Abstract：
Microplastics and heavy metals pollution is recognised as a major problem affecting aquatic ecosystems. For this reason, this study aims to assess the toxicity of different concentrations of polyethylene microplastics (PE-MPs) (0.0, 500, and 1000 μg L-1) with a mean size of 15-25 μm and lead acetate Pb(C2H3O2)2 (0.0, 2.5, and 5 mg L-1), both individually and in combination, through the exposure of the freshwater grass shrimp, Caridinia fossarum for 15 days, focusing on microplastic interaction with co-occurring contaminants. After being exposed to both contaminants, either individually or in combination, significant alterations in numerous biochemical markers were observed. Specifically, exposure to lead acetate alone resulted in significant changes across ALP, AST, ALT, LDH, GGT, and BChE enzyme activity levels indicating hepatotoxicity and neurotoxicity. Also, Pb exposure led to alterations in total antioxidant capacity, MDA, total lipids, and glycogen contents, signalling the onset of oxidative stress. Exposure to PE-MPs alone led to changes in ALP, LDH, GGT, and BChE enzyme levels, and in MDA, total lipids, and glycogen samples\' contents. Remarkably, the study observed increased bioaccumulation of lead acetate in samples treated with the combination, emphasizing the synergistic impact of PE-MPs on the toxicity of lead acetate. This synergy was also evident in AST and ALT enzyme activity levels and MDA contents. This underscores the necessity for measures to address both microplastic pollution and heavy metal contamination, taking into account the synergistic behaviour of MPs in the presence of concurrent contaminants.
摘要：
微塑料和重金属污染被认为是影响水生生态系统的主要问题。出于这个原因,本研究旨在评估平均尺寸为15-25μm的不同浓度的聚乙烯微塑料（PE-MPs）（0.0、500和1000μgL-1）和醋酸铅（C2H3O2）2（0.0、2.5和5mgL-1）的毒性，无论是单独还是组合，通过暴露淡水草虾，15天，关注微塑料与共存污染物的相互作用。暴露于这两种污染物后，无论是单独还是组合，观察到许多生化标志物的显着变化。具体来说,单独暴露于醋酸铅导致整个ALP的显著变化，AST,ALT,LDH,GGT,和BChE酶活性水平表明肝毒性和神经毒性。此外，铅暴露导致总抗氧化能力的改变，MDA,总脂质，和糖原含量，发出氧化应激的信号。单独接触PE-MP导致ALP的变化，LDH,GGT,和BChE酶水平，在MDA中，总脂质，和糖原样本的含量。值得注意的是,该研究观察到用组合处理的样品中乙酸铅的生物累积增加，强调PE-MPs对醋酸铅毒性的协同影响。这种协同作用在AST和ALT酶活性水平和MDA含量方面也很明显。这强调了采取措施解决微塑料污染和重金属污染的必要性，考虑到MP在并发污染物存在下的协同行为。
