm fertilizer meaning the plastics enter waterways through runoff. Fionn Ferreira, winner of the 2019 Google Science Fair, is developing a device for the removal of microplastic particles from water using a

ferrofluid Ferrofluid is a liquid that is attracted to the poles of a magnet. It is a colloidal liquid made of nanoscale ferromagnetic or ferrimagnetic particles suspended in a carrier fluid (usually an organic solvent or water). Each magnetic particle ...

Collection devices

Computer modelling done by

The Ocean Cleanup The Ocean Cleanup is a nonprofit environmental engineering organization based in the Netherlands, that develops technology to extract plastic pollution from the oceans and intercept it in rivers before it can reach the ocean. After initial t ...

, a Dutch foundation, has suggested that collection devices placed nearer to the coasts could remove about 31% of the microplastics in the area. On September 9, 2018, The Ocean Cleanup launched the world's first ocean cleanup system, 001 aka "Wilson", which is being deployed to the Great Pacific Garbage Patch. System 001 is 600 meters long that acts as a U-shaped skiff that uses natural oceanic currents to concentrate plastic and other debris on the ocean's surface into a confined area for extraction by vessels. The project has been met with criticism from oceanographers and plastic pollution experts, though it has seen wide public support. In addition, some bacteria have adapted to eat plastic, and some bacteria species have been genetically modified to eat (certain types of) plastics. Other than degrading microplastics, microbes had been engineered in a novel way to capture microplastics in their biofilm matrix from polluted samples for easier removal of such pollutants. The microplastics in the biofilms can then be released with an engineered 'release' mechanism via biofilm dispersal to facilitate with microplastics recovery.

Education and recycling

Increasing education through recycling campaigns is another proposed solution for microplastic contamination. While this would be a smaller-scale solution, education has been shown to reduce littering, especially in urban environments where there are often large concentrations of plastic waste. If recycling efforts are increased, a cycle of plastic use and reuse would be created to decrease our waste output and production of new raw materials. In order to achieve this, states would need to employ stronger infrastructure and investment around recycling. Some advocate for improving recycling technology to be able to recycle smaller plastics to reduce the need for production of new plastics.

Action for creating awareness

On April 11, 2013, in order to create awareness,

Italian Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance language *** Regional Ita ...

artist Maria Cristina Finucci founded The Garbage Patch State under the patronage of

UNESCO The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations (UN) aimed at promoting world peace and security through international cooperation in education, arts, sciences and culture. It ...

and the Italian Ministry of the Environment. The

U.S. Environmental Protection Agency The Environmental Protection Agency (EPA) is an Independent agencies of the United States government, independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon pro ...

(EPA) launched its "Trash-Free Waters" initiative in 2013 to prevent single-use plastic wastes from ending up in waterways and ultimately the ocean. EPA collaborates with the

United Nations Environment Programme The United Nations Environment Programme (UNEP) is responsible for coordinating responses to environmental issues within the United Nations system. It was established by Maurice Strong, its first director, after the United Nations Conference on th ...

–Caribbean Environment Programme (UNEP-CEP) and the

Peace Corps The Peace Corps is an independent agency and program of the United States government that trains and deploys volunteers to provide international development assistance. It was established in March 1961 by an executive order of President John F ...

to reduce and also remove trash in the

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

. EPA has also funded various projects in the

San Francisco Bay Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Go ...

including one that is aimed at reducing the use of single-use plastics such as disposable cups, spoons and straws, from three

University of California The University of California (UC) is a public land-grant research university system in the U.S. state of California. The system is composed of the campuses at Berkeley, Davis, Irvine, Los Angeles, Merced, Riverside, San Diego, San Franci ...

campuses. Additionally, there are many organizations advocating action to counter microplastics and that is spreading microplastic awareness. One such group is the Florida Microplastic Awareness Project (FMAP), a group of volunteers who search for microplastics in coastal water samples. There is also increased global advocacy aimed at achieving the target of the United Nations Sustainable Development Goal 14 which hopes to prevent and significantly reduce all forms of marine pollution by 2025.

Funding

The Clean Oceans Initiative is a project launched in 2018 by the public institutions

European Investment Bank The European Investment Bank (EIB) is the European Union's investment bank and is owned by the EU Member States. It is one of the largest supranational lenders in the world. The EIB finances and invests both through equity and debt solutions ...

Agence Française de Développement The French Development Agency (french: Agence française de développement, AFD) is a public financial institution that implements the policy defined by the French Government. It works to fight poverty and promote sustainable development. This pub ...

and

KfW Entwicklungsbank The KfW, which together with its subsidiaries DEG, KfW IPEX-Bank and FuB forms the KfW Bankengruppe ("banking group"), is a German state-owned investment and development bank, based in Frankfurt. As of 2014, it is the world's largest national d ...

. The goal of the organisations was to provide up to €2 billion in lending, grants and technical assistance until 2023 to develop projects that remove pollution from waterways (with a focus on macroplastics and microplastics) before it reaches the oceans. The effort focuses on initiatives that demonstrate efficient methods of minimising plastic waste and microplastics output, emphasising on riverine and coastal areas. In February 2022, the initiative stated that it would increase its financing aim to €4 billion by the end of 2025. At the same time, the

European Bank for Reconstruction and Development The European Bank for Reconstruction and Development (EBRD) is an international financial institution founded in 1991. As a multilateral developmental investment bank, the EBRD uses investment as a tool to build market economies. Initially focus ...

(EBRD) became the Clean Oceans Initiative's sixth member. By the beginning of 2022, more than 80% of this target has been achieved, with €1.6 billion being used in long-term financing for public and private sector initiatives that minimise the discharge of plastics, microplastics, and other pollutants through enhanced solid waste, wastewater, and storm water management.

Policy and legislation

With increasing awareness of the detrimental effects of microplastics on the environment, groups are now advocating for the removal and ban of microplastics from various products. One such campaign is "Beat the Microbead", which focuses on removing plastics from personal care products. The Adventurers and Scientists for Conservation run the Global Microplastics Initiative, a project to collect water samples to provide scientists with better data about microplastic dispersion in the environment.

has sponsored research and global assessment programs due to the trans-boundary issue that microplastic pollution constitutes.Morris and Chapman: "Marine Litter", "Green Facts: Facts on Health and the Environment", 2001–2015 These environmental groups will keep pressuring companies to remove plastics from their products in order to maintain healthy ecosystems.

China

China banned in 2018 the import of recyclables from other countries, forcing those other countries to re-examine their recycling schemes. The Yangtze River in China contributes 55% of all plastic waste going to the seas. Including microplastics, the

Yangtze The Yangtze or Yangzi ( or ; ) is the longest river in Asia, the third-longest in the world, and the longest in the world to flow entirely within one country. It rises at Jari Hill in the Tanggula Mountains (Tibetan Plateau) and flows ...

bears an average of 500,000 pieces of plastic per square kilometer.

Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it i ...

reported that China dumps 30% of all plastics in the ocean.

United States

In the US, some states have taken action to mitigate the negative environmental effects of microplastics. Illinois was the first US state to ban cosmetics containing microplastics. On the national level, the

Microbead-Free Waters Act 2015 The Microbead-Free Waters Act of 2015 is a United States law that prohibits the addition of plastic microbeads in the manufacturing of certain personal care products, such as toothpaste. The purpose of the law is to reduce water pollution caused by ...

was enacted after being signed by President

Barack Obama Barack Hussein Obama II ( ; born August 4, 1961) is an American politician who served as the 44th president of the United States from 2009 to 2017. A member of the Democratic Party, Obama was the first African-American president of the U ...

on December 28, 2015. The law bans "rinse-off" cosmetic products that perform an exfoliating function, such as toothpaste or face wash. It does not apply to other products such as household cleaners. The act took effect on July 1, 2017, with respect to manufacturing, and July 1, 2018, with respect to introduction or delivery for introduction into interstate commerce.United States. Microbead-Free Waters Act of 2015. . Approved 2015-12-28. On June 16, 2020, California adopted a definition of 'microplastics in drinking water', setting the foundation for a long-term approach to studying their contamination and human health effects. On July 25, 2018, a microplastic reduction amendment was passed by the U.S. House of Representatives. The legislation, as part of the Save Our Seas Act designed to combat marine pollution, aims to support the

NOAA The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...

's Marine Debris Program. In particular, the amendment is geared towards promoting NOAA's Great Lakes Land-Based Marine Debris Action Plan to increase testing, cleanup, and education around plastic pollution in the Great Lakes. President

Donald Trump Donald John Trump (born June 14, 1946) is an American politician, media personality, and businessman who served as the 45th president of the United States from 2017 to 2021. Trump graduated from the Wharton School of the University of Pe ...

signed the re-authorization and amendment bill into effect on October 11, 2018.

Japan

On June 15, 2018, the Japanese government passed a bill with the goal of reducing microplastic production and pollution, especially in aquatic environments. Proposed by the Environment Ministry and passed unanimously by the Upper House, this is also the first bill to pass in Japan that is specifically targeted at reducing microplastic production, specifically in the personal care industry with products such as face wash and toothpaste. This law is revised from previous legislation, which focused on removing plastic

marine debris Marine debris, also known as marine litter, is human-created waste that has deliberately or accidentally been released in a sea or ocean. Floating oceanic debris tends to accumulate at the center of gyres and on coastlines, frequently washing ...

. It also focuses on increasing education and public awareness surrounding recycling and plastic waste. The Environment Ministry has also proposed a number of recommendations for methods to monitor microplastic quantities in the ocean (Recommendations, 2018). However, the legislation does not specify any penalties for those who continue manufacturing products with microplastics.

European Union

The

European Commission The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body o ...

has noted the increased concern about the impact of microplastics on the environment. In April 2018, the European Commission's

Group of Chief Scientific Advisors The Scientific Advice Mechanism is a service created by the European Commission which provides independent science advice directly to European Commissioners to inform their decision-making. The Mechanism consists of two parts: the Group of Chief ...

commissioned a comprehensive review of the scientific evidence on microplastic pollution through the EU's

. The evidence review was conducted by a working group nominated by European academies and delivered in January 2019. A Scientific Opinion based on the SAPEA report was presented to the Commission in 2019, on the basis of which the commission will consider whether policy changes should be proposed at a European level to curb microplastic pollution. In January 2019, the European Chemicals Agency (ECHA) proposed to restrict intentionally added microplastics. The European Commission's Circular Economy Action Plan sets out mandatory requirements for the recycling and waste reduction of key products e.g. plastic packaging. The plan starts the process to restrict addition of microplastics in products. It mandates measures for capturing more microplastics at all stages of the lifecycle of a product. E.g. the plan would examine different policies which aim to reduce release of secondary microplastics from tires and textiles. The European Commission plans to update the

Urban Waste Water Treatment Directive The Urban Waste Water Treatment Directive 199191/271/EEC European Union directive concerning urban waste water "collection, treatment and discharge of urban waste water and the treatment and discharge of waste water from certain industrial sec ...

to further address microplastic waste and other pollution. They aim to protect the environment from industrial and urban waste water discharge. A revision to the EU Drinking Water Directive was provisionally approved to ensure microplastics are regularly monitored in drinking water. It would require countries must propose solutions if a problem is found.

United Kingdom

The Environmental Protection (Microbeads) (England) Regulations 2017 ban the production of any rinse-off personal care products (such as exfoliants) containing microbeads. This particular law denotes specific penalties when it is not obeyed. Those who do not comply are required to pay a fine. In the event that a fine is not paid, product manufacturers may receive a stop notice, which prevents the manufacturer from continuing production until they have followed regulation preventing the use of microbeads. Criminal proceedings may occur if the stop notice is ignored.

References

Sources

External links

NOAA Marine Debris Program
* {{Authority control Plastics and the environment Environmental impact of products Water pollution

Classification

Primary microplastics

Secondary microplastics

Other sources: as a by-product/dust emission during wear and tear

Nanoplastics

Sources

Car and truck tires

Clothing

Cosmetics industry

Fishing industry

Manufacturing

Packaging and shipping

Personal protective equipment

Face masks

Plastics

Bottled water

Baby bottles

Single-use plastic products

Sewage treatment plants

Effects on the environment

Biological integration into organisms

Humans

Persistent organic pollutants and Emerging organic contaminants

Where microplastics can be found

Air

Water

Oceans

Ice cores

Freshwater

Soil

Human body

Prevention

Treatment

Filtering

Collection devices

Education and recycling

Action for creating awareness

Funding

Policy and legislation

China

United States

Japan

European Union

United Kingdom

See also

References

Sources

External links