Distribution and Impact of Microplastics in the Aquatic …
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fishes found in shallow oceanic habitats (epipelagic zone: 1–3 m depth) had higher
MPs ingestion levels than species found in the deeper oceanic habitats (mesopelagic:
>200 m depth). As a result, the epipelagic fish (Rastrelliger kanagurta) had higher
MP exposure than the mesopelagic fish (Istiophorus platypterus) [21]. Similarly,
Kumar et al. [22] also detected MPs size ranges of 0.5–1 mm in the gut and intestine
of Rastrelliger kanagurta and Epinephelus merra fishes sampled from Thirespuram
and Punnakayal landing sites of Tuticorin, India. The FTIR analysis has shown that
30% of the fishes samples contained polyethylene and polypropylene MPs particulates. The recognized MPs were existed in microfibers (80%) with red, black, and
translucent colors, and fragments (20%) [22].
Another field study revealed the existence of MPs (>20-μm) in guts and gills
of thirteen species of coastal fishes at Hangzhou Bay and Yangtze Estuary, China
[23]. As depicted in Table 1, the result showed MPs concentration at an estimated
percentage of (22–100%) in the guts and (22–89%) gills of fish collected samples.
The mean abundance of MPs in the gut and gills of the fish samples varied from
0.3–5.3 items/individual (i.e., 0.1–8.8 items/g in the gut) to 0.3–2.6 items/individual
(i.e., 0.1 to 5.2 items/g in the gill), respectively. But, MPs were not detected in the
liver or muscle tissue of Lateolabrax maculate. Further to the occurrence of MPs,
the μ-FTIR observation identified 10 polymer types and the dominant polymer was
polyester, followed by polypropylene and polyethylene. The μ-FTIR-based polymer
identification also validated that the most common plastics found in the gut and gill
as PE and PP from polyesters (PES). Meanwhile, the shape, as well as size patterns
of MPs, are different in gut and gill while fibrous MPs with small size are lodged in
gill. In addition to plastic polymers, the non-plastic (cotton) from the muscle of the
fish was identified which can be ascribed to background contagion of the fish [23].
Another investigation on MPs marine biota also shows the existence and effects
of polystyrene (PS) exposure on Scrobicularia plana clam tissues [24]. Upon examination of MPs, the species were exposed to 1 mg/L of 20 μm PS for 14 days,
followed by seven days of depuration. The infrared spectroscopy detected the presence of MPs in clam tissues in which 1 mg/L of PS could be accumulated in the gills
and digestive gland. The effects of these MPs further evaluated through a battery of
biomarkers and the result showed that MPs caused damage in antioxidant capacity,
DNA, neuron, and oxidative damage of Scrobicularia plana. Furthermore, PS inhibits
the Anti-cholinesterase (AChE) activity in clam gills even after seven days of depuration [24]. Furthermore, the chronic exposure to PS causes genotoxicity and the
detoxification of PS microplastics in tissues is inefficient indicating potential trophic
transfer [24].
The possibility of the occurrence of MPs through ingestion has been assessed
in the early larvae stages of wild fish in the western English Channel. The FTIR
analysis revealed the ingestion of MPs by fish larvae and identified 2.9% of wild
fish larvae had ingested MPs. Most of the detected ingested MPs were nylon,
polyamide-polypropylene, and rayon with 66% fibrous and blue while 34% of them
were fragments and 16% red in color. In addition, the ingested microfibers have a
strong resemblance to polymer characteristics found in water samples [25]. Likewise, Desforges et al. [26] inspected plastic ingestion by species of zooplankton
73
fishes found in shallow oceanic habitats (epipelagic zone: 1–3 m depth) had higher
MPs ingestion levels than species found in the deeper oceanic habitats (mesopelagic:
>200 m depth). As a result, the epipelagic fish (Rastrelliger kanagurta) had higher
MP exposure than the mesopelagic fish (Istiophorus platypterus) [21]. Similarly,
Kumar et al. [22] also detected MPs size ranges of 0.5–1 mm in the gut and intestine
of Rastrelliger kanagurta and Epinephelus merra fishes sampled from Thirespuram
and Punnakayal landing sites of Tuticorin, India. The FTIR analysis has shown that
30% of the fishes samples contained polyethylene and polypropylene MPs particulates. The recognized MPs were existed in microfibers (80%) with red, black, and
translucent colors, and fragments (20%) [22].
Another field study revealed the existence of MPs (>20-μm) in guts and gills
of thirteen species of coastal fishes at Hangzhou Bay and Yangtze Estuary, China
[23]. As depicted in Table 1, the result showed MPs concentration at an estimated
percentage of (22–100%) in the guts and (22–89%) gills of fish collected samples.
The mean abundance of MPs in the gut and gills of the fish samples varied from
0.3–5.3 items/individual (i.e., 0.1–8.8 items/g in the gut) to 0.3–2.6 items/individual
(i.e., 0.1 to 5.2 items/g in the gill), respectively. But, MPs were not detected in the
liver or muscle tissue of Lateolabrax maculate. Further to the occurrence of MPs,
the μ-FTIR observation identified 10 polymer types and the dominant polymer was
polyester, followed by polypropylene and polyethylene. The μ-FTIR-based polymer
identification also validated that the most common plastics found in the gut and gill
as PE and PP from polyesters (PES). Meanwhile, the shape, as well as size patterns
of MPs, are different in gut and gill while fibrous MPs with small size are lodged in
gill. In addition to plastic polymers, the non-plastic (cotton) from the muscle of the
fish was identified which can be ascribed to background contagion of the fish [23].
Another investigation on MPs marine biota also shows the existence and effects
of polystyrene (PS) exposure on Scrobicularia plana clam tissues [24]. Upon examination of MPs, the species were exposed to 1 mg/L of 20 μm PS for 14 days,
followed by seven days of depuration. The infrared spectroscopy detected the presence of MPs in clam tissues in which 1 mg/L of PS could be accumulated in the gills
and digestive gland. The effects of these MPs further evaluated through a battery of
biomarkers and the result showed that MPs caused damage in antioxidant capacity,
DNA, neuron, and oxidative damage of Scrobicularia plana. Furthermore, PS inhibits
the Anti-cholinesterase (AChE) activity in clam gills even after seven days of depuration [24]. Furthermore, the chronic exposure to PS causes genotoxicity and the
detoxification of PS microplastics in tissues is inefficient indicating potential trophic
transfer [24].
The possibility of the occurrence of MPs through ingestion has been assessed
in the early larvae stages of wild fish in the western English Channel. The FTIR
analysis revealed the ingestion of MPs by fish larvae and identified 2.9% of wild
fish larvae had ingested MPs. Most of the detected ingested MPs were nylon,
polyamide-polypropylene, and rayon with 66% fibrous and blue while 34% of them
were fragments and 16% red in color. In addition, the ingested microfibers have a
strong resemblance to polymer characteristics found in water samples [25]. Likewise, Desforges et al. [26] inspected plastic ingestion by species of zooplankton