Abundance and characteristics of microplastic in cultured green mussels Perna viridis in Sorsogon Bay, Philippines

Abstract

Microplastic ingestion by marine organisms is becoming an emergency threat to seafood industry, with farmed mussels as of particular interest. The context of trophic transfer accords that humans are at large into exposure to microplastic through its consumption. In the province of Sorsogon, Philippines, green mussel Perna viridis is sorted into various 'grading label': Small (5.0-6.9 cm), Medium (7.0-8.9 cm) and Jumbo (≥9.0 cm) and are marketed within and outside the province. Total microplastic varied from 0.31 to 2.5 items/ individual. Mussel size ranged from 5.0-6.9 cm showed the highest microplastics (2.57 items/ individual) while mussels below 2.9 cm has the least microplastic (0.31 item/individual). The majority of ingested microplastics were lines, while their colors and sizes varied. Fourier Transform Infrared Spectroscopy (FT-IR) indicated organosiloxane and polyethylene terephthalate as the most common polymer type identified. The results suggested that microplastics detected in the mussels are relatively within the narrow range with no significant differences of its distribution across its categorical sizes. With the results can be used as a baseline contribution for the risk assessment of microplastic pollution in Sorsogon bay.

Full text

~ 282 ~
International Journal of Fisheries and Aquatic Studies 2021; 9(6): 282-287
E-ISSN: 2347-5129
P-ISSN: 2394-0506
(ICV-Poland) Impact Value: 5.62
(GIF) Impact Factor: 0.549
IJFAS 2021; 9(6): 282-287
© 2021 IJFAS
www.fisheriesjournal.com
Received: 07-09-2021
Accepted: 09-10-2021
Mark Ariel D Malto
Magallanes Campus, Sorsogon
State University, Philippines
Antonino B Mendoza
Graduate Studies, Bicol
University Tabaco Campus,
Philippines
Plutomeo M Nieves
Graduate Studies, Bicol
University Tabaco Campus,
Philippines
Renan U Bobiles
Graduate Studies, Bicol
University Tabaco Campus,
Philippines
Alex P Camaya
Graduate Studies, Bicol
University Tabaco Campus,
Philippines
Skorzeny De Jesus
Graduate Studies, Bicol
University Tabaco Campus,
Philippines
Corresponding Author:
Mark Ariel D Malto
Magallanes Campus, Sorsogon
State University, Philippines
Abundance and characteristics of microplastic in
cultured green mussels Perna viridis in Sorsogon
Bay, Philippines
Mark Ariel D Malto, Antonino B Mendoza, Plutomeo M Nieves, Renan U
Bobiles, Alex P Camaya and Skorzeny De Jesus
DOI: https://doi.org/10.22271/fish.2021.v9.i6d.2612
Abstract
Microplastic ingestion by marine organisms is becoming an emergency threat to seafood industry, with
farmed mussels as of particular interest. The context of trophic transfer accords that humans are at large
into exposure to microplastic through its consumption. In the province of Sorsogon, Philippines, green
mussel Perna viridis is sorted into various ‘grading label’: Small (5.0-6.9 cm), Medium (7.0-8.9 cm) and
Jumbo (≥9.0 cm) and are marketed within and outside the province. Total microplastic varied from 0.31
to 2.5 items/ individual. Mussel size ranged from 5.0-6.9 cm showed the highest microplastics (2.57
items/ individual) while mussels below 2.9 cm has the least microplastic (0.31 item/individual). The
majority of ingested microplastics were lines, while their colors and sizes varied. Fourier Transform
Infrared Spectroscopy (FT-IR) indicated organosiloxane and polyethylene terephthalate as the most
common polymer type identified. The results suggested that microplastics detected in the mussels are
relatively within the narrow range with no significant differences of its distribution across its categorical
sizes. With the results can be used as a baseline contribution for the risk assessment of microplastic
pollution in Sorsogon bay.
Keywords: microplastic, FTIR, mussel, Sorsogon
Introduction
Previous studies have implicated the Philippines as one of the highest contributors of plastics
to the marine environment ranking 3rd, contributing 0.28–0.75 million metric tons of marine
plastic per year (Jambeck et al., 2015; Lebreton et al. 2017) [1, 2]. Microplastics, defined as
plastic materials or fragments <5 mm, are most likely the most numerically abundant plastic
debris items in the ocean today (Law and Thompson, 2014) [3]. The quantities of microplastics
will inevitably increase due to the degradation of large, single plastic items, ultimately
breaking down into millions of microplastic pieces (Cozar et al., 2014) [4].
One of the primary environmental risks associated with microplastics is their bioavailability to
marine organisms (Wright et al., 2013; Desforges et al., 2015) [5, 6]. Green Mussel Perna
viridis are of particular interest because they are cosmopolitan species, sedentary and have
extensive filter-feeding nature exposing them directly to chemicals and pollutants present in
the water column. Microplastic effects to different marine organisms have been already
recorded, compromising them into physiological consequences. And into context of trophic
transfer, the humans are at large into exposure to microplastic through the consumption of
these seafood (Farrell and Nelson, 2013; Watts et al., 2014) [7, 8].
This bivalve species is also not new in the province of Sorsogon, having its fisheries industry
for several decades. Its cultivation is considered to be as one of the country’s top mussel
producers. Its market in the province are sorted into various ‘grading label: Small (5.0-6.9 cm),
Medium (7.0-8.9 cm) and Jumbo (≥9.0 cm). And is mostly exported outside the province while
the rest of its production is locally consumed. Sizes below 5.0 cm are likewise being retailed to
fishpond operators as trash feed for their mangrove crab culture and to fishermen as bait to
their fishing. Suggesting that the size of the shell is usually important, and not how much
mussel meat is in. Thus, this study was proposed to identify characterize and quantify

~ 283 ~
International Journal of Fisheries and Aquatic Studies http://www.fisheriesjournal.com
microplastics found in different sizes of cultured green
mussels P. viridis in Sorsogon Bay, Philippines.
Materials and Methods
Sample Collection and Sampling Sites
A total of one-hundred fifty mussel P. viridis were collected
from three sites along the coastal water of Sorsogon bay from
January to March 2021 (Table 1). The samples were directly
collected from the sites using stainless steel scalpels and
forceps (Figure 1). In order to provide an ample
representation of the bay, sampling sites were haphazardly
selected from three mussel farm sites. Fifty mussels from each
farm site (ten individuals per size category) were collected
and was transferred to the laboratory for microplastic
analysis.
Fig 1: Sorsogon Bay located within the Philippines and zoomed in showing the sampling sites in Sorsogon City, in the municipality of
Casiguran and in the municipality of Juban, Sorsogon, Image from Yñiguez et al., 2018 [9].
Table 1: Length and weight and microplastic abundance in P. viridis
P. viridis size
category (cm)
Number of
individuals
Shell length
(cm)
Soft tissue weight (g/
individual)
Number of items/
individual
Number of items/ g
wet weight
<2.9
30
2.37 ± 0.07
0.37 ± 0.03
0.3056 ± 0.03
0.8351 ± 0.16
3.0-4.9
30
3.93 ± 0.09
1.88 ± 0.13
2.0833 ± 0.29
1.1454 ± 0.26
5.0-6.9
30
5.65 ± 0.11
4.58 ± 0.32
2.5033 ± 0.35
0.4217 ± 0.06
7.0-8.9
30
7.27 ± 0.07
6.45 ± 0.30
1.9667 ± 0.29
0.2760 ± 0.04
>9.0
30
9.39 ± 0.06
9.85 ± 0.12
2.3333 ± 0.39
0.2313 ± 0.04
Quality assurance and quality control
To avoid contamination, all of the liquid (freshwater,
saltwater and hydrogen peroxide) were filtered with 1 mm
filter paper prior to use. All of the containers and beakers
were rinsed three times with filtered water. The samples were
immediately covered if they were not in used. All of the
experimental procedures were finished as soon as possible.
Hydrogen peroxide treatment
The shell length and weight of each bivalve were recorded.
Each sample was pooled into ~5 g of soft tissue each (Li et
al., 2015 and Li et al., 2016) [10] [11]. Approximately 200 mL
of 30% H2O2 was added to each bottle to digest the organic
matter. The bottles were covered and placed in a drying oven
at 65 °C for 24 h and then at room temperature for 24-48 h to
extend the digestion effect of the soft tissue.
Floatation and filtration with saline (NaCl) solution
A concentrated saline solution was prepared to separate the
microplastics from dissolved liquid of the soft tissue via
floatation. Approximately 800 mL of filtered NaCl solution
was added to each bottle. The liquid was mixed and retained
overnight. The overlying water was directly filtered over
Whatman filter paper using a vacuum system. Then the filter
were placed into clean petri dishes with a cover for further
analysis.
Observation of microplastic
The filters were observed under OPTIKA LAB-20
stereomicroscope and OPTIKA B-290TB digital inspection
microscope powered by PROVIEW v.4.815674.20191008 for
imaging, particle size and shape identification and
quantification. Colors were identified using Colors.exe
software (Otaka et al. 2002) [12] adopting the 12 basic color
terms of the ISCC-NBS (Inter-Society Color Council National
Bureau of Standards) System of Color Designation as
recommended by Kershaw et al. (2019) [13]. A proportion of
10% from all of the samples visually examined were validated
through Attenuated Total Reflectance (ATR) Fourier
Transform Infrared (FTIR) Spectroscopy (Perkin Elmer FT-
IR Spectrometer Frontier).
Statistical analysis
Statistical test for normality was performed using the SPSS
version 25.0 and a confidence level of 95% (p=0.05). Shell
length (cm), shell weight (g) and soft tissue weight (g) were
presented as mean ± standard error. One-Way ANOVA test
were performed to determine the significant differences of the

~ 284 ~
International Journal of Fisheries and Aquatic Studies http://www.fisheriesjournal.com
items/ individual and items/ gwet weight among the categories of
P. viridis sizes.
Results
Characteristics of microplastic in P. viridis
Multiple types of microplastic, including fragments, foams,
films, lines and pellets, occurred in the tissues of P. viridis.
Lines were the most popular microplastic shape and consisted
67% of the total microplastic found on the different class sizes
of green mussel. Pellet were the least common shape and
were not observed at all except for mussels with sizes 3.0 –
4.9 cm. Lines were only found exclusively in the mussels with
sizes below 2.9 cm (Figure 2).
Fig 2: Characteristics of microplastic found in P. viridis of Sorsogon bay in terms of (a) shape; (b) size; and (c) color.
The most diverse colors were observed in lines followed by
films. With the most popular colors blue, transparent, red,
green and black. Overall the lines were usually blue and
transparent. The size of the microplastics ranged from 100 µm
to 5 mm in the bodies of the green mussel were examined.
Microplastics with sizes 250 µm and 500 µm were the most
common in green mussels, each consisting 25% of the
microplastics calculated (Figure 2).
Fig 3: (a) Identification of micro plastics with Attenuated Total Reflectance - Fourier transformed Infrared Spectroscopy (ATR-FTIR). The
measurements in the figure were performed under the transmittance mode. (b) Photographs of different types of microplastic found the P. viridis
of Sorsogon bay.
Of the visually identified microplastic, 10% of these particles
were validated for ATR-FTIR analysis. Of this subsample,
only 62% were identified as microplastic composing 24%
organosiloxane and 33% polyethylene terephthalate (PET) or
polyester fiber. Natural fiber identified were cellulose
materials composing 43% of the total samples.
Abundance of microplastic in P. viridis
The number of total microplastic varied from 0.31 to 2.5
items/ individual and from 0.23 to 1.15 items/ gwet weight.
Mussel ranging the size of 5.0-6.9 cm showed the highest
detected microplastics (2.57 items/ individual) while mussels
with sizes below 2.9 cm has the least (0.31 item/individual).
One-way ANOVA revealed that there was no significant
differences found on the number of items per individual
across its class sizes F(4,91)=0.95, p=0.44 but not with the
number of items per tissue weight F(4,91)=15.32, p=0.00.
(Figure 4).A Tukey post hoc test revealed that the
microplastic item in soft tissues of green mussels was
significantly lower in class size 5.0-6.9cm (0.42±0.06
item/gwet weigh, p=0.00), class size 7.0-8.9cm (0.28±0.04
item/gwet weigh, p=0.00) and class size >9.0cm (0.23±0.04

~ 285 ~
International Journal of Fisheries and Aquatic Studies http://www.fisheriesjournal.com
item/gwet weigh, p=0.00) compared to class size 3.0-4.9cm
(1.14±0.26 item/gwet weigh p=0.77)). There is no statistically
significant difference between the class size 3.0-4.9cm and
class size <2.9cm (0.83±0.23 item/gwet weigh p=0.77) (Figure
4).
Fig 4: Mean abundance of microplastics. The letters (a and b) indicate the results of One-way ANOVA. Bars with the same letters indicates no
significant difference.
Discussion
We found that microplastic pollution was detected in different
aquaculture farms in Sorsogon bay. Compared to other
published literature, the level of microplastic in Sorsogon Bay
were approximately lower (Table 2). In terms of variation, we
predicted more microplastic in larger mussels. As expected
microplastic abundance (item/ individual) in the larger
mussels were relatively higher than the smallest sizes. In
contrast, when microplastic abundance were considered as
(items/ gwet weight), the highest microplastic abundance was in
3.0-4.9cm size class and was low in the largest mussel
(>9cm). This was because the mean number of microplastic
per mussel was relatively consistent (~0.3 items/ individual)
across the largest mussels (5.0-6.9, 7.0-8.9, 9.0+mm), even as
mass was higher in the larger mussels. Moreover, there is no
correlation both on the items found per individual
rs(94)=0.048, p=0.646 and on the number of items per soft
tissue weight rs(94)=-0.070, p=0.496.
Table 2: Comparison of microplastic pollution in bivalves n the present study vs the previous studies.
Species and sources
Treatment
method
Identification method
Types of
microplastic
Levels of microplastic
References
Perna viridis
Philippines
30% H2O2
Visual identification and verified with
ATR-FTIR
Lines (fibers)
0.3 – 2.5 items/
individual
This study
Perna viridis
Philippines
30% H2O2
Visual identification and verified with
ATR-FTIR
Lines (fibers)
0.23 – 1.15
items/ g wet weight
This study
Perna viridis
Philippines
30% H2O2
Visual identification
Fibers
0.27 –0.41
items/ g wet weight
Bilugan et al., 2021
[14]
Perna viridis
Vietnam
10% KOH
Visual identification and verified with
an µ-FT-IR
Fibers
2.6 items/ individual
Nam, P.N. et al.,
2019 [15]
Perna viridis
China
30% H2O2
LUMOS microscopy ATR mode
Fibers
0.77 - 8.22 items
individual
Qu et al., 2018 [16]
Mytilus edulis
United Kingdom
30% H2O2
Visual identification and verified with
an µ-FT-IR
Fibers
1.1 - 6.4
items/individual
Li et al., 2018 [17]
Mytilus edulis
China
30% H2O2
Visual identification and verified with
an µ-FT-IR
Fibers
1.5 - 7.6
items/individual
Li et al., 2016 [11]
Mytilus
galloprovincialis
Northern Ionian Sea
30% H2O2
Visual identification and verified with
ATR-FTIR
Fibers, fragments
1.95 ± 1.14
items/individual
Digka et al., 2018
[18]
In case of seafood safety, the number of microplastic is useful
than total mass. Following exposure diet, consumers purchasing mussels of grading label small to jumbo sizes (5.0-
≥9.0 cm) would likely to ingest ~44 to ~23 particles per 100g

~ 286 ~
International Journal of Fisheries and Aquatic Studies http://www.fisheriesjournal.com
portion. If accounting for a 57% representation for the actual
microplastic found on this study, this results in to ~24 to ~13
microplastic particles per 100g. This number is comparably
smaller to the ~70 microplastic particles per 100g portion of
microplastic in UK supermarkets. According to EFSA
statement, only microplastics smaller than 150µm may
translocate across the human gut epithelium (EFSA
CONTAM Panel, 2016) [19] which equates to an estimated
15% of the particles recovered from farmed mussels of
Sorsogon Bay (figure 2) and the absorption of these
penetrating organs may be limited to ≤0.3% (EFSA
CONTAM Panel, 2016) [19]. Likewise, on the initial study of
Catarino et al., 2018 [20], the risk of plastic ingestion via
mussel consumption is minimal when compared to fiber
exposure during a meal via dust fallout in a household.
This detection of microplastic on farmed green mussels of
Sorsogon bay, only suggest the increasing evidence of
microplastic contamination to this known seafood, and its
entry to our diet is a function of the waste that we disposes of.
Despite majority of identified microfibers were cellulose,
probably from biodegradable textile cottons, its effect to
human ingestion is still lacking.
Organosiloxanes is an evidence of possible waste from
silicon-containing products such as baking utensils and pans,
baby nipples, and pacifiers, medical devices and implants,
water-repellent windshield coating, construction lubricants
and sealants as well as deodorant creams and moisturizers.
The primary health concerns associated with siloxanes have
focused primarily on D4 and D5 compounds that are toxic and
bioaccumulative. Siloxane products can be avoided through
reading product labels and purchasing toxic-chemical free
cookware alternative like glass or ceramics (Meghan J, 2021)
[21]. Polyethylene terephthalate (PET) detection are also
daunting, which are mainly used in the plastic industry. PET
has become widely used in the plastic industry as resin form
for plastic bottles, food jars, food trays and as fiber form for
textiles (known as polyester), monofilament, carpet, and
films. While it is generally considered a “safe" plastic, and
does not contain BPA, in the presence of heat it can leach
antimony trioxide and phthalates. Both of these are dangerous
to health. While antimony may contribute to menstrual and
pregnancy issues, phthalates are endocrine disruptors (Filella
M, 2020) [22].
With this findings, it indicates that there is a haphazard waste-
mismanagement introduction of this plastic wastes into the
bay. Its prevalence should be investigated and its waste
management practices should be revisited both on land and in
the shoreline.
Since human health consequences of different types of
microplastic in seafood are still evolving, its detection in this
kind of seafood is worth considering. Especially that public
perception on the risk from microplastics are increasing as
agitated in media. If consumers perceive that the seafood
contain microplastics, there is a potential that their
interpretation of the relative risks involve may result in
behavioral change or in the reduction of seafood
consumption. Clearly, this would result in the loss of income
in the seafood industry, and loss of safe nutritious protein for
consumers (Bergmann et al., 2015) [23].
Though this marine pollution concern is ubiquitous and
increasingly evident, with Sorsogon bay is clearly no
exception to this paradigm, this evidence of microplastic
occurrence in the farmed green mussels of Sorsogon bay of
varying grading label on its market will hopefully drive
effective social perception and behavioral change work on
supporting measures addressing the issue.
Conclusion and Recommendation
The study investigated the abundance and characteristics of
microplastic in cultured green mussels in Sorsogon Bay.
Commercially marketed into various ‘grading label’: small,
medium and jumbo, the species was detected with
microplastic. Primary results from the study were, (i) low
abundance of microplastic, as compared to other published
literatures with no significant differences on the microplastic
items per individual on various ‘grading label’ but not on
microplastic items per soft tissue weight (ii) lines or fibers
dominated the microplastic shape, blue as the most popular
color, 250µm to 500µm as the most common microplastic
size and organosiloxanes and polyethylene terephthalate
(PET) were the detected polymer types. Its detection to
cultured green mussels in Sorsogon bay is an evidence that
the bay is no exception to this ubiquitous type of marine
pollution. Indicating that there is a haphazard waste-
mismanagement introduction into the bay needing visitation
and investigation. Since public perception on seafood-
containing microplastic can lead to their behavioral change in
seafood consumption, perception survey should be conducted
in preparation for the risk-assessment of microplastic
occurrence in commercial bivalves of Sorsogon bay.
References
1. Jambeck JR, Geyer R, Wilcox C, Siegler TR, Perryman
M, Andrady A, et al. Plastic waste inputs from land into
the ocean. Science. 2015;347:768-71.
2. Lebreton LCM, van der Zwet J, Damsteeg J, Slat B,
Andrady A, Reisser J. River plastic emissions to the
world’s oceans. Nature Communications. 2017;8:15611.
3. Law KL, Thompson RC. Microplastic in the seas.
Science. 2014;345:144-5.
4. Cozar A, Echevarria F, Gonzalez-Gordillo JI, Irigoien X,
Ubeda B, Hernandez-Leon S, et al. Plastic debris in the
open sea. Proceedings of the National Academy of
Sciences. 2014;111(28):10239-10244.
5. Wright SL, Thompson RC, Galloway TS. The physical
impacts of microplastics on marine organisms: a review.
Environmental Pollution. 2013;178:483-492.
6. Desforges JW, Galbraith M, Ross PS. Ingestion of
microplastics by zooplankton in the Northeast Pacific
Ocean. Arch. Environ. Contam. Toxicol. 2015;69:320-
330. http://dx.doi.org/10.1007/s00244-015-0172-5.
7. Farrell P, Nelson K, Trophic level transfer of
microplastic: Mytilus edulis (L.) to Carcinus maenas (L.).
Environmental Pollution. 2013;177:1-3.
https://doi.org/10.1016/j.envpol.2013.01.046.
8. Watts AJR, Lewis C, Goodhead RM, Beckett SJ, Moger
J, Tyler CR. Uptake and retention of microplastics by the
shore crab Carcinus maenas. Environmental Science and
Technology. 2014;48(15):8823-8830.
9. Yñiguez AT, Maister J, Villanoy CL, et al. Insights into
the dynamics of harmful algal blooms in a tropical
estuary through an integrated hydrodynamic-Pyrodinium-
shellfish model. Harmful Algae. 2018;80:1-14.
doi:10.1016/j.hal.2018.08.010.
10. Li J, Yang D, Li L, Jabeen K, Shi H. Microplastics in
commercial bivalves from China. Environmental
Pollution. 2015;207:190-195.
11. Li J, Qu X, Su L, Zhang W, Yang D, Kolandhasamy P,

~ 287 ~
International Journal of Fisheries and Aquatic Studies http://www.fisheriesjournal.com
Li D. Microplastics in mussels along the coastal waters of
China. Environmental Pollution. 2016;214:177-184.
12. Otaka I, Kumagai K, Inagaki Y, Shimoyama M, Saegusa
K, Hara T. Simple and inexpensive software designed for
the evaluation of color. American Journal of
Ophthalmology. 2002;133(1):140-142.
13. Kershaw PJ, Turra A, Galgani F. Guidelines or the
monitoring and assessment of plastic litter and
microplastics in the ocean. GESAMP
(IMO/FAO/UNESCO-
IOC/UNIDO/WMO/IAEA/UN/UNEP/UNDP/ISA Joint
Group of Experts on the Scientific Aspects of Marine
Environmental Protection). 2019;99:130.
14. Bilugan QM, Limbago JS, Gutierrez RL. Detection and
quantification of microplastics from cultured green
mussel Perna viridis in Bacoor Bay, Cavite, Philippines.
Sustinere Journal of Environment and Sustainability.
2021;5(2):64-145.
15. Nam PN, Tuan PQ, Thuy DT, Quynh LTP, Amiard F.
Contamination of microplastic in bivalve: first evaluation
in Vietnam. Vietnam Journal of Earth Sciences.
2019;41(3):252-258. https://doi.org/10.15625/0866-
7187/41/3/13925.
16. Qu X, Su L, Li H, Liang M, Shi H. Assessing the
relationship between the abundance and properties of
microplastics in water and in mussels. Science of The
Total Environment. 2018;621:679-686.
17. Li J, Green C, Reynolds A, Shi H, Rotchell JM.
Microplastics in mussels sampled from coastal waters
and supermarkets in the United Kingdom. Environmental
Pollution. 2018;241:35-44.
18. Digka N, Tsangaris C, Torre M, Anastasopoulou A, Zeri
C. Microplastics in mussels and fish from the Northern
Ionian Sea. Marine Pollution Bulletin. 2018;135:30-40.
19. European Food Safety Authority. EFSA Journal
published by John Wiley and Sons Ltd on behalf of
European Food Safety Authority. 2016.
20. Catarino AI, Macchia V, Sanderson WG, Thompson RC,
Henry TB. Low levels of microplastics (MP) in wild
mussels indicate that MP ingestion by humans is minimal
compared to exposure via household fibres fallout during
a meal. Environmental Pollution. 2018;237:675-684.
21. Meghan J. The scoop on Siloxane. Force of Nature. 2021;
accessed 10 November 2021, <
https://www.forceofnatureclean.com/chemical-free-
living-siloxanes/>
22. Filella M. Antimony and PET bottles: checking facts.
Chemosphere. 2020;261:127732.
23. Bergmann M, Gutow L, Klages M. Marine
Anthropogenic Litter. Edn 1, Springer, Cham.
2015;XVIII:447. https://doi.org/10.1007/978-3-319-
16510-3.