Are reproduction impairments of free spawning marine invertebrates exposed to zero-valent nano-iron associated with dissolution of nanoparticles?

Abstract

Studies were carried out to assess the effects of coating applied to zero-valent nano-iron (nZVI) on early life stage development of three key marine invertebrate species Mytilus galloprovincialis, Ciona intestinalis and Psammechinus milliaris. Embryo development was assessed following a 2-h exposure of the sperm to concentrations of two nZVIs of up to 10 mg l^-1 followed by in vitro fertilisation. Disruption of embryo development was most severe in sea squirts followed by mussel, while the urchin embryos were not significantly affected as compared with controls. An over twofold decrease in fertilisation success alongside significant delay in the embryo development was observed, and the effect was more severe with the coated form, possibly owing to its better colloidal stability. We provide in vitro evidence for the rapid dissolution (within 2 h) of nZVI in seawater to a degree that concentration of total solute Fe released from the coated ZVI particles exceeds safe limits of NOECs established for dissolved Fe.

Keywords::

• Zero-valent nano-iron
• nanoparticles
• Mytilus galloprovincialis
• Psammechinus milliaris
• Ciona intestinalis
• embryo development assay
• nanoremediation

Acknowledgements

This work contributes to the NERC funded program Oceans 2025 (Theme 3—Coastal and shelf processes). Sherain Al-Subiai is financially supported by the Kuwait Institute for Scientific Research (KISR), State of Kuwait. RDH acknowledges support from NERC (NE/G001812/1). Andrew Fisher is kindly acknowledged for the ICPMS analyses and Dr Bjorn Stolpe for nanoparticle characterisation at FENAC, Birmingham, UK. The experiments on sea squirts were carried out at the Anton Dohrn Zoological Institute in Naples supported by the Assemble grant (2047/G6) awarded to EK and OD.