Sub-chronic toxicity of polystyrene microplastics in Danio rerio: evidence from hematological, biochemical, oxidative stress, and histopathological biomarkers
- 1Entomology Laboratory, Department of Zoology, School of Life Sciences, Periyar University , , ,
- 2Department of Environmental Science, Periyar University , , ,
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 LC50 value of PS-MPs to be 89.1 μg/L, and morphogenetic abnormalities were also observed. Based on the LC50, 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.
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BibTeX
@article{devapriya2026subchronic,
title = {{Sub-chronic toxicity of polystyrene microplastics in Danio rerio: evidence from hematological, biochemical, oxidative stress, and histopathological biomarkers}},
author = {Palanisamy Devapriya and Suresh Kalaivani and Velliangiri Devi and Ramakrishnan Poopal and Rajan Maheswaran},
journal = {Frontiers in toxicology},
year = {2026},
month = oct,
doi = {10.3389/ftox.2026.1960709},
url = {https://europepmc.org/article/PMC/PMC13727540},
note = {CC BY},
}
RIS
TY - JOUR
TI - Sub-chronic toxicity of polystyrene microplastics in Danio rerio: evidence from hematological, biochemical, oxidative stress, and histopathological biomarkers
AU - Palanisamy Devapriya
AU - Suresh Kalaivani
AU - Velliangiri Devi
AU - Ramakrishnan Poopal
AU - Rajan Maheswaran
PY - 2026
DA - 2026/10/20
JO - Frontiers in toxicology
DO - 10.3389/ftox.2026.1960709
UR - https://europepmc.org/article/PMC/PMC13727540
AB - 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 LC50 value of PS-MPs to be 89.1 μg/L, and morphogenetic abnormalities were also observed. Based on the LC50, 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.
SN - 2673-3080
ER -