Metal Oxide Engineered Nanomaterials Involved in Energy Storage Technologies and Their Effect in Soil Microbial Communities and Function.

A growing human population has driven an increased demand for energy and new ways to storage it. Metal oxide engineered nanomaterials (MO-ENMs), including nano molybdenum oxide (nanoMoO₃), nano nickel oxide (nanoNiO) and nano lithium oxide (nanoLi₂O), have found wide application with emerging fuel cell and energy storage technologies. However, the production and application of ENMs will lead to inevitable environmental release during all life cycle phases; manufacturing, delivery, use, and/or disposal. Environmental concentrations of most ENMs are unknown, but exposure modeling studies suggest soil as the major sink of ENMs released to the environment.  Our previous work showed that all nanoMoO₃, nanoNiO, and nanoLi₂O have some toxic effects on soil function and microbial communities. Soil treated with nanoMoO₃ and nanoNiO showed a response that was reversed after <6 days of incubation. However, soil treated with nanoLi₂O at 458 µg Li/g showed an increased greenhouse gas (CH₄, and CO₂) production and effects of soil enzymes with: β-glucosidase activity decreased while urease increased. All MO-ENMs shifted the three domains of microbial community structures at increasing metal concentrations, except for the archaeal community treated with nanoLi₂O.  Our efforts are now focused on understanding how these MO-ENMs affect soil microbial communities taxonomically and functionally. In this presentation we will: i. Compare soil microbial community composition using amplicon survey (16S rRNA) and shotgun metagenomics; ii. Determine soil microbial functional potential using amplicon survey (16S rRNA) and shotgun metagenomics, and physiological profiles; and iii. Compare soil microbial community composition and functional potential responses of MO-ENMs with their bulk forms. Beyond understanding nano effects in soil system, we intend to move forward to better understand how perturbations impact soil stability and resilience.