Chagas Thales Quintão, Araújo Amanda Pereira da Costa, Malafaia Guilherme
Biological Research Laboratory, Post-graduation Program in Conservation of Cerrado Natural Resources, Goiano Federal Institute - Urutaí Campus Urutaí, GO, Brazil.
Post-graduation Program in Environmental Science, Federal University of Goiás, GO, Brazil.
Sci Total Environ. 2021 Mar 20;761:143231. doi: 10.1016/j.scitotenv.2020.143231. Epub 2020 Oct 24.
The toxicological safety of products developed as alternative for conventional plastics (i.e., petroleum derivatives) inevitably demands conducting (eco)toxicological studies. Thus, the aim of the current study was to evaluate the biochemical toxicity of polyethylene microplastics (PE MPs) (representative of conventional MPs) and polylactic acid biomicroplastics (PLA BioMPs) in Aphylla williamsoni larvae used as experimental models. Animals subjected to short exposure to both pollutants (48 h), at environmentally relevant concentration (6 mg/L). At the end of the experiment, different toxicity biomarkers were evaluated. To assess the possible impact of pollutants on the nutritional status of the animals, the total protein, total soluble carbohydrate and triglyceride levels were determined. However, we did not observe differences between the groups, which suggests that PE MPs and PLA BioMPs did not affect the animals' energy metabolism, inducing them to a nutritional deficit. However, larvae exposed to PLA BioMPs have shown increased nitrite and lipid peroxidation levels, which supports the hypothesis that these pollutants increase oxidative stress processes in the animals evaluated, which can affect the animals' physiological homeostasis from different changes. In addition, the decrease in superoxide dismutase activity and of total thiols levels, in these same animals, is suggestive of the impact of PLA BioMPs on the antioxidant defenses, causing a REDOX imbalance, never before reported. On the other hand, decreased AChE activity was only observed in larvae exposed to PLA BioMPs, which demonstrates the anticholinergic activity of the tested polymers; the consequences of which include changes in different neurophysiological functions. Thus, the current study has helped improving the scientific knowledge about impacts caused by PLA BioMPs on freshwater ecosystems, as well as corroborated assertions about the risks posed by such biopolymers on these environments.
作为传统塑料（即石油衍生物）替代品开发的产品的毒理学安全性不可避免地需要进行（生态）毒理学研究。因此，本研究的目的是评估作为实验模型的威廉姆森无叶蝇幼虫中聚乙烯微塑料（PE MPs）（传统微塑料的代表）和聚乳酸生物微塑料（PLA BioMPs）的生化毒性。动物在环境相关浓度（6毫克/升）下短时间暴露于两种污染物（48小时）。在实验结束时，评估了不同的毒性生物标志物。为了评估污染物对动物营养状况的可能影响，测定了总蛋白、总可溶性碳水化合物和甘油三酯水平。然而，我们没有观察到各组之间的差异，这表明PE MPs和PLA BioMPs不会影响动物的能量代谢，不会导致它们出现营养缺乏。然而，暴露于PLA BioMPs的幼虫显示亚硝酸盐和脂质过氧化水平升高，这支持了这样一种假设，即这些污染物会增加所评估动物的氧化应激过程，这可能会通过不同的变化影响动物的生理稳态。此外，在这些相同的动物中，超氧化物歧化酶活性和总硫醇水平的降低表明PLA BioMPs对抗氧化防御有影响，导致氧化还原失衡，这是以前从未报道过的。另一方面，仅在暴露于PLA BioMPs的幼虫中观察到乙酰胆碱酯酶活性降低，这证明了所测试聚合物的抗胆碱能活性；其后果包括不同神经生理功能的变化。因此，本研究有助于提高关于PLA BioMPs对淡水生态系统影响的科学知识，并证实了关于此类生物聚合物对这些环境构成风险的断言。
