Institute of Science and Technology, São Paulo State University, UNESP, 3 de Março Avenue 511, Alto da Boa Vista, 18087-180, Sorocaba, Brazil.
Department of Ecology, Institute of Biosciences, University of São Paulo, USP, Matão Street 321, 05508-090, São Paulo, Brazil.
Ecotoxicology. 2023 Apr;32(3):300-308. doi: 10.1007/s10646-023-02640-z. Epub 2023 Mar 11.
Microplastic (MP) is yet another form of chronic anthropogenic contribution to the environment. MPs are plastic particles (<5 mm) that have been widely found in the most diverse natural environments, but their real impacts on ecosystems are still under investigation. Here, we studied the toxicity of naturally aged secondary polypropylene (PP) MPs after constant exposure to ultraviolet radiation (26 µm) to the third instar larvae of Chironomus sancticaroli, a dipteran species. The concentrations tested were 13.5; 67.5; and 135 items g of dry sediment. C. sancticaroli organisms were investigated for fragment ingestion, mortality and changes in enzymatic biomarkers after 144 h of exposure. The organisms were able to ingest MPs from the first 48 h, and the amount of items internalized was dose-dependent and time-dependent. Overall, the results show that mortality was low, being significant at the lowest and highest concentrations (13.5 and 135 items g). Regarding changes in biochemical markers, after 144 h MDA and CAT activities were both significantly altered (increased and reduced, respectively), while SOD and GST levels were unchanged. In the present study, naturally aged polypropylene MPs induced biochemical toxicity in C. sancticaroli larvae, with toxicity being higher according to exposure time and particle concentration.
微塑料（MP）是人类对环境造成的另一种慢性人为污染。MP 是指粒径小于 5 毫米的塑料颗粒，已广泛存在于各种自然环境中，但它们对生态系统的实际影响仍在研究之中。在这里，我们研究了经过持续暴露于紫外线（26 微米）后自然老化的二次聚丙烯（PP）MP 对三化刺股摇蚊幼虫的毒性，三化刺股摇蚊是一种双翅目物种。测试的浓度分别为 13.5；67.5；和 135 个 g 干沉积物中的项目。研究了 C. sancticaroli 生物体在暴露 144 小时后对片段摄入、死亡率和酶生物标志物变化的影响。生物体能够在最初的 48 小时内摄入 MPs，并且内化的项目数量与剂量和时间有关。总体而言，结果表明死亡率较低，在最低和最高浓度（13.5 和 135 个 g）时具有统计学意义。关于生化标志物的变化，144 小时后 MDA 和 CAT 活性均显著改变（分别增加和减少），而 SOD 和 GST 水平保持不变。在本研究中，自然老化的聚丙烯 MPs 诱导了 C. sancticaroli 幼虫的生化毒性，毒性随暴露时间和颗粒浓度的增加而增加。
