Toxicity of zero-valent iron nanoparticles to a trichloroethylene-degrading groundwater microbial community

Abstract

The microbiological impact of zero-valent iron used in the remediation of groundwater was investigated by exposing a trichloroethylene-degrading anaerobic microbial community to two types of iron nanoparticles. Changes in total bacterial and archaeal population numbers were analyzed using qPCR and were compared to results from a blank and negative control to assess for microbial toxicity. Additionally, the results were compared to those of samples exposed to silver nanoparticles and iron filings in an attempt to discern the source of toxicity. Statistical analysis revealed that the three different iron treatments were equally toxic to the total bacteria and archaea populations, as compared with the controls. Conversely, the silver nanoparticles had a limited statistical impact when compared to the controls and increased the microbial populations in some instances. Therefore, the findings suggest that zero-valent iron toxicity does not result from a unique nanoparticle-based effect.

Keywords:

• Nanoparticle
• zero-valent iron
• anaerobic
• microbial
• toxicity
• iron
• trichloroethylene

Acknowledgments

Author Kara M. Zabetakis would like to express appreciation for the support and insight provided by Dr. Sheryl Ehrman of the University of Maryland, College Park. The authors also acknowledge the support of the Maryland Surface Analysis Center and the Maryland NanoCenter and its NispLab.

Funding

The Surface Analysis Center and NispLab are supported in part by the NSF as MRSEC Shared Experimental Facilities. This research was made possible by SMART – DOD fellowship to Kara M. Zabetakis.