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Microplastic fragments and microbeads in digestive tracts of planktivorous fish from urban coastal waters


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We investigated microplastics in the digestive tracts of 64 Japanese anchovy (Engraulis japonicus) sampled in Tokyo Bay. Plastic was detected in 49 out of 64 fish (77%), with 2.3 pieces on average and up to 15 pieces per individual. All of the plastics were identified by Fourier transform infrared spectroscopy. Most were polyethylene (52.0%) or polypropylene (43.3%). Most of the plastics were fragments (86.0%), but 7.3% were beads, some of which were microbeads, similar to those found in facial cleansers. Eighty percent of the plastics ranged in size from 150 μm to 1000 μm, smaller than the reported size range of floating microplastics on the sea surface, possibly because the subsurface foraging behavior of the anchovy reflected the different size distribution of plastics between surface waters and subsurface waters. Engraulis spp. are important food for many humans and other organisms around the world. Our observations further confirm that microplastics have infiltrated the marine ecosystem, and that humans may be exposed to them. Because microplastics retain hazardous chemicals, increase in fish chemical exposure by the ingested plastics is of concern. Such exposure should be studied and compared with that in the natural diet.
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Scientific RepoRts | 6:34351 | DOI: 10.1038/srep34351
Microplastic fragments and
microbeads in digestive tracts
of planktivorous sh from urban
coastal waters
Kosuke Tanaka & Hideshige Takada
We investigated microplastics in the digestive tracts of 64 Japanese anchovy (Engraulis japonicus)
sampled in Tokyo Bay. Plastic was detected in 49 out of 64 sh (77%), with 2.3 pieces on average and up
to 15 pieces per individual. All of the plastics were identied by Fourier transform infrared spectroscopy.
Most were polyethylene (52.0%) or polypropylene (43.3%). Most of the plastics were fragments (86.0%),
but 7.3% were beads, some of which were microbeads, similar to those found in facial cleansers. Eighty
percent of the plastics ranged in size from 150 μm to 1000 μm, smaller than the reported size range
of oating microplastics on the sea surface, possibly because the subsurface foraging behavior of the
anchovy reected the dierent size distribution of plastics between surface waters and subsurface
waters. Engraulis spp. are important food for many humans and other organisms around the world. Our
observations further conrm that microplastics have inltrated the marine ecosystem, and that humans
may be exposed to them. Because microplastics retain hazardous chemicals, increase in sh chemical
exposure by the ingested plastics is of concern. Such exposure should be studied and compared with
that in the natural diet.
e plastic use continues to increase worldwide, and some waste plastics are released into the oceans1,2. Plastic
debris is ubiquitous in the oceans around the world; it is estimated that at least 5.25 × 1012 plastic particles weigh-
ing 2.7 × 105 t are currently oating at sea3. In particular, microplastics (dened as plastics < 5 mm4) are the most
common size fraction in seawater3,5,6. ey are divided into primary and secondary microplastics by their sources.
Primary microplastics are plastic particles originally manufactured at those sizes. Secondary microplastics are
fragments generated by the breakdown of larger pieces. Fragmentation of plastics at sea occurs through photo-
degradation, physical impacts, and other processes, and results in the generation of a larger number of smaller
particles2. Most microplastics in the marine environment are secondary3,7,8.
To the best of our knowledge, this is the rst report that chemically identied microbeads, which are one of
the major primary microplastics, in sh. Microbeads are spherical or amorphous particles used in personal care
and cosmetic products9. ey are made most commonly of polyethylene (PE), followed by nylon, polypropylene
(PP), poly(methyl methacrylate) (PMMA), and poly(ethylene terephthalate) (PET)10. Microbeads are discarded
down the drain and carried to sewage treatment plants (STPs). Although they are eciently removed by settling
during treatment, a small but signicant proportion is discharged in nal euent11. In addition, combined sewer
overows introduce microbeads into receiving waters. Aer their discharge, microbeads stay in water bodies for
a long time because of their non-biodegradable nature. Microbeads have been reported in surface waters12,13. e
other primary microplastics include plastic resin pellets, industrial scrubbers, and plastic powder. e pellets are
feedstock for consumer products, and are generally cylindrical or disk-shaped14. Industrial scrubbers include
synthetic ‘sandblasting’ media made from polymers such as acrylic, polystyrene, melamine, and polyester15.
Marine plastics aect a wide range of species, from invertebrates to seabirds and whales16. Microplastics are
bioavailable to many species16, and are easily ingested by planktivorous or smaller organisms17. Physical impacts
such as injury or clogging of the digestive tract18 and impairment of feeding capacity have been observed19.
Moreover, because microplastics contain hazardous chemicals sorbed from seawater as well as retained addi-
tives20, their toxicological impacts are of concern. An increasing number of reports document the ingestion of
Laboratory of Organic Geochemistry, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509,
Japan. Correspondence and requests for materials should be addressed to H.T. (email:
Received: 15 March 2016
Accepted: 13 September 2016
Published: 30 September 2016
Scientific RepoRts | 6:34351 | DOI: 10.1038/srep34351
plastics, including microplastics, by sh species21–26. However, only a few studies22,25,26 reported polymer types.
is information is essential to assessing the risks of chemicals associated with ingested plastics, because the com-
position and magnitude of the chemicals vary among polymer types; for example, PE absorbs more hydrophobic
chemicals, such as polychlorinated biphenyls (PCBs), than other polymers20. In addition, specic additives are
compounded into specic polymers; for example, phthalates in PVC or hexabromocyclododecane (HBCDD) in
polystyrene27,28. e identication of polymer types is important also to identifying the sources of microplastics,
as are detailed observations of shape and size; for example, microbeads are made mostly of PE, and some of
them are spherical. In particular, the discrimination between primary and secondary microplastics is essential
for source control. We investigated the plastics in Japanese anchovy (Engraulis japonicus) caught in Tokyo Bay,
o the Tokyo metropolitan area (Fig.1). e population in the drainage basin is 29 million, which accounts
for one-fourth of the total population of Japan29. Tokyo Bay receives river water, sewage, industrial wastewater,
and surface runo from the city. We assumed that domestic and industrial activities are important sources of
microplastics in Tokyo Bay. Sewage from a large proportion of the population in the catchment is treated by com-
bined sewer systems, so untreated wastewater is occasionally discharged into the bay during heavy rain.
Plastics in sh. We found plastics in the digestive tracts of 49 of the 64 anchovies (77%). Each sh had an
average of 2.3 (± 2.5) pieces of ingested microplastic, and from 0 to 15 pieces of debris. All of the plastics were
photographed (Supplementary Table S1) and identied by FT-IR (Fig.2). Among all 150 pieces found, there were
129 fragments (86.0%), 11 beads (7.3%), 8 laments (5.3%), and 2 foams (1.3%) (Table1, Fig.3a). e beads
comprised 6 spherical PE beads, 1 granular PE bead (an aggregation of 1 large sphere and some small spheres),
Figure 1. Sampling location in Tokyo Bay. Sixty-four Japanese anchovy (Engraulis japonicus) were caught
on 23 August 2015. Map created using QGIS47 and data provided by the Geospatial Information Authority of
Figure 2. Spectra of FT-IR analysis and photographs of plastic fragments. All suspected plastics were
identied by FT-IR and photographed. Two examples are shown.
Scientific RepoRts | 6:34351 | DOI: 10.1038/srep34351
2 granular PP beads (shaped like a bunch of grapes), and 2 spherical white PS beads (Fig.4). e longest length of
the pieces ranged from 150 to 6830 μ m (average 783 μ m ± 1020) (Fig.5), and the width ranged from 68 to 1880 μ m
(average 345 μ m ± 272). e plastics consisted primarily of PE (52.0%) and PP (43.3%), followed by PS (2.0%),
ethylene/propylene copolymer (2.0%), and ethylene/propylene/diene terpolymer (0.7%) (Fig.3b). Most plastics
were white (40.0%) or transparent (31.0%), with a lower presence of green (12.3%), yellow and yellowed (12.3%),
black (2.6%), brown (1.3%), and pink (0.6%).
Microbeads in personal care products. We investigated plastic particles in four brands of facial cleansers
(labeled M1, M2, R1, S1) manufactured by three companies. All four products contained plastic particles, iden-
tied by FT-IR as PE, as stated in the list of ingredients. e size of all microbeads ranged from around 10 μ m
to 500 μ m. M2 and S1 contained spherical microbeads of PE, with average diameters of 314 ± 120 μ m (M2) and
188 ± 80 μ m (S1). M1, M2, and R1 contained amorphous particles (irregular shapes, including thread-like) of
PE, with average lengths of 247 ± 96 μ m (M1), 295 ± 54 μ m (M2), and 117 ± 58 μ m (R1) (Fig.6). e spherical
microbeads in M2 were blue and transparent, and those in S1 were transparent. All of the amorphous particles
were transparent or white.
e frequency of occurrence of plastics in the digestive tract of Japanese anchovy, at 77%, is one of the highest
recorded in shes22,24. Most of the ingested plastics were fragments, followed by beads and laments derived from
shing gear, and most were PE or PP (Table1, Fig.3). is proportion of plastics is consistent with those in previ-
ous studies of plastic debris in surface seawater, which were dominated by fragments3,7,8 and by PE or PP7,30,31. e
fragments have various surface features, such as sharp edges with cracks, rounded shapes with smooth surfaces,
or degraded rough surfaces (Supplementary Table S1). Although we couldn’t identify the sources of the frag-
ments, their appearance may relate to their origin or history of degradation in the environment. Further study for
their source identication is needed. Among the major polymers, only PE and PP are less dense than seawater,
and therefore they predominate in surface water2. Japanese anchovy are known to stay in pelagic shallow water
at around 10 m depth32, and thus the proportion of ingested plastics reects that of the water. e predominance
of fragments has been also observed in sh from the North Pacic Central Gyre21 and in sh at a market in
Indonesia24. On the other hand, bers accounted for 68.3% of plastics in sh from the English Channel, which
were identied as rayon, polyamide, or polyester22. Fibers were also predominant in sh from the USA24. is
dierence may be due to regional source dierences or feeding habits of sh species; further studies are needed.
To the best of our knowledge, our study provides the rst evidence of the ingestion of microbeads, suspected of
being derived from personal care products, by sh. Beads accounted for 7.3% of the plastics in the anchovies, and
most were PE (Table1, Fig.4). ese articial shapes strongly indicate that they are manufactured as micro-sized
products. Over 90% of products with microbeads list polyethylene in the ingredients, and the others include PP
(calculated from lists provided by Beat the Microbead10). Our results conrm the presence of PE particles in four
brands of facial cleansers popular on the Japanese market, and spherical microbeads in two of them (Fig.6). e
spherical PE beads detected in the sh were similar in size and appearance to those in the facial cleansers (Figs4
and 6). One of PE beads in the anchovy was shaped like a single large sphere aggregated with some small spheres
Fragment Bead Filament Foam T OTA L
PE 70 7 1 78
PP 54 2 7 2 65
PS 1 2 3
Others 4 4
TOTAL 129 11 8 2 150
Table 1. Total number of plastic pieces in the digestive tract of Japanese anchovy (Engraulis japonicus) by
shape and polymer. PE, polyethylene; PP, polypropylene; E/P, ethylene/propylene copolymer; PS, polystyrene.
“Others” include ethylene/propylene copolymer and ethylene/propylene/diene terpolymer.
Figure 3. Types of plastics recovered from digestive tracts of Japanese anchovy (Engraulis japonicus).
(a) Percentage by shape. (b) Percentage by polymer.
Scientific RepoRts | 6:34351 | DOI: 10.1038/srep34351
(Fig.4e). Because it was reported that some facial cleansers contain granular PE microbeads as well as spherical
ones33, the non-spherical PE bead in the anchovy is likely to be originated from such granular microbeads in the
personal care products. Both PP beads we found in anchovy were granular and were shaped like a bunch of grapes
(Fig.4j,k), and may also be derived from personal care products. However, personal care products that contain
PP beads are uncommon on the Japanese market based on our survey. It is also reported that only a few percent of
products contains PP beads while PE accounts for > 90 percent on the world market10. e detection frequency of
PP beads relative to PE beads seems higher than expected from the current market share, so PP beads in the sh
may be derived from other sources. Finally, the white polystyrene beads that we found accorded with the shape
and size of pre-expanded polystyrene beads, which are spherical and measure 0.1 to 2 mm34.
Eriksen et al.12 found many multi-colored spherical polymers of < 1 mm in surface waters of the Laurentian
Great Lakes of North America12. Mani et al.13 detected opaque spherules identied as PE on the surface of the
Rhine River13. ese studies identied them as microbeads used in consumer products such as facial cleans-
ers12,13. Some studies found spherical microplastics in some organisms, such as in commercial bivalves from
China35 and in zooplankton samples from the English Channel36, but the polymer types were not reported. It is
Figure 4. Photographs of microbeads ingested by Japanese anchovy (Engraulis japonicus). Scale bar
represents 500 μ m. All photographs were taken in reected light, but in the case of d, only photographs taken
with transmitted light are available.
Figure 5. Size distribution of plastics in Japanese anchovy (Engraulis japonicus).
Scientific RepoRts | 6:34351 | DOI: 10.1038/srep34351
dicult to discuss sources without information on polymer types, because there are other sources of spherical
microplastics than personal care products, as indicated by the presence of many non-PE spherical beads (such as
acrylic, polyurethane, and polyester copolymers) on the sea surface in a South Korean bay37.
Microbeads in personal care and cosmetic products are discarded down the drain aer use and go through
several treatment processes. Although 95% to 99.9% of them are removed by settling at STPs, the remainder are
discharged with euent and end up in the aquatic havitats11. More importantly, combined sewer overows can
brings large amounts of untreated wastewater containing microbeads to coastal waters; in Tokyo, about half of
the population in the catchment (29 million) is served by combined sewer systems38. When heavy rain (gener-
ally > 5 mm) falls, sewer overows occur and could ush microbeads out. On the basis of the capacity of STPs
and precipitation patterns in Tokyo, overows occur around 50 times a year39, implying that ~7% ([50 days/365
days] × 0.5) of microbeads used in the catchment are discharged into aquatic environments without settling dur-
ing treatment.
We found spherical microbeads in sh stomachs. As we could not distinguish amorphous microbeads (Fig.6)
from degraded microplastic fragments, the “fragments” may include amorphous microbeads, and the distribution
of microbeads may be underestimated.
e size distribution of microplastics in the anchovies was dierent from those reported in surface seawaters
around Japan6. Over 80% was < 1000 μ m and more than half was < 500 μ m in size (Fig.5), although anchovy
can ingest prey from several tens of μ m40 to > 5 mm (such as zooplankton we found in the gut of some shes).
In the surface waters around Japan, however, microplastics (< 5 mm) larger than 1 mm dominate smaller ones,
which account for around 20% of all microplastics, and the size distribution peaked around 1 mm6. Although
the number of smaller microplastics in seawater samples is underestimated owing to sampling bias due to net
size (350-μ m mesh), the dierence in the size distribution of microplastics between the anchovies and surface
seawaters is clear only in the comparison of microplastics of > 400 μ m. is dierence is probably due to the
feeding characteristics of Japanese anchovy, which are pelagic lter feeders and ingest suspended particles in
subsurface waters. Because smaller plastic particles have lower rise velocities, smaller plastics (0.5–1.0 mm) were
more abundant in subsurface water than in surface water in the North Atlantic Gyre5. If the same vertical prole
of microplastics occurs in Tokyo Bay and smaller plastics are more abundant than larger plastics in the subsurface
water, by feeding in subsurface water the anchovies could accumulate smaller microplastics in their digestive
tract. More studies are necessary to understand the vertical proles of microplastics of various size ranges.
Japanese anchovy is widely distributed around Japan and is a common food in Japan. It is one of the most
caught fish species in Japan41, and is typically eaten without removal of the digestive tract. Nine species of
Engraulis are distributed in coastal waters around the world and are ecologically important because of their huge
Figure 6. Photographs of polyethylene microbeads in four brands of facial cleansers. (a) Brand M1,
irregular shapes. (b) Brand M2, blue and transparent spheres and irregular shapes. (c) Brand R1, irregular
shapes. (d) Brand S1, transparent spheres.
Scientific RepoRts | 6:34351 | DOI: 10.1038/srep34351
biomass and their central role in the diet of many sh, birds, and marine mammals42. Our observations further
conrm that microplastics have inltrated marine ecosystems globally, and humans are now exposed to them,
although plastics within the observed size range (0.2–5 mm) would be excreted if we ate contaminated anchovies.
But plastics in the marine environment contain various hazardous chemicals, both additives compounded during
manufacture and hydrophobic chemicals adsorbed from seawater20. e ingestion of microplastics by anchovies
may increase the body burden of the hazardous chemicals to both anchovies and humans. Regarding chemicals
sorbed to microplastics, their transfer and accumulation in sh tissue upon ingestion were demonstrated by labo-
ratory exposure experiments43,44. On the other hand, anchovies and humans are exposed to hazardous chemicals
through natural prey, too. e low number of microplastics that we found in the anchovies (~2 pieces per sh on
average) suggests that chemical exposure through the ingested microplastics is minor compared with that from
the natural diet. However, inputs of plastics into the oceans and number of ingested plastics in sh will continue to
increase if no action is taken, and exposure of additive-derived chemicals may become more important in future.
Once plastics are discharged into the marine environment, they are dicult to recover, especially if they are
small. erefore, reducing the amount discharged from land to the oceans is the rst priority. To the best of
our knowledge, this is the rst study to identify and conrm microbeads in sh by examining polymer types
and shapes. e USA and some other countries now regulate microbeads from rinse-o personal care products.
Japanese cosmetics companies have just started voluntary elimination of microbeads from their products. While
laudable, it is important to note that these regulations do not cover all products containing microbeads and other
forms of microplastics. Global controls on microbeads should be considered, with restrictions on a wider range of
products. More importantly, however, plastic fragments should be regulated with rst priority, because a majority
of the microplastics in the sh were fragments. For the eective regulation, identication of the origins or origi-
nal products of individual fragments are necessary. eir appearance (shape) and color can be connected to the
original products, though both, especially the former, are altered by photo-oxidation. Identication of additive
chemicals specic to specic original products or their usage may help source identication. Control of plastic
products which can be easily fragmented is important to solving pollution of the marine environment by plastics.
Sampling and processing. e Japanese anchovy (Engraulis japonicus) were caught by shing using Sabiki
rigs from a pier in Tokyo Bay (35°25 43 N 139°41 15 E) (Fig.1) from 07:00 to 14:00 on 23 August 2015. e
depth of the water there was around 15 to 20 m, and the sh were caught at a range of 5 to 10 m from the surface.
We collected 64 anchovy. e sh were put in iced water and dissected at the laboratory the same day. Aer
measurement of their body length (112.5 mm ± 6.4 mm), we removed the whole of the digestive tract (from top
of the esophagus to the anus) and put it into a 10-mL glass vial that had been baked for 4 h at 550 °C in advance.
Each vial then received 7–8 mL (> 3× the volume of the gut) of 10% KOH solution to digest organic material23,24.
e vials were incubated at 40 °C for 10 days, during which digestion was observed to be completed in 3 to 4
days. Each vial was then shaken around 20 times to break up the mass of indigestible materials such as shells of
zooplankton, and all oating material was collected in another vial. Pieces larger than 200 μ m were clearly visible.
e precipitate that remained in the vial was put on a glass Petri dish and examined under a microscope, but no
particles not resembling natural prey were observed. Because our target sh (anchovy) is commonly caught by
recreational-shing and eaten by people and our procedure of shing and dissection is exactly same as what peo-
ple sh and cook it by, our procedure has no ethical problem. Our procedure of measurement of microplastics in
the digestive tract does not conict with ethical rules for animal experiment of our university.
Classication and identication of plastics. All oating items suspected to be plastic polymers were
photographed individually (Supplementary Table S1), and the color and shape were recorded. e denition of
the shape of microplastics is as follows: fragments: particles produced by fragmentation of larger materials, beads:
particles manufactured as micro-sized products, either spherical or an aggregate of spheres, pellets: granules
manufactured as a raw material of larger plastic products, generally in the size range of 2–5 mm with shape of a
cylinder or a disk, foams: foams made from polymer, lms: so fragments of thin polymers derived from plastic
bags or wrapping paper and so on, sheets: hard fragments of thin polymers, laments: thread-like polymers pro-
duced by fragmentation of ropes or lines used in shing, > 50 μ m, and bers: thread-like polymers derived from
textiles, including clothing and furnishings, 50 μ m. e 50-μ m threshold for bers was chosen because typical
textile bers have a diameter of 10 to 20 μ m (up to 50 μ m)45, and the diameter of monolaments used in shing
ropes or lines is larger than several hundred μ m46.
We analyzed all of the pieces of suspected plastic (n = 173) by Fourier transform infrared (FT-IR) spectroscopy
(Nicolet iS10, ermo Scientic) to identify polymer types. e IR absorbance from 450 to 4000 cm1 was compared
with spectra in the soware database, with a similarity threshold of > 70%. Twelve particles were identied as having
a natural origin, 11 could not be identied, and the others (i.e., 150 pieces) were identied as synthetic polymers.
To avoid contamination, we kept samples sealed in a vial or Petri dish at all times except when picking out the
suspected plastics. A procedural blank analysis found no plastics. To estimate airborne contamination, we put
Petri dishes (total 17 000 mm2) on a table near the work bench for 1 day to collect airborne particles. We collected
3 polymer bers (PET, polyamide [similarity < 70%], and polyolen [similarity < 70%]), and more than 10 cot-
ton or wood bers, but no other bers. is means that procedural contamination did not signicantly aect the
results in the present study.
Microbeads in personal care and cosmetic products. We examined plastics in personal care products
to determine the features of the plastic beads used in them. We bought four major brands of facial cleansers that
listed polyethylene as an ingredient. ey were labeled M1, M2, R1, and S1. We mixed several grams of product
in distilled water and identied oating solid particles by FT-IR.
Scientific RepoRts | 6:34351 | DOI: 10.1038/srep34351
1. Jambec, J. . et al. Plastic waste inputs from land into the ocean. Science 347, 768–771 (2015).
2. Andrady, A. L. Microplastics in the marine environment. Mar. Pollut. Bull. 62, 1596–1605 (2011).
3. Erisen, M. et al. Plastic Pollution in the World’s Oceans: More than 5 Trillion Plastic Pieces Weighing over 250 000 Tons Aoat at
Sea. PLoS ONE 9, e111913 (2014).
4. GESAMP. Sources, fate and eects of microplastics in the marine environment: a global assessment. Vol. ep. Stud. GESAMP No. 90
(ed. ershaw, P. J.) 14 (IMO/FAO/UNESCO-IO C/UNIDO/WMO/IAEA/UN/UNEP/UNDP Joint Group of Experts on the Scientic
Aspects of Marine Environmental Protection, 2015).
5. eisser, J. et al. e vertical distribution of buoyant plastics at sea: an observational study in the North Atlantic Gyre. Biogeosciences
12, 1249–1256 (2015).
6. Isobe, A., Uchida, ., Toai, T. & Iwasai, S. East Asian seas: A hot spot of pelagic microplastics. Mar. Pollut. Bull. 101, 618–623
7. eisser, J. et al. Marine Plastic Pollution in Waters around Australia: Characteristics, Concentrations, and Pathways. PLoS ONE 8,
e80466 (2013).
8. Cozar, A. et al. Plastic debris in the open ocean. Proc. Natl. Acad. Sci. USA 111, 10239–10244 (2014).
9. UNEP in Plastic in cosmetics. Are we polluting the environment through our personal care? 10–15 (UNEP, 2015).
10. Beat the Microbead. Product lists (2015) Available at: http://w (Accessed: 19th December 2015).
11. ochman, C. M. et al. Scientic Evidence Supports a Ban on Microbeads. Environ. Sci. Technol. 49, 10759–10761 (2015).
12. Erisen, M. et al. Microplastic pollution in the surface waters of the Laurentian Great Laes. Mar. Pollut. Bull. 77, 177–182 (2013).
13. Mani, T., Hau, A., Walter, U. & Burhardt-Holm, P. Microplastics prole along the hine iver. Sci. ep. 5, 17988 (2015).
14. Hesett, M. et al. Measurement of persistent organic pollutants (POPs) in plastic resin pellets from remote islands: Toward
establishment of bacground concentrations for International Pellet Watch. Mar. Pollut. Bull. 64, 445–448 (2012).
15. Gregory, M. . Plastic ‘scrubbers’ in hand cleansers: a further (and minor) source for marine pollution identied. Mar. Pollut. Bull.
32, 867–871 (1996).
16. ühn, S., Bravo ebolledo, E. & van Franeer, J. In Marine Anthropogenic Litter (eds Bergmann, Melanie, Gutow, Lars & lages,
Michael) Ch. 4, 75–116 (Springer International Publishing, 2015).
17. Lusher, A. In Marine Anthropogenic Litter (eds Bergmann, Melanie, Gutow, Lars & lages, Michael) Ch. 10, 245–307 (Springer
International Publishing, 2015).
18. Wright, S. L., ompson, . C. & Galloway, T. S. e physical impacts of microplastics on marine organisms: a review. Environ.
Pollut. 178, 483–492 (2013).
19. Cole, M., Lindeque, P., Fileman, E., Halsband, C. & Galloway, T. S. e Impact of Polystyrene Microplastics on Feeding, Function
and Fecundity in the Marine Copepod Calanus helgolandicus. Env iron. Sci. Technol. 49, 1130–1137 (2015).
20. Teuten, E. L. et al. Transport and release of chemicals from plastics to the environment and to wildlife. Philos. T  Soc. B. 364,
2027–2045 (2009).
21. Boerger, C. M., Lattin, G. L., Moore, S. L. & Moore, C. J. Plastic ingestion by plantivorous shes in the North Pacic Central Gyre.
Mar. Pollut. Bull. 60, 2275–2278 (2010).
22. Lusher, A. L., McHugh, M. & ompson, . C. Occurrence of microplastics in the gastrointestinal tract of pelagic and demersal sh
from the English Channel. Mar. Pollut. Bull. 67, 94–99 (2013).
23. Foeema, E. M. et al. Plastic in North Sea Fish. Environ. Sci. Technol. 47, 8818–8824 (2013).
24. ochman, C. M. et al. Anthropogenic debris in seafood: Plastic debris and bers from textiles in sh and bivalves sold for human
consumption. Sci. ep. 5, 14340 (2015).
25. Avio, C. G., Gorbi, S. & egoli, F. Experimental development of a new protocol for extraction and characterization of microplastics
in sh tissues: First observations in commercial species from Adriatic Sea. Mar. Environ. es. 111, 18–26 (2015).
26. ummel, C. D. et al. Plastic ingestion by pelagic and demersal sh from the North Sea and Baltic Sea. Mar. Pollut. Bull. 102, 134–141
27. amrin, M. A. Phthalate riss, phthalate regulation, and public health: a review. J. Toxicol. Env. Heal. B 12, 157–174 (2009).
28. Alaee, M. Arias, P. Sjödin, A. & Bergman, Å. An overview of commercially used brominated ame retardants, their applications,
their use patterns in dierent countries/regions and possible modes of release. Environ. Int. 29, 683–689 (2003).
29. anto egional Development Bureau, Ministry of Land, Infrastructure, Transport and Tourism. Plan for restoration of water
environment in Toyo Bay (2006) Available at: http://www.i/chiii00000044.html (Accessed: 2nd January 2016).
30. Hidalgo-uz, V., Gutow, L., ompson, . C. & iel, M. Microplastics in the Marine Environment: A eview of the Methods Used
for Identication and Quantication. Environ. Sci. Technol. 46, 3060–3075 (2012).
31. Isobe, A. et al. Selective transport of microplastics and mesoplastics by driing in coastal waters. Mar. Pollut. Bull. 89, 324–330
32. Inoue, M. & Ogura, M., e swiming-water depth for Anchovy shoals in Toyo Bay (in Japanese). B. JPN. SOC. SCI. FISH. 24 (1958).
33. Fendall, L. S. & Sewell, M. A. Contributing to marine pollution by washing your face: Microplastics in facial cleansers. Mar. Poll ut.
Bull. 58, 1225–1228 (2009).
34. lodt, .-D. & Gougeon, B. In Modern Styrenic Polymers: Polystyrenes and Styrenic Copolymers (ed Scheirs, J. & Priddy, D. B.)
163–201 (John Wiley & Sons, Ltd, 2003).
35. Li, J., Yang, D., Li, L., Jabeen, . & Shi, H. Microplastics in commercial bivalves from China. Env iron. Pollut. 207, 190–195 (2015).
36. Cole, M. et al. Isolation of microplastics in biota-rich seawater samples and marine organisms. Sci. ep. 4, 4528 (2014).
37. Song, Y., Hong, S., Jang, M., Han, G. & Shim, W. Occurrence and Distribution of Microplastics in the Sea Surface Microlayer in
Jinhae Bay, S outh orea. Arch. Environ. Contam. Toxicol. 69, 279–287 (2015).
38. Japan Sewage Wors Association. Sewage wors statistics (in Japanese) (Japan Sewage Wors Association, 2013).
39. Mizuawa, . & Taada, H. In Chemistry of environmental pollution (in Japanese) 9–11 (Maruzen, 2015).
40. Yoshida, M., Ieuchi, H., Sugino, . & amizono, M. Food habits of Japanese Anchovy in the coastal area of the Chiuzen Sea. Bull.
Fuuoa. Fisheries. Mar. Technol. es. cent. 9, 19–24 (1999).
41. Ministry of Agriculture, Forestry and Fisheries. Statistical Yearboo (2015) Available at:ei/iau/
nenji_e/nenji_index.html (Accessed: 2nd January 2016).
42. Cury, P. et al. Small pelagics in upwelling systems: patterns of interaction and structural changes in “wasp-waist” ecosystems. ICES
J. Mar. Sci. 57, 603–618 (2000).
43. Wardrop, P. et al. Chemical Pollutants Sorbed to Ingested Microbeads from Personal Care Products Accumulate in Fish. Environ.
Sci. Technol. 50, 4037–4044 (2016).
44. ochman, C., Hoh, H., urobe, T. & Teh, S. Ingested plastic transfers hazardous chemicals to sh and induces hepatic stress. Sci. ep.
3, 3263 (2013).
45. Sinclair, . In Textiles and Fashion (ed Sinclair, .) 3–27 (Woo dhead Publishing, 2015).
46. Chattopadhyay, . In Technical Textile Yarns (eds Alagirusamy, . & Das, A.) 3–55 (Woodhead Publishing, 2010).
47. QGIS. Development Team. QGIS Geographic Information System (2013) Available at: (Accessed: 10th January
48. Geospatial Information Authority of Japan. Global Map Japan version 2.1 (2015) Available at:anyochiri/
gm_japan_e.html (Accessed: 10th January 2016).
Scientific RepoRts | 6:34351 | DOI: 10.1038/srep34351
We are grateful to Dr. Hiroaki Furumai for providing information on the population served by combined
sewer systems and Dr. Satoshi Nakaba for providing microscope. We thank Dr. John Farrington for invaluable
comments on the manuscript. e present study was supported by a Grant-in-Aid from the Ministry of Education
and Culture of Japan (Projects No. 26-8120 and No. 26550038) and the Environment Research and Technology
Development Fund (project no. 4-1502).
Author Contributions
K.T. designed the study, conducted the eld sampling and experimental work and wrote the paper. H.T. advised
on experimental design, provided laboratory facilities (FT-IR) and supervised the paper.
Additional Information
Supplementary information accompanies this paper at
Competing nancial interests: e authors declare no competing nancial interests.
How to cite this article: Tanaka, K. and Takada, H. Microplastic fragments and microbeads in digestive tracts of
planktivorous sh from urban coastal waters. Sci. Rep. 6, 34351; doi: 10.1038/srep34351 (2016).
is work is licensed under a Creative Commons Attribution 4.0 International License. e images
or other third party material in this article are included in the article’s Creative Commons license,
unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license,
users will need to obtain permission from the license holder to reproduce the material. To view a copy of this
license, visit
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Supplementary resource (1)

... However, since this method proved plastic being ingested was a relevant issue in the fish local to Kanagawa Prefecture consumers, it allowed me to move forward to a more advanced method. This provided a better representation of the microplastics in each fish (18). ...
... KOH dissolves organic material (GI) while leaving the plastic in the solution. After reading about KOH, I decided to seek inspiration from Tanaka and Takada's method (18). First, I dissected fish by cutting from anus to mouth, following CLEAR's method. ...
Up to 12.7 million tonnes of plastic is estimated to be polluting oceans. Ranking as the fifth-highest plastic using country, Japan has an exceptionally high usage of single wrapped items. Additionally, as an island-nation, fish is vital to everyday life, making up approximately 40% of protein in Japanese diets. Based on these observations, I wondered how the overuse of plastic in Japan poses an ecological risk to marine species and their consumers local to Kanagawa Prefecture. To answer this question, I completed a plastic audit at a convenience store, took qualitative observations of plastic waste at three waterways, and dissected locally sourced fish to characterize ingested plastic. I found 83.4% of the convenience store’s items within the recorded sections had plastic wrapping or pieces. Additionally, each waterway observed had both plastic and marine species present. Using visual and chemical dissection, all fish had microplastics present in their gastrointestinal tract, including two species that are typically eaten whole in Japan. Out of the fourteen microplastics found through the chemical digestion method, six were classified as plastic microfibers, four were likely thread plastic, three were see-through pieces of plastic film, and one was a foam pellet. Overall, these results are concerning as previous studies have found that microplastics can carry persistent organic pollutants. Both bioaccumulation and biomagnification result in large levels of contaminants building up at the top of the food chain. It is presumed that the increasing consumption of microplastics will have negative implications on organ systems such as the liver, gut, and hormones.
... The color of microplastics in this study was based on the ISCC-NBS basic color designation system recommended by GESAMP (2019). Meanwhile, the type/morphology of microplastic was identified based on Tanaka and Takada (2016) with several modifications to the following characteristics: (1) Pellets are microplastic granules that are round or cylindrical in shape; ...
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This is the first study to examine the presence and physicochemical properties of microplastics in mullets (Mugil cephalus) from four coastal areas in East Java, Indonesia. Three locations on the north coast are affected by two largest rivers, Bengawan Solo River and Brantas River, whereas one location in the south coast is slightly impacted by river flow. The abundance, color, shape, and size were examined in the gills, stomach, and intestines of fish samples. The average abundance of microplastics was 10.87 particles/individual in gills, 7.43 particles/individual in stomach, and 4.35 particles/individual in intestines. Black (72.4%) and pellets (62.7%) were the most abundant microplastics found. Most of them are in size of less than 100 μm (71.0%). Microplastics type of polymer was identified with Fourier transform infrared spectroscopy, while the chemical compounds including additives such as plasticizers contained in MPs samples were analyzed using gas chromatography-mass spectrometry. Seven different types of polymers were identified, including polyethylene, polyurethane, polyethylene terephthalate, polypropylene, polyvinyl chloride, polystyrene, and polycarbonate. Cyclohexadiene, one of the plasticizers detected, has the highest concentration of 81.82%.
... About 90% of the microbeads used in personal care products are made of polyethylene; but polypropylene and polystyrene are also being used 25 . It was proven that these microbeads from personal care products are rinsed off during usage and end up in drainage systems and then to wastewater treatment systems where it will pass through and find its way to ingestion by animals and human 26 . ...
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Microplastic pollution in different environmental matrices is a serious concern in the recent times. Personal care products and washing of synthetic fabrics are some of the main sources of microplastic pollution. In this work, a novel simplified, effective and sustainable method for extraction of microplastic particles from face scrub and laundry wastewater was developed. Different parameters affecting the extraction were analysed and the extraction process was optimised. The extraction efficiency of the proposed method was found to be ~ 94.1 ± 1.65%, which was slightly better than the previously available method with an advantage of ease in extraction and lesser time and resource consuming. The developed method was used to demonstrate the extraction of microplastic particles from 12 face scrub samples with different brands. It was found that the samples contained microplastic particles of varying size. The physical and chemical structure intactness of microplastic particles during the extraction was also analysed and found to be acceptable. The developed extraction method was also applied for the extraction of microfibers from the laundry wastewater. It was found that this proposed method is suitable to make the cleaner extracted samples for an easy and more effective qualitative and quantitative analysis of MPs.
... Kibria (2022) reviewed and compiled a global list of fish species contaminated with MPs, which shows that 07 fish species from Japan were contaminated with MPs. Out of 07 species, the following commercial fish species were contaminated with MPs: Chub mackerel, Scomber japonicus (1.5 MPs/fish; 52.5 % of fish ingested MPs) (Yagi et al., 2022); Japanese anchovy, Engraulis japonicus (2.3 MPs/fish; 77 % of fish ingested MPs) (Tanaka and Takada, 2016); Japanese jack mackerel, Trachurus japonicus (1.3 MPs/fish; 30.1 % of fish ingested MPs) (Yagi et al., 2022); John dory, Zeus faber (1.17 MPs/fish; 16.17 % of fish ingested MPs) (Yagi et al., 2022); Long spine snipefish, Macroramphosus scolopax (1.0 MPs/fish; 7.7 % of fish ingested MPs) (Yagi et al., 2022); Whitefin trevally, Carangoides equula (1.0 MPs/ fish; 13.7 % of fish ingested MPs) (Yagi et al., 2022) and Yellowback Seabream, Dentex tumifrons (1.0 MPs/fish; 6.7 % of fish ingested MPs) (Yagi et al., 2022). The MPs contamination of commercial fish varies between 6.7 % and 77 % indicating low to medium MP ingestion occurred in fish. ...
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Although investigation of microplastics (MPs) present in air environment has been intensively carried out, quantification, characteristics, and distribution of MPs released from the waste burning furnace (WBF) has been missing in literature. The aim of this study was to characterize the presence of MPs released from WBFs and analyze their associated health impacts. The examined locations were at two WBFs (nominated as TPS1 and TPS2) in Sidoarjo, Indonesia. MPs were collected using a 9 cm diameter glass beaker for a period of 8 h at two different sampling points, which are 3 and 15 m from each WBF. Several characteristics of MPs in terms of the number of particles, size, shape, color, and polymer type were comprehensively characterized. This study found that the obtained MPs were of fiber type and in the range of 46–77 and 41–59 particles at TPS1 and TPS2, respectively. In general, the polymer types of MPs were, respectively, cellophane and polytetrafluoroethylene at TPS1 and TPS2. Moreover, it was estimated that about 1.9–2.3 MPs can enter the human body via inhalation. This study offers a pilot examination of MPs released from WBF and findings from this study are crucial to provide new knowledge as a basis to carefully regulate the use of WBF particularly that are located closely to local community.
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Fish feed is becoming an increasingly vital source of nourishment for farmed fish, which are mainly coming from marine fish and agricultural sources. Anthropogenic particles, such as microplastics, are abundant in both marine fish and agricultural byproducts that are utilized to make fish feed. This study investigated whether fish feed could be a source of microplastic contamination, and revealed that a 20 weeks adult farmed tilapia fish might consume up to 268.45±1.438 microplastic particles via fish feed where finisher type feeds were found to be mostly contributory in this number. The microplastics were initially observed with a stereomicroscope and FESEM-EDS. Polymeric composition of microplastics was determined to be polypropylene (PP), nylon-6 (NY-6), polyethylene terephthalate (PET), polystyrene (PS), polyvinyl alcohol (PVA), polyethylene (PE), high-and low-density polyethylene (HDPE, LDPE), ethylene vinyl acetate (EVA), polycarbonate (PC), poly vinyl acetate (PVAc), poly urethane (PU) and polyvinyl chloride (PVC) by FTIR. Results also revealed that the size of microplastic particles in all fish feed ranged from 14 µm to 4480 µm, with 550±45.45 to 11600±56.1 microplastic particles/kg of fish feed. The FESEM-EDS data demonstrated to overlook the microplastic surface along with attachment of heavy metals onto that surface such as Pb, Ni, and Co in finisher type feed that could create additional health risks.
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