Exploring medium‐term impact of oxide nanoparticles on soil microbial activity by isothermal microcalorimetry and urease assay

The entry of oxide nanoparticles (NPs) into the environment mandates study of their impact on the soil ecosystem. This study explored the medium‐term impact (about 120 days) of oxide NPs on the soil microbial community and urease activity through isothermal microcalorimetry and enzyme assay. The soil samples were separately treated with four types of oxide NPs (ZnO, Al 2 O 3 , TiO 2 , and SiO 2 NPs) at 1 μg/g soil or 500 μg/g soil compared with a control, and incubated for up to 120 days. Except for some sort of acute toxicity, the NPs have no significant deleterious effect (P > 0.05) on the soil microbial community and urease activity along with the incubation time lengthening, which suggests that incubation time played a more essential role in modifying the antibacterial activity than the nature of oxide NPs. That is the medium‐term impacts of oxide NPs on the soil microbial process was not very simple and monofactorial. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 395–403, 2016