DOI: 10.5061/dryad.fn2z34v1d
title: Suspected microplastic counts and characteristics in fish muscle and gastrointestinal tissue

description: Microplastics, or particles &lt;5mm in diameter, comprise a
 significant portion of marine plastic pollution. These particles can be
 directly or indirectly taken up by fish and have been detected in multiple
 fish tissues. Ingestion of plastic particles was recently reported for
 free-ranging bottlenose dolphins (Tursiops truncatus) inhabiting Sarasota
 Bay, FL, USA, a community that also has prevalent exposure to plasticizers
 (i.e., phthalates) at concentrations higher than human reference
 populations. The sources of these exposures for Sarasota Bay bottlenose
 dolphins are currently unknown, but plastic-contaminated prey could be a
 possible vector. To test this hypothesis, muscle and the contents and
 tissues of the gastrointestinal tract (GIT) from prey fish collected in
 Sarasota Bay were screened for suspected plastic particles, and particle
 properties (e.g., color, shape, surface texture) were compared to those
 observed in gastric samples from bottlenose dolphins.  In total,
 29 fish across four species (hardhead catfish, Ariopsis felis (n=2);
 pigfish, Orthopristis chrysoptera (n=12); pinfish, Lagodon rhomboides
 (n=10); and Gulf toadfish, Opsanus beta (n=5)) were collected from two
 sampling stations in Sarasota Bay, FL during September 2022. Suspected
 plastic particles were observed in 97% of fish (n=28), and particle
 abundance was higher for GIT tissue than muscle. Fish and dolphin samples
 contained fibers and films; however, foams were most abundant in dolphin
 samples and not observed in fish. Fragments, including tire wear particles
 (TWP), were not observed in dolphin samples, TWP fragments were not
 observed in bottlenose dolphin gastric samples, but 23.1% and 32.0% of
 fish muscle and GIT samples, respectively, contained at least one TWP
 fragment. While some similarities in particle properties were shared
 between dolphins and fish, small sample sizes and incongruent findings for
 foams and TWP particles suggest that further investigation is warranted to
 understand the potential for trophic transfer.
description: Microplastic screening of fish tissues followed methods used in
 Lusher et al., (2017) and Hart et al., (2022). Briefly, muscle and
 gastrointestinal (i.e., stomach and intestine) tissue from each fish were
 placed into a glass beaker, and organic (non-plastic) material in the
 samples was digested by adding a 10% potassium hydroxide (KOH) solution
 and incubated at 60°C for 24–72 hours (Karami et al., 2017). Following
 digestion, samples were vacuum filtered onto GF/A 1.6 µm glass fiber
 filters in a fume hood and left to dry in covered glass petri
 dishes. <br><br>Particles of at least 35 µm were characterized
 visually using a dissection microscope (Leica EZ4, magnification 8-35x)
 according to physical attributes including shape (e.g., fiber, film,
 fragment, foam), surface texture (e.g., smooth, rough, rubber), and color
 (e.g., transparent, blue, black; Shim et al., 2017). Various parameters
 were used to identify potential plastic material. For example, suspected
 plastic fibers were indicated by a smooth, uniform surface with a length
 that exceeded the width (Lusher et al., 2020). Suspected plastic fragments
 were characterized by smooth or angular edges that appeared to be broken
 from a larger piece of debris (Lusher et al., 2020). Fragments were
 further identified as tire wear particles (TWP) if they were black,
 cylindrical, had a rubbery surface texture, and maintained their shape
 when manipulated with forceps (Leads and Weinstein, 2019).  Suspected foam
 particles were characterized by a round shape and honeycomb-like porosity
 (Manikanda Bharath et al., 2023). Suspected fiber bundles were
 characterized by 20 or more fibers tangled together in a way that prevents
 them from being separated (Unsworth et al. 2022; Rochman et al. 2019). All
 particles at least 100 µm in size and with characteristics previously
 described were tested with a hot needle (250°C) and suspected to be of
 plastic origin if the needle left a mark on or melted the particle surface
 (De Witte et al., 2014; Devriese et al., 2015; Leads and Weinstein, 2019).
 Fourier Transform Infrared (FTIR) spectroscopy was available for polymer
 identification of particles ranging from 500 µm to 5 mm. 
description: ## Fish Microplastics Data\_Repository Twenty-nine fish across four
 species (hardhead catfish, Ariopsis felis (n=2); pigfish, Orthopristis
 chrysoptera (n=12); pinfish, Lagodon rhomboides (n=10); and Gulf toadfish,
 Opsanus beta (n=5)) were collected from two sampling stations in Sarasota
 Bay, FL during September 2022. Both muscle and gastrointestinal (GIT)
 samples were screened for microplastics in 21 fish, while 10 fish were
 screened using either muscle (n=5) or GIT (n=5). Particles of at least 35
 µm were characterized visually using a dissection microscope (Leica EZ4,
 magnification 8-35x) according to physical attributes including shape
 (e.g., fiber, film, fragment, foam), surface texture (e.g., smooth, rough,
 rubber), and color (e.g., transparent, blue, black; Shim et al., 2017).
 All particles at least 100 µm in size and with characteristics previously
 described were tested with a hot needle (250°C) and suspected to be of
 plastic origin if the needle left a mark on or melted the particle surface
 (De Witte et al., 2014; Devriese et al., 2015; Leads and Weinstein, 2019).
 Ninety-seven percent of fish screened (n=28) had evidence of at least one
 suspected plastic particle in either muscle or GI tissue. Among the four
 fish species investigated in this study, suspected plastic particles were
 observed in both muscle and GIT tissue/contents, with particles more
 abundant in GIT. ## Description of the data and file structure Data are
 structured in long format. Each row represents the attributes of a
 particle (count, color, shape). “Sample Batch” indicates the timing of the
 fish collection. “Fish ID” identifies an individual fish. For GIT samples,
 digestate was filtered through several different sieves, indicated by
 “Sieve Size” and “# Fractions”. “NA” for “Sieve Size” indicates that a
 sieve was not used during sample processing. “Sample Label” corresponds to
 the sample collected from a fish or the label on a dissection or digestion
 blank. “Sample Type” indicates whether the data represented in the row
 comes from muscle, GIT, or blank evaluations. “Net Sample Mass (g)” is the
 mass of an individual sample of muscle or GIT. “Dissection/Collection
 Date” is the date when muscle, GIT, or blanks were collected. “Dissection
 or Field Blank ID” indicates the label for a corresponding blank that was
 collected during fish dissection. “Digestion Blank ID” indicates the label
 for a corresponding blank that was collected during the digestion process.
 “Particle Type” provides information on the particle shape (e.g., fiber,
 film, foam). Note: “Fragment_TWP” indicates fragments with characteristics
 similar to tire wear particles (TWP), while “Fragment-nonTWP” do not have
 those characteristics. “Color” refers to the color of the corresponding
 particle. “Quantity” indicates the number of particles of a particular
 color and shape/type that were observed. “Hot Needle” indicates that the
 particle reacted to a hot soldering needle, as described in the Methods
 section. “Collection Lat” and “Collection Long” indicate the geographic
 coordinates where the fish was collected. ## Sharing/Access information
 N/A ## Code/Software These data were created with Microsoft Excel