Toxicity assessment of TiO2-conjugated Carbon-based nanohybrid material on a freshwater bioindicator cladoceran, Daphnia magna

Terrence S. Malatjie, Tarryn L. Botha, Memory Tekere, Alex T. Kuvarega, Thabo T.I. Nkambule, Bhekie B. Mamba, Titus A.M. Msagati

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

The application of nanocomposite materials fabricated from titanium dioxide nanoparticles (TiO2 NPs) and different carbon (C) allotropes have gained popularity in water treatment applications due to their synergistic properties. Studies to date have focused on simple forms of nanomaterials (NMs), however, with the technology development, there is a dramatic increase in production and application of these complex NMs which could result in toxicological impacts on organisms when released into aquatic environments. This raises serious concerns about their safety and the need to ascertain their potential adverse effects on aquatic organisms. While conjugated TiO2 NPs/carbon-based nanohybrids (TiO2/C-NHs) may exhibit enhanced photocatalytic activity, there is no research in the scientific community regarding their toxicological effects on D. magna, which are indicators of freshwater pollution. In this study, two under-represented TiO2/C-NHs (i.e., TiO2- conjugated carbon nanofiber (CNF), and TiO2-conjugated multi-walled carbon nanotube (CNT)) were investigated for their toxic effects on D. magna, through a series of acute toxicity tests with a set of sublethal biochemical biomarkers of oxidative stress. The lethal toxicity and oxidative stress formation of TiO2/C-NHs over 48 h revealed a concentration-dependant increase in D. magna mortality. The primary mechanism identified was the generation of ROS, which was in line with toxicity results. Light microscopy and CytoViva® images visualized D. magna interaction with the NPs, which accumulated and appeared as dark materials in the lines of the gut tract. The collective results indicate that TiO2/C-NHs have the potential to cause an effect on freshwater organisms when released into the environment. However, the relevance of TiO2/C-NHs effects needs further chronic toxicity studies since they show promise to be used in nano-bioremediation materials to treat wastewaters.

Original languageEnglish
Article number106176
JournalAquatic Toxicology
Volume247
DOIs
Publication statusPublished - Jun 2022
Externally publishedYes

Keywords

  • Carbon nanoparticles
  • CytoViva®
  • Daphnia magna
  • Nanocomposites
  • Nanotoxicity
  • TiO

ASJC Scopus subject areas

  • Aquatic Science
  • Health, Toxicology and Mutagenesis

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