Laboratory of Ecotoxicology, Department of the Environment, National Institute for Agricultural and Food Research and Technology (INIA-CSIC), A-6, Km. 7.5, E-28040 Madrid, Spain.
Department of Cell Biology, School of Medicine, Complutense University, Ciudad Universitaria, E-28040 Madrid, Spain.
Environ Pollut. 2022 Oct 15;311:120001. doi: 10.1016/j.envpol.2022.120001. Epub 2022 Aug 19.
The number of published studies evaluating the effects of microplastics (MPs) in fish has increased in the last decade. However, of the available studies, few have explored the long-term effects of MPs on fish growth and reproduction and have resorted to MPs in the form of μm-sized beads/microspheres. In this study, 6-10 day-old post-hatch medaka (Oryzias latipes) fish were exposed to 50 (i.e. 1X) and 500 (i.e. 10X) μg of heterogeneously sized and irregularly shaped virgin polystyrene (PS) MP particles (200-μm range)/L for 150 days. These concentrations corresponded to respective daily mean values of 247 and 3087 particles/L administered through the diet. The PS MPs dietary exposure resulted in body burdens of 114 and 440 particles/g fish on day 50, and of 78 and 173 particles/g fish on day 100 since the respective exposures to the 1X and the 10X treatments started. The biometric analyses found no incidence of PS MPs ingestion on overall fish growth and development. The histological survey in the 10X group did not reveal alterations in gills or in the digestive tract. Mild alterations in other organs were seen and included increased fluid material in the peritoneal cavity, glomerular and tubular alterations in kidneys, and differences in the diameter of the thyroid follicles and thickness of the follicular epithelial cells. The initial days of the reproductive phase revealed MP-related differences in the number of gravid females, fecundity, and fertilization rates. Overall, these values reverted to normal rates throughout the succeeding days. No significant effects of PS MPs exposure were evidenced on offspring success. The 150-day PS MPs dietary exposure used in this study provided clues of histological effects and a reproduction delay. However, it did not seem to compromise overall growth/thriving and the ongoing reproduction.
在过去十年中，评估微塑料（MPs）对鱼类影响的已发表研究数量有所增加。然而，在现有的研究中，很少有研究探索 MPs 对鱼类生长和繁殖的长期影响，并且多采用 μm 大小的珠状/微球形式的 MPs。在这项研究中，6-10 日龄孵化后的斑马鱼（Oryzias latipes）暴露于 50（即 1X）和 500（即 10X）μg 异质大小和不规则形状的原始聚苯乙烯（PS）MP 颗粒/L 中 150 天。这些浓度分别对应于通过饮食给予的每日平均 247 和 3087 个/L 粒子。PS MPs 饮食暴露导致鱼体 50 天的体内负荷为 114 个颗粒/g 鱼，100 天的体内负荷为 78 个颗粒/g 鱼，因为分别开始暴露于 1X 和 10X 处理。生物计量分析发现，PS MPs 的摄入没有影响鱼类的整体生长和发育。10X 组的组织学调查没有显示出对鳃或消化道的改变。在其他器官中观察到轻微的改变，包括腹腔内液体物质增加、肾脏肾小球和管状改变，以及甲状腺滤泡直径和滤泡上皮细胞厚度的差异。在繁殖阶段的最初几天，发现与 MP 相关的妊娠雌鱼数量、生育力和受精率存在差异。总体而言，这些值在随后的几天内恢复正常。PS MPs 暴露没有对后代的成功产生显著影响。本研究中使用的 150 天 PS MPs 饮食暴露提供了组织学影响和繁殖延迟的线索。然而，它似乎并没有损害整体生长/活力和正在进行的繁殖。
