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A field survey to collect microplastics with sizes < 5 mm was conducted in the Southern Ocean in 2016. We performed five net-tows and collected 44 pieces of plastic. Total particle counts of the entire water column, which is free of vertical mixing, were computed using the surface concentration (particle count per unit seawater volume) of microplastics, wind speed, and significant wave height during the observation period. Total particle counts at two stations near Antarctica were estimated to be in the order of 100,000 pieces km− 2.
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Microplastics in the Southern Ocean
Atsuhiko Isobe
, Kaori Uchiyama-Matsumoto
, Keiichi Uchida
, Tadashi Tokai
Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8580, Japan
Observation and Research Center for Ocean Systems, Tokyo University of Marine Science and Technology,4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
abstractarticle info
Article history:
Received 29 May 2016
Received in revised form 15 September 2016
Accepted 19 September 2016
Available online 26 September 2016
Aeld survey to collect microplastics with sizes b5 mm was conducted in the Southern Ocean in 2016. We per-
formed ve net-tows and collected 44 pieces of plastic. Total particle counts of the entire water column, which is
free of vertical mixing,were computed using the surfaceconcentration (particle count per unit seawater volume)
of microplastics, wind speed, andsignicant wave height during the observation period. Total particle counts at
two stations near Antarctica wereestimated to be in the order of 100,000 pieces km
© 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license
Total particle count
Mismanaged plastic waste can escape into the natural environment,
particularly in regions with high population density (Jambeck et al.,
2015). Numerous plastic fragments are typically found in the oceans
of the Northern Hemisphere in areas where plastic debris has degraded
on beaches (Andrady, 2011). A number of recent studies have reported
the collection of tiny plastic fragments with diameters of b5 mm (re-
ferred to as microplastics) in open oceans, including the Arctic polar wa-
ters (Thompson et al., 2004; Goldstein et al., 2012; Cózar et al., 2014;
Eriksen et al., 2014; Reisser et al., 2015; Lusher et al., 2015), marginal
seas (de Lucia et al., 2014; Isobe et al., 2015), and coastal waters
(Isobe et al., 2014). Table 1 summarizes the concentrations (particle
count per unit seawater volume) of pelagic microplastics reported in
the Northern Hemisphere. Importantly, microplastics can act as a trans-
port vector of chemical pollutants into the marine ecosystem, owing to
the absorption of pollutants onto their surfaces (Mato et al., 2001;
Teuten et al., 2009), and their subsequent ingestion by organisms as
small as zooplankton (Desforges et al., 2015). If the discharge of pelagic
microplastics into the oceans continues, such pollution will be unavoid-
able in the future.
Based on the synthesis of the results of several Southern Hemisphere
surveys, it has been suggested that pelagic microplastics are less wide-
spread in the Southern oceanic regions, compared with the oceans of
the Northern Hemisphere (see Fig. S5 in Cózar et al. (2014)). This may
indicate that microplastics have not yet spread across the oceans of
the Southern Hemisphere. However, there have been few comprehen-
sive surveys of the distribution of microplastics in the Southern Hemi-
sphere (Fig. S1 in Cózar et al. (2014)), and previous ndings are
inconclusive. In particular, it is currently unclear whether pelagic
microplastics can be detected in the Southern Ocean (also known as
the Antarctic Ocean); a marine area with the lowest population in the
world, where minimal mismanagement of plastic is likely to occur. Ob-
servations of a signicant concentrationof microplastics inthe Southern
Ocean would suggest that pelagic microplastics have already spread
across the world's oceans. Global plastic production has increased by
N500 times over the last 60 years (Thompson et al., 2009). However,
microplastic surveys in the Southern Ocean have not been reported in
peer-reviewed publications, except for a small number of surveys con-
ducted in the Drake Passage close to South America (unpublished, but
data were used in Cózar et al. (2014) and Eriksen et al. (2014)).
In the present study, we conducted microplastic surveys in the
Southern Ocean from January 30 to February 4, 2016, at ve stations
along a route from Fremantle to Hobart, Australia, using a T/V
Umitaka-maru belonging to Tokyo University of Marine Science and
Technology (Fig. 1). Wind speed and signicant wave height were mea-
sured on thevessel, and hourly averaged data were recorded during the
surveys (Fig. 2). These data were used to deduce the vertical distribution
of microplastics for comparison with data collected in other oceans
under different wind and wave conditions. A Neuston net (5552; RIGO
Co., Ltd., Tokyo, Japan) was used for sampling the small plastic frag-
ments. The mouth, length, and mesh size of the net were 75 × 75 cm,
3 m, and 0.35 mm, respectively. The T/V Umitaka-maru towed the Neus-
ton net around each station continuously for 2040 min at a constant
speed of 23 knots. To avoid collecting plastic fragments originating
from the ship, the net was positioned at a distance of approximately
Marine Pollution Bulletin 114 (2017) 623626
Corresponding author at: Research Institute for Applied Mechanics, Kyushu
University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan.
E-mail addresses: (A. Isobe),
(K. Uchiyama-Matsumoto), (K. Uchida),
(T. Tokai).
0025-326X/© 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (
Contents lists available at ScienceDirect
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2 m during the towing, and thereafter was rinsed on the deck by
pouring seawater from the outside of the net. A ow meter (5571A;
RIGO Co., Ltd.) was installed at the net mouth. Once the surveys were
completed, the ow-meter readings and net mouth dimensions (75 ×
75 cm) were used to estimate the volume of water ltered during
each tow.
The seawater samples, including the suspended matter, were sent to
Kyushu University for the extraction of plastic fragments. The small
plastic fragments were rst observed using a monitor display via a
USB camera (HDCE-20C; AS ONE Corporation, Osaka, Japan) attached
to a stereoscopic microscope (SZX7; Olympus Corporation, Tokyo,
Japan) and identied visually by their colour and shape. Polymer types
were identied using a Fourier transform infrared spectrophotometer
(FT-IR alpha; Bruker Optics K.K., Tokyo, Japan) when the fragments
were too small for visual differentiation between microplastics and bio-
logical matter. Expanded-polystyrene particles (three particles were de-
tected), bers (a single piece), and biological elements were all
removed before any further analyses. Primary microplastics suchas pel-
lets were not detected in the present surveys.
The numbers of plastic fragments in each size range were counted
with an increment of 0.1 mm for microplastics b5 mm and 1 mm for
mesoplastics N5 mm. The sizes were dened by the longest length of
each irregularly shaped fragment visible on the monitor display, mea-
sured using image-processing software (ImageJ; downloaded from numbers within each size range were there-
after divided by the water volumes measured by the ow meter at each
sampling station to convert them to a measure of concentration in units
of the number of pieces m
Direct comparison of microplastic concentrations observed in differ-
ent ocean areas under different wave and wind conditions can be dif-
cult because light-weight microplastics are vulnerable to vertical
mixing caused by oceanic turbulence, and because the vertical distribu-
tion (and thesurface concentration observed usinga Neuston net) is af-
fected by these oceanic conditions (Kukulka et al., 2012; Reisser et al.,
2015; Isobe et al., 2015). The surface concentrations of microplastics ob-
tained in different oceans can be converted to the total particle count
(particle count per unit area) by vertically integrating the concentration
at depths using the wind speed and signicant wave heights measured
during each microplastic survey (hereinafter, wind/wave correction).
The total particle count, which is regarded as the quantity of pelagic
microplastics in the entire water column, is independent of vertical
mixing. Thus, it is a useful measure for the comparison of microplastic
quantities in different oceans.
Let us consider microplastics with size δ. Assuming an equilibrium
state between plastic rise (terminal) velocity (w) and vertical diffusion
with the diffusivity (A
), we anticipate that their concentration (N
) will
decrease exponentially into deeper layers (Kukulka et al., 2012; Reisser
et al., 2015) as follows:
where N
denotes the concentration of microplastics collected using a
Neuston net, wis set to 0.0053 mm s
obtained experimentally
(Reisser et al., 2015), and zis the vertical axis in the upward direction
from the sea surface. Parameter A
, with respect to the oceanic turbu-
lence in the upper layer is computed as:
where u
represents the frictional velocity of water (=0.0012 U), kis the
vonKarmancoefcient (0.4), Hs is the signicant wave height, and Uis
the wind speed. The applicability of the above formulation was exam-
ined by Reisser et al. (2015) in the North Atlantic gyre using multi-
level net towing. In the present study, wind speed and wave height
were averaged over 24 h before each survey. Vertically integrating Eq.
(1) from the sea surface (z=0)totheinnitely deep layer (z−∞)
yields the total particle count of microplastics per unit area, M
Table 1
Observed surface microplastic concentration reported by previous studies. Apart from
Goldstein et al. (2012), who synthesized the previous surveys, the studiesbelow comput-
ed the concentrations using particle counts and seawater volume measured by a ow
Oceans Concentration (pieces m
East Asian seas (Isobe et al., 2015) 3.70
N. Atlantic (accumulation area) (Reisser et al., 2015) 1.70
Seto Inland Sea (Isobe et al., 2014) 0.39
Arctic polar waters (Lusher et al., 2015) 0.34
Mediterranean Sea (de Lucia et al., 2014) 0.15
N. Pacic(Goldstein et al., 2012) 0.12
100°E 110°E 120°E 130°E 140°E 150°E
1(20) 2(18)
125°E 135°E 145°E
Fig. 1. Survey stations. The digits in parentheses denote the particle count (number of
pieces) of microplastics collected at each station. The survey stations around Japan are
shown in the inset map.
29 30 31 1 2 3 4 5 6
Jan. Feb. 2016
12 3 4 5
Fig. 2. Temporal variation of signicant wave heightand wind speed measuredduring the
surveyperiod. The black (red)curve indicatesthe wave height (wind speed)for which the
ordinateis shown on the left (right) side of the gure. The graybars show the observation
periods at the ve stations in Fig. 1.
624 A. Isobe et al. / Marine Pollution Bulletin 114 (2017) 623626
per unit area), as follows:
Integrating Eq. (3) over microplastic sizes smaller than 5 mm gives the
total particle count of microplastics.
Overall, 44 pieces of microplastic, excluding bers and expanded
polystyrene, were collected over the course of the surveys (see photos
[ac] in Fig. 3 as examples). Of the 44 fragments, one fragment (photo
[c] in Fig. 3) was 5.5 mm in length, slightly larger than the b5 mm def-
inition of microplastics (Andrady, 2011;Cole et al., 2011). However, this
fragment was considered as a microplastic fragment for convenience in
the presentstudy. In this short report, we focus specically on the con-
centrations of pelagic microplastics in the Southern Ocean. The analysis
of other types of data from these 44 samples, including biofouling
(Morét-Ferguson et al., 2010) and carbonyl index (Andrady et al.,
1993; Satoto et al., 1997) will be examined in the next phase of our
The microplastics were predominantly found at Stas. 1 and 2, south
of 60°S (nearest Antarctica),while only two pieces of microplastic were
detected at each of Stas. 3, 4, and 5 (Fig. 1). The results indicated that the
abundance of plastic fragments was negligibly small in the latter three
stations, because the fragment count was so low that may have been
due to contamination by theship, in spite of the effort to avoidcollecting
ship-derived plastics. Of the 44 fragments, 29 were made of polyethyl-
ene, polypropylene, and polyethylene combined with unidentied
polymers. These microplastics can be carried long distances because
they are less dense than seawater (~1025 kg m
). However, 14 of
the remaining 15 microplastics were made of polystyrene, and 1 was
made of polyvinyl chloride, which are all denser than seawater. These
dense microplastics are unlikely to have drifted independently in the
upper ocean. We speculate that they were likely to have been detected
in the surface water because they were entangled with drifting pelagic
objects such as zooplankton and krill, which were collected concurrent-
ly with the microplastics.
As with microplastics collected in mid-latitudes (Cózar et al., 2014;
Isobe et al., 2014; Isobe et al., 2015), high concentrations of
microplastics were found only in the smaller size range (Fig. 3). This re-
sult is likely to have been due to single pieces of plastic debris gradually
degrading into multiple tiny pieces as they move within the environ-
ment. Nevertheless, it is of particular interest that mesoplastics (diame-
ter: N5 mm) were rarely observed in the present surveys. The absence
of relatively fresh(i.e., less degraded) mesoplastics implies that the
areas around the Southern Ocean are unlikely to be signicant sources
of pelagic plastic debris, and that any tiny fragments must have been
transported considerable distances.
Integrating the concentration data shown in Fig. 3 with sizes data
from fragments b5 mm yields the averaged concentration of
microplastics at each station (Table 2). Except for Sta. 1, the concentra-
tions of pelagic microplastics in the Southern Ocean were found to be 1
2 orders of magnitudesmaller than those reported in the North Pacic,
Arctic polar waters, Mediterranean Sea, and the Seto Inland Sea of Japan
(Table 1). Furthermore, the concentrations we observed were 23 or-
ders of magnitude smaller than areas of other oceans with highconcen-
trations of pelagic microplastics, including the East Asian seas and the
accumulation (frontal) area of the North Atlantic (Table 1). However,
the microplastic concentration observed at Sta. 1 was comparable
with those observed in the oceans of the Northern Hemisphere.
As mentioned above, the total particle count, as a measure of the
quantity of pelagic microplastics in the entire water column, is useful
for the comparison of microplastic abundance in different oceans. The
current microplastic surveys in the Southern Ocean were conducted
under stormy conditions with wind speeds and signicant wave heights
of 10 m s
and 3.3 m, respectively, averaged over the survey period
(Fig. 2). However, in previous studies in both the East Asian seas
(Isobe et al., 2015) and the Seto Inland Sea (Isobe et al., 2014), the
microplastics were collected under relatively calm conditions, with
wind speeds of b5ms
and signicant wave heights of b1m.Thesur-
face concentrations in these areas may have been lower if the surveys
had been conducted under the same severe conditions as the present
surveys. Thus, there is clearly room to conclude that the abundance of
pelagic microplastics in the Southern Ocean is lower than in many
other areas. We computed the total particle counts at Stas. 1 and 2,
where relatively large amounts of microplastic were collected (Table
Table 3
Comparison of the total particle counts estimated in different oceans. The total particle
count in each oceanwas computed in Isobe et al. (2015) by averaging the total particle
counts for data from various oceans reported by Eriksen et al. (2014).
Oceans Total particle count (pieces km
East Asian seas
N. Pacic
World's oceans
Seto Inland Sea
Sta. 1 286,000
Sta. 2 136,000
Isobe et al. (2015).
Eriksen et al. (2014).
Isobe et al. (2014).
Table 2
Results of microplastic surveys at each station.
Sta. Date Particle count
Seawater volume
(pieces m
1 Jan 30, 2016 20 202 9.9 × 10
2 Jan 31, 2016 18 392 4.6 × 10
3 Feb 1, 2016 2 566 3.5 × 10
4 Feb. 2, 2016 2 502 4.0 × 10
5 Feb. 4, 2016 2 417 4.8 × 10
Average 3.1 × 10
510 20 30<
4321 mm
610-3 pieces/m3
×10-1 pieces/m3
Fig. 3. Size distribution of plastic fragments in the Southern Ocean (black bars; present
study), Seto Inland Sea (red; Isobe et al., 2014),and East Asian seasaround Japan (gray;
Isobe et al., 2015). The location of the Seto Inland Sea and stations around Japan are
shown in Fig. 1. The bar height at each size range indicates the concentration averaged
over all survey stations. Note that the intervals of size ranges are 0.1 mm for
microplastics b5 mm, 1 mm for mesoplastics b10 mm, and 10 mm for mesoplastics N
10 mm. The left ordinate is used for microplastics in the Southern Ocean, while the
black (red) ordinate on the right side is used for those in the East Asian seas (Seto
Inland Sea). The photographs (a), (b), and (c) are of microplastics collected in the
Southern Ocean in the size rangescorrespondingto the columns with the same letter at
the top. The photographs include a 5-mm grid, with grid lines of 0.3 mm.
625A. Isobe et al. / Marine Pollution Bulletin 114 (2017) 623626
2). The approximate estimation of the total particle count around the
East Asianseas is still oneorder of magnitude greater than atthese sta-
tions in the Southern Ocean (Table 3). However, it should be noted that
the total particle counts at Stas. 1 and 2 were comparable with the aver-
age counts observed in the other oceans.
Importantly, the microplastics concentrations observed close to Ant-
arctica (Stas. 1 and 2) were more abundant than those observed at the
offshore stations (Stas. 3, 4, and 5), although they were likely to have
originated from northern inhabited areas, as suggested by the size dis-
tribution (Fig. 3). Stas. 1 and 2 were located south of the oceanic fronts
(convergence zone) around Antarctica (see Fig. 4 for schematic view),
and were located around the southern boundary of the Antarctic Cir-
cumpolar Current (ACC; see Fig. 7 in Orsi et al., 1995). Unlike seawater
subducted into the abyssal ocean by deep convection around Antarctica,
buoyant microplastics have typically been found to remain in the upper
ocean; see Fig. 2 of Reisser et al. (2015) for the dense concentration of
microplastics in the uppermost layer. This implies that the microplastics
are likely to be trapped around Antarcticaonce they are transported be-
yond the ACC and oceanic fronts. However, more comprehensive
microplastic surveys in the Southern Ocean are required to conrm
this speculation.
Signicant concentration of microplastics in the Southern Ocean
would suggest that marine plastic pollution has spread across the
world's oceans. Thecurrent surveys revealed a relatively dense concen-
tration of microplastics in the Southern Ocean, comparable with con-
centrations observed in the Northern Hemisphere oceans (two of ve
stations in the present case). The present ndings raise concern about
the widespread nature of marine plastic pollution, indicating that plas-
tic-free ocean environments are increasing rare.
The authors sincerely thank the Captain, ofcers, and crews of the
Umitaka-maru for their assistance during the eld surveys. We thank
the journal reviewer for valuable suggestions to improve the manu-
script. This research was supported by the Environmental Research
and Technology Development Fund (4-1502) of the Ministry of the En-
vironment, Government of Japan, and by MEXT for physical and chem-
ical oceanographic observations under the Japanese Antarctic Research
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100°E 110°E 120°E 130°E 140°E 150°E
25°S ×105 pieces/km2
Fig. 4. Observed total particle counts and schematic view of oceanic conditions in the
Southern Ocean. The bars at Stas. 1 and 2 indicate the total particle counts listed in Table
3; see the reference scale shown in the upper left corner. The particle counts at Stas. 3,
4, and 5 were not shown because the numbers of collectedmicroplastics were negligibly
small. We referred to Fig. 6.7 in Tomczac and Godfrey (1994) for the positions of three
oceanic fronts in the schematic view. The arrows represent the Antarctic Circumpolar
Current, placed approximately on the curves along which the wind-stress curl vanishes
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626 A. Isobe et al. / Marine Pollution Bulletin 114 (2017) 623626
... Waller et al., 2017) in many compartments of the Antarctic environment, including marine surface waters (e.g. Cincinelli et al., 2017;Isobe et al., 2017;Lacerda et al., 2019;Kuklinskia et al., 2019;Jones-Williams et al., 2020;Suaria et al., 2020), freshwater streams (González-Pleiter et al., 2020), coastal sediments (Almela and González, 2020), marine sediments (Munari et al., 2017;Reed et al., 2018;Sfriso et al., 2020) and glaciers (González-Pleiter et al., 2021), in the vicinity of scientific stations and in Antarctic Specially Protected Areas (ASPAs). Several interactions between the Antarctic fauna and microplastics have also been detected, including vertebrates (e.g. ...
... All items were classified as styrofoam (expanded polystyrene, EPS), a material that has already been reported in the study area (e.g. Convey et al., 2002;Ivar do Sul et al., 2011;Isobe et al., 2017;Lacerda et al., 2019;Anfuso et al., 2020;Waluda et al., 2020). These studies have recorded mostly large meso-or macroplastics, mainly originated from packaging and fishing activities, that could be considered the main 'marine local sources' of plastic litter identified in Antarctica. ...
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Plastic and microplastic debris is transported by ocean currents over long distances, reaching remote areas, far from its original source. In Polar Regions, microplastics (MPs) can come from local activities or be transported from lower latitudes, with the former being the likely and major source. Although historically Antarctica was considered isolated from the global ocean, there is recent evidence of materials and organisms being transported in and out of the Southern Ocean, despite its multi-front structure. During the austral summer of 2019, beach surveys were conducted on the NW coast of the Fildes Peninsula (King George Island). The beach was characterised, and the first 2 cm of sediment from 5 quadrants (50 × 50 cm) along 100 m of the highest strandline were collected. Large microplastics (LMPs) and mesoplastics (MesoPs) were isolated, counted, measured, weighed and classified by shape. Polymer composition was analysed by FTIR and ageing estimated by Carbonyl Index. We found 293 items of LMPs (188 items) and MesoPs (105 items), with a total average density (±SD) of 234.4 ± 166 items m-2. Foams (130.4 ± 76.3), fragments (58.4 ± 56.0) and pellets (44.0 ± 50.5) were the most abundant shapes. The main polymers found were polystyrene, polypropylene, and polyethylene. We found pellets among the MesoPs, being the first record for beaches in Antarctica. The presence of these primary MPs south of 62°S not only alerts about their possible direct consequences on Antarctic ecosystems, but also gives empirical evidence for the passive entry of plastic debris from lower latitudes through cross-frontal exchanges, providing new evidence of a global connectivity of the Southern Ocean. Despite increasing research, knowledge of plastics dynamics and their impact in the Southern Ocean and Antarctica is still limited but certainly necessary.
... Due to this, Antarctica can act as an indicator of physical, chemical and biological effects caused by anthropogenic stresses (Huiskes et al., 2006). Research on microplastics in the Antarctic has focused on the marine environment, where particles have been detected in deep sea sediments in the Weddell Sea (Van Cauwenberghe et al., 2013), marine sediments from the western Antarctic Peninsula (Reed et al., 2018) and the Ross Sea (Munari et al., 2017), south of the Polar Front (Cózar et al., 2014), and in the surface waters of the Southern Ocean and Antarctic Peninsula (Absher et al., 2019;Cincinelli et al., 2017;Isobe et al., 2017;Suaria et al., 2020;Waller et al., 2017;Lacerda et al., 2019). Microplastics were recently identified for the first time in a freshwater Antarctic Specially Protected Area (ASPA) on Livingston Island, which is used for long-term ecological monitoring due to its pristine nature and use as a reference for inland water research (González-Pleiter et al., 2020). ...
... As the size distribution of identified microplastics is skewed towards smaller particles (Fig. 4), it is likely that particles smaller than the smallest particle observed (50 µm) are present but not able to be detected due to the magnification limit of the stereomicroscope (20 µm) and difficulties in handling particles < 50 µm. The abundance of microplas-tics has previously been shown to increase with decreasing size (Isobe et al., 2017;Levermore et al., 2020), which corresponds to the findings of this study (Fig. 4). The size distribution from our study was comparable to those measured in the remote Pyrenees (Allen et al., 2019). ...
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In recent years, airborne microplastics have been identified in a range of remote environments. However, data throughout the Southern Hemisphere, in particular Antarctica, are largely absent to date. We collected snow samples from 19 sites across the Ross Island region of Antarctica. Suspected microplastic particles were isolated and their composition confirmed using micro-Fourier transform infrared spectroscopy (µFTIR). We identified microplastics in all Antarctic snow samples at an average concentration of 29 particles L−1, with fibres the most common morphotype and polyethylene terephthalate (PET) the most common polymer. To investigate sources, backward air mass trajectories were run from the time of sampling. These indicate potential long-range transportation of up to 6000 km, assuming a residence time of 6.5 d. Local sources were also identified as potential inputs into the environment as the polymers identified were consistent with those used in clothing and equipment from nearby research stations. This study adds to the growing body of literature regarding microplastics as a ubiquitous airborne pollutant and establishes their presence in Antarctica.
... Various environmentalists are working on controlling the pollution as the microplastics, unlike macroplastics, are tedious to be traced and removed after exposure (Browne et al. 2007). Environmentalists have found that different environments including the terrestrial environment (Liu et al. 2018;Machado et al. 2017), marine environment (Isobe et al. 2017;Absher et al. 2018), fresh-water systems (Pivokonsky et al. 2018) are being contaminated with microplastic particles. The issue got greater concern when the microplastic particles were found in various human food items, drinking water, and air (Pivokonsky et al. 2018;Tong et al. 2020;Liu et al. 2019). ...
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Synthetic textile materials are noted as one of the major contributors to microfiber release from household laundry. The higher usage of synthetic textiles was noted as one of the major reasons for the leaching of microfibers into the aquatic system. Though few laundry aids are available to control the release of microfiber from laundry, no successful methods were developed to control it in the fabric itself. Hence, this research aimed to analyze the effectiveness of surface modification of polyester fabric using lipase enzyme and its impact on microfiber shedding. Taguchi’s L9 orthogonal array was adopted to optimize the enzyme treatment process parameters to reduce microfiber shedding. The results showed that enzyme concentration was the major influencing factor with a contribution of 35.56%, followed by treatment pH (35.247%), treatment time (17.46%), and treatment temperature (11.74%). The optimization with S/N ratio showed minimum microfiber shedding at an enzyme concentration of 0.5 gram per liter (gpl), treatment temperature of 55°C, 6.5 pH, and a treatment time of 45 minutes. Knitted polyester fabric treated with the optimized enzyme treatment condition showed a significant reduction (p<0.05) in microfiber shedding (count—79.11% and mass—85.68%). The surface changes and the interaction of the enzyme on the fabric were confirmed by hydrolytic activity and FTIR analysis. The optimized treatment on different knit structures and fabric with different grams per square meter (GSM) indicated the versatility of the treatment irrespective of fabric parameters. The repeated laundry process (20 washing cycles) showed that the enzyme-treated samples had a significant level (p<0.05) of reduction in shedding than the control sample. The difference in shedding after 20 washes supports the efficiency and longevity of the enzyme treatment process in reducing microfiber shedding.
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Microplastics are one of the major pollution problems of nowadays, have been found in both marine environments and various fish species worldwide. In this study, the presence of microplastics in digestive systems and gills of 6 species from the Scombridae family on the coast of Karachi in Pakistan was investigated. A total of 336 fish were examined for the presence of microplastic in gills and digestive systems. Microplastics were detected in digestive systems and gills in 11.11%-19.51% and 58.62%-85.71% of total individuals, respectively. The amount of microplastic varied from 0.19 to 1.12 items.ind-1 in digestive system and 1.5 to 7.04 items.ind-1 in gill. Fibre was dominant both gills (98.67-99.17%) and digestive systems (100%). More extensive and further investigations are needed on microplastic contamination of the biota on Pakistan coast.
This study collected 100–1000 L of surface water from 70 to 74 sites in the Inner Gulf of Thailand in both dry and wet seasons to investigate the relationship between the spatiotemporal distribution of microplastics and environmental variables. The quantity of microplastics in the wet season (34.59 ± 46.02 pieces/L) was significantly higher than the dry season (8.70 ± 15.34 pieces/L). Spatial distribution revealed an abundance of microplastics in river estuaries and seasonal current circulations. Polymeric characterization results showed that the plastic samples primarily consisted of polypropylene and polyethylene. New functional groups, including carbonyl, hydroxyl, and vinyl groups, were found in the chemical structures of the microplastic samples. The amount of freshwater runoff and the negative relationship with salinity confirmed that the river is the key factor in the transportation of microplastics to the coastal sea.
Microplastics have attracted worldwide attention due to their potential threat to the marine ecosystem, with such pollutants even detected in the polar seas. Although in-depth research on microplastics has increased in recent years, studies in Antarctic waters remain relatively scarce compared with coastal waters and open oceans. In this study, microplastics in surface and subsurface Antarctic waters were investigated. The average microplastic abundance in the surface water was 0.10 ± 0.14 items/m³, with highest abundance in the Ross Sea, and the average microplastic abundance in the subsurface water was 1.66 ± 1.20 items/m³, with highest abundance in the Dumont d'Urville Sea. Polyester was the main microplastic in the surface waters (87.3%), while polypropylene (33.1%), polyester (28.7%), and polyethylene (22.8%) were the dominant microplastics in the subsurface waters. Results indicate that microplastic pollution in Antarctic waters may come from the Antarctic continent as well as southward transport from the ocean at mid- and low latitudes.
The polar plastics research community have recommended the spatial coverage of microplastic investigations in Antarctica and the Southern Ocean be increased. Presented here is a baseline estimate of microplastics in the nearshore waters of South Georgia, the first in situ study of the north-east coast of the island. Our results show that the microplastic concentration in seawater at twelve stations in proximity to King Edward Point Research Station ranged from 1.75 ± 5.17 MP/L (mean ± SD), approximately one order of magnitude higher than similar studies of sea surface waters south of the Polar Front. Levels of microplastics in freshwater (sampled from Gull Lake) and precipitation (collected adjacent to the research station) were 2.67 ± 3.05 MP/L, and 4.67 ± 3.21 MP/L respectively. There was no significant difference in the microplastic concentration between seawater sites, and no significant bilateral relationship between concentration and distance from the research station outlets. We report an average concentration of 1.66 ± 3.00 MP/L in wastewater collected from the research station but overall, the counts of microplastics were too low to attach any statistical significance to the similarity in the microplastic assemblages of seawater and wastewater, or assemblages retrieved from penguin species in the region in other studies. Using a calculation described in contemporary literature we estimate the number of microfibres potentially being released from ships and stations annually in the region but acknowledge that further samples are needed to support the figures generated. More extensive research into microplastic distribution, characteristics, and transport in the region is recommended to fully compute the level of risk which this pollutant represents to the ecosystem health of this remote region.
Microplastics debris in the marine environment have been widely studied across the globe. Within these particles, the most abundant and prevalent type in the oceans are anthropogenic microfibers (MFs), although they have been historically overlooked mostly due to methodological constraints. MFs are currently considered omnipresent in natural environments, however, contrary to the Northern Hemisphere, data on their abundance and distribution in Southern Oceans ecosystems are still scarce, in particular for sub-Antarctic regions. Using Niskin bottles we've explored microfibers abundance and distribution in the water column (3–2450 m depth) at the Burdwood Bank (BB), a seamount located at the southern extreme of the Patagonian shelf, in the Southwestern Atlantic Ocean. The MFs detected from filtered water samples were photographed and measured using ImageJ software, to estimate length, width, and the projected surface area of each particle. Our results indicate that small pieces of fibers are widespread in the water column at the BB (mean of 17.4 ± 12.6 MFs.L⁻¹), from which, 10.6 ± 5.3 MFs.L⁻¹ were at the surface (3–10 m depth), 20 ± 9 MFs.L⁻¹ in intermediate waters (41–97 m), 24.6 ± 17.3 MFs.L⁻¹ in deeper waters (102–164 m), and 9.2 ± 5.3 MFs.L⁻¹ within the slope break of the seamount. Approximately 76.1% of the MFs were composed of Polyethylene terephthalate, and the abundance was dominated by the size fraction from 0.1 to 0.3 mm of length. Given the high relative abundance of small and aged MFs, and the oceanographic complexity of the study area, we postulate that MFs are most likely transported to the BB via the Antarctic Circumpolar Current. Our findings imply that this sub-Antarctic protected ecosystem is highly exposed to microplastic pollution, and this threat could be spreading towards the highly productive waters, north of the study area.
Marine and coastal sediments from the harbor of Cartagena (Spain) and its adjoining beach were investigated regarding their microplastic burden. Fibers accounted for 47.62% and 61.66% in marine and coastal sediments, respectively, followed by films (31.43% and 18.76%) and fragments (20.95% and 18.65%). Polyvinyl (36.07%), polypropylene (21.31%), and polyethylene (18.03%) were isolated for marine sediments, and low-density polyethylene (40.71%), polypropylene (20.16%), and acrylate (11.37%) for coastal sediments. Highest concentrations were found in the deepest marine sediments (24.0 m) and in the furthest zone from the seashore for coastal sediments (18 m). Carbonyl index increased in the intermediate area (12.5 m) for marine sediments (0.51), whilst vinyl index was maximum for the deepest samples (1.94), reporting Norrish type I and II reactions, respectively. Coastal sediments collected close to the high tide line displayed the highest average values for both indices, 1.57 and 1.29, respectively, indicating a higher exposition to weathering variables.
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To investigate concentrations of pelagic micro- (<5mm in size) and mesoplastics (>5mm) in the East Asian seas around Japan, field surveys using two vessels were conducted concurrently in summer 2014. The total particle count (pieceskm(-2)) was computed based on observed concentrations (piecesm(-3)) of small plastic fragments (both micro- and mesoplastics) collected using neuston nets. The total particle count of microplastics within the study area was 1,720,000pieceskm(-2), 16 times greater than in the North Pacific and 27 times greater than in the world oceans. The proportion of mesoplastics increased upstream of the northeastward ocean currents, such that the small plastic fragments collected in the present surveys were considered to have originated in the Yellow Sea and East China Sea southwest of the study area.
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Plastic, as a form of marine litter, is found in varying quantities and sizes around the globe from surface waters to deep-sea sediments. Identifying patterns of microplastic distribution will benefit an understanding of the scale of their potential effect on the environment and organisms. As sea ice extent is reducing in the Arctic, heightened shipping and fishing activity may increase marine pollution in the area. Microplastics may enter the region following ocean transport and local input, although baseline contamination measurements are still required. Here we present the first study of microplastics in Arctic waters, south and southwest of Svalbard, Norway. Microplastics were found in surface (top 16cm) and sub-surface (6 depth) samples using two independent techniques. Origins and pathways bringing microplastic to the Arctic remain unclear. Particle composition (95% fibres) suggests they may either result from the breakdown of larger items (transported over large distances by prevailing currents, or derived from local vessel activity), or input in sewage and wastewater from coastal areas. Concurrent observations of high zooplankton abundance suggest a high probability for marine biota to encounter microplastics and a potential for trophic interactions. Further research is required to understand the effects of microplastic-biota interaction within this productive environment.
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Millimetre-sized plastics are numerically abundant and widespread across the world's ocean surface. These buoyant macroscopic particles can be mixed within the upper water column by turbulent transport. Models indicate that the largest decrease in their concentration occurs within the first few metres of water, where in situ observations are very scarce. In order to investigate the depth profile and physical properties of buoyant plastic debris, we used a new type of multi-level trawl at 12 sites within the North Atlantic subtropical gyre to sample from the air–seawater interface to a depth of 5 m, at 0.5 m intervals. Our results show that plastic concentrations drop exponentially with water depth, and decay rates decrease with increasing Beaufort number. Furthermore , smaller pieces presented lower rise velocities and were more susceptible to vertical transport. This resulted in higher depth decays of plastic mass concentration (milligrams m −3) than numerical concentration (pieces m −3). Further multi-level sampling of plastics will improve our ability to predict at-sea plastic load, size distribution, drifting pattern, and impact on marine species and habitats.
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Plastic pollution is ubiquitous throughout the marine environment, yet estimates of the global abundance and weight of floating plastics have lacked data, particularly from the Southern Hemisphere and remote regions. Here we report an estimate of the total number of plastic particles and their weight floating in the world’s oceans from 24 expeditions (2007–2013) across all five sub-tropical gyres, costal Australia, Bay of Bengal and the Mediterranean Sea conducting surface net tows (N5680) and visual survey transects of large plastic debris (N5891). Using an oceanographic model of floating debris dispersal calibrated by our data, and correcting for wind-driven vertical mixing, we estimate a minimum of 5.25 trillion particles weighing 268,940 tons. When comparing between four size classes, two microplastic ,4.75 mm and meso- and macroplastic .4.75 mm, a tremendous loss of microplastics is observed from the sea surface compared to expected rates of fragmentation, suggesting there are mechanisms at play that remove ,4.75 mm plastic particles from the ocean surface.
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There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. However, the global load of plastic on the open ocean surface was estimated to be on the order of tens of thousands of tons, far less than expected. Our observations of the size distribution of floating plastic debris point at important size-selective sinks removing millimeter-sized fragments of floating plastic on a large scale. This sink may involve a combination of fast nano-fragmentation of the microplastic into particles of microns or smaller, their transference to the ocean interior by food webs and ballasting processes, and processes yet to be discovered. Resolving the fate of the missing plastic debris is of fundamental importance to determine the nature and significance of the impacts of plastic pollution in the ocean.
Microplastics are increasingly recognized as being widespread in the world’s oceans, but relatively little is known about ingestion by marine biota. In light of the potential for microplastic fibers and fragments to be taken up by small marine organisms, we examined plastic ingestion by two foundation species near the base of North Pacific marine food webs, the calanoid copepod Neocalanus cristatus and the euphausiid Euphausia pacifia. We developed an acid digestion method to assess plastic ingestion by individual zooplankton and detected microplastics in both species. Encounter rates resulting from ingestion were 1 particle/every 34 copepods and 1/every 17 euphausiids (euphausiids > copepods; p = 0.01). Consistent with differences in the size selection of food between these two zooplankton species, the ingested particle size was greater in euphausiids (816 ± 108 μm) than in copepods (556 ± 149 μm) (p = 0.014). The contribution of ingested microplastic fibres to total plastic decreased with distance from shore in euphausiids (r 2 = 70, p = 0.003), corresponding to patterns in our previous observations of microplastics in seawater samples from the same locations. This first evidence of microplastic ingestion by marine zooplankton indicate that species at lower trophic levels of the marine food web are mistaking plastic for food, which raises fundamental questions about potential risks to higher trophic level species. One concern is risk to salmon: We estimate that consumption of microplastic-containing zooplankton will lead to the ingestion of 2–7 microplastic particles/day by individual juvenile salmon in coastal British Columbia, and ≤91 microplastic particles/day in returning adults.
Plastic debris in the marine environment is widely documented, but the quantity of plastic entering the ocean from waste generated on land is unknown. By linking worldwide data on solid waste, population density, and economic status, we estimated the mass of land-based plastic waste entering the ocean. We calculate that 275 million metric tons (MT) of plastic waste was generated in 192 coastal countries in 2010, with 4.8 to 12.7 million MT entering the ocean. Population size and the quality of waste management systems largely determine which countries contribute the greatest mass of uncaptured waste available to become plastic marine debris. Without waste management infrastructure improvements, the cumulative quantity of plastic waste available to enter the ocean from land is predicted to increase by an order of magnitude by 2025. Copyright © 2015, American Association for the Advancement of Science.