Monday, November 13, 2006

The Impact of Fullerenes on the Soil Microbial Community Composition and Function.

Zhonghua Tong, Marianne Bischoff, Loring Nies, Bruce Applegate, and Ronald Turco. Purdue University, Department of Agronomy, 915 W. State Street, West Lafayette, IN 47907-2054

Since their discovery in 1985, fullerenes (C60) have received considerable attention due to their unique characteristics and many potential applications. As the development of nanotechnology industry continues, large amounts of carbon nanoparticles will be produced, used and possibly released into soil and the environment. The nascent state of the nano-product industry calls for important early assessment of environmental impacts before significant releases have occurred. Recent work has shown that pristine C60 fullerenes have either harmful or limited biological consequences. The antibacterial activities of fullerenes have been investigated using water soluble fullerene derivatives or C60 water suspension and have shown the nanomaterial, when prepared under specific conations, can be toxic to bacteria. However, these projects have been conducted in liquid-pure culture systems. Clearly the impact of manufactured nanomaterials on key soil processes must be addressed so that an unbiased discussion concerning the environmental consequences of nanotechnology can take place. In this study, soils were treated with either 1 μg g-1 of C60 in aqueous suspension (nC60) or 1000 μg g-1 of granular C60, a control containing equivalent tetrahydrofuran residues as generated during nC60 formation process or water and incubated for 30 days. Treatment effects on soil basal respiration, glucose-induced respiration, soil microbial community size and structure as evaluated using total phospholipid derived phosphate and fatty acid profiles and the community structure as evaluated by extraction of total genomic DNA and followed by PCR amplification using universal primers for the bacterial variable V3 region followed by DGGE were evaluated. In addition, the soil enzymatic activities for β-glucosidase, acid-phosphatase, dehydrogenase and urease, as effected by the additions were followed. Our observations show that the introduction of fullerene, as either C60 or nC60, has little impact on the structure and function of the soil microbial community and microbial processes.

Handout (.pdf format, 150.0 kb)