Work

Sub-chronic toxicity of polystyrene microplastics in Danio rerio: evidence from hematological, biochemical, oxidative stress, and histopathological biomarkers

Year: 2026

Type: article

Abstract: Polystyrene microplastics (PS-MPs) have emerged as widespread aquatic contaminants with the potential to induce multiple toxic effects in fish. This study investigated the physicochemical characteristics and sub-chronic toxicity of PS-MPs in Danio rerio over 20 days. SEM revealed irregular and aggregated PS-MPs with micrometre-scale dimensions (approximately 1–200 µm), while DLS showed a hydrodynamic diameter of 1,115.5 nm with a polydispersity index (PDI) of 0.569. Acute toxicity analysis determined the LC 50 value of PS-MPs to be 89.1 μg/L, and morphogenetic abnormalities were also observed. Based on the LC 50 , the fish were exposed to Treatment I-2.5 μg/L, Treatment II-25 μg/L, and an untreated control; the sub-chronic exposure induced noticeable physiological, biochemical, and histopathological alterations. Hematological analysis revealed a significant increase in RBC count and a decrease in WBC count in exposed fish. Plasma glucose and total protein levels were significantly reduced, indicating metabolic impairment. LPO levels increased in the gills, demonstrating enhanced oxidative damage. Antioxidant responses were tissue-specific, with SOD and GPx activities significantly elevated in the gill, gut, and brain, whereas GST activity decreased in all three tissues. AChE activity was markedly reduced in the brain, indicating an altered neurophysiological response following PS-MP exposure. Histopathological examination revealed alterations in the gill, gut, and brain tissues of exposed fish. Overall, these findings demonstrate that prolonged exposure to PS-MPs induces oxidative stress, metabolic disturbances, neurotoxicity, immune dysregulation, and tissue damage in D. rerio , highlighting the ecological risks posed by microplastic pollution in freshwater ecosystems.

Source: Frontiers in Toxicology

DOI: 10.3389/ftox.2026.1960709

Authors: Palanisamy Devapriya, Suresh Kalaivani, Velliangiri Devi, Ramakrishnan Poopal, Rajan Maheswaran

Institution: Periyar University

Language: English

Topic: Microplastics and Plastic Pollution

Subfield: Pollution

Field: Environmental Science

Domain: Physical Sciences

SDGs: Clean water and sanitation, Life below water, Good health and well-being

Open Access status: gold

Estimated APC paid: $3,077