摘要

塑料废物的广泛存在和积累已被全球公认为一个关键问题。然而，关于纳米塑料对淡水无脊椎动物的不利影响的信息有限。在该研究中，测量了聚苯乙烯纳米塑料对淡水跳蚤Daphnia pulex中的生理变化（例如，存活，生长和繁殖）和胁迫防御基因（氧化应激介导的和热休克蛋白）的表达水平的影响。结果表明，D。pulex的消化器官在暴露于纳米塑料颗粒后呈强荧光，并且纳米塑料的48小时半数致死浓度（LC 50）被确定为76.69mg / L.在21天的慢性毒性试验中，观察到体长的剂量和时间依赖关系，并且在0.5和1mg / L组中第一次卵的时间显着延长。离合器的时间延迟了，所有治疗组的每个女性的总后代和离合器的数量都减少了。此外，0.1mg / L组的每个离合器的后代显着减少。随着纳米塑料浓度的增加，应激防御基因（SOD，GST，GPx和CAT）的表达首先被诱导然后被抑制。在所有治疗组中诱导热休克蛋白（HSP70和HSP90）的基因表达。我们的研究结果表明，纳米塑料可以被淡水枝角类植物D. pulex摄取，影响其生长和繁殖，并诱导应激防御。

The widespread occurrence and accumulation of plastic waste have been globally recognized as a critical issue. However, there is limited information on the adverse effects of nanoplastics on freshwater invertebrates. In this study, the effects of a polystyrene nanoplastic on physiological changes (e.g., survival, growth, and reproduction) and expression levels of stress defense genes (oxidative stress-mediated and heat shock proteins) in the freshwater flea Daphnia pulex were measured. The results showed that the digestive organs of D. pulex were strongly fluorescent after exposure to the nanoplastic particles, and the 48-h median lethal concentration (LC 50) of the nanoplastic was determined to be 76.69 mg/L. In the 21-day chronic toxicity test, dose- and time-dependent relationships were observed for body length, and the time to first eggs was significantly prolonged in the 0.5 and 1 mg/L groups. The time to clutch was delayed, and total offspring per female and number of clutches were decreased in all the treatment groups. In addition, the offspring per clutch were significantly decreased in the 0.1 mg/L group. As the nanoplastic concentration increased, expression of stress defense genes (SOD, GST, GPx, and CAT) was first induced and then inhibited. The gene expressions of heat shock proteins (HSP70 and HSP90) were induced in all the treatment groups. Our results suggest that nanoplastics can be ingested by the freshwater cladoceran D. pulex and affect its growth and reproduction as well as induce stress defense.

https://www.ncbi.nlm.nih.gov/pubmed/30312919