Suspected microplastic counts and characteristics in fish muscle and gastrointestinal tissue

Microplastics, or particles <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 acro..., 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. 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 sm..., , ## 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 par...微塑料（Microplastics）指直径小于5毫米的颗粒，是海洋塑料污染的重要组成部分。此类颗粒可被鱼类直接或间接摄取，且已在多种鱼类组织中被检出。近期有研究报道，栖息于美国佛罗里达州萨拉索塔湾的野生宽吻海豚（Tursiops truncatus）体内存在塑料颗粒摄入情况；该种群同时普遍暴露于邻苯二甲酸盐（phthalates）类增塑剂中，其暴露浓度高于人类参考人群。目前萨拉索塔湾宽吻海豚的此类暴露来源尚不明确，但受塑料污染的猎物可能是潜在传播媒介。为验证这一假说，研究人员对萨拉索塔湾采集的猎物鱼类的肌肉组织、胃肠道内容物及组织进行了疑似塑料颗粒筛查，并将颗粒的物理属性（如颜色、形状、表面纹理）与宽吻海豚胃部样本中观察到的颗粒进行了比对。本次研究共纳入29尾…… 鱼类微塑料筛查参考了Lusher等人（2017）与Hart等人（2022）的研究方法。简要流程为：将每尾鱼的肌肉组织与胃肠道（gastrointestinal tract, GIT）组织置于玻璃烧杯中，加入10%氢氧化钾（KOH）溶液以消解样品中的有机（非塑料）物质，随后在60℃条件下孵育24至72小时（Karami et al., 2017）。消解完成后，将样品置于通风橱中经真空过滤至GF/A 1.6 μm玻璃纤维滤膜上，随后移入加盖的玻璃培养皿中晾干。使用体视显微镜（Leica EZ4，放大倍数8-35倍）对尺寸≥35 μm的颗粒进行目视表征，依据形状（如纤维、薄膜、碎片、泡沫）、表面纹理（如光滑、粗糙、橡胶质感）及颜色（如透明、蓝色、黑色；Shim et al., 2017）等物理属性进行分类。研究人员通过多项参数识别潜在塑料材料，例如疑似塑料纤维以…… ## 鱼类微塑料数据存储库（Fish Microplastics Data Repository） 2022年9月，研究人员从美国佛罗里达州萨拉索塔湾的两个采样站点采集了4个物种共29尾鱼类：硬头海鲶（Ariopsis felis，n=2）、猪鱼（Orthopristis chrysoptera，n=12）、松鲷（Lagodon rhomboides，n=10）以及海湾蟾鱼（Opsanus beta，n=5）。其中21尾鱼类同时开展了肌肉与胃肠道（GIT）组织的微塑料筛查，剩余10尾仅开展单一组织筛查（肌肉组织5尾，胃肠道组织5尾）。再次使用体视显微镜（Leica EZ4，放大倍数8-35倍）对尺寸≥35 μm的颗粒按物理属性（形状：纤维、薄膜、碎片、泡沫；表面纹理：光滑、粗糙、橡胶质感；颜色：透明、蓝色、黑色；Shim et al., 2017）进行目视表征。所有尺寸≥100 μm且符合前述特征的颗粒均采用250℃热针进行测试，若热针在颗粒表面留下痕迹或使其熔融，则判定其为塑料来源……