Multi-biomarker assessment of metal-oxide nanoparticle toxicity in Chironomus riparius

Abstract

The increasing production and utilization of metal-oxide nanoparticles (NPs) such as titanium dioxide (TiO2), cerium dioxide (CeO2), and magnetite (Fe3O4) have raised concerns regarding their environmental impact. This study aimed to assess the sub-organismal biomarkers of Chironomus riparius larvae exposed to these NPs, focusing on target organs, potential DNA damage, oxidative stress parameters, and hemoglobin levels. Chronic exposure experiments were conducted using OECD guidelines, with histological analyses revealing shortened microvilli in the midgut of larvae treated with CeO2 and Fe3O4 NPs. DNA damage, as measured by the comet assay, was significantly higher in larvae treated with CeO2 and Fe3O4 NPs. Oxidative stress parameters, including thiobarbituric acid reactive substances (TBARS) and advanced oxidation protein products (AOPP), were elevated in groups treated with CeO2 and Fe3O4 NPs, with significantly higher activity of catalase (CAT) was also noticed in the latter group. Group treated with TiO2 NPs had increased activity of superoxide dismutase (SOD). Hemoglobin levels were significantly affected, with increased concentrations in TiO2 and Fe3O4 treated groups, and decreased levels in the CeO2 treated group. The results of the study support the multi-biomarker approach as highly beneficial in understanding the mechanisms of NPs toxicity in aquatic ecotoxicology by detecting histopathological biomarkers along with sub-organismal biomarkers such as DNA damage, oxidative stress parameters, and hemoglobin concentration.

Keywords

• Histopathology
• Chironomidae
• Biomarkers
• Nanoparticles
• Metal-oxides
• Genotoxicity