Department of Biology, Loyola University of Chicago, 1032 W Sheridan Road, Chicago, Illinois, 60660, USA.
Field Museum of Natural History, Chicago, Illinois, 60605, USA.
Ecol Appl. 2021 Jul;31(5):e02320. doi: 10.1002/eap.2320. Epub 2021 Apr 21.
Plastic is pervasive in modern economies and ecosystems. Freshwater fish ingest microplastics (i.e., particles <5 mm), but no studies have examined historical patterns of their microplastic consumption. Measuring the patterns of microplastic pollution in the past is critical for predicting future trends and for understanding the relationship between plastics in fish and the environment. We measured microplastics in digestive tissues of specimens collected from the years 1900-2017 and preserved in museum collections. We collected new fish specimens in 2018, along with water and sediment samples. We selected four species: Micropterus salmoides (largemouth bass), Notropis stramineus (sand shiner), Ictalurus punctatus (channel catfish), and Neogobius melanostomus (round goby) because each was well represented in museum collections, are locally abundant, and collected from urban habitats. For each individual, we dissected the digestive tissue from esophagus to anus, subjected tissue to peroxide oxidation, examined particles under a dissecting microscope, and used Raman spectroscopy to characterize the particles' chemical composition. No microplastics were detected in any fish prior to 1950. From mid-century to 2018, microplastic concentrations showed a significant increase when data from all fish were considered together. All detected particles were fibers, and represented plastic polymers (e.g., polyester) along with mixtures of natural and synthetic textiles. For the specimens collected in 2018, microplastics in fish and sediment showed similar patterns across study sites, while water column microplastics showed no differences among locations. Overall, plastic pollution in common freshwater fish species is increasing and pervasive across individuals and species, and is likely related to changes in environmental concentrations. Museum specimens are an overlooked source for assessing historical patterns of microplastic pollution, and for predicting future trends in freshwater fish, thereby helping to sustain the health of commercial and recreational fisheries worldwide.
塑料在现代经济和生态系统中无处不在。淡水鱼会摄入微塑料（即粒径<5 毫米的颗粒），但目前尚无研究检测其微塑料摄入的历史模式。测量过去微塑料污染的模式对于预测未来的趋势以及了解鱼类和环境中的塑料之间的关系至关重要。我们测量了 1900 年至 2017 年间采集的、保存在博物馆收藏中的标本的消化组织中的微塑料。我们在 2018 年收集了新的鱼类标本以及水和沉积物样本。我们选择了四种鱼类：大口黑鲈（Micropterus salmoides）、细鳞斜颌鲴（Notropis stramineus）、斑点叉尾鮰（Ictalurus punctatus）和黑褐拟鳞鲀（Neogobius melanostomus），因为它们在博物馆收藏中都有很好的代表，在当地很丰富，并且从城市栖息地采集。对于每个个体，我们从食道到肛门解剖消化组织，将组织进行过氧化物氧化，在解剖显微镜下检查颗粒，并使用拉曼光谱法对颗粒的化学成分进行表征。在 1950 年之前，任何鱼类都没有检测到微塑料。从中世纪到 2018 年，当综合考虑所有鱼类的数据时，微塑料浓度显示出显著增加。所有检测到的颗粒都是纤维，代表塑料聚合物（例如聚酯）以及天然和合成纺织品的混合物。对于 2018 年采集的标本，研究地点的鱼类和沉积物中的微塑料具有相似的模式，而水柱中的微塑料在地点之间没有差异。总体而言，常见淡水鱼类的塑料污染正在增加，并且在个体和物种之间普遍存在，这可能与环境浓度的变化有关。博物馆标本是评估历史微塑料污染模式和预测未来淡水鱼类趋势的被忽视的来源，从而有助于维持全球商业和休闲渔业的健康。
