EnvironmentAsia
The international journal published by the Thai Society of Higher Education Institutes on Environment
Available online at www.tshe.org/ea/index.html
EnvironmentAsia 9(2) (2016) 48-54
DOI
Qualitative Assessment and Management of Microplastics in
Asian Green Mussels (Perna viridis) Cultured in Bacoor Bay,
Cavite, Phillipines
Cristian Ryan Argamino and Jose Isagani B. Janairo
Biology Department, De La Salle University, 2401 Taft Avenue, Manila 0922 Philippines
Abstract
Microplastics (> 5 mm) have gained popularity in research and the public eye in recent years. This is due to the fact
that they contain persistent organic pollutants (POPs) which pose potential risks to the environment and human health.
Bivalves, which are filter feeders, are considered to be good indicators of marine pollution. In this preliminary study, Asian
green mussel (Perna viridis), an example of edible bivalve, cultured in Bacoor Bay, Cavite, Philippines was subjected to
qualitative analysis to determine the presence of microplastics. Through microscopic analysis, microplastics were found
present in the acid-digested mussel soft tissue. A management program is suggested for policy makers and stakeholders to
reduce the negative impact of microplastic pollution to both humans and the marine environment.
Keywords: microplastics; qualitative assessment; Perna viridis; marine pollution; environmental management
1. Introduction
Plastics are popular due to several properties such
as weight, strength and cost. The rise of consumption
over the past few decades has been a huge challenge
in terms of controlling environmental pollution. The
increase in the number of plastics amassed in the
environment is mainly caused by their inert property (slow degradation rate) and usage (improper
disposal of plastic waste) (Nor and Obbard, 2014).
Despite their benefits, the contribution of plastic to
environmental degradation has been significant in
causing damage to marine organisms. Previous studies
have shown that plastics (i.e. microplastics) are ingested
at different trophic levels which can potentially cause
bioaccumulation. This phenomenon can affect
biological processes of marine organisms. In addition,
food safety and human health are also at risk, if these
affected organisms are consumed (Vandermeersch
et al., 2015).
It has been estimated that up to about 12.7 million
tons of plastic still ended up in the ocean in 2010
(Jambeck et al., 2015; Andrady and Neal, 2009; Van
Cauwenberghe et al., 2015). The Philippines was
ranked No. 3 by mass of mismanaged plastic waste
following China and Indonesia. In 2010, plastic
marine debris in the Philippines ranged from 0.28-0.75
MMT (Million Metric Tons) per year (Jambeck et al.,
2015). Marine plastic debris primarily come from
land-based sources (80%) through leakage while only
marine aquaculture and fisheries only contribute 20%
of these pollutants (Ocean Conservancy, 2015). In
recent years, the emergence of a form plastic has been
studied for its role in pollution - microplastics. Although
there has been no universally accepted definition at
the moment (Van Cauwenberghe et al., 2015), individual
and group researches have contributed their own
description of microplastics. In 2004, microplastic
size was defined at around 20 microns (Thompson
et al., 2004). In 2009, the size adapted was <5 mm. This
characterization of microplastic size was also accepted
by the Joint Group of Experts on the Scientific Aspects
of Marine Environmental Protection (GESAMP) (Nor
and Obbard, 2014). Other researchers have presented
microplastics as particles with <1 mm size which
is argued to be more instinctive since ‘micro’ refers
to the micrometer range (Van Cauwenberghe et al.,
2015). As a marine pollutant, microplastics exist in two
forms - primary and secondary. Primary microplastics, directly move into water bodies through ground
runoff. These are mainly composed of virgin plastic
pellets, scrubbers, and microbeads. These plastic forms
are abundant in cosmetic products like exfoliants as
well as industrial abrasives (Andrady, 2011). On the
C. Ryan Argamino et al. / EnvironmentAsia 9(2) (2016) 48-54
other hand, secondary microplastics are degradation
products of larger plastics (mesoplastic/macroplastic)
which are already in the ocean or seashore. Microplastics
in this form are produced via several pathways such
as mechanical, photo (oxidative) and/ or biological
degradation (Masura et al., 2015). Majority of
microplastics in the marine environment are
secondary microplastics formed through the weathering
of plastic in the seashore. Plastics on beaches have a
faster degradation rate due to the higher temperature
(of sand) as compared to both plastics deep in the
ocean or floating on the water surface (Andrady, 2011).
Mussels, locally known as tahong, are generally
defined as mollusk bivalves which grow in the wild
or through aquaculture. These suspension feeders are
considered to be one of the best biological indicators
of marine pollution because of various characteristics
including their geographical distribution. Their tissues
accumulate pollutants due to their feeding mechanism
and their tendency to stay attached to surfaces which
make them relatively inactive in terms of mobility
thus rendering them as good pollution gauges. They
can also be easily sampled and thus, allow for frequent
experiments and monitoring (Vasanthi et al., 2012;
Figueiras et al., 2002; Chase et al., 2001). The species
of mussel used in this experiment is Perna viridis
(P.vidiridis). P. viridis is a large species of mussel
ranging from 8-16 cm (Rajagopal et al., 2006). Their
habitat includes hard surfaces (rocks, pilings and
floating docks, as well as sandy or muddy bottoms about
a foot below the low tide mark) (McGuire and Stevely,
2009). Their diet includes microscopic phytoplankton,
zooplankton and suspended organic detritus in the water
(Rajagopal et al., 2006). In the Philippines, P. viridis
or tahong is considered as one of the seven major
aquaculture species (Food and Agricultural
Organization, 2006). Aquaculture of tahong can
be traced back to 1955 which was initiated by the
Philippine Bureau of Fisheries and Aquatic
Resources in Binakayan, Cavite (Yap, 1999). Although it is a source of food locally, discretion is
advised for consumption due to their tendency for
bioaccumulation of toxins substances detrimental to
human health (McGuire and Stevely, 2009). Thus,
determining the presence of microplastics in these
marine species will not only be instrumental to
profiling marine pollution but will also serve as a tool
in improving guidelines for food safety.
In this study, we present our findings regarding the
presence of microplastics in cultured bivalves available
for human consumption. These particles were positively
identified through microscopic analysis and other
qualitative criteria. In addition, management procedures
according to best practices were also discussed which
will aid policy makers in reducing the risk posed by
these pollutants to the environment and human health.
Figure 1. Map of Bacoor Bay (Google Maps)
49
C. Ryan Argamino et al. / EnvironmentAsia 9(2) (2016) 48-54
Figure 2. Semi-transparent microplastics
2. Materials and Methods
3. Results and Discussion
Bacoor Bay-cultured samples (P.viridis) were
obtained from Sineguelasan Seafood Terminal in
Bacoor, Cavite, Philippines. The mussel samples were
harvested on January 2016. Fig. 1 shows a map of
Metro Manila and its adjacent provinces. The drop pin
marks the location of Bacoor Bay where the samples
were cultured and harvested. All glassware were
thoroughly cleaned and rinsed with filtered deionized
water (Elga PURELAB Flex) to avoid contamination
dilution (Van Cauwenberghe and Janssen, 2014).
Wet digestion using acid was used to extract
the microplastics for the samples (Vandermeersch
et al., 2015). Twenty milliliters (20 mL) of 70% HNO3
(UNIVAR) were added to three mussels in an
Erlenmeyer flask. Five replicates were prepared.
Mussel tissues in acid were left in in the hood for 40
hours to achieve optimum digestion. The samples were
then heated until boiling for 15-20 minutes using a hot
plate to evaporate the acid and dry the sample. Twenty
milliliters of warm deionized water (~80 degrees
Celsius) were added to each vessel for dilution (Van
Cauwenberghe and Janssen, 2014). Digested samples
were then subjected to vacuum filtration using a
Buchner funnel and Whatman Filter Paper Grade 1
(11-micron pore size). Filters were dried for 2 hours
in an oven at 40 degrees Celsius. Dried filters were
analyzed for the presence of microplastics using a Nikon
SMZ 745T Stereomicroscope (Van Cauwenberghe and
Janssen, 2014; Song et al., 2015).
Previous studies confirmed the presence of
microplastics from marine samples using different
methods. Raman Spectroscopy (Van Cauwenberghe
and Janssen, 2014), Fourier Transform Infrared
Spectroscopy coupled with either a Microscope or
an Attenuated Total Reflectance attachment (Nor and
Obbard, 2014), as well as the Fluorescence Microscope
(Noren, 2007) were utilized by various studies. The
absence of these instruments should not be a hindrance
in the analysis of this important class of pollutants.
Thus, the following criteria were used in determining
the presence of microplastics (Noren, 2007):
a) No cellular or organic structures are visible in
the plastic particle/fibre.
b) Clear and homogeneously colored particles
(blue, red, black and yellow)
c) If the particle transparent or whitish, it shall be
examined with extra care in a microscope under high
magnification.
Figs. 2 and 3 show examples of microplastics
observed in each of the five samples.
Microplastics observed in the samples were all
found to be < 1mm. Transparent whitish and reddish
particles measuring at around 10 to 30 microns (0.1
to 0.3 mm) were observed in Samples 1, 2, and 5.
On the other hand, blue fibers (~0.5 mm in length)
were observed in Sample 3 and 4. These observations
qualify in the abovementioned criteria (Noren, 2007)
p
c
e
t
y
Figure 3. Fiber micropplastics
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C. Ryan Argamino et al. / EnvironmentAsia 9(2) (2016) 48-54
t Figure 4. Microplastic Managementt
i presencef of microplastics
m
therefore, confirming the
M
MWith the confirmation
w
h the presence of
in P. viridis.
of
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5
microplastics in this preliminary study, ufurther
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research on microplastics can now be focused yon)their
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presence needs to be addressed by policy makers
a and
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management
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summarizedain Fig. 4 (GESAMP,
2015).
aT
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The first
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program
d e is a
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Comprehensive
Waste Generation Management
o
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(CWGM) (Fig. 5) which can haveo a big impact
h in
i
decreasing the
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r to 41% fmass decrease
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mismanagede plastic waste by 2025.1CWGM involves
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a or potential
n sourcesl of
s the
identification
pollutant. In this case, microplastics ingested by
bivalves can be attributed to sources such as urban
inputs, fisheries, and aquaculture. Another aspect
of CWGM is life cycle assessment which includes
value-chain models and the popular 3R method
(reduce, reuse, recycle). Life cycle assessment of
plastics particularly the product disposal chain is an
important task of management. This assessment will
lead to a targeted approach which are prerequisites
of an efficient and cost-effective method of reducing
microplastic impact (Vegter et al., 2014). The 3Rs in
im
f
m
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particular
should be targeted toward reducing
marine
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o
debris by giving economic incentives to stakeholders.
5
s
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The last aspecta of this program
is the reductions of
) f
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eThis can be
microplastic
input
(GESAMP,
2015).
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implemented
through policies
i e
n r whichteban or regulate
primary
microplastics.
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ny
cm
M United States
y l of America
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enacted
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and
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d a introduction
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intentionally-added
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2015).
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o
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t upr of polyethylene. Policies
o
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c
r Plastics in
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e
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a
usually
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a
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c
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e either by
studies on alternative
packaging
materials
significantly reducing the amount plastic used or
redesigning and formulating alternative materials which
can be easily and safely degraded to non-threating
products (for both human and marine life) will decrease
marine litter output. Physical screening and waste
treatment technologies are also mitigation options to
prevent microplastics from entering not only the marine
environment but also groundwater which can pose risks
to terrestrial animals and humans (Vegter et al., 2014).
Fig. 5. shows Comprehensive Waste Management
Program for Microplastics.
o
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f
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Figure 5. Comprehen
nsive waste generation
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C. Ryan Argamino et al. / EnvironmentAsia 9(2) (2016) 48-54
t
Figure 6. Risk Percepttion and Manaagement of Miicroplastics
a
i
e
Another dimension of the proposed management
e
a
m
a
m
scheme is obtaining feedback from stakeholders on
a
m
m
n by microplastic
h u
their perception of the risks posed
n
h
aand Management)
mo
contamination
a (Risk Perception
m
h awareness eone the
(Fig. 6). It hstarts with promoting
e
m
e
impacts of these pollutants to humans
and uthe
p
ostakeholders
w and
environment
o alike. Educating
w
i t
fa t
making themi understandfathe hazardsa of microplastic
e
e
contamination
tool efor management
e is an effective
e
a
e
(Dippo, 2012).
e Another key aspect ofo communicating
l
the risks involved is to convert complex terms
to a language that can be fully understood by the
stakeholders. Developing a management plan for
this social, behavioral, and psychological aspect of
microplastic management involves surveys, psychological
studies, and acknowledging demographic differences.
These include regional, cultural, economic, educational,
and other variances in behaviour and perceptions
(GESAMP, 2015).
A comprehensive management framework is
shown in Fig. 7. To mitigate the effects of microplastic
contamination to marine and human life, policies
should be put into place to strengthen the foundation
of the measures to be employed. The illustration also
shows the pillars of mitigation action and management
which include research, implementation, and regulation.
Research entities from the government (Department
of Science and Technology, Academic Institutions,
National Fisheries Research and Development
Institute,) are tasked to develop infrastructure, methods,
t
a
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a
e
m
h
m
a technologies
m
s prevent microplastic
i
and
that will
s
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u
o
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entry to the marine environment. Implementation
o
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u lap of Local tGovernment
responsibilityowill fall on the
u
e Provincial to the Municipal
am
o
Units from the
Level
a
o
h
m
e
I
headed by the Environmental
and Natural Resources
p
u that policies
s I are being
e implemented
u
Officer
to
ensure
s
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t
t
m
using the developed technologies.
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bodies
a
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m m
c
sucht as the Environmental
Management
Bureau
and
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c
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e
a
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h
Bureau
of Fisheries and Aquatic
Resources
will act
a
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s
as anu auditing entity to ensure
that effluents
and
s
o
marine bodies are checked in terms of microplastic
levels.
e
t
m
h
h
m
M
a
o
4. Conclusions
Microplastics were found present in Bacoor
bay-cultured tahong (P. viridis). This preliminary
study confirms a microplastic pollution problem in
the Bacoor Bay and Manila Bay area and thus,
the need for further research on quantitating and
characterizing these pollutants is of utmost importance.
Management and mitigation procedures to prevent
the entry of microplastics (both primary and
secondary) require policy makers, stakeholders,
government agencies, non-government organizations,
and academic institutions to work in sync to put up a
strong and effective management framework with
research, implementation, and regulation as its pillars
and policy as its foundation.
Figure 6. Risk Percepttion and Manaagement of Miicroplastics
a
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C. Ryan Argamino et al. / EnvironmentAsia 9(2) (2016) 48-54
t 7. Microplastic
k
Figure
Managementt Framework
c
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d - (FAO).
e hNational
c Food- and
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Organization
Acknowledgements
o
c
o o
BAquaculture
aSector Overview
B B(NASO). Viale
c
o
a delle
r
e
a
d
z
o
o
p
r
a di Caracallad00153 [homepage
z
Terme
on the oInternet].
The authors would like to thank the Provincial
Gov-e
m
r
e r Italy: m2006; 1: paras 28 e[cited m
Rome,
2016 m
Jan 19].
ernment of Cavite for assisting
in the procurement
of them
p
r
e p
mAvailable
r m
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e
samples and the Biology Laboratory
of DLSU
for providing
d and reagents
u for conducting
o
t
snaso_philippines/en.
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u
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t
GESAMP.
a
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y fate and effects
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r microplastics
y in the
marine
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a
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Received 31 March 2016
Accepted 28 April 2016
Correspondence to
Associate Professor Dr. Jose Isagani B. Janairo
Biology Department, College of Science,
De La Salle University,
2401 Taft Avenue,
Manila 0922
Philippines
E-mail: jose.isagani.janairo@dlsu.edu.ph
54