Raza Muhammad Haris, Jabeen Farhat, Ikram Salma, Zafar Saba
Department of Zoology, Government College University Faisalabad, Faisalabad, Pakistan.
Department of Physics, Government College University Faisalabad, Faisalabad, Pakistan.
Environ Sci Pollut Res Int. 2023 Jan;30(3):6828-6848. doi: 10.1007/s11356-022-22440-y. Epub 2022 Aug 26.
Microplastic (MP) pollution in the aquatic environment is an emerging subject worldwide. So far, very few investigations have been reported on the riverine fish population. This study investigated the implications of microplastics for three freshwater fish species (Labeo rohita, Cirrihinus mrigala, and Sperata seenghala) as bioindicators of this pollution. Raman spectroscopy was used to confirm MP polymer type and their distribution in water, sediments, and in different organs (gut, gills, liver, and muscles) of Labeo rohita, Cirrihinus mrigala, and Sperata seenghala collected from River Ravi at two sites (site I, Dhand Nano Dogar and site II, Jhamra). These selected sites were situated predominantly near agricultural lands and received polluted water from nearby sewerage and industries that represented potential sources of microplastic pollution. Histological analysis was combined with Raman spectroscopy to assess the effects of MPs on fish organs. MPs were identified in water and sediment samples with an average load (per 0.5 L or per 0.5 kg) of 33 items and 64 items for water and sediments at site I and 27 items and 19 items at site II, respectively. Of total MPs identified, 56.9% were found in bottom feeder C. mrigala, 37.91% in column feeder L. rohita, and 5.21% in S. seenghala at site I while at site II 60% were found in C. mrigala, 29% in L. rohita and 10.34% in S. seenghala. This was linked with more plastic accumulation in sediments from the nearby residential sewerage and industrial effluent flow. In this study, the identified MPs polymers were in the order of polyvinyl chloride (PVC) > polystyrene (PS) > propylene (PP) > polyethylene (PE). Among plastic shapes, fiber (58%) was the dominant plastic in water followed by fragment (21%), sheet (12%), and cube (9%). In sediment, the fragment was the common plastic shape with 51% followed by fiber (28%), sheet (19%), and cube (2%). Fragments (62.9%) in water and fibers (68.4%) in sediments were abundant at site 2. Microplastic mean occurrence in organs was in the order of gut > gills > muscles > liver at both sites. Significant histological alterations were observed in all three species including intestinal edema, hyperplasia, hepatocyte infiltration, accumulation of lipid droplets in the liver, lamellar fusion and breakage in gills, and muscle fiber necrosis. This study showed MP occurrence in the selected freshwater fishes, so further research is needed to assess plastic pollution in the riverine fish population of Pakistan. This study appeared to be the first in the selected area, as no significant information regarding plastic pollution in that riverine system was found when this study was conducted.
水生环境中的微塑料（MP）污染是全球一个新兴课题。到目前为止，关于河流鱼类种群的调查报道极少。本研究调查了微塑料对三种淡水鱼（印度野鲮、麦瑞加拉鲮和丝尾鳠）的影响，将其作为这种污染的生物指标。拉曼光谱用于确认微塑料的聚合物类型及其在水、沉积物以及从拉维河两个地点（地点I，丹德纳米多噶尔；地点II，贾姆拉）采集的印度野鲮、麦瑞加拉鲮和丝尾鳠的不同器官（肠道、鳃、肝脏和肌肉）中的分布。这些选定地点主要位于农田附近，接收来自附近污水和工业的污染水，这些是微塑料污染的潜在来源。组织学分析与拉曼光谱相结合，以评估微塑料对鱼类器官的影响。在水和沉积物样本中鉴定出了微塑料，地点I水和沉积物的平均负荷（每0.5升或每0.5千克）分别为33个和64个，地点II为27个和19个。在鉴定出的所有微塑料中，地点I底栖摄食的麦瑞加拉鲮中发现56.9%，中层摄食的印度野鲮中发现37.91%，丝尾鳠中发现5.21%；而在地点II，麦瑞加拉鲮中发现60%，印度野鲮中发现29%，丝尾鳠中发现10.34%。这与附近生活污水和工业废水排放导致沉积物中更多的塑料积累有关。在本研究中，鉴定出的微塑料聚合物顺序为聚氯乙烯（PVC）＞聚苯乙烯（PS）＞聚丙烯（PP）＞聚乙烯（PE）。在塑料形状中，纤维（58%）是水中的主要塑料形状，其次是碎片（21%）、薄片（12%）和立方体（9%）。在沉积物中，碎片是常见的塑料形状，占51%，其次是纤维（28%）、薄片（19%）和立方体（2%）。地点2水中的碎片（62.9%）和沉积物中的纤维（68.4%）含量丰富。两个地点微塑料在器官中的平均出现顺序为肠道＞鳃＞肌肉＞肝脏。在所有三个物种中均观察到显著的组织学改变，包括肠道水肿增生、肝细胞浸润、肝脏中脂滴积累、鳃小片融合和破裂以及肌纤维坏死。本研究表明在所选定的淡水鱼中存在微塑料，因此需要进一步研究以评估巴基斯坦河流鱼类种群中的塑料污染情况。本研究似乎是所选区域的首次研究，因为在开展本研究时未发现关于该河流系统塑料污染的重要信息。
