Division of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
Division of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
Chemosphere. 2021 May;271:129591. doi: 10.1016/j.chemosphere.2021.129591. Epub 2021 Jan 8.
Fragmented microplastics (MPs) are emerging contaminants in freshwater environments; however, long-term assessment of their toxicity remains limited. This study aimed to evaluate and compare the chronic toxicity (21 d) of synthesized polyethylene MP fragments and commercial polyethylene MP beads to Daphnia magna. Ingestion of small- and large-sized MP fragments (17.23 ± 3.43 and 34.43 ± 13.09 μm, respectively) by D. magna was significantly (p < 0.05) higher, by 8.3 and 5.2 times, respectively, than that of MP beads (39.54 ± 9.74 μm). The survival of D. magna exposed to small- and large-sized MP fragments (20 and 60%, respectively) was significantly (p < 0.05) lower than that of individuals exposed to MP beads (90%). In particular, small-sized MP fragments significantly (p < 0.05) reduced algal feeding (from 95% to 76%), body length (from 4.20 mm to 3.98 mm), and the number of offspring (from 109 to 74) in D. magna, when compared with MP beads, likely due to their longer retention time and greater interference in the digestive tract. These findings suggest that fragmentation of MPs into μm-scale particles can pose a significant ecological risk to aquatic organisms; moreover, further studies are required to identify the underlying toxicity mechanism.
碎片化微塑料（MPs）是淡水环境中新兴的污染物；然而，其长期毒性评估仍然有限。本研究旨在评估和比较合成聚乙烯 MP 碎片和商业聚乙烯 MP 珠对大型溞（Daphnia magna）的慢性毒性（21 天）。大型溞对小尺寸和大尺寸 MP 碎片（分别为 17.23 ± 3.43μm 和 34.43 ± 13.09μm）的摄入量明显（p<0.05）更高，分别是 MP 珠（39.54 ± 9.74μm）的 8.3 倍和 5.2 倍。暴露于小尺寸和大尺寸 MP 碎片的大型溞的存活率（分别为 20%和 60%）明显（p<0.05）低于暴露于 MP 珠的个体（90%）。特别是小尺寸 MP 碎片显著（p<0.05）降低了藻类的摄食率（从 95%降至 76%）、体长（从 4.20mm 降至 3.98mm）和繁殖后代数量（从 109 降至 74），与 MP 珠相比，这可能是由于其在消化道中的滞留时间更长且干扰更大。这些发现表明，MPs 碎片化至 μm 级颗粒可能对水生生物构成重大生态风险；此外，需要进一步研究以确定潜在的毒性机制。
