Tiny Particles, Big Problems: The Threat of Microplastics to Marine Life and Human Health

Abstract

Microplastics, primarily derived from plastic waste, are pervasive environmental pollutants found across aquatic and terrestrial ecosystems. This review investigates microplastics’ presence, distribution, and impacts in marine ecosystems, with a particular focus on fish species. Research indicates that microplastics are present in various anatomical parts of fish, including the gastrointestinal tracts and gills, with significant implications for marine biodiversity and human health through seafood consumption. The review also highlights the sources of microplastics, such as synthetic textiles, packaging, and personal care products, and explores the pathways through which these particles enter marine environments. Advanced detection techniques have identified microplastics in human tissues, underscoring the urgency of addressing this environmental threat. Comprehensive strategies are essential to mitigate microplastic pollution and protect both marine life and human health.

1. Introduction

Microplastics infiltrate water, air, and soil worldwide. Scientists have provided various insights into their harmful impacts, yet a clear understanding of the extent of their damage to human and animal health remains elusive [1,2]. Nonetheless, there is a consensus that microplastics significantly harm marine ecosystems and are recognised as hazardous pollutants [3]. The primary contributor to microplastic pollution in oceans is the fragmentation of plastic debris originating from waste that enters the ocean from various sources [4].

1.1. Sources of Microplastics

The world is full of plastics, which generate microplastics and nanoplates that are available everywhere, such as water, air, and soil. They have become significant environmental pollutants, posing risks to wildlife and human health. In the following, we will discuss the sources of microplastics and nanoplastics.

The release of tiny synthetic particles or fibres from clothing, textiles, or other synthetic materials into the environment is often very small and can easily become airborne or wash into water systems [5,6]. Similarly, plastic packaging in modern consumer goods contributes to microplastic pollution during both opening and disposal processes [7]. Personal care and cosmetic products, especially prevalent in densely populated urban areas, are also implicated as sources of environmental contamination by microplastics [8,9]. Also, the wear and tear of tyres release microplastics into the environment, a factor often overlooked but significant in exacerbating contamination [10]. Commercial fishing activities inadvertently generate microplastics through processes like netting and gear abrasion [11,12]. Even seemingly harmless items like toy building bricks can be unsuspected reservoirs of microplastics and nanoplastics, posing risks to children who are more susceptible to exposure [13]. Furthermore, industrial activities such as the deterioration of building materials [14] and the transformation of plastic furniture by fire contribute to microplastic and nanoplastic pollution [15]. Advancements in technology, such as Raman imaging, have facilitated the detection and characterisation of these tiny particles across various matrices, such as kitchen blenders [16], smartphones [17], printed toner powders [18], chopping boards [19], cut Polyvinyl Chloride (PVC) pipes [20], non-stick cookware [21], kitchen sponges [22], burned disposable gloves [23], PPE masks [24], rubber bands [25], and haemodialysis waters [26]. Recently, microplastics have also been found in bottled drinking water [27,28] as well as cookware [29]. Details are given in Figure 1.

1.2. Microplastics in Fish Species

Over the years, researchers have shown that microplastics are found in different fish species, and the details of this literature are discussed below.

In 2016, it was seen that Mussels from China’s coastline contained microplastics, with higher levels in wild mussels and those from areas with intensive human activities, primarily fibres and fragments, with a significant proportion smaller than 250 μm, suggesting that mussels could be used as a bio-indicator of microplastic pollution [30]. Also, microplastics were found in 77% of Japanese anchovy in Tokyo Bay, with an average of 2.3 pieces per fish, mostly polyethylene and polypropylene fragments, with some microbeads and a size range of 150 μm to 1000 μm, indicating that microplastics have penetrated the marine ecosystem [31].

In 2017, it was observed that adult grass shrimp exposed to microplastics of various sizes and shapes experienced acute toxicity, with mortality rates ranging from 0% to 55%, and that the shape and size of the particles significantly influenced ingestion and residence time in the gut and gills, with fibres causing significantly higher mortality [32]. Also, only 1 out of 400 North Sea fish (0.25%) had ingested microplastics, with two particles found in a single Sprat, and the particles were identified as polymethylmethacrylate [33]. Moreover, microplastics were found in the livers of the European anchovy, European pilchard, and Atlantic herring, with 80% of anchovy livers containing large microplastics (124–438 μm) [34].

In 2018, it was found that the windward beaches along Trindade Island’s eastern coast exhibited a notable concentration of debris, primarily consisting of small plastic fragments. Furthermore, this debris already engaged with the island’s wildlife, including seabirds and endangered land-dwelling crabs, adversely affecting these populations [35]. Later, microplastics and other debris were found in all seawater and mussel samples from U.K. coastal waters and supermarkets, with higher levels in pre-cooked supermarket mussels, presenting a route for human exposure [36]. Also, microplastics were found in various tissues of fish and a crustacean from five sites of the Musa Estuary and the Persian Gulf, with a total of 828 microplastics detected, mainly fibrous fragments of various colour and sizes, and some suspected to be paint fragments, raising concerns about the potential transfer of synthetic materials into humans [37]. Moreover, fish from the Persian Gulf contained microplastics and metals, with concentrations increasing with fish size [38]. In addition, microplastics were found in 26 individual fish from 26 species along the Saudi Arabian coast of the Red Sea. Most microplastics were films (61.5%) and fishing thread (38.5%), made of polypropylene and polyethylene [39]. Also, only 2.1% of 292 planktivorous fish (6 individuals) in the Southeastern Pacific coast had microplastics in their digestive tract. It was found that the microplastics were degraded fragments and threads, 1.1–4.9 mm long, and of various colours [40].

In 2019, it was observed that marine plastic litter posed a significant risk to the fin whale in the Mediterranean, with the highest risk of plastic ingestion in the Central Ligurian Sea, and all three sources of plastic litter contributing to impacting cetaceans in the Pelagos Sanctuary [41]. Also, 9 out of 11 marine fish species found in Seri Kembangan, Malaysia, contained plastic debris in their viscera and gills. Up to 76.8% of isolated particles were plastic polymers, with sizes ranging from 200 to 34,900 μm [42]. Moreover, it was seen that different fish species from Haizhou Bay, China, had microplastics in their tissues, where the microplastics were mostly fibres, black or grey, and made of cellophane. It was also observed that the skin and gills had more microplastics than the gut, and scaleless fish had higher microplastic abundances in their skin [43].

In 2020, it was observed that sea anemones, abundant along the Amazon coast, ingest meso- and microplastics, with 75.6% of the examined individuals containing plastic particles, primarily fibres (84%), followed by fragments and films, with a mean of 1.6 items per individual, and a weak positive correlation between anemone weight and plastic particles [44]. Also, microplastics were found in 12 fish species from the Beibu Gulf, with 0.027–1 item per individual, mostly transparent fibres, polyester, and nylon, with demersal fish having a higher microplastic abundance [45]. Additionally, microplastic contamination was found in the seawater and fish from Tuticorin, the southeastern coast of India, with epipelagic fish having higher levels; most microplastics were small blue fibres, with polyethylene being the most common type [46]. Moreover, microplastics were found in 49% of 150 fish from the Northeast Atlantic Ocean, and the estimated human intake through fish consumption ranged from 518 to 3078 microplastic items per year per capita [47]. Also, microplastic pollution was found in the Han River and its tributaries, with varying concentrations and types. Polyethylene, silicone, and polystyrene were most common in the river, while polytetrafluoroethylene, polyethylene, and polyester dominated in the tributaries. Microplastics were found in fish intestines and gills, but not flesh, with fragments being the most common form [48]. In addition, microplastics were found in brown shrimp and tiger shrimp from the Northern Bay of Bengal, Bangladesh. A total of 33 and 39 microplastic items were found, respectively, with an average of 3.40 and 3.87 items per gram of gastrointestinal tract. Filament and fibre shapes were most common, with black being the dominant colour [49]. Also, microplastics were present in the guts of rabbitfish (Siganus fuscescens) in coastal Philippines, with semi-synthetic microfibers (rayon) being dominant in sediment samples from Silliman Beach but absent in the fish guts [50].

In 2021, it was observed that Longnose stingrays in the Western Atlantic Ocean had ingested microplastics, with almost a third of the examined specimens containing microplastics in their stomach contents, primarily fibres (82%), blue in colour (47%), and made of polyethylene terephthalate (PET) (35%) [51]. Also, microplastics were found in the water, sediment, and marine organisms (shellfish and finfish) in the Sal Estuary, Goa, India, with high concentrations in finfish, as well as small-sized microplastics dominant in biota [52]. Moreover, 85.4% of commercial fish from the Bohai Sea had ingested microplastics, with an average of 2.14 items per individual, mostly fibrous and PET [53].

In 2022, it was observed that microplastic contamination was widespread in dolphinfish from the Eastern Pacific Ocean, averaging 9.3 pieces per individual, with the majority being polyester (46.8%) and polyethylene terephthalate (38.1%) [54]. Also, microplastics were found in 14 marine dried fish products from seven Asian countries, mostly fibres, with polyethylene, polyethylene terephthalate, and polystyrene being the main polymers, and the highest count was in Etrumeus micropus from Japan [55]. Moreover, microplastics were found in dried Bombay duck and ribbon fish from the Bay of Bengal, with higher levels in samples from Kuakata; fibres were the most common type, followed by fragments and other types, with polyethylene, polystyrene, and polyamide polymers identified [56]. Furthermore, microplastics were found in the water, sediment, and fish samples from Mumbai’s coastal waters, where fibres were the most common shape, and eleven types of plastic polymers were identified [57]. In addition, microplastics were found in 47.8% of 180 fish specimens from the Northern Adriatic Sea, with a total of 233 fragments identified. The mean concentration ranged from 1.75 to 4.11 items/individual across six species, and polyethylene and polypropylene microplastics were found, ranging in size from 0.054 to 0.765 mm [58]. Also, microplastics were found in the gills and guts of 26 fish species in Haizhou Bay and the adjacent waters, with blue fibre being the most common form [59].

In 2023, it was found that 30% of fish from 24 beaches in the Machado River, Western Brazilian Amazon, had microplastics in their digestive tracts, with 617 microplastics found; contamination was higher in fish from beaches closer to urban settlements, particularly carnivorous fish [60]. Also, microplastics were found in three fish species from the Bay of Bengal, with dried fish having significantly higher amounts than fresh fish; fibres were the most common type found, followed by fragments and other types, with most being small and red, and low-density polyethylene was the most common polymer [61]. Moreover, 35 freshwater fish species in India were analysed, and the highest abundance of microplastic contamination was found in Channa punctatus. Fiber-type microplastics were the most dominant, while polyethylene-type polymer microplastics were found mainly in edible tissue [62]. In addition, microplastics were found in fish species from the Pasig and Marikina Rivers in the Philippines, and polypropylene and polyethylene fragments were the most common microplastics identified [63]. Also, a separate research study observed that the Sundarbans mangrove forests in Bangladesh were highly contaminated with microplastics. It was noted that nine fish species had microplastics in their gastrointestinal tract and muscles, where most particles were smaller than 1 mm and black in colour, with polyamide being the most abundant polymer type [64].

1.3. Microplastics Detected in Different Regions and Different Fish Species

The infiltration of microplastics into marine habitats is a pervasive issue affecting a multitude of species. Research has identified their presence in the digestive systems of numerous marine organisms, spanning from the majestic whales to the humble yellow crabs and green turtles [35,41]. Among the affected species, the Longnose stingray, Cangicum anemone, shrimp, mussels, dolphin, various molluscs, and even Japanese anchovies have been found to ingest these harmful particles [30,31,32,36,44,51,52,54,65]. Notably, microplastics have also been detected in fish populations from diverse regions, such as the Beibu Gulf in the South China Sea, the Machado River in the Western Brazilian Amazon, and the Bohai Sea in China [45,53,60]. Furthermore, the global scope of this issue is evident in the presence of microplastics in dried marine fish sourced from different countries [55,56].

Table 1. List of regions and fish specifies where microplastics are detected.

Ref.	Region	Fish Species
[52]	Goa, India	Gray mullet, Catfish, Whipfin silver-biddy, Pearlspot
[37]	Persian Gulf	Mackerel, Longfin lizardfish, Barramundi, Tongue sole
[66]	Tyrrhenian Sea, Italy	Gray mullet, Annular seabream, Red mullet
[67]	Western Pacific Ocean	Highfin seabream, Flying gurnard
[61]	Bay of Bengal	Bombay duck, Ribbon fish, Hairfin anchovy
[46]	Tuticorin, India	Bombay duck, Goldspot herring, White sardine, Indian mackerel, Skipjack tuna, Sailfish
[47]	Northeast Atlantic Ocean	European seabass, Atlantic horse mackerel, Atlantic chub mackerel
[48]	Han River, South Korea	Carp, Crucian carp, Bluegill, Bass, Catfish, Snakehead
[57]	Mumbai coast, India	White sardine, Shrimp, Belanger croaker, Bombay duck, Malabar sole fish
[49]	Northern Bay of Bengal, Bangladesh	Brown shrimp, Tiger shrimp
[68]	South America	Brown hoplo
[62]	India	Spotted snakehead, Rohu, Bata labeo, Spotted mahseer, Amphibious barb
[63]	Pasig and Marikina Rivers, Philippines	Nile tilapia, Manila Sea catfish, Armored catfish
[58]	Adriatic Sea, Italy	European pilchard or sardine, European anchovy, European hake, Spotted flounder, Striped red mullet, Rock goby
[33]	North Sea, Netherlands	Atlantic herring, Sprat, Common dab, Whiting
[38]	Persian Gulf	Shrimp scad, Orange-spotted Grouper, Pickhandle barracuda, Bartail flathead
[64]	Mongla port, Bangladesh	Ilish, Bhetki, Poa, Tengra, Payra, Loitta, Chemo, Bele
[43,59]	Haizhou Bay, China	Kamala River sprat, Red-finned mudskipper, Half-smooth tongue sole, Blackbarred sandperch, Chinese silver pomfret
[50]	Central Philippines	Rabbitfish

provides a comprehensive overview of the fish species affected by microplastic contamination, emphasising the widespread nature of this environmental concern. These findings collectively highlight microplastic pollution’s global distribution and their impact on marine ecosystems.

1.4. Microplastics Detected in Different Body Parts of Fishes

Table 2. List of observed parts of fish, region of collection of fish, data analysis techniques, and name of the software used.

Ref.	Observed Parts	Region of Collection	Microscope	Data Analysis Approach and Software
[36]	Mussel tissues	United Kingdom	Olympus SZX10 (Tokyo, Japan)	Statistical
[54]	Gills, stomachs, intestinal tracts, and muscles	Eastern Pacific Ocean	Leica M205A, OPUS 7.8 (Wetzlar, Germany)	Statistical
[52]	Gastrointestinal tracts	Goa, west coast of India	AIM-3800, Olympus SX10	Statistical, PAST
[45]	Gastrointestinal tracts, and gills	Beibu Gulf, South China Sea	Olympus SZX10, Nicolet iN 10	Experimental
[53]	Gastrointestinal tracts	Bohai Sea, China	Olympus, SZX10, Nicolet™ iN10	Statistical, SPSS v. 20
[55]	Gastrointestinal tracts, muscles and gills	Taiwan, Thailand, Japan, China, South Korea, Vietnam, Sri Lanka	Olympus SZX16, JobinYvon LabRAM HR800	Statistical
[56]	-	Cox’s Bazar and Kuakata, Bay of Bengal, Bangladesh	Daffodil MCX100 (Gurgaon, India), Nicolet iS5 FT-IR (Green Bay, WI, USA)	Statistical, SPSS v. 22
[66]	Muscles and gills	Tyrrhenian sea, Italy	Nicolet™ iN10, Omnic™ Picta™	Statistical
[61]	Muscles and gills	Chattogram and Kuakata, Bay of Bengal, Bangladesh	Daffodil MCX100, Nicolet iS5 FT-IR	Statistical
[46]	Gastrointestinal tracts	Tuticorin, Southeast coast of India	Thermo Nicolet model iS5 (Waltham, MA, USA)	Statistical
[47]	Gastrointestinal tracts, muscles and gills	Northeast Atlantic Ocean	LEICA S9i	Statistical, SPSS v. 24
[48]	Gastrointestinal tract, gills, and fillets	Han River, South Korea	FTIR Microscope, NicoletTM iN10TM MX	Experimental
[57]	Gastrointestinal tracts	Mumbai coast, India	SZX16 Model	Statistical, SPSS v. 20
[49]	Gastrointestinal tracts	Northern Bay of Bengal, Bangladesh	XSZ-107BN, IR Affinity-1, Model-8900	Statistical, R software
[68]	Gastrointestinal tracts, and Stomachs	Pajeú river, Northeast of Brazil	dissecting microscope (45×)	Statistical, R v. 3.2.1
[62]	Gastrointestinal tracts, muscles and gills	Lucknow, Uttar Pradesh, India	Leica, EZ4, Witec Alpha 300RA	Statistical, GraphPad PRISM v. 8.4.0
[63]	-	Pasig River, Marikina River, Philippines	Olympus Microscope BX41, Origin-Prov2021	Experimental
[58]	-	Adriatic Sea	Nikon SMZ745T, LabSpec 6 (Tokyo, Japan )	Experimental
[42]	Viscera and gills	Malaysia	Motic SMZ-140 (Hong Kong), Horiba LabRam HR (Tokyo, Japan)	Statistical, SPSS v. 24
[33]	Digestive tract	Coasts of the Netherlands, Belgium, France and Great Britain	Scimitar 1000 FT-IR	Experimental
[38]	Muscles	Northeast of Persian Gulf, Iran	Inductively coupled plasma mass spectrometry	Statistical
[34]	Livers	Mediterranean Sea, Europe	Olympus Provis AX-70, LabRam 300	Experimental
[64]	Gastrointestinal tracts, and muscles	Pasur river, Mongla, Bangladesh	Motic B410E, Stemi 508	Statistical
[43]	Gut, skin and gills	Haizhou Bay, China	Nikon SMZ 1500N, Thermo Nicolet iN10 MX	Statistical, SPSS v. 23
[59]	Gills and guts	Haizhou Bay, China	Olympus SZX2-FOF	Statistical, SPSS v. 25
[39]	-	Saudi Arabian coast of the Red Sea	Stemi 2000 Zeiss (Oberkochen, Germany)	Statistical, RStudio v. 1.1.419
[40]	Digestive tract	Coasts of Panama, Colombia, Ecuador, Peru, and Chile	Agilent Handheld 4300 FTIR (Santa Clara, CA, USA)	Experimental
[69]	-	West coast of India	Olympus DSX 110, LUMOS II	Statistical, SPSS v. 22

illustrates the various research endeavours focusing on marine fish species, detailing the anatomical regions examined for microplastic presence, the geographical origins of the specimens, and the data analysis methodologies employed. The investigations predominantly prioritise the gastrointestinal tracts and gills of fish, with statistical analysis emerging as most commonly utilised approach by researchers.

Different types of plastic polymers have been found in different fish species, and their percentage presence in fish species is shown in

Table 3. Percentage of different types of polymers found in fish species.

	References
Types of Polymers (Microplastics)	[54]	[45]	[53]	[55]	[61]	[46]	[63]	[43]	[39]	[69]
PE	0.7	6	0.5	36	38	54	30.95	13	42	33
PET	38.1	0	16.9	26	0	0	2.38	4.5	0	4
PS	5	0	0.4	18	22	7	2.38	0	4	14.5
PVC	0	0	0	12	16	0	0	0	8	11.5
PP	7.9	6	2.5	8	0	7	57.14	15	42	21.5
PES	46.8	44	0	0	0	14	0	0	0	0
PMMA	0	6	0	0	0	3	0	0	0	0
PA	0	38	0.4	0	13	15	0	8	0	0
EVA	0	0	0	0	9	0	0	0	0	0
Polyethylene-polypropylene copolymer	1.4	0	0	0	0	0	7.14	0	0	0
PAN	0	0	0.9	0	0	0	0	0	4	0
PVAc	0	0	0.5	0	0	0	0	0	0	0
PB	0	0	0.2	0	0	0	0	0	0	0
PC	0	0	0.2	0	0	0	0	0	0	6.5
PMMA	0	0	0	0	0	0	0	0	0	4
PVA	0	0	0	0	0	0	0	0	0	5
Unidentified	0.1	0	0	0	2	0	0.01	19.5	0	0
Non-plastic particles	0	0	0	0	0	0	0	6.5	0	0
CP	0	0	77.5	0	0	0	0	33.5	0	0

. PE, PET, PS, PP, and PES are observed to be the most detected polymers in fish species. Additionally, CP is not a plastic polymer but a natural polymer, which is also highly found in fish species.

1.5. Microplastics in Human Body

Humans are exposed to microplastics through various sources, including air, water, food, and soil. In particular, fish is a significant component of the human diet, and the presence of microplastics in fish means that humans are indirectly exposed to microplastic pollution. In 2024, researchers have discovered that these microplastics are potentially associated with cardiovascular diseases [70] and have identified microplastics in different types of human arteries [71]. Researchers have also uncovered tiny plastic particles, including microplastics, within bodily fluids [72]. Laser direct infrared spectroscopy has enabled scientists to detect and measure microplastics in tissues like the endometrium [73], gallstones [74], placenta [75], and even in the amniotic fluid of preterm births [76]. Furthermore, microplastics have been found in human urine and kidney tissue [77,78], lower limb joints [79], vitreous humor [80], and lung tissue [81]. Advanced detection methods have revealed microplastics in the testes and semen [82,83], and even blood [84] itself. Even samples of human stool [85], and from patients undergoing heart surgery [86], have shown traces of microplastics. Details are presented in

Table 4. Presence of microplastics in human organs, fluids, and waste products.

Ref.	Sample Type	Detection Method	Type of Microplastics	Average Concentrations
[71]	Arteries	Pyrolysis–Gas Chromatography–Mass Spectrometry	PET (73.70%), PA-66 (15.54%), PVC (9.69%), PE (1.07%)	118.66 ± 53.87 μg/g tissue
[72]	Bodily fluids	Raman Microspectroscopy	PP (13.04%), PS (43.48%), PTFE (4.35%), PVB (8.70%), PA-6 (8.70%), LDPE (8.70%), PEAA (4.35%), PSAN (4.35%), PVA (4.35%)	-
[73]	Endometrium	Laser Direct Infrared Spectroscopy	EAA (34.58%), FR (14.87%), CPE (11.47%), PE (9.95%), ACR (7.76%), PET (6.63%), PP (6.68%), PS (0.85%), PVC (0.98%), EVA (0.41%), PU (2.09%), BR (2.61%)	0 to 117 particles/100 mg
[74]	Gallstones	Pyrolysis–Gas Chromatography–Mass Spectrometry and Laser Direct Infrared Spectroscopy	PS, PE, PP, PET, EVA	-
[75]	Placenta	Laser Direct Infrared Spectroscopy	PVC (43.27%), PP (14.55%), PBS (10.90%), PET (7.27%), PC (6.91%), PS (5.82%), PA (5.45%), polyester fibre (2.91%), PE (1.45%), PAM (0.73%), PSF (0.73%)	2.70 ± 2.65 particles/g
[78]	Urine	Micro-Fourier Transform Infrared Spectroscopy	Healthy donors: PE (27%), PS (16%), PP (12%), Endometriosis participants: PTFE (59%), PE (16%)	-
[79]	Lower limb joints	Micro-Fourier Transform Infrared Spectroscopy	PET (27.1%), PE (21.9%), RA (12.0%), PES (11.1%), PP (9.3%), PA (8.5%), PVC (4.7%), PS (4.4%), PC (2.0%)	5.24 ± 2.07 particles/g
[80]	Vitreous humor	Pyrolysis–Gas Chromatography–Mass Spectrometry and Laser Direct Infrared Spectroscopy	PA (74.8%), PVC (7.3%)	-
[81]	Lung tissue	Micro-Fourier Transform Infrared Spectroscopy	PP (23%), PET (18%), RA (15%), PE (10%), PTFE (10%), PS (8%), PAN (2%), PES (2%), PMMA (3%), PUR (3%)	1.42 ± 1.50 MP/g of tissue
[82]	Testes and semen	Pyrolysis–gas Chromatography–Mass Spectrometry	Semen: PVC (25%), PE (25%), PA (17%), PS (13%), PP (13%), PET (7%) Testis: PS (67.7%), PVC (12.9%), PE (12.9%), PP (6.5%)	Semen: 0.23 ± 0.45 particles/mL, Testis: 11.60 ± 15.52 particles/g
[84]	Blood	Pyrolysis–gas Chromatography–Mass Spectrometry	PE, PS, PET, PMMA	1.6 µg/mL
[85]	Stool	Fourier-Transform Infrared Microspectroscopy	PP (62.8%), PET (17.0%), PS (11.2%), PE (4.8%), PVC (0.54%), PU (0.40%), PA (0.54%), PC (0.67%)	-

.

2. Conclusions and Future Outlook

Microplastic pollution in marine environments represents a significant and growing environmental challenge with extensive implications for marine biodiversity, ecosystem functionality, and human health. This review has underscored the ubiquity of microplastics in marine ecosystems, tracing their origins to various sources such as synthetic textiles, packaging, and personal care products. Once introduced into the environment, these microplastics infiltrate marine food webs, impacting a wide array of marine organisms, particularly fish.

The ingestion of microplastics by fish has been well documented, with particles being found in their gastrointestinal tracts, gills, and other tissues. These ingested microplastics can cause physical harm, such as blockages and injuries, as well as physiological stress, including reduced feeding, impaired growth, and reproductive issues. Furthermore, microplastics can act as vectors for harmful chemicals and pathogens, exacerbating their detrimental effects on marine life. Human exposure to microplastics primarily occurs through the consumption of seafood. The detection of microplastics in human tissues and their potential link to health issues such as inflammation, cellular damage, and endocrine disruption raises significant concerns. Despite the advancements in detection techniques and growing evidence of the adverse effects, the complete extent of microplastic pollution’s impact on human health remains underexplored. Comprehensive and long-term studies are essential to mitigate microplastic pollution’s impacts. Future research should focus on the chronic effects of microplastic exposure on marine organisms and the subsequent implications for human health. Such studies should consider various species, developmental stages, and environmental conditions to provide a holistic understanding.

Furthermore, identifying and quantifying the primary sources and pathways through which microplastics enter marine environments is crucial for developing targeted mitigation strategies. Enhanced detection methods and data collection and analysis standardisation are necessary to accurately assess microplastic concentrations across different matrices and studies. Innovation in material science to develop biodegradable alternatives to conventional plastics can offer a sustainable solution to reducing plastic pollution. However, understanding these alternatives’ degradation process and environmental impact is vital for ensuring their effectiveness. The development of effective policies and regulations is critical to addressing the issue of microplastic pollution. Interdisciplinary research that integrates environmental science, public health, and policy studies can inform the creation of regulations to reduce plastic production and improve waste management practices. Evaluating the effectiveness of existing policies will also be beneficial in shaping future interventions.

Public awareness and education play a pivotal role in combating microplastic pollution. Educating communities about the sources, impacts, and mitigation strategies can foster behavioural changes that reduce plastic waste. Innovative and effective educational campaigns can engage the public in environmental stewardship. Therefore, addressing the complex issue of microplastic pollution requires a multifaceted approach involving comprehensive research, innovative solutions, effective policies, and public engagement. By advancing our understanding and implementing targeted actions, we can protect marine ecosystems and safeguard human health from the pervasive threat of microplastics.