Interactions between multi-walled carbon nanotubes and plankton as detected by Raman spectroscopy

Jack R Howarth; Alvin Orbaek White; Ali Hedayati; Yubiao Niu; Richard E Palmer; Kam W Tang

doi:10.1016/j.chemosphere.2022.133889

Interactions between multi-walled carbon nanotubes and plankton as detected by Raman spectroscopy

Chemosphere. 2022 May:295:133889. doi: 10.1016/j.chemosphere.2022.133889. Epub 2022 Feb 4.

Authors

Jack R Howarth¹, Alvin Orbaek White², Ali Hedayati³, Yubiao Niu⁴, Richard E Palmer⁴, Kam W Tang⁵

Affiliations

¹ Department of Biosciences, Faculty of Science & Engineering, Swansea University, SA2 8PP, UK.
² Energy Safety Research Institute, Faculty of Science & Engineering, Swansea University, SA1 8EN, UK; Chemical Engineering, Faculty of Science and Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, UK. Electronic address: alvin.OrbaekWhite@swansea.ac.uk.
³ TECNALIA, Basque Research and Technology Alliance (BRTA), Alava Science and Technology Park, Leonardo da Vinci 11, 01510, Vitoria-Gasteiz, Spain.
⁴ Nanomaterials Lab, Mechanical Engineering, Faculty of Science and Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, UK.
⁵ Department of Biosciences, Faculty of Science & Engineering, Swansea University, SA2 8PP, UK. Electronic address: k.w.tang@swansea.ac.uk.

PMID: 35131272
DOI: 10.1016/j.chemosphere.2022.133889

Abstract

Raman spectroscopy has been commonly used in materials science to detect chemicals. Based on inelastic scattering of light after incident photons interact with a molecule, it has high potential for non-destructive detection of specific contaminants in living biological specimens. The increasing use of carbon nanotubes (CNTs) increases its chance to enter the aquatic habitats through direct discharge, surface runoff and atmospheric deposition, but their potential environmental impacts remain poorly known. We tested the use of Raman spectroscopy to investigate the interactions between multi-walled CNTs (MWCNTs) and aquatic plankton in vivo. For phytoplankton cells (Scenedesmus obliquus) that were exposed to MWCNTs, Raman spectroscopy was able to distinguish between background biological material and MWCNTs that adhere to the cells (G-band peak at 1590 cm^-1 and D-band peak at 1350 cm^-1 in the Raman spectra that were unique to MWCNTs). Harmful effects of MWCNT exposure manifested as lower photosynthetic efficiency and/or lower specific growth rate in the phytoplankton. MWCNT particles also adhered to the body surface of zooplankton, especially the carapace. Both Ceriodaphnia sp. and Daphnia sp. ingested MWCNTs directly, which was verified by the signature G-band and D-band Raman peaks in the zooplankton gut region. MWCNTs remained in the gut overnight after the zooplankton had been returned to clean water, showing that the zooplankton retained MWCNTs inside their body for an extended time, thereby increasing the chance to disperse and transfer the contaminants throughout the aquatic food web. Our results demonstrate that Raman spectroscopy is a promising method for non-destructive investigation of the uptake and dynamic fate of CNTs and other contaminants in aquatic organisms.

Keywords: Aquatic food web; Carbon nanotubes; Phytoplankton; Raman spectroscopy; Zooplankton.

MeSH terms

Animals
Daphnia
Nanotubes, Carbon* / chemistry
Nanotubes, Carbon* / toxicity
Plankton
Spectrum Analysis, Raman
Water Pollutants, Chemical* / chemistry

Substances

Nanotubes, Carbon
Water Pollutants, Chemical