Sinha Ankit Anand, Jamdar Krupa, Prabhu Aakanksha, D'Costa Avelyno
Zoology Discipline, School of Biological Sciences & Biotechnology, Goa University, Taleigao Plateau, Goa, India.
J Appl Toxicol. 2025 Sep 19. doi: 10.1002/jat.4935.
Microplastic (MPs) pollution has emerged as a critical environmental stressor with growing implications for freshwater ecosystems. This study investigates the sub-lethal toxicological effects of polystyrene (PS-MPs) and polyethylene microplastics (PE-MPs) on Oreochromis mossambicus under controlled laboratory conditions. Acute toxicity tests established the 96-h LC values, identifying PE-MPs as significantly more toxic than PS-MPs. Sub-lethal concentrations-15.33, 30.66, and 76.34 mg/L for PE-MPs and 50, 250, and 500 mg/L for PS-MPs-were selected based on the LC values and applied in a 14-day semi-static exposure set-up. Tissue-specific MPs accumulation analysis revealed a dose-dependent retention of MPs in gill, gastrointestinal, and liver tissues. Biochemical assays indicated significant disruptions in oxidative stress markers and metabolic enzymes. Significant increases in catalase (CAT), superoxide dismutase (SOD), and thiobarbituric acid reactive substances (TBARS) levels were observed, along with alterations in alanine aminotransferase (ALT), alkaline phosphatase (ALP), and essential macromolecules (proteins, carbohydrates), indicating oxidative and metabolic stress. Genotoxicity, assessed by the micronucleus assay, demonstrated a concentration-dependent increase in micronucleated erythrocytes, indicative of chromosomal damage. Histopathological evaluations of gill and intestinal tissues revealed MPs-induced structural alterations, supporting the observed altered biochemical and genotoxic responses. These findings offer mechanistic insights into the sub-lethal toxicity of MPs, highlighting their potential to induce oxidative imbalance, genotoxicity, and histoarchitectural damage in tilapia. The study underscores the urgent need for comprehensive risk assessments and mitigation strategies to address microplastic contamination in inland aquatic systems.
微塑料（MPs）污染已成为一个关键的环境压力源，对淡水生态系统的影响日益增大。本研究在可控的实验室条件下，调查了聚苯乙烯微塑料（PS-MPs）和聚乙烯微塑料（PE-MPs）对莫桑比克罗非鱼的亚致死毒理学效应。急性毒性试验确定了96小时的半数致死浓度（LC值），发现PE-MPs的毒性明显高于PS-MPs。根据LC值选择了亚致死浓度——PE-MPs为15.33、30.66和76.34毫克/升，PS-MPs为50、250和500毫克/升，并应用于14天的半静态暴露试验设置中。组织特异性微塑料积累分析显示，鳃、胃肠道和肝脏组织中微塑料的保留呈剂量依赖性。生化分析表明氧化应激标志物和代谢酶受到显著干扰。观察到过氧化氢酶（CAT）、超氧化物歧化酶（SOD）和硫代巴比妥酸反应物质（TBARS）水平显著升高，同时丙氨酸转氨酶（ALT）、碱性磷酸酶（ALP）和必需大分子（蛋白质、碳水化合物）发生改变，表明存在氧化和代谢应激。通过微核试验评估的遗传毒性表明，微核红细胞呈浓度依赖性增加，表明存在染色体损伤。鳃和肠道组织的组织病理学评估显示微塑料诱导的结构改变，支持了观察到的生化和遗传毒性反应的改变。这些发现为微塑料的亚致死毒性提供了机制性见解，突出了它们在罗非鱼中诱导氧化失衡、遗传毒性和组织架构损伤的潜力。该研究强调了迫切需要进行全面的风险评估和缓解策略，以应对内陆水生系统中的微塑料污染。
