Microplastics drifting through rivers, lakes, and oceans constantly release a complex blend of dissolved organic chemicals into the waters and sunlight exacerbate the deleterious impact on aquatic ecosystem and ultimately it encroaches the food chain. Have a glimpse into the far-reaching consequences ensuing from microplastics on human health &environment.
In the current era of technology and sophistication, the excessive and indiscriminate use of plastics and their irresponsible disposal, which contaminates the environment, is ubiquitous. The microplastics contaminate both the land or terrestrial ecosystem as well as the waters. The aquatic environment is under the threat of chemical contamination and its detrimental impact is inflicted up on the living organisms.
What are microplastics?
Microplastics are tiny plastic fragments (under 5mm) either broken-down from larger plastics or intentionally manufactured sources (like microbeads), They are scattered everywhere and contaminate oceans, water, food, and air. This article by dr sanjana chronicles the impact of microplastics on the aquatic and marine ecosystems as well as on human health.
The term “microplastics” was first introduced in 2004 by Professor Richard Thompson, a marine biologist.
Microplastics pose mammoth threats to the environment and health as they can enter the food chain and potentially trigger inflammation within cells and damage organs.
The existence of microplastics in the environment is often established through aquatic studies. Researches point out that the recent decades have witnessed a surge in the quantity of microplastics in aquatic ecosystems.
How do microplastics enter the ecosystem?
Microplastics enter the natural ecosystems primarily from a variety of sources, including cosmetics, chemicals, industrial and construction wastes, fabrics and food packaging. Various types of Paints are the largest source of microplastic leakage into the ocean and waterways.
Secondary microplastics arise from the degradation of larger plastic products through natural weathering processes after entering the aquatic environment.
Water bottles, soda bottles, fishing nets, plastic bags, microwave containers, tea bags and tire wear top the list of plastics entering the ecosystems.
It is a significant concern that the cosmetic industry contributes microplastics, which can inadvertently enter both the human body and aquatic environments. The scrubbers used in exfoliating, hand cleansers and facial scrubs, have now replaced traditionally used natural ingredients, including ground almond shells, oatmeal, and pumice. Instead microbeads, a form of microplastics are added into them which enter the skin as well as draining water while pedicures, manicure and facials procedures are done.
Microplastics from primary and secondary sources contaminate aquatic and marine environment. Approximately 35% of all ocean microplastics come from textiles or clothing, primarily due to the erosion of polyester, acrylic, or nylon-based clothing, often during the washing process.
Recreational and commercial fishing, marine vessels, and marine industries are all sources of plastic that can directly enter the marine environment. Fishing gear is a form of plastic debris with a marine source of deposition in aquatic system. Discarded or lost fishing gear can drift a long distance and depth in oceanic waters.
Microplastics also exist in drinking water from various sources, bottled water, seafood, salt, sugar, tea bags, milk, and in many other substances entering the food chain. They are linked with countless, profound impacts on the ecosystem and biodiversity.
Impact of microplastics on aquatic life & agriculture
A study shows that 65 million microplastics are released into water sources every day. In 2017, more than eight million tons of plastics entered the oceans, greater than 33 times as much as that of the total plastics accumulated in the oceans by 2015.
The devastating impact on marine as well as terrestrial ecosystems is that microplastics are consumed by organisms living in the ocean including the reefs and other marine organisms and eventually it spreads to food chain and then to terrestrial and atmospheric ecosystems.
Plastic bottles and caps that are used in bottled water have been confirmed as sources of microplastics in drinking-water.
Materials containing polyvinyl chloride (PVC), polycarbonate, polypropylene, and acrylic, can degrade overtime releasing microplastics
Microplastics may also have been widely distributed in soil, especially in agricultural systems through water draining the area and through direct dumping. They can get into the water transport system of plants, and then move to the roots, stems, leaves, and fruits. Once microplastics enter agricultural systems through sewage sludge, compost, and plastic mulching, they will cause food pollution.
Under the influence of sunlight, wind, waves and other factors, plastic degrades into small fragments known as microplastics, or even nanoplastics.
Nanoplastics are believed to be a risk to environmental and human health owing to their small size. They can cross cellular membranes and affect the functioning of cells. Nanoplastics are lipophilic and studies show that polyethylene nanoplastics can be incorporated into the hydrophobic core of lipid bilayers of the cell membranes.
According to a study Nano plastics may cross the epithelial membrane of fish accumulating in various organs including the gallbladder, pancreas, and the brain. Nanoplastics are believed to cause interruptions in bone cell activities, causing improper bone formation.
Sunlight augments fragmentation process to form microplastics
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.
The smallest microplastic reportedly detected in the oceans in 2017 was 1.6 micrometres in diameter. It is an alarming news that microplastics have a high probability of ingestion and accumulation in the cells and tissues of living organisms. The toxic chemicals of aquatic and marine ecosystem leaks into the food chain eventually.
A study shows that microplastic-derived dissolved organic matter (MPs-DOM) in natural surface waters, differ from those of natural organic matter (NOM).
The new findings provide the most comprehensive molecular-level data so far of how microplastic-derived dissolved organic matter [ MPs DOM] forms and changes in natural aquatic environments.
The research, published in the journal New Contaminants, examined four common types of plastic and compared the chemicals they released with naturally occurring dissolved organic matter found in rivers.
By combining kinetic modelling with fluorescence spectroscopy, high-resolution mass spectrometry, and infrared analysis, the research team showed that each plastic type releases its own unique chemical mixture.
Detailed chemical analyses showed that MPs DOM contains a wide range of molecules derived from plastic additives, monomers, oligomers, and fragments formed through photo oxidized reactions. Plastics with aromatic structures, such as PET and PBAT, generated especially complex chemical mixtures.
Impact of microplastics on human health
Micro and nano plastics can cause adverse health impacts on the human body, including physical stress and damage, apoptosis, necrosis, inflammation, oxidative stress and immune responses. All these processes ultimately lead to organ damage.
Microplastic pollution has been linked with respiratory diseases and inflammation, however, the causative role is still unclear. Microplastics accumulate in the brain, mainly polyethylenes and cause cellular damage to neuronal tissues
Microplastics often contain chemical additives like phthalates and bisphenol A (BPA), which are known endocrine-disrupting chemicals. Simply, these are chemical compounds which can disrupt the hormonal rhythm of human body.
Microplastics can disrupt the hypothalamic-pituitary-gonadal (HPG) axis, and lead to reproductive health impairment and infertility.
According to a study conducted by Harvard, microplastics have been linked to inflammation, cell death, lung and liver effects, changes in the gut microbiome, and altered lipid and hormone metabolism.
In a nut shell, the inflammatiory impact of microplastics has been proved beyond any doubts by a large number of research studies conducted worldwide.
A recent study unfolds the fact that exposure to microplastics can alter gene expression, potentially leading to vascular disease and long-lasting conditions.
The environmental risks from microplastics
The chemical compounds released by microplastics can affect aquatic ecosystems in a myriad ways. The microplastic-derived dissolved organic matter [MPs DOM ] is composed of small, biologically accessible molecules that may stimulate or suppress microbial growth, disrupt nutrient cycles, or interact with metals and other pollutants.
A few studies suggests that MPs DOM can produce reactive oxygen species. The reactive oxygen species influence the formation of disinfection byproducts, and alter how pollutants attach to particles in water.
Marine biologists in 2017 discovered that three-quarters of the underwater seagrass 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 epibionts (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… [and] only the second discovery of microplastics on marine plant life anywhere in the world.
A study published in 2023 shows that microplastic exposure led to cognitive impairment in hermit crabs, which could potentially impact their survivability.
It is an alarming fact that plastics can cause impaired cognition in animals. Further extensive studies are to be conducted in this regard as the impact on flora and fauna affect human beings also in the shortest interval as the living organisms are connected through food chains.
As MPs DOM is chemically complex and constantly changing, the researchers suggest that machine learning tools could help forecast how these substances behave in natural waters. Such models could improve risk assessments related to ecosystem health, pollutant transport, and carbon cycling.
The unregulated flow of microplastics into rivers and oceans is a dreadful scenario that demands immediate attention from environmentalists and the legal systems regulating international waters and pollution.
As plastics continue to fragment and degrade under sunlight, the release of MPs DOM is expected to increase overtime causing more grave consequences on all the ecosystems.
Fragmentation of plastics and their long-term environmental impact is still not fully understood. Therefore, vigilance and alertness is necessary in the disposal of plastics into the environment.
In the future, the dynamic derivation of MPs-DOM can be further studied using artificial intelligence techniques, such as machine learning, to support a comprehensive assessment of its environmental implications.
How to reduce microplastics in your environment?
- Choose natural fabrics over synthetics.
- Wash synthetic clothes less often and use cold water.
- Filter your water.
- Reduce overall plastic consumption.
- Avoid negligent plastic dumping
- Keep the aquatic ecosystem clean removing plastics
- promote booklet and banners cautioning against disposing fabrics, organic matter, plastics etc. in rivers and oceans as part of religious rituals and festivities
- Conserve water and protect rivers and oceans against pollution.
- Regulate sewage and industrial waste disposal into marine environment and aquatic ecosystems.
I conclude this article with a note that existence of mankind and biosphere is solely dependent on ecosystems. Love your ecosystems and preserve them with your ingenious wisdom and unity in decision making for posterity as well as for their existing life forms.
written by dr sanjana p
Reference for further reading
- Molecular-level insights into derivation dynamics of microplastic-derived dissolved organic matter.
- https://www.maxapress.com/article/doi/10.48130/newcontam-0025-0016
- https://med.stanford.edu/news/insights/2025/01/microplastics-in-body-polluted-tiny-plastic-fragments.html Microplastics and our health: What the science says
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