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The effect of fiber type (cotton, polyester, and rayon), temperature, and use of detergent on the number of microfibers released during laundering of knitted fabrics were studied during accelerated laboratory washing (Launder-Ometer) and home laundering experiments. Polyester and cellulose-based fabrics all shed significant amounts of microfibers and shedding levels were increased with higher water temperature and detergent use. Cellulose-based fabrics released more microfibers (0.2–4 mg/g fabric) during accelerated laundering than polyester (0.1–1 mg/g fabric). Using well-controlled aquatic biodegradation experiments it was shown that cotton and rayon microfibers are expected to degrade in natural aquatic aerobic environments whereas polyester microfibers are expected to persist in the environment for long periods of time.
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Marine Pollution Bulletin
journal homepage:
Microbers generated from the laundering of cotton, rayon and polyester
based fabrics and their aquatic biodegradation
Marielis C. Zambrano
, Joel J. Pawlak
, Jesse Daystar
, Mary Ankeny
, Jay J. Cheng
Richard A. Venditti
Department of Forest Biomaterials, College of Natural Resources, North Carolina State University, Raleigh, NC 27695-8005, United States
Cotton Incorporated, Cary, NC 27513, United States
Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC 27695-7625, United States
Nicholas School of the Environment, Duke University, Durham, NC 27708, United States
Aquatic environments
The eect of ber type (cotton, polyester, and rayon), temperature, and use of detergent on the number of
microbers released during laundering of knitted fabrics were studied during accelerated laboratory washing
(Launder-Ometer) and home laundering experiments. Polyester and cellulose-based fabrics all shed signicant
amounts of microbers and shedding levels were increased with higher water temperature and detergent use.
Cellulose-based fabrics released more microbers (0.24 mg/g fabric) during accelerated laundering than
polyester (0.11 mg/g fabric). Using well-controlled aquatic biodegradation experiments it was shown that
cotton and rayon microbers are expected to degrade in natural aquatic aerobic environments whereas polyester
microbers are expected to persist in the environment for long periods of time.
1. Introduction
In the last 60 years, the production of resin and bers has increased
signicantly from two million metric tons (Mt) in 1950 to around 380
Mt. in 2015 (Geyer et al., 2017;Plastics Europe, 2017;Statista, n.d.).
Geyer et al. (2017) estimated that 8300 Mt. of plastics have been pro-
duced up to 2015 generating approximately 6300 Mt. of plastic waste
from which 9% have been recycled, 12% incinerated, and 79% accu-
mulated in landlls and natural environments. The accumulation of
plastics in the environment is a subject of concern for industries, gov-
ernments, and communities (Rochman et al., 2013;Thevenon et al.,
2011;Thompson et al., 2010), especially in water sources (Thompson
et al., 2004).
The presence of plastics in water bodies can be the origin of dif-
ferent problems such as aesthetic issues, entanglement and suocation
of marine animals in plastic nets, plastic ingestion by the fauna, ad-
sorption of pollutants and pathogens in plastics particles and trans-
portation in the ecosystems (Moore, 2008;Thevenon et al., 2011).
Plastics found in the environment may be classied according to
their size and source. Macroplastics are big pieces (> 5 mm) generated
from poor waste management strategies. Particles below 5 mm in size
are commonly called microplastics (Boucher and Friot, 2017;Eriksen
et al., 2014;Moore, 2008;Thevenon et al., 2011;Wagner et al., 2014).
In general, microplastics are classied into two forms. Primary micro-
plastics are discharged to the environment at the micro size; these can
be plastics manufactured in the micro size such as scrubbing agents or
pellets, or particles produced from the abrasion during wear and use of
plastic goods such as tires and synthetic textiles (Boucher and Friot,
2017). Secondary microplastics are produced from the fragmentation of
mismanaged plastic waste in the environment (Boucher and Friot,
2017). Nevertheless, there is no consensus about the microplastics de-
nition in the scientic community. After a comprehensive review of
reported methods for describing and identifying microplastics, Frias
and Nash (2019) proposed a new denition of microplastics that con-
siders their physical and chemical properties, size, and origin: Micro-
plastics are any synthetic solid particle or polymeric matrix, with regular or
irregular shape and with size ranging from 1 μm to 5 mm, of either primary
or secondary manufacturing origin, which are insoluble in water. In that
study nanoplastics were considered < 1 μm.
Microplastics are oating in the world's oceans, rivers, lakes, and
are depositing in sediments (Browne et al., 2011;Eriksen et al., 2014;
GESAMP, 2015;Miller et al., 2017;Thompson et al., 2010;Wagner
et al., 2014). It has been estimated that a minimum of 5.25 trillion
plastic particles weighing about 270,000 tons are oating in the world's
oceans and 93% of these plastics particles are in the micro size range
(Eriksen et al., 2014). This represents ~ 0.1% of the world's plastic
Received 8 November 2018; Received in revised form 25 February 2019; Accepted 26 February 2019
Corresponding author.
E-mail address: (R.A. Venditti).
Marine Pollution Bulletin 142 (2019) 394–407
0025-326X/ Published by Elsevier Ltd.
annual production (Eriksen et al., 2014).
Available studies have demonstrated that marine fauna is suscep-
tible to microplastics ingestion (Thevenon et al., 2011;Wagner et al.,
2014). The presence of anthropogenic debris in seafood for human
consumption has been observed (Miranda and de Carvalho-Souza,
2016;Rochman et al., 2015). There is also evidence of microplastic
ingestion by humans (Schwabl, 2018). Microplastics have been ob-
served even in commercial food-grade salts (Kim et al., 2018). Conse-
quently, microplastic pollution is raising concerns regarding human
Even though the microplastics are relatively inert, due their large
surface-to-volume ratio and chemical composition, they can adsorb
pollutants and pathogens and transfer them via ingestion to other
trophic levels, even to humans through the food chain (Egbeocha et al.,
2018;GESAMP, 2015;Rummel et al., 2017;Wagner et al., 2014;Wang
et al., 2018). It has been shown that microplastics sampled from dif-
ferent environments adsorbed toxic compounds such as polychlorinated
biphenyls (PCB), dichloro diphenyl trichloroethane (DTT), hexa-
chlorocyclohexane (HCH), polycyclic aromatic hydrocarbons (PAHs),
polybrominated diphenyl ethers (PBDE), hexabromocyclododecane
(HBCD), heavy metals, nonylphenols (NP), and peruoroalkyl sub-
stances (Akhbarizadeh et al., 2017;Chen et al., 2018;Holmes et al.,
2014;Llorca et al., 2014;Mato et al., 2001;Vedolin et al., 2018;Wang
et al., 2018). Several studies indicated that microplastics and macro-
plastic debris distributed at various concentrations in aquatic ecosys-
tems around the world aect the growth, development, behavior, re-
production, and mortality of aquatic animals (Chae and An, 2017).
However, other authors consider that at environmentally relevant
concentrations, microplastics have not been shown to have harmful
eects to aquatic fauna and do not represent a signicant exposure
route for toxic chemical compared to prey consumption in aquatic birds
or organisms (Burton, 2017;Henry et al., 2019).
There are many dierent sources of primary microplastics and one
of the main challenges is to prevent the generation and leakage of these
particles to the environment from their origin (Boucher and Friot, 2017;
GESAMP, 2015). Although wastewater treatment plants (WWTPs) have
shown good eciency in microplastic removal, they are not designed
for that purpose (Lares et al., 2018;Magnusson and Norén, 2014;
Talvitie et al., 2015). Microplastics, mainly particles and bers smaller
than 100 μm, have been observed in wastewater euents at low con-
centration (Browne et al., 2011;Lares et al., 2018;Magnusson and
Norén, 2014;McCormick et al., 2014;Mintenig et al., 2017;Talvitie
et al., 2015, 2017a, 2017b;Wolet al., 2018). However, the large
volumes of euents discharged every day to the water bodies and the
use of sewage sludge (where most of the microplastics are retained) as
soil amendment/fertilizer represent an important source of micro-
plastics introduced into the environment (Lares et al., 2018;Mintenig
et al., 2017;Nizzetto et al., 2016;Talvitie et al., 2017b). These mi-
croplastics are found mainly in the ber-like form in some euents
(Lares et al., 2018;Mason et al., 2016;Mintenig et al., 2017;Talvitie
et al., 2015, 2017a, 2017b). These bers are predominantly made of
polyester, and more specically, polyethylene terephthalate (PET)
(Lares et al., 2018;Mintenig et al., 2017;Talvitie et al., 2017a;Wol
et al., 2018;Ziajahromi et al., 2017). Nevertheless, some studies also
indicate that cellulose-based bers are present in the wastewater ef-
uents (Lares et al., 2018;Talvitie et al., 2017b, 2015; Ziajahromi et al.,
All of these bers are common in the textile industry and it is be-
lieved that they enter the WWTPs from the euent of the washing
machines (Browne et al., 2011;McCormick et al., 2014;Thompson
et al., 2010). In addition, in less developed countries, it is common to
discharge home laundering euents directly into the environment
(Boucher and Friot, 2017).
The International Union for Conservation of Nature (IUCN)
(Boucher and Friot, 2017), estimated that between 0.8 and 2.5 Mt./year
of primary microplastics are released into the ocean. From this, it is
estimated that 35% are micro-size bers released from textiles during
laundering (Boucher and Friot, 2017). Fibers at the micro-size are
commonly named microbers by the environmental science commu-
nity. Microbers could be made of synthetic polymers, in that case, they
will also be microplastics. Natural bers also represent a large pro-
portion of the textile industry and the fate of these microbers are
largely unknown in published literature (Henry et al., 2019;Ladewig
et al., 2015;Mishra et al., 2019;Salvador Cesa et al., 2017). The term
microberis also used in the textile industry to refer to fabrics made
of ne polyester or polyamines bers, < 1 denier (mass in grams of
9000 m) and a ber cross-section smaller than 10 μm(Henry et al.,
2019;Salvador Cesa et al., 2017). To avoid confusion in this study, the
term microber will refer exclusively to the synthetic, articial, and
natural bers (< 5 mm) released from fabrics during laundering.
Several studies have quantied the number of microbers released
during home laundering, however, there is lack of standardization in
the methods used and the metrics that are needed to incorporate a re-
liable value in environmental sustainability assessments (Henry et al.,
2019;Salvador Cesa et al., 2017).
Browne et al. (2011) observed that polyester garments (blankets,
eeces, and shirts) can shed > 1900 bers per wash. All garments re-
leased > 100 bers per liter of euent, with > 180% more from
eeces than other construction types. Carney Almroth et al. (2018)
reported, using a laboratory scale washing machine, that eece and
microeece synthetic fabrics shed the greatest amount of bers, up to
7360 bers m
in one wash, indicating that the fabric construc-
tion plays a major role in the shedding ability of fabrics. Likewise,
Napper and Thompson (2016) observed that 6 kg of synthetic material
fabrics (polyester, polyester-cotton blend, and acrylic fabrics) could
release about 140,000 to 700,000 bers per wash in commercial home
laundering washing machines. Another study showed that the re-
covered microber mass per garment tested, jackets or sweaters made
of polyester eece or nylon shell with nonwoven polyester insulation,
ranged from approximately 0 to 2 g, exceeding 0.3% of the unwashed
garment mass (Hartline et al., 2016).
Hernandez et al. (2017) showed in their study of polyester fabrics
that the use of detergent during home laundering is the aspect that has
the greatest eect on the generation of microbers. Approximately 75%
more microbers were released when using detergent regardless of type
(liquid, powder, or surfactant) and dosage, 0.025 vs 0.1 mg bers/g
textile washed, without and with detergent, respectively (Hernandez
et al., 2017). De Falco et al. (2018) observed a similar tendency with
polyester and polypropylene woven and knitted fabrics. The use of
detergents promoted an increase of microbers released from fabrics
during laundering; in this case, the powder detergent induced more
microber shedding than the liquid one in domestic washing and, in
general, products for industrial washing have a higher impact than
domestic washing detergents (De Falco et al., 2018).
De Falco et al. (2018) saw a 35% decrease in microber shedding
when using a softener. Nevertheless, the inuence of temperature and
softener use in the microber generation have been less consistent and
signicant between studies than the eect of detergent use (De Falco
et al., 2018;Hernandez et al., 2017;Napper and Thompson, 2016;Pirc
et al., 2016).
When comparing washing machine types, it was observed that top-
load machines shed more ber mass than front-load machines (Hartline
et al., 2016). Additionally, Hartline et al. (2016) reported that me-
chanically aged-fabrics release more bers than new fabrics. Never-
theless, sequential washing experiments have shown that the number of
microbers released during laundering is generally reduced with in-
creased washing cycles until reaching a constant level (Carney Almroth
et al., 2018;Napper and Thompson, 2016;Pirc et al., 2016;Sillanpää
and Sainio, 2017).
To our knowledge, there has been only one study that investigates
the eect of the type of polymer yarn material used in textiles with the
same fabric constructions. However, natural bers were not included in
M.C. Zambrano, et al. Marine Pollution Bulletin 142 (2019) 394–407
this study, only synthetic bers such as polyester, acrylic, and nylon
were compared (Carney Almroth et al., 2018). In most research, the use
of dierent fabric constructions and/or textile goods studied does not
allow a fair comparison of the ber polymer composition eect on
microber generation.
Sillanpää and Sainio (2017) reported the mass, 0.12 to 0.33% w/w
per mass of fabric washed, and number, 2.1 × 10
to 1.3 × 10
per kg of fabric washed, of microbers released during sequential home
laundering washing cycles of polyester and cotton fabrics of dierent
constructions. The results of this study indicate that cotton fabrics have
a higher tendency than polyester fabrics to shed bers during washing,
however, the dierences in fabric constructions make it dicult to
derive a nal conclusion from this data (Sillanpää and Sainio, 2017).
In the research reported herein of fabric shedding during laun-
dering, dierent ber polymer materials were studied all with the same
knit construction. Accelerated laboratory laundering and home laun-
dering experiments were performed and the shed microber quantity
and characteristics were determined. Polyester and cotton knitted fab-
rics were evaluated since they represent the greatest portion of the
global ber production for natural and synthetic bers, respectively
(Mills, 2011). As well, a rayon knitted fabric was included in this study
as a representation of the regenerated cellulosic bers in the market. In
addition, methods to predict ber shedding based on fabric and yarn
mechanical properties are proposed and evaluated herein.
Another important dimension to the laundering microber issue is
their fate in the environment. Surprisingly, little is known about the
biodegradation of textile bers in aquatic environments. Most de-
gradation studies have been focused on biodegradable and synthetic
polymers intended for packaging applications in composting environ-
ments (Eubeler et al., 2009, 2010;Karamanlioglu and Robson, 2013;
Lešinský et al., 2005;Lucas et al., 2008;Pagga et al., 1996;Starnecker
and Menner, 1996). There have been no studies on aquatic biode-
gradation of textile bers known to the authors of this study. In addi-
tion, there is an emerging concern about the role of natural and arti-
cial bers on the distribution of chemical pollutants in aquatic
environments (Ladewig et al., 2015). Therefore, this research includes a
study of the aquatic biodegradation of the yarns of the major textile
bers, cotton, polyester, rayon, and polyester-cotton blends as a
starting point to dierentiate the eect of ber polymeric material on
the fate of the microbers in aquatic environments.
2. Materials and methods
2.1. Fabrics and yarns
Four interlock fabrics without nishing were manufactured by
Cotton Incorporated to perform the laundering experiments; the spun
yarns contained 100% cotton, 100% rayon, 100% polyester, and 50%/
50% polyester/cotton (Table S1). The weft knitted interlock construc-
tion was made on a 24-cut circular knitting machine (24 needles/in.).
Spun yarns from staple bers with a size of 40/1 Ne (English Cotton
Count, 40 ×840 yards of one single yarn weight 1 pound) were used to
knit the fabrics (Table S2). As pre-treatment, all fabrics were scoured to
remove impurities from the bers such as wax, fats, pectin, proteins,
and organic acids, and improve their wettability. Additionally, fabrics
containing cotton were also bleached. These fabrics were dyed with
dierent colors to assess cross-contamination. The spun yarns cut in
1 cm length were used in the biodegradation experiments. These yarns
were pre-treated as were the fabrics and did not contain nishes or
2.2. Accelerated laundering experiments
2.2.1. Washing protocol
The behavior of the fabrics during laundering was studied at dif-
ferent conditions using the AATCC (American Association of Textile
Chemist and Colorists) standard SDL Atlas Launder-Ometer (South
Carolina, USA) with metal canisters of 550 mL capacity. The fabrics
were cut in square pieces of size 4in × 4in using an ATOM Swing Arm
Clicker Presses model SE20C (Italy). The edges were secured using the
1150 MDA Serger Machine Brand Bernina (Thurgau, Switzerland) with
white 100% polyester yarn brand Excell to avoid errors by the excessive
release of microbers through the edges of the fabrics, these edges were
approximately 12% of the total sample weight. Each piece of fabric
weighed approximately 23 g. A cleaning cycle was performed on the
fabric pieces. In each metal canister 25 metals balls (6 mm of diameter),
150 ml of deionized (DI) water and the fabric sample were added. The
cleaning cycle of the fabric was done for 16 min at the temperature of
interest. The cleaning wash is a very important step in this procedure; it
allows the removal of bers and impurities present in the fabrics from
the manufacturing process.
Cold (25 °C) and warm (44 °C) laundering experiments were con-
ducted with deionized (DI) water and detergent solution (AATCC
Monograph 6-2016, 2017). According to the conditions studied, 25
metals balls (6 mm diameter), 150 ml of DI water or detergent solution
and the fabric sample were added to a 550 ml metal canister and
tumbled for 16 min. The detergent solution was prepared with 1. 47 g of
the 2003 AATCC Standard Reference Liquid Laundry Detergent with
optical brightener (AATCC Monograph 2-2005, 2017) dissolved in one
liter of DI water (AATCC Test Method 135-2015, 2017). For each
condition and fabric type, eight to ten canisters were prepared for the
Launder-Ometer. In addition, a canister with the cleaning agent and the
metal balls but with no fabric was used as a blank during the ltrate
2.2.2. Laundering ltrate analysis
After the washing protocol, all the liquid (150 mL) inside each
canister was recovered in individual glass bottles of 16 oz. capacity,
eight to ten replicates were collected for each fabric type and condition.
The mass of microbers released during laundering was recovered by
ltration using Whatman glass microber lter papers grade GF/C,
47 mm and 1.2 μm particle retention, whereas the quantication of
individual bers and their length and width distributions were obtained
with the HiRes Fiber Quality Analyzer (FQA), OpTest Equipment Inc.
(Ontario, Canada). These analyses were also made on the liquid col-
lected from the canisters without fabrics used in each condition as
blanks to account for the potential inuence of the washing agent and
the background variability.
2.2.3. Statistics
The eect of temperature and use of detergent on the microber
generation during laundering was evaluated with a linear mixed model
using SAS 9.4 and Excel 2016. This model assumes data non-linearity
and assesses if the eect of fabric type, temperature, and use of de-
tergent inuence the microbers generation at a signicant level
α= 0.05. The details of this model are described in the Supplementary
material (S 1.1.4).
2.3. Home laundering experiments
2.3.1. Washing/drying protocol
The Whirlpool Washing Machine Model WTW57005WO (Michigan,
USA) with temperature control system Quick Temp SDL ATLAS (South
Carolina, USA) and the Dryer Whirlpool Model WED57005WO
(Michigan, USA) were cleaned carefully prior to performing this pro-
tocol (Supplementary material section S 1.2.1). The fabrics were cut to
obtain samples of 4 lb. (1.8 kg), representative of a large load in a home
laundering washing machine (AATCC Test Method 135-2015, 2017).
The samples were weighed using an OHAUS Champ bench scale (New
Jersey, United States). In addition, the edges of the fabric were secured
using the 1150 MDA Serger Machine Brand Bernina (Thurgau, Swit-
zerland) with white 100% polyester yarn brand Excell to avoid errors
M.C. Zambrano, et al. Marine Pollution Bulletin 142 (2019) 394–407
by the excessive release of microbers through the edges of the fabrics.
As a rst step, each sample was washed with tap water using the normal
wash load setting to remove the loose bers and impurities from the
manufacturing process and storage.
Before starting the washing cycle, a circular nylon mesh ltering
screen of 20 μm Sefar 0320/14 of 24 cm of diameter was secured at the
discharge pipe of the washing machine to collect the microbers gen-
erated during the laundering process. The temperature control system
was congured to have 115 °F (46 °C) during the washing cycle and
80 °F (27 °C) during the rinsing cycle. Once the washing cycle was
completed, the fabric sample was transferred to the drying machine.
The drying process was set at high temperature (heavy load) for 60 min.
After the rst cycle of washing and drying was completed, the
procedure was repeated two more times with the same fabric to study
how subsequent washings inuence the microbers generation.
Samples collected during washing on the nylon mesh were re-dispersed
in water prior to further analysis. The nylon mesh was washed ve
times with 100 mL of DI water to remove the bers retained and this
water was collected in a clean glass beaker (1 L). A new nylon mesh was
used in each washing cycle to avoid cross-contamination. The re-dis-
persed sample was ltered through a Whatman glass microber lter
paper grade GF/C (47 mm and 1.2 μm particle retention) and the lter
paper was dried at 105 °C overnight and weighed.
2.4. Correlations between microber shedding and physical testing of yarns
and fabrics
The tensile properties of yarns used to knit the fabrics were mea-
sured by the single-strand method (ASTM D2256/D2256M 10, 2015)
in the dry and wet states. The tensile tester MTS Q Test 5 (Minnesota,
USA) was used to perform the test in 1 Grab 10 in. GL mode. The yarns
were conditioned for 24 h prior to testing under the standard atmo-
sphere for textile testing (70 ± 2 °F and 65 ± 2% relative humidity)
and the dry tests were performed in the same environment. For the wet
state tests, the samples were submerged for 5 min in DI water and
loaded immediately in the tensile tester. For the dry state, 15 strands
were tested of each yarn sample; and for the wet state, only 10 strands
of each yarn sample were evaluated. The initial speed of the machine
was adjusted between samples and conditions to achieve a breaking
time of 20 ± 3 s during the experiments (Table S5). The Maxi-Mar-
tindale Abrasion tester from James H. Heal and Co. Ltd. (Halifax, UK)
was used to measure the abrasion resistance of the fabrics used for the
laundering experiments following the Martindale Abrasion Tester
Method (ASTM D4966 12, 1992). Three replicates of each fabric
were prepared, circular specimens of 1.5 in (38 mm). Standard wool
abrasion fabric was used as an abrasion agent applying a pressure of
9 KPa and 20,000 rubs. The fabrics were conditioned for 24 h prior to
testing under standard atmosphere for textile testing (70 ± 2 °F and
65 ± 2% relative humidity) and the test was performed under the
same environment. The mass loss of the fabric after the abrasion test
was obtained by weighing the sample before and after the test using the
balance Voyager Pro OHAUS, precision = 0.1 mg (New Jersey, United
2.4.1. Statistics
SAS 9.4 and Excel 2016 software versions were used to assess the
dierences in breaking load between the types of yarns, in wet and dry
state, and in abrasion resistance between the types of fabrics at a sig-
nicant level α= 0.05. Pair comparisons between the types of yarns
were made using PROC ANOVA and PROC GLM within conditions (dry
and wet state). The PROC MIXED procedure was used to analyze the
fabric abrasion resistance data based on a linear mixed model taking as
xed the eect of the type of fabric tested. There is a signicant dif-
ference between compared variables when the p-value obtained from
the tests is < 0.05.
2.5. Aquatic biodegradation of yarns
The aquatic biodegradation of the spun yarns was assessed by
measuring the oxygen demand of the yarns in a closed respirometer
using as inoculum aerobic microorganisms in the activated sludge from
the Neuse River WWTP in Raleigh, NC (ISO 14851:1999, 2005). The
activated sludge was added to the asks within 72 h after collection.
The concentration of suspended solids in the activated sludge was
measured (ISO 11923: 1997, 1997) and the inoculum was added to the
asks to achieve a concentration of 30 mg of solids per liter of testing
medium to simulate biodegradation in natural environments. For the
preparation of each ask, a magnetic stirrer bar was inserted in each
bottle with the appropriate amounts of test medium and inoculum to
have 400 mL of testing medium in each ask. The standard test medium
(nutrients) for the ISO 14851 was used.
The level of biodegradation was determined by comparing the
oxygen uptake (Ou) with the theoretical oxygen demand (ThOD) of the
spun yarns. Microcrystalline Cellulose (MCC), 20 μm powder from
Aldrich Chemistry, was used as reference material to check the in-
oculum activity during the test.
After measurement and adjustment of the pH to 7, the asks were
aerated using aquarium pumps to achieve oxygen saturation in the
medium for 15 min at the beginning of the experiment and after each
measurement. The dissolved oxygen (DO) concentration after satura-
tion was measured. The DO in the medium was measured with an Orion
StarA123 Dissolved Oxygen Portable Meter (Thermo Fisher Scientic,
Massachusetts, USA) and the pH meter Accumet XL150 from Fisher
Scientic (New Hampshire, USA). The DO meter was calibrated prior
measurments with moisture saturated air (100% Relative Humidity)
and the pH meter was calibrated using buer solutions (pH 4, 7, and
10) from Fisher Chemicals (New Hampshire, USA). The asks were
closed tightly, incubated in a water bath at a constant temperature
(25 °C) and stirred at 300rpm. The test medium was allowed one week
of incubation to let the microorganisms use the organic matter already
present in the activated sludge and allow the stabilization of the in-
oculum to the test medium. After this incubation period, the test ma-
terials (spun yarns and MCC) were added to each ask.
Every week, or more frequently depending on oxygen depletion
rates, the concentration of DO in each ask was measured and the pH
adjusted to 7. The asks were then aerated to saturate the test medium
with oxygen and maintain the aerobic environment for the biode-
gradation process. After saturation, the DO in each ask was measured.
This procedure was performed to account for the oxygen consumption
during the course of the experiment.
Based on the standard method, this test should be considered valid if
the degree of biodegradation of the reference material is > 60% and the
biological oxygen demand (BOD) of the blank did not exceed 60 mg/L
at the end of the test (ISO 14851:1999, 2005).
Several samples were collected at the end of the experiment. The
liquid portion was separated from the solids remaining by ltration
using Whatman glass microber lter papers grade GF/C (47 mm and
1.2 μm particle retention). The liquid portion was used to measure the
nitrication interferences to account for the oxygen consumed by ni-
trication reactions. In the solid portion, scanning electron microscope
(SEM) images were taken and elemental analysis and Fourier-transform
infrared spectroscopy (FTIR) were performed and compared with the
same analyses on test materials before the biodegradation experiment.
2.5.1. Statistics
SAS 9.4 and Excel 2016 software versions were used to assess the
dierences in biodegradation between the types of yarns. Pair com-
parisons between the types of yarns were made using a non-parametric
model for ANOVA (Wilcoxon Model) with a signicance level α= 0.05.
There is a signicant dierence between the variables compared when
the p-value obtained from the test is < 0.05.
M.C. Zambrano, et al. Marine Pollution Bulletin 142 (2019) 394–407
3. Results and discussion
3.1. Microbers generation during accelerated laundering at small scale
3.1.1. Eect of fabric material
All fabric types released signicant amounts of microbers, with
rayon, cotton, and polyester/cotton fabrics of the same knit construc-
tion releasing signicantly more microbers during accelerated
washing than polyester fabrics (Fig. 1). Similar behavior was observed
by Sillanpää and Sainio (2017) in domestic washing, after 5 sequential
washes, cotton fabrics released up to 1.0 × 10
bers per kg of fabric
washed whereas polyester fabrics shed up to 5.0 × 10
bers per kg of
fabric washed.
The result reported here for the microbers released during ac-
celerated laundering of blended knitted fabric (50%/50% polyester/
cotton) versus 100% polyester knitted fabric is dierent than the be-
havior described by Napper and Thompson (2016). They showed that
65% polyester/35% cotton jumper fabrics released signicantly fewer
bers than polyester and acrylic jumper fabrics. These jumper fabrics
were not all made in the same way as they were purchased from
commercial retailers and were not specied as the same brands. This
suggests that the inuence in fabric and yarn construction and pro-
portion of the components of the blend play a major role in the mi-
crobers generation during laundering and should not be generalized.
The generation of microbers with length between 25 and 200 μm had
the same or higher number magnitude than the microbers released
from the fabrics during laundering with length > 200 μm, at the con-
ditions of this study (data shown in Fig. S10).
The inuence of fabric structure was also reported elsewhere
(Carney Almroth et al., 2018;De Falco et al., 2018). Carney Almroth
et al. (2018) observed that polyester eece fabrics shed signicantly
more bers than knit fabrics (polyester, nylon, and acrylic), about 1200
and 9 bers per 100 cm
of fabric, respectively. Whereas, De Falco et al.
(2018) noted the highest release of microbers from woven polyester
with respect to knit polyester and woven polypropylene.
3.1.2. Eect of detergent use
The eect of the washing solution on the mass of microbers re-
leased during accelerated laundering is also presented in Fig. 1. All
materials at 25 °C and at 44 °C showed an increased mass of microbers
released during the laundering with detergent. There was a statistically
signicant increase (p-value < 0.05) in the microbers mass released
when the detergent solution was used as a washing agent for all fabric
types at 44 °C (Fig. S9, A). For cotton, rayon, and polyester/cotton
fabrics, the increase in microbers generated by the presence of de-
tergent during accelerated laundering was statistically signicant (p-
value < 0.05) also at 25 °C (Fig. S9, B).
Similarly, the data obtained using the FQA (Fig. 2) shows the same
tendency as the gravimetric measurements, the number of microbers
released during laundering are increased with detergent and this in-
crease is statistically signicant (p-value < 0.05) for all but the rayon
fabric (Fig. 2, A). Generally, the main inuence of the detergent in the
washing solution is attributed to the generation of microbers with
25200 μm in length, which outnumber, from a count basis, the mi-
crobers with length > 200 μm, Fig. 2.
In fact, several options have been proposed to reduce the number of
microbers released into the euent wash water, such as The GUPP-
YFRIEND washing bag, the Coral ball, and lters that retain the bers
for later disposal (Cora Ball, n.d.;Environmental Enhancements, 2019;
Filtrol, n.d.;Guppyfriend, n.d.). Nevertheless, our results show that
there is an important portion of microbers with a size below 200 μm
that cannot be addressed by these trapping mechanisms.
McIlwraith et al. (2019) showed that the Lint LUV-R lter that can
be installed at the euent pipe of the washing machine can capture
87% of the bers released by a 100% polyester eece blanket during
washing and the Coral ball only trapped 26%. The bers lost in the
euent water were also measured. After using the Coral ball, the length
of the bers did not change signicantly compared to the length of the
bers collected from the euent with no mitigation strategy
(1.5 ± 0.5 mm). However, this was not the case when the Lint LUV-R
lter was used; the length of the bers decreased signicantly to
0.4 ± 0.1 mm, since these mechanisms cannot trap bers smaller than
Fig. 1. Distribution of the mass of microbers generated during accelerated laundering per mass of fabric washed at dierent conditions; washing with detergent
(WD), washing without detergent (WOD), and dierent temperatures. The dierent types of fabrics are shown in dierent colors: purple for cotton, pink for polyester,
green for rayon, and orange for the polyester/cotton blend. The length of the box represents the interquartile range (IQR, the range between the 25th and 75th
percentiles), the mean is represented by a square and the median by a horizontal line in the box, and the vertical lines (whiskers) represent the range within 1.5 IQR.
(For interpretation of the references to colour in this gure legend, the reader is referred to the web version of this article.)
M.C. Zambrano, et al. Marine Pollution Bulletin 142 (2019) 394–407
their pore size, in this case, 150 μm(McIlwraith et al., 2019).
According to these results, it can be concluded that the presence of
surfactant assists the mobilization process of the broken/loose bers
from the fabric to the washing solution, also reported in previous stu-
dies made with polyester and acrylic fabrics during home laundering
(Carney Almroth et al., 2018;Hernandez et al., 2017).
3.1.3. Eect of temperature
The eect of temperature on the microbers generation in the
presence of detergent solution and in deionized water is reported in
Fig. 1. The mass of microbers released from the fabrics during laun-
dering increased at a higher temperature for all types of fabrics,
nevertheless, the dierence was only statistically signicant for cotton
(p-value < 0.05) (Fig. S9, C and D).
The FQA results were similar to the gravimetric analysis (Fig. 2). In
all cases, the total number of microbers released using detergent so-
lution or DI water increased with higher temperature. These increases
were not found to be statistically signicant at p-value < 0.05 in some
cases (Fig. 2, B). Uncertainty on the eect of temperature on the mi-
crober generation during laundering has been reported, even at ex-
tended washing times (Hernandez et al., 2017;Napper and Thompson,
In general, the swelling action of water on cellulose-based bers
increases with temperature. The water acts as a plasticizer, lubricating
and softening the amorphous regions of the cellulose bers by the
disruption of the hydrogen bonds between the cellulose chains. This
causes a reduction in the glass transition temperature of the amorphous
regions and a decrease in mechanical properties such as stiness and
resiliency in regenerated bers such as rayon (Bryant and Walter,
1959). Essentially the increase of temperature promotes the swelling of
cellulosic bers, and as a consequence, the textile structure, generating
free space for the mobilization of the broken bers from the fabric
construction. The swollen fabric structure generates expanded material
expected to enhance fuzz formation due to the shear forces during
washing. Polyester does not swell in water as much as cellulosic bers
and its relatively lower changes in microber generation at higher
temperatures are in agreement with this (Bryant and Walter, 1959).
3.1.4. Fiber size distribution
The size distribution of the released microbers collected was
measured using the FQA. The FQA only measures the size distribution
of bers with length > 200 μm. The length distribution of the micro-
bers with length > 200 μm at 44 °C without detergent is presented in
Fig. 3. Very few microbers > 2.5 mm were detected. The length dis-
tribution of microbers released by rayon fabrics was broader than the
other fabrics tested. Cotton, polyester, and the blended (polyester/
cotton) fabrics released a greater proportion of shorter microbers than
did the rayon.
The width or diameter of the microbers released is dierent de-
pending on the fabric material. Cotton and rayon microbers are
thicker than polyester microbers, Fig. 4. The width distribution of the
microbers generated from polyester/cotton blended fabrics during
laundering is bimodal as expected when the two types of microbers
are both being released in the washing solution. Similar size distribu-
tions were observed in the microbers recovered from laundering of
Fig. 2. Number of microbers generated during accelerated laundering per
mass of fabric washed. A - Eect of detergent use on the generation of micro-
bers at 44 °C. B - Eect of temperature on the generation of microbers,
without detergent (WOD). Error bars represent the standard error (N = 4, ex-
cept for Polyester at 25 °C with N = 5). Signicant dierences are indicated by
* (p < 0.05).
Fig. 3. Fiber Length Distribution of microbers (T = 44 °C, without detergent).
The normalized values are presented based on the percentage of total micro-
bers counted by the FQA within the size range, 2000 to 19,000 microbers
measured per sample. The vertical dotted lines indicate the FQA detection limit
for ber length.
Fig. 4. Fiber Width Distribution (T = 44 °C, without detergent). The normal-
ized values are presented based on the percentage of total microbers counted
by the FQA within the size range, 1000 to 15,000 microbers measured per
sample. The vertical dotted lines indicate the FQA detection limit for ber
M.C. Zambrano, et al. Marine Pollution Bulletin 142 (2019) 394–407
fabrics at dierent temperatures, with or without detergent.
3.2. Microbers generation during home laundering
In agreement with the accelerated laundering experiments, all fab-
rics released microbers with fabrics made of cellulose-based bers
(cotton and rayon) releasing more microbers than polyester during
laundering for all of the three cycles in series, Fig. 5.
There was a consistent decrease in the number of microbers re-
leased with increasing washing cycles, but there was still very sig-
nicant amounts of microbers being released during the third cycle.
This is in agreement with other studies showing the number of micro-
bers released during laundering is generally reduced with increased
cycles until reaching a constant amount (Carney Almroth et al., 2018;
Napper and Thompson, 2016;Pirc et al., 2016;Sillanpää and Sainio,
In the accelerated laundering experiments, more microbers were
generated per weight of fabric washed than in the home laundering
experiments as a result of the more intense mechanical action of the
metal balls; approximately forty times more mass was shed. There is
general agreement between the accelerated and home laundering ex-
periments for the relative amounts of microbers shed for the dierent
fabrics with a correlation coecient of 0.8 (Fig. S19, Supplementary
material). Thus, accelerated laboratory laundering can be used as a
method to assess the relative dierence in shedding capacity of fabrics
in a simple, well-controlled way without the burdensome, labor-in-
tensive eorts involved in using the home washing machine that is
poorly suited for quantitative analysis. Home laundering machines
utilize large quantities of water and have complex washing compart-
ments and inlet and outlet piping and valves that make accurate re-
covery of microbers dicult. In addition, the accelerated laundering
experiments provide larger quantities of microbers than home laun-
dering that are easier to capture and measure gravimetrically.
Regarding the size of the microbers (length > 200 μm), in the
home laundering experiments, longer microbers were obtained than in
the accelerated laundering experiments, in agreement with the hy-
pothesis that the lower intensity action during home laundering
washing does not break oas many small microbers (Fig. 6). In ad-
dition, for both the accelerated and home laundering experiments,
rayon fabrics generated longer microbers, followed by cotton, polye-
ster/cotton, and polyester, respectively. In addition, SEM images
showed that the shedded bers were approximately the same width as
the original bers in the yarns in the fabrics prior to washing for both
accelerated and home laundering washing (Figs. S20 and S21).
3.3. Predictive tests for the microbers generation during laundering
Certainly, microber generation during laundering involves many
factors such as fabric type and geometry (woven, knit, or nonwoven),
yarn type (twist, evenness, hairiness, and number of bers), processing
history (spinning, knitting or weaving, scouring, bleaching, dyeing,
nishing, and drying processes), and physicochemical properties of the
bers (Hernandez et al., 2017).
In this study, all the above-mentioned variables were the same ex-
cept the physicochemical properties of the bers in the yarns, thus, to
understand why some knitted fabrics released more microbers than
others, the microber generation process during laundering was com-
pared using the schematic model for pilling formation of fabrics. This
process is composed of several steps: fuzz formation (a ber with a
loose end extending out of the fabric), swelling, brillation, pill for-
mation (entanglement of the bers), and pill wear o(Geology, 1966;
Okubayashi et al., 2005;Okubayashi and Bechtold, 2005). In this case,
it is proposed that the shedding capacity of the fabrics depends mainly
on the fuzz formation step and how easy these bers are broken by the
mechanical action of the washing machine before forming the pill
(Fig. 7). The breakage of the staple bers is the main contribution to
microber formation and release. In this study, most shed microbers
were < 2 mm long (Figs. 3 and 6) whereas the staple bers are much
longer. Generally, natural staple bers are classied as short staple -
bers (length between 25 and 60 mm) and long staple bers (length >
60 mm) (Elhawary, 2015). For cotton bers, the US Cotton Fiber Chart
2017/2018 reported the length for US cotton bers ranging from 1.11
in (28.19 mm) to 1.17 in (29.72 mm) (Cotton Incorporated, n.d.). Ad-
ditionally, synthetic or semi-synthetic bers are generally uniformly cut
in lengths higher than 32 mm for staple ber applications (Barnet, n.d.).
The fuzz formation step depends on the friction, shape, thickness,
stiness, and abrasion resistance of the bers (Geology, 1966;
Okubayashi et al., 2005;Okubayashi and Bechtold, 2005). Therefore, to
assess how easy the fuzz forms and the bers break, some mechanical
properties were evaluated: the abrasion resistance of the fabrics and the
tensile breaking load and hairiness of the same yarn types used to
construct these fabrics.
The tensile breaking load of the yarns is presented in Table 1 for the
dry and wet states. Polyester, which does not swell signicantly in
water, showed similar breaking loads for both the wet and dry states.
The polyester yarns presented signicantly higher breaking load com-
pared to the other yarns, explaining to some extent why polyester
fabrics released fewer microbers than the other fabrics studied.
In contrast to polyester, rayon and cotton yarns had dierent be-
haviors in the dry and wet states. In the wet state, rayon yarns were
Fig. 5. Mass of microbers generated during home laundering after subsequent
washing per mass of fabric washed. The same fabric sample (N = 1) was wa-
shed and dried three times. Fig. 6. Mean length of microbers (> 200 μm) released during home laun-
dering and accelerated laundering (T = 44 °C, with detergent). The mean va-
lues are presented based on the number of bers measured by the FQA, 2000 to
5000 microbers per sample. Error bars represent a 95% condence level.
M.C. Zambrano, et al. Marine Pollution Bulletin 142 (2019) 394–407
weaker while cotton yarns were stronger compared against the re-
spective dry yarns. In fact, cotton bers have higher crystallinity and
molecular weight than rayon bers. The cellulose chains in the non-
crystalline regions of the cotton bers tend to rearrange and orient if a
force is applied increasing their tensile strength (Hajime et al., 2000).
Additionally, the crystallites in the cotton in the wet state are
maintained as a reinforcing component. In rayon, there is a lower
crystallinity and thus a lower wet strength of the yarns. According to
the results of the tensile tests, cotton yarns were signicantly stronger
than rayon yarns when wet. However, the microbers generation of the
cotton and rayon fabrics were similar and not predicted by dierences
in the tensile strength results.
Other parameters to consider are the hairiness and evenness of the
yarns which are critical measurements for the quality of the yarn and
also aect the microber generation during laundering. The char-
acteristics of the yarns used in this study are presented in Table S2
(Supplementary material). They have similar yarn count and twist; the
main dierences are due to their strength properties, discussed above,
and their evenness and hairiness.
Evenness is a measure of how uniform the yarn is in terms of mass
and cross-section variation per unit length (ASTM D1425/
D1425M14, 2014;Hasler and Honegger, 1954;Slater, 1986;Soares
et al., 2008). Higher coecient of variation percents are an indication
of uneveness, poor appearance and quality and lower yarn strength. In
this case, the yarn samples have similar evenness except for the 50/50
polyester/cotton yarn that has a higher coecient of variation.
Moreover, hairiness is a measurement of the amount of free bers
loops and ends protruding from the yarn surface at a certain distance.
High hairiness aects the appearance of textiles products and increases
the surface friction of yarn and fabrics and their pilling tendency,
therefore, it can aect the microbers generation during laundering
(Barella, 1957, 1983;Krupincová and Meloun, 2013;Majumdar, 2010;
Manich and Barella, 1997;Yuvaraj and Nayar, 2012). The hairiness
depends on several factors such as the twisting levels and the diameter
Fig. 7. Proposed mechanism for the microbers release during laundering from fabrics and yarns made of polyester bers (blue dashed line, left) and cellulosic bers
(green solid line, right). The loose bers (fuzz) come out of the textile structure during wear and use (FUZZ FORMATION). Then, these bers are broken in the
washing cycle by the mechanical action of the washing machine, FIBER BREAKING. In the presence of water and detergent, cellulosic bers swell (SWELLING), due
to the mechanical action of the washing cycle these bers could also be brillated (FIBRILLATION) and broken (FIBER BREAKING). Adapted from Okubayashi et al.,
2005 and Okubayashi and Bechtold, 2005. (For interpretation of the references to colour in this gure legend, the reader is referred to the web version of this article.)
Table 1
Breaking Load of Spun Yarns measured by the single-strand method (ASTM D2256/D2256M 10, 2015).
Sample Break load (N) Strain at break (%)
Dry state
Wet state
Dry state
Wet state
Mean Std Dev Mean Std Dev Mean Std Dev Mean Std Dev
Cotton yarns dry state 1.8053 0.1655 2.2742 0.1912 5.6944 0.554 8.6700 0.7837
Polyester yarns dry state 4.3364 0.3176 4.4316 0.1800 10.7539 0.5252 10.5975 0.6643
Polyester/cotton yarns dry state 2.2028 0.1414 2.2804 0.2320 13.1837 0.9946 14.1328 0.9308
Rayon yarns dry state 1.7077 0.1113 0.9884 0.1097 15.3462 1.1053 15.3316 1.7243
SD Standard Deviation.
M.C. Zambrano, et al. Marine Pollution Bulletin 142 (2019) 394–407
of the yarn, and the rigidity, elongation, tenacity, and length of the
bers (Barella, 1957, 1983;Majumdar, 2010).
The hairiness measurement also provides an indication of which
yarns have more tendency to form fuzz on the surface. The Zweigle
Hairiness parameter indicates the number of bers protruding 3 mm or
more from the yarn surface in 100 m of yarn (Krupincová and Meloun,
2013). The hairiness of the yarns used to knit the fabrics in this study is
presented in Fig. 8. In decreasing order, 100% cotton spun yarn has
higher hairiness followed by 100% polyester spun yarns, 100% rayon
spun yarns, and 50/50 polyester/cotton spun yarns. In general terms, it
can be said that the similarity in microbers generation between rayon
and cotton bers may be related to the high hairiness of cotton and low
tensile strength of rayon yarns. Polyester yarns have relatively similar
hairiness to rayon but the bers are much stronger, which does not
generate a large number of microbers during laundering. In the case of
50/50 polyester/cotton, the hairiness is low but the variation in even-
ness is considerably high which can lead to poor abrasion resistance.
Moreover, the abrasion resistance of the knitted fabrics was studied
using the Martindale Abrasion Tester. The weight loss of the fabrics was
determined after 20,000 cycles of the wool abrasion fabric scraping the
surface of the fabrics, reecting the resistance of the fabric to shed mass
under the mechanical action of the washing and drying cycles. The
results presented in Table 2 show that rayon knitted fabrics are less
resistant to abrasion followed by cotton, polyester/cotton and polyester
knitted fabrics with a signicant dierence between them.
The breaking load of the yarns and the abrasion resistance of the
fabrics in this study correlate with the number of microbers released
during laundering (Figs. 9 and 10). These correlations exist for all
conditions but at dierent levels (Figs. S22 and S23).
In summary, it is expected that fabrics with higher abrasion re-
sistance, low hairiness, and higher yarn breaking strength would have a
lower tendency to form fuzz and/or release microbers during the
mechanical action of washing.
3.4. Aquatic biodegradation of yarns
The aquatic biodegradability of the microbers shed in the en-
vironment via home laundering provides a good indication of their
persistence in the environment. The aquatic biodegradability was stu-
died following the ISO standard method for ultimate aerobic biode-
gradability of plastic materials in aqueous mediums (ISO 14851:1999,
Zweigle Hairiness
A – 100 % Cotton Spun Yarn
Zweigle Hairiness
B – 100 % Polyester Spun Yarn
Zweigle Hairiness
C – 100 % Rayon Spun Yarn
Zweigle Hairiness
C – 50/50 Polyester/Cotton Spun Yarn
Fig. 8. Selected optical microscope images of the spun yarns. The Zweigle hairiness data for each yarn is indicated.
Table 2
Abrasion resistance of knitted fabrics measured as the weight loss of the fabrics
by the action of the Martindale Abrasion Tester (ASTM D4966 12, 1992).
Sample Weight loss SD
Rayon knitted fabrics 5.63% 0.28
Cotton knitted fabrics 3.34% 0.22
Polyester/cotton knitted fabrics 1.63% 0.12
Polyester knitted fabrics 0.11% 0.13
SD Standard Deviation, N = 3.
M.C. Zambrano, et al. Marine Pollution Bulletin 142 (2019) 394–407
2005) using the yarns used to knit the fabrics and a low concentration
of activated sludge solids to simulate natural aquatic environments. The
yarns have bers with similar width to the shedded microbers during
laundering and as such are reasonable materials to evaluate for relative
biodegradability. The percentage of biodegradation was measured
comparing the oxygen uptake of the system with the theoretical oxygen
demand ThOD calculated according to the total organic carbon in each
sample. The nitrication interferences during the experiments were not
signicant compared to the oxygen consumption due to biodegradation
of the polymeric materials studied. At the end of the experiment, the
reference material (microcrystalline cellulose) reached 84% degrada-
tion (Fig. 11) indicating the inoculum was working and the BOD of the
blank was 12 mg/L, it did not exceed 60 mg/L, as required by a valid
experiment (ISO 14851:1999, 2005).
The biodegradation curves of the materials over the 243 days are
shown in Fig. 11. Only the polyester material had fully reached the
plateau phase; the other materials including the microcrystalline cel-
lulose were continuing to consume oxygen, albeit a slow rate towards
the end of the experiment (Fig. 11). The percentage of biodegradation
after the 243 days, subtracting the nitrication interferences (oxygen
consumed in nitrication reactions), was 75.90 ± 12.35% for cotton
yarns, 62.21 ± 13.29% for rayon yarns, 39.76 ± 3.52% for 50/50
Polyester/Cotton Yarns, and 4.05 ± 0.75% for polyester yarns. The
results are as expected, the cellulose-based materials are a readily
available source of carbon for the microorganisms. The polyester, on
the other hand, being hydrophobic and non-sugar based is not degraded
by the microorganisms (Li et al., 2010).
There is no pass/fail criteria for aquatic biodegradability in the ISO
method 14851 and it is generally understood that there does not exist a
clear biodegradability threshold to certify a material as biodegradable
in aquatic and marine environments (European Bioplastics, 2018).
Nevertheless, the tests were performed under valid conditions based on
the method criteria, 60% of degradation in the biodegradable reference
material (microcrystalline cellulose) and < 60 mg/L of oxygen con-
sumption occurred at the end of the test (ISO 14851:1999, 2005).
The withdrawn standard for non-oating biodegradable plastics in
the marine environment (ASTM D7081-05, 2005) specied that to
consider a plastic product biodegradable in marine environments >
30% of the organic carbon must be converted to carbon dioxide (CO
within 180 days at 30 °C with satisfactory disintegration after 12 weeks
and 90% of biodegradation in an active environment such as com-
posting. However, until now there is no replacement for this standard
clarifying these requirements but clearly in this experiment for all
materials, except for polyester, > 30% of the carbon was converted to
Fig. 9. Mass of microbers generated during accelerated laundering (T = 25 °C, without detergent) vs A - Breaking Load of Yarns in Wet State and B - Weight Loss of
the fabrics after 20,000 cycles in the Martindale abrasion tester. Mean values are shown for all the variables.
Fig. 10. Mass of microbers generated during accelerated laundering (T = 25 °C, with detergent) vs A - Breaking Load of Yarns in Wet State and B - Weight Loss of
the fabrics after 20,000 cycles in the Martindale abrasion tester. Mean values are shown for all the variables.
M.C. Zambrano, et al. Marine Pollution Bulletin 142 (2019) 394–407
(Fig. 11).
With respect to the biodegradation of cellulosic bers, rayon is ex-
pected to have a higher biodegradability than cotton due to the dif-
ferences in crystallinity, orientation and moisture regain of these bers;
rayon has lower crystallinity and higher moisture regain than cotton
due to the antiparallel conguration of cellulose II within the rayon
ber structure (Battista, 1950;Howsman, 1949;Niu et al., 2012;Park
et al., 2004)
The amorphous regions are easier to degrade, chemically
and enzymatically than crystalline regions in polymeric materials
(Mochizuki and Hirami, 1997). Nevertheless, in this study, the dier-
ence in the biodegradation percentage between the three types of cel-
lulosic materials was not signicant. In the cellulosic samples, the
variability of the data could be related to the changes in the levels of
oxygen in the asks that aect the behavior of the microorganisms. The
oxygen supply was not constant during the experiment, every week or
as needed the bottles were saturated with oxygen for 15 min using an
aquarium pump and air stones to diuse the air in the test medium to
reach around 8 mg/L of dissolved oxygen. The dierences in the oxygen
levels represent the oxygen consumed during the biodegradation pro-
cess to convert the organic carbon to CO
The curves in Fig. 11 indicate that polyester and polyester/cotton
yarns had reached more of a plateau than did microcrystalline cellulose,
rayon, and cotton. In addition, 50/50 polyester/cotton yarns reached a
plateau phase at about 40% of biodegradation, as would be expected
from a weighted average of the polyester and cotton degradation re-
sults. As expected, only the cotton in the blend degraded during the
experiment, conrmed by FTIR (section S 2.4.4, Supplementary mate-
Polyester yarns did not degrade under the test conditions. The
biodegradation of polyester and cotton fabrics have also been tested
under the action of natural soil under aerobic laboratory controlled
conditions and a large scale composting facility (Li et al., 2010). After
90 days in natural soil, cotton fabrics without nishing agents achieved
around 23% of biodegradation and polyester fabrics only 13% (Li et al.,
2010). In composting, the cotton fabrics weight loss was 55% and
polyester fabrics only 20% in 90 days (Li et al., 2010). Moreover, the
normal microbial communities in the environment do not attach to
polyester (Bajpai et al., 2011). It has been shown that bacterial ad-
herence in polyester fabrics was low compared to cotton and polyester/
cotton blended fabrics (Bajpai et al., 2011). In addition, polyester is less
susceptible to fragmentation of the structure by hydrolysis due to its
high hydrophobicity and low moisture regain (Fuzek, 1985;Li et al.,
Herein, cotton spun yarns were completely disintegrated during
biodegradation. The rayon sample showed evidence of some partially
degraded small bers in the suspension at the end of the experiment. In
the case of polyester, the yarns did not undergo signicant changes. The
50/50 cotton/polyester blended yarn shows no intact cotton bers after
biodegradation, in agreement with the FTIR results. Images of the re-
sidual solids and initial yarns are shown in the Supplementary material
(Figs. S29 and S30).
Despite the variation in the biodegradation data, these results are in
line with the behavior expected, that cellulose-based bers are biode-
gradable. Cellulose-based fabrics release more microbers in laun-
dering but they degrade readily in aerobic aquatic environments. More
research is needed to understand the ow of microbers and improve
the removal eciency in the WWTPs.
3.5. Environmental implications of microbers from laundering
The eciency of WWTPs in microplastics removal has been re-
ported to be higher than 98% (Lares et al., 2018;Magnusson and Norén,
2014;Talvitie et al., 2015). The microplastics are mainly retained in the
sewage sludge, nevertheless, most of these results were reported with
microplastics > 250 μm being analyzed (Lares et al., 2018;Magnusson
and Norén, 2014), only Talvitie et al. (2015) evaluated particles and
bers > 20 μm in size.
Most of the microplastics (particles and bers) are removed in pri-
mary and secondary treatment (clarication, sedimentation, and
aerobic bioreactors or activated sludge treatment) (Talvitie et al.,
2017b, 2015). Traditional tertiary treatments such as gravity sand l-
ters, or biological ltration are very ecient to further remove mi-
croplastics after secondary treatment (Carr et al., 2016;Mintenig et al.,
2017;Talvitie et al., 2017b, 2015). In addition, advanced technologies
such as membrane bioreactors (0.4 μm pore size), rapid sand lters,
dissolved air otation, and disc lters as tertiary treatments have the
potential to trap up to 99.9% of the microplastics escaping the sec-
ondary treatment (Lares et al., 2018;Talvitie et al., 2017a). Never-
theless, WWTPs are not designed to capture microplastics and these
advanced technologies are still not implemented in most of the pro-
Without a doubt, WWTPs are a route for microplastics entering
aquatic environments. Despite the high removal eciency, the high
volume of euents discharged constantly to aquatic environments
Fig. 11. Biodegradation curves of the textile yarns used to knit the fabrics used for the laundering experiments. The percentage of biodegradation is based on the
oxygen uptake versus the theoretical oxygen demand. The error bars represent the standard error (n = 3 for all materials, except MCC with n = 1).
M.C. Zambrano, et al. Marine Pollution Bulletin 142 (2019) 394–407
contribute signicantly to the microplastic pollution problem. Talvitie
et al. (2017b) estimated, on average, 1.97 × 10
per day are discharged into the Baltic Sea from wastewater euent.
Taking into consideration the annual discharges of 12 WWTPs in Lower
Saxony (Germany), Mintenig et al. (2017) predicted a total discharge of
to 4 × 10
microplastics (particles and bers) per WWTP an-
nually. In the US, Mason et al. (2016) estimated that the daily dis-
charges from a municipal WWTP ranged from around 50,000 up to
nearly 15 million particles. Likewise, Lares et al. (2018) forecasted that
approximately 1.0 × 10
and 4.6 × 10
microplastics were discharged
daily with the nal euent and digested sludge from the Kenklaver-
onniemi WWTP (Finland), respectively. These numbers vary depending
on the location, type of euents, demand and capacity, the population
in the area, weather conditions, and type of treatment. In addition,
there is a lack of standardization on the methods used to collect and
identify these microplastics from the dierent points in the wastewater
treatment process that could cause over or underestimation of these
values. Another problem that needs to be considered is the transfer of
microplastics to agricultural soils by the use of WWTPs sludge as fer-
tilizer. In Europe, it was estimated that 63,000430,000 tons of mi-
croplastics are applied to farmlands per year (Nizzetto et al., 2016). The
consequences in agricultural sustainability and human health of this
activity are also not well understood (Nizzetto et al., 2016).
In some wastewater euents, microbers represent an important
proportion of the microplastics found in the wastewater euents (Lares
et al., 2018;Mason et al., 2016;Mintenig et al., 2017;Talvitie et al.,
2015, 2017a, 2017b). In general, it has been reported that these mi-
crobers are predominantly made of polyester, and more specically,
polyethylene terephthalate (PET) (Lares et al., 2018;Mintenig et al.,
2017;Talvitie et al., 2017a;Wolet al., 2018;Ziajahromi et al., 2017).
In most of the WWTP assessments on microplastics, the removal
eciency of cellulose-based bers has been ignored. However, cellu-
lose-based bers have been observed in the euents of WWTPs (Lares
et al., 2018;Talvitie et al., 2017b, 2015; Ziajahromi et al., 2017).
Talvitie et al. (2017b) found that 30% of the microlitter collected from
the wastewater euent was bers and from that 66% was comprised of
cellulose-based bers and 33% of the bers were polyester bers (PET).
Moreover, in this study, we observed that around 50% of the mi-
crobers released during laundering were below 200 μmin size in all
the fabric types evaluated and that these particles still have the po-
tential to escape the wastewater treatment process. The smallest size
fractions are the most common microplastics (particles and bers) ob-
served in the euents of the WWTPs (10 μm100 μm) (Mintenig et al.,
2017;Talvitie et al., 2017a, 2017b;Wolet al., 2018). Nevertheless,
another study that analyzes larger microplastics (> 250 μm), including
bers, also reported that > 50% of the microplastic recovered in the
euents were smaller than 1 mm (Lares et al., 2018). In addition, Wol
et al. (2018) reported that the microbers recovered from the WWTP
euents ranged between 100 μm and 1000 μm in length similar to the
results herein (Fig. 4).
Similarly, many studies that have been focused on the ecotoxicity of
micro and nanoplastics in marine and freshwater ecosystems overlap
with the size of the microbers observed in our study, nevertheless
cellulose-based bers were generally not considered (Chae and An,
2017). These studies observed various eects on the growth, develop-
ment, behavior, reproduction, and mortality of aquatic animals (Chae
and An, 2017). However, there is a lot of uncertainty about the sig-
nicance of these toxicity studies due to (1) the dierences between
simulated lab conditions and environmentally relevant concentrations
of micro and nanoplastics, (2) the unknown long-term eects of these
small plastics on aquatic organisms, and (3) the possible eects on
human health from trophic transfer of micro and nanoplastics through
the food chain (Burton, 2017;Chae and An, 2017). Kosuth et al. (2018)
estimated that the average person ingests 5,800 synthetic particles,
such as synthetic microbers, a year from tap water, beer, and sea salt
alone. However, only one study examined microplastics in stool
samples (Schwabl, 2018) with particles between 50 and 500 μm in size
observed in all the samples evaluated, 18 to 172 particles per 10 g of
stool. No bers were reported, however, the microplastics were mainly
comprised of polypropylene (62.8%) and polyethylene terephthalate
(17%) (Schwabl, 2018).
The sorption mechanisms between microplastics/microbers and
chemicals are controlled by the physical-chemical properties of the
materials, the nature of chemicals, temperature, and solution chemistry
(pH, salinity, etc.) (Wang et al., 2018). Synthetic microbers such as
polyester being low surface energy materials will interact more strongly
with non-polar organic chemicals in a stronger way than will cellulose-
based microbers. Natural based bers have distinct surface chemis-
tries and have a dierent role in the environment; they may adsorb
dierent chemicals than do synthetic bers (Grancaric et al., 2005). It is
therefore important to study microbers throughout their life cycle,
including both the generation and environmental fate of these mate-
4. Conclusions
The shedding mechanism of microbers from textiles and their
biodegradability are fundamental to understand how to reduce the
presence of these bers in aquatic environments. In summary, all ber
types released signicant amounts of microbers during laundering,
however, cellulose-based fabrics released more microbers than
polyester with the same fabric structures. The ber and yarn physico-
chemical properties play a major role in the microber generation.
Fabrics with higher abrasion resistance, low hairiness, and higher yarn
breaking strength have a lower tendency to form fuzz and/or release
microbers during the mechanical action of washing. From the laun-
dering parameters studied, the use of detergent increases the generation
of microbers, the surfactant promotes the mobilization process of -
bers from the fabric to the washing solution. In general, accelerated
laundering experiments results correlated with home laundering ex-
periments but accelerated laundering experiments were easier to con-
trol and had better sensitivity and repeatability. Despite the fact that
the cellulose-based fabrics shed more microbers than the polyester
fabric, cotton and rayon bers degrade in aquatic conditions whereas
polyester bers do not and are expected to persist in the environment
for a long time. More research is needed to understand the fate of textile
microbers and their additives in the environment.
The authors declare no competing nancial interest.
Cotton Incorporated (United States) and the Cotton Research and
Development Corporation (Australia) nancially supported this re-
search. We would like to thank Suzanne Holmes and Angela Massengill
from the Product Evaluation Laboratory and Tony Evans from the Color
Services Laboratory at Cotton Incorporated for their support with
training and equipment for the laundering experiments and mechanical
testing of yarns and fabrics. In addition, Harry Frost (University of
Surrey, UK) took the optical microscope images to complement the
hairiness data measurements. Moreover, the Neuse River Wastewater
Treatment Plant in Raleigh, NC, USA contributed with the activated
sludge used as a source of microorganisms for the biodegradation ex-
periments. Finally, Heather Starkey (NC State University) provided
support for the statistical analysis.
Appendix A. Supplementary data
Supplementary data to this article can be found online at https://
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M.C. Zambrano, et al. Marine Pollution Bulletin 142 (2019) 394–407
... Microfibers are known to mainly originate from textiles and are often composed of synthetic polymers, most notably polyester, which are resistant to degradation (Browne et al. 2011;Dubaish and Liebezeit 2013;Zambrano et al. 2019Zambrano et al. , 2020Zambrano et al. , 2021a. However, there are still many other sources of generating microfibers, including nonwovens. ...
... Experiments were conducted in order to determine the propensity of the material to shed fibers or particles under mechanical actions in aquatic conditions, following methodology described in previous research for fabrics (Zambrano et al. 2019). As shown in Fig. 1, micro-particle generation of commercial wet wipes was investigated using a Launder Ometer (SDL Atlas, LLC, SC, USA), which is most often used for testing fabric dye fastness. ...
... Table 4 shows the overall result of microfiber generation for commercial nonwoven products. Compared to the textile fabrics investigated under the same experimental conditions (Zambrano et al. 2019), more microfibers in general were generated from commercial nonwoven fabrics. According to Zambrano et al. (2019), generally less than 3 mg of microfibers are generated per gram of fabric at room temperature with or without detergent present. ...
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Nonwoven products are widely used in disposable products, such as wipes, diapers, and masks. Microfibers shed from these products in the aquatic and air environment have not been fully described. In the present study, 15 commercial single-use nonwoven products (wipes) and 16 meltblown nonwoven materials produced in a pilot plant were investigated regarding their microfiber generation in aquatic and air environments and compared to selected textile materials and paper tissue materials. Microfibers shed in water were studied using a Launder Ometer equipment (1–65 mg of microfibers per gram material), and microfibers shed in air were evaluated using a dusting testing machine that shakes a piece of the nonwoven back and forth (~ 4 mg of microfibers per gram material). The raw materials and bonding technologies affected the microfiber generation both in water and air conditions. When the commercial nonwovens contained less natural cellulosic fibers, less microfibers were generated. Bonding with hydroentangling and/or double bonding by two different bonding methods could improve the resistance to microfiber generation. Meltblown nonwoven fabrics generated fewer microfibers compared to the other commercial nonwovens studied here, and the manufacturing factors, such as DCD (die-to-collector distance) and air flow rate, affected the tendency of microfiber generation. The results suggest that it is possible to control the tendency of microfiber shedding through the choice of operating parameters during nonwoven manufacturing processes.
... Science of the Total Environment 834 (2022) 155429 When the larger plastics are released into the environment, they eventually turn into microplastics due to a combination of environmental weathering processes such as photodegradation, oxidation, hydrolysis, and biodegradation (Andrady, 2015;Gewert et al., 2015;Zambrano et al., 2019). Depending on the microplastic's origin, they are divided into two categories as "Primary" microplastics and "Secondary" microplastics (Sundt et al., 2014). ...
... Besides, the majority of these studies were only focused on fiber losses during the washing. Only a few studies have investigated the impact of drying the fabrics on microfiber release (O'Brien et al., 2020;Pirc et al., 2016;Tao et al., 2022;Zambrano et al., 2019). However, microfiber releases from the acrylic fabrics during drying were missing in these studies. ...
Increasing uses of synthetic textiles are now a concerning issue as these synthetic textiles are shedding microfibers during the laundering of the fabrics and are considered as a potential source of microplastics (size <5 mm). In addition, manmade fibers like polyester, acrylic, and nylon represent 60% of the worldwide consumption of textile fibers. The novelty of this study is to assess the releasing trends of microfibers from acrylic fabrics during washing and drying under different conditions from a portable washer and dryer machine. Washing and drying effluents were filtered out which were further quantified with gravimetric analysis to determine the net weight of the released microfibers. Among different washing parameters, the mean length and diameter of the released microfibers were found to be approximately 2411 ± 1500 μm and 18 ± 4 μm, respectively. The results indicate that the release of microfibers increased by 2 and 1.4 times respectively when washing and drying time increased from 30 min to 60 min due to high mechanical stresses and longer rotational forces on the fabrics. The use of detergent during washing also promoted more microfiber release (162.49 ± 44.21 mg/kg) when compared to without detergent (60.22 ± 13.32 mg/kg). Moreover, microfibers were released approximately 1.8 times higher from washing when washed with 40 °C of water than with 20 °C of water. However, subsequent washing and drying cycles showed decreasing patterns of microfiber release as microfiber released 45% and 67% less during the 7th washing and drying cycle, respectively, compared to the 1st cycle. Results of this study would help to understand the releasing patterns of microfibers which can help to improve the existing systems to reduce the microplastic emissions from laundering.
... In relation to polyester, it is a filament fiber that has less hairiness and cannot generate many microfibers during abrasion. This feature may contribute to polyester showing better pilling resistant properties than cotton fiber-based fabrics (Zambrano et al., 2019). The visual representation in Figure 3 also strengthens this explanation, there has no significant impact of pilling on 100% polyester and 100% viscose-based fabric. ...
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The physical properties of weft knitted fabrics can be modified according to the fabric structure and the raw material used to manufacture the final fabric. This research demonstrates the influence of fiber types and fabric structure on some specific physical properties such as bursting strength, wicking behavior, pilling effect, and abrasion resistance of weft knitted fabrics. For this purpose, in this research study, one natural fiber cotton, one regenerated fiber viscose, and one synthetic fiber polyester were used. At the same time, to avoid any conflicts of the other fabric production factors, the number of feeders, machine diameter, needle gauge, stitch length was kept constant during the production of the weft-knitted fabrics. Moreover, three different structures of single jersey fabric like plain single jersey, single lacoste, and double lacoste were used to produce nine single jerseys of weft knitted fabric, while in each knit structure, three fabrics were produced using 100% cotton, 100% viscose, and 100% polyester fiber. Statistical analysis has been performed along with factorial analysis of variance (ANOVA) followed by simple main effect and simple comparison analysis. The finding illustrates that both fiber types and fabric structure regulate the physical properties of weft knitted fabrics. The polyester fiber seems to possess excellent mechanical properties such as bursting strength, abrasion, and pilling resistance without any influence of fabric structures studied in this research. However, both the fiber types and fabric structure combinedly influence the wicking of weft knitted fabrics. Additionally, it has been assumed that the influence of fiber types and fabric structure on strength, pilling, abrasion-resistant, and wicking properties of fabrics also combined with the areal density and extensibility of weft knitted fabrics.
... Laundry temperature is also having a significant impact on the microfiber release from the textile fabric. Research results confirmed a significant increment in microfiber release from polyester, amide, and acetate fabrics while laundry temperature was increased from 30 to 40 and 60 °C (Zambrano et al. 2019). ...
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The production, use, and disposal of synthetic textiles potentially release a significant amount of microfibers into the environment. Studies performed on municipal wastewater treatment plants (WWTPs) effluent reported a higher presence of microfibers due to the mix of domestic laundry effluent through sewage. As municipal WWTPs receive influents from households and industries, it serves as a sink for the microfibers. However, research on textile industry WWTPs that primarily treat the textile fabric processing wastewater was not explored with the concern of microfibers. Hence, the review aims to analyze the existing literature and enlighten the impact of WWTPs on microplastic emission into the environment by specifically addressing textile industry WWTPs. The results of the review confirmed that even after 95–99% removal, municipal WWTPs can emit around 160 million microplastics per day into the environment. Microfiber was the dominant shape identified by the review. The average microfiber contamination in the WWTP sludge was estimated as 200 microfibers per gram of sludge. As far as the industry-specific effluents are analyzed, textile wet processing industries effluents contained > 1000 times higher microfibers than municipal WWTP. Despite few existing studies on textile industry effluent, the review demonstrates that, so far, no studies were performed on the sludge obtained from WWTPs that handle textile industry effluents alone. Review results pointed out that more attention should be needed to the textile wastewater research which is addressing the textile wet processing industry WWTPs. Moreover, the sludge released from these WWTPs should be considered as an important source of microfiber as they contain more quantity of microfibers than the effluent, and also, their routes to the environment are huge and easy.
... Positive correlation between yarn hairiness and release of MPF was observed by Özkan for hairiness higher than 4 mm (Özkan and Gündoğdu, 2020). Another study also correlated hairiness together with easiness to form fuzz and MPF extraction (Zambrano et al., 2019). However, the hairiness was compared between different types of fabrics (cotton, rayon, and PET) and the study discussed potential mechanisms of MPF production during washing, also taking the wear phase into account, and did not test the hypothesis that most fibers were already embedded in the textiles. ...
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Synthetic fibers, especially polyester, have over past decades managed to overtake and dominate the textile industry. Microplastic fibers are shed from synthetic textiles during their user phase, primarily during washing. However, there is little known about their origin, except that they are likely embedded in textiles already since their production. Therefore, we systematically examined the presence of microplastic fibers during the process of yarn production. We started with one bale and took samples from the bale opening step throughout carding, sliver handling and finally to spinning. We extracted microplastic fibers from all samples in order to quantify and characterize them. We also investigated the impact of process parameters, especially 4 different spinning methods (ring, compact, rotor, and air-jet spinning). We found microplastic fibers in all studied samples, ranging between 44 fibers/g to 8057 fibers/g. Rotor-spun yarns were identified as a material with a high content of microplastic fibers (2000–8000/g) while the other samples, including yarns spun with alternative methods, showed fiber numbers in tens and hundreds of fibers/g. Varying the operational settings of carding and spinning had none to minimal impacts on fiber number with the exception of rotor spinning, where we observed a 4 fold increase when the speed was increased by 25%. The released fibers have each a unique fiber length distribution with varying medians: 210 μm for rotor yarns, 330 μm for air-jet yarns and 530–580 μm for ring and compact yarns. The results from this study will allow textile companies to select processes or operating conditions that minimize the presence of microplastic fibers.
... × 10 3 fibres, subjected to the kind of synthetic textiles (Napper et al., 2015). The number of fibres released is strongly influenced by the number of washing cycles per week, type of detergents used, temperature of the water, amount of water used, and the nature of clothes (Cesa et al., 2017;Koelmans et al., 2019;Zambrano et al., 2019). Microfibers that reach the aquatic environment from the effluent of WWTPs can be laden with pathogens and may potentially enter into the networks of the aquatic food chain and can threaten human health. ...
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Microplastics (MPs) are emerging as a serious environmental concern, with wastewater treatment plants (WWTPs) acting as the main entry routes for MPs into aquatic and terrestrial ecosystems. On a global scale, our literature review found that MP research in WWTPs has only been conducted on 121 WWTPs in 17 countries, with the majority of the work being done in Europe (53%), followed by the United States of America and Canada (24%), Asia (18%), and Australia (5%) in recent years. MPs in WWTPs are primarily derived from Personal Care and Cosmetic Products (PCCPs), which are primarily composed of polyethylene (PE) derivatives. Based on the studies, microfibers (57%) and fragments (47%) are observed to be the most common MP forms in influents and effluents of WWTPs. The chemical characterization of MPs detected in WWTPs, showed the occurrence of polyethylene (PE) (22%), polystyrene (PS) (21%), and polypropylene (13%). Although MP retention/removal efficiencies of different treatment technologies vary from medium to high, deliberations on sludge disposal on agricultural soils containing MPs and MP intrusion into groundwater are required to sustainably regulate MP contaminant transport. Thus, the development of efficient detection methods and understanding their fate are of immense significance for the management of MPs. Despite the fact that ongoing research in MPs and WWTPs has unquestionably improved our understanding, many questions and concerns remain unanswered. In this review, the current status of the detection, occurrence, and impact of MPs in WWTPs across the world are systematically reviewed to prioritize policy-making to recognize the WWTPs as global conduits of MPs.
The present epoch of man deserves to be formalized a distinct period, the Anthropocene, within the geological time scale. Plastics, a unique identifier of the Anthropocene, survives as stratigraphic markers in the soil to guide future archeologists exploring human era. Plastics are a sub‐class of an even larger group of materials called the polymers, characterized by their unique long chain‐like molecular architecture, made up of repeating structural units. In the 1970s, a dimension of plastic waste came to light with the discovery of plastic litter in the marine environment. Finding ways to minimize the environmental impact of plastics, given the future increase in production levels, is critical to ensure sustainability. Specifically, three strategies towards sustainability deserve close attention: energy economy, feedstock economy, and minimizing toxicity. Packaging, the leading application of plastics has a global market size exceeding US$240B. As with packaging, only a handful of different plastics are used in building construction.
The microplastics (MPs) are considered one of the most threatening pollutants. One of the main concerns is their continuous and cumulative flow to water environments, as they are very difficult to be removed. Microfibers (MFs) are a significant type of MPs, with textile articles as one of the most renowned sources. This review aims to provide the current status of these MFs as pollutants, discussing possible alternatives from the manufacturing until the final disposition of MFs. There are many alternatives to reduce these pollutants from reaching the environment but also gaps that need to be further evaluated and addressed. Besides, it should be noticed that alternatives could be complementary between them. Some viable and non-contaminating solutions to reduce this pollution are currently on the market. Also, one relevant aspect is the final disposition or usage of the retained MFs to avoid them from reaching aquatic environments.
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.
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Samples from the secondary clarifier effluent of a waste water treatment plant (serving 98500 inhabitants) were analyzed to determine the microplastics (MP) emission. The samples were collected using a stainless steel centrifugal pump and filtered through a 10 µm stainless steel cartridge filter. Microplastics particles (MPPs) and microplastics fibers (MPFs) were recovered by chemical and physical sample purification. To remove natural organic matter, the samples were first subjected to oxidative treatment with H2O2 and NaClO. Inorganic materials were subsequently removed by density separation in ZnCl2 (ρ = 1.9 g/cm³) using a centrifuge. Special centrifuge tubes were developed for this purpose. Sample analysis was performed on a Si filter by Raman micro-spectroscopy. Particles with a diameter (dp) ≥ 10 µm were analyzed. The results were differentiated by dry and wet weather samples. On average, 5900 MPPs m-3 were identified in the effluent on wet weather days compared to 3000 MPPs m-3 on dry weather days. Most of the MPPs detected were in the 30 µm < dp < 100 µm size range. The MPFs ranged between 100 µm and 1000 µm in length. While most of the MPFs were of PET origin, the MPPs consisted mainly of PET, PP, PE and PS.
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ABSTRACT: Ingestion of microplastics by marine organisms is a common occurrence in marine ecosystems, but the experimental demonstration of the effects of ingested microplastics on marine organisms has only recently become an important subject of research. In this review, the ingestion of microplastics by marine organisms, its attendant potential consequences and specific hypothet- ical questions for further studies are discussed. The formation of heteroaggregates in the gut of prey organisms may delay microplastic clearance, potentially increasing the chances of microplas- tic trophic transfer to predators. Also, the survival and energetics of keystone species at lower trophic levels are negatively affected by ingestion of microplastics, thereby raising questions about the transfer of energy and nutrients to organisms at higher trophic levels. Further, since microplastics are able to adsorb and concentrate organic pollutants up to 1 million times more than the pollutant concentration in ambient waters, the ingestion of such small plastic fragments is, a probable route for the entrance and biomagnification of toxic chemicals in the marine food web. However, the equilibrium state between pollutant concentration in marine organisms and that of surrounding waters makes it unclear whether the ingestion of microplastics actually increases the pollutant load of organisms. Finally, microplastic ingestion can cause endocrine dis- orders in adult fish, which could result in neoplasia via epigenetic programming. Therefore, microplastic pollution may be a contributory cause of increased incidents of neoplasia in marine animals. The amount of microplastics in marine waters will steadily rise, and questions about their impact on marine ecosystems will linger.
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Plastic pollution has been well documented in natural environments, including the open waters and sediments within lakes and rivers, the open ocean and even the air, but less attention has been paid to synthetic polymers in human consumables. Since multiple toxicity studies indicate risks to human health when plastic particles are ingested, more needs to be known about the presence and abundance of anthropogenic particles in human foods and beverages. This study investigates the presence of anthropogenic particles in 159 samples of globally sourced tap water, 12 brands of Laurentian Great Lakes beer, and 12 brands of commercial sea salt. Of the tap water samples analyzed, 81% were found to contain anthropogenic particles. The majority of these particles were fibers (98.3%) between 0.1–5 mm in length. The range was 0 to 61 particles/L, with an overall mean of 5.45 particles/L. Anthropogenic debris was found in each brand of beer and salt. Of the extracted particles, over 99% were fibers. After adjusting for particles found in lab blanks for both salt and beer, the average number of particles found in beer was 4.05 particles/L with a range of 0 to 14.3 particles/L and the average number of particles found in each brand of salt was 212 particles/kg with a range of 46.7 to 806 particles/kg. Based on consumer guidelines, our results indicate the average person ingests over 5,800 particles of synthetic debris from these three sources annually, with the largest contribution coming from tap water (88%).
Microfibers are emerging pollutants with widespread distribution in the environment and have adverse ecological impacts. Approximately 2 million tonnes of microfibers are released into the ocean every year from various sources, of which 700,000 micro fleeces are released from each garment through domestic laundry. Microfibers are the major marine pollutant throughout the world estimating 13 million tonnes of coastal synthetic fabric waste entering the ocean each year, out of which 2.5 million tonnes enter through adjoining rivers. It is anticipated that, to date, 1.5 million trillion of microfibers are present in the ocean. Microfibers are mistakenly ingested by marine animals and cause hazardous effects to aquatic species. Microfiber treatment techniques are under progress for efficient control of this pollutant. This article focuses on global microfiber generation and its sources, pathway of its entry into the environment and food chain, potential threat to aquatic animals and humans, present treatment technologies, and future challenges.
Polymer science is one of the most revolutionary research areas of the last century, instigated by the discovery of Bakelite, the first synthetic plastic. Plastic, once a revolutionary material, has gradually become a global environmental threat with ubiquitous distribution. The term ‘microplastics’ coined in 2004, is used to describe the smaller plastic particles recorded, however there is still no all-inclusive definition that accurately encompasses all criteria that could potentially describe what a microplastic is. Here, the authors focus on the currently reported methods for describing and identifying microplastics and propose a new definition that incorporates all the important descriptive properties of microplastics. This definition not only focuses on size and origin, but also considers physical and chemical defining properties. While this manuscript may promote debate, it aims to reach a consensus on a definition for microplastics which can be useful for research, reporting and legislative purposes.
Textiles release fibres to the environment during production, use, and at end-of-life disposal. Approximately two-thirds of all textile items are now synthetic, dominated by petroleum-based organic polymers such as polyester, polyamide and acrylic. Plastic microfibres (<5 mm) and nanofibres (<100 nm) have been identified in ecosystems in all regions of the globe and have been estimated to comprise up to 35% of primary microplastics in marine environments, a major proportion of microplastics on coastal shorelines and to persist for decades in soils treated with sludge from waste water treatment plants. In this paper we present a critical review of factors affecting the release from fabrics of microfibres, and of the risks for impacts on ecological systems and potentially on human health. This review is used as a basis for exploring the potential to include a metric for microplastic pollution in tools that have been developed to quantify the environmental performance of apparel and home textiles. We conclude that the simple metric of mass or number of microfibres released combined with data on their persistence in the environment, could provide a useful interim mid-point indicator in sustainability assessment tools to support monitoring and mitigation strategies for microplastic pollution. Identified priority research areas include: (1) Standardised analytical methods for textile microfibres and nanofibres; (2) Ecotoxicological studies using environmentally realistic concentrations; (3) Studies tracking the fate of microplastics in complex food webs; and (4) Refined indicators for microfibre impacts in apparel and home textile sustainability assessment tools.
Previous studies have identified microplastics (MPs) in commercial table salts but could not exactly address the origin of the MPs because of several limitations. The present study is based on the hypothesis that commercial sea salts can act as an indicator of MP pollution in the surrounding environment unless the MPs are filtered out during the manufacturing process. A total of 39 different salt brands produced at geospatially different sites, including 28 sea salt brands from 16 countries on six continents, were investigated. A wide range of MP contents (in number of MPs per kg of salt; n/kg) was found: 0 – 1,674 n/kg (excluding one outlier of 13,629 n/kg) in sea salts, 0 – 148 n/kg in rock salt, and 28 – 462 n/kg in lake salt. Relatively high MP contents were identified in sea salts produced in Asian countries. The abundance of MPs in unrefined sea salts (n=25) exhibited significant linear correlations with plastic emissions from worldwide rivers (r=0.57; p=0.003) and with the MP pollution levels in surrounding seawaters (r=0.68; p=0.021) in the published literature. The results indicate that