The effect of inorganic nanoparticles (ZnO, Cr2O3, CuO and Ni) and their bulk counterparts on enzyme activities in different soils

- Effect of nanoparticles on the soil enzymatic activities was investigated.
- Nanoparticles affected soil enzymatic activity in different ways depending on soil.
- Nano-CuO affected the most frequently on enzymatic activity inhibition.

The objective of the study was to determine the effect of nanoparticles (NPs) and their bulk counterparts on the enzymatic activity of two soils. The study comprised analyses of the effect of four NPs (ZnO, CuO, Cr2O3, Ni) on the activity of dehydrogenase, urease, acidic and alkaline phosphatase in two soils with different physicochemical properties. The effect of the concentration of NPs (10, 100 and 1000 mg/kg), size of particles and contact time between NPs and soil (24 and 196 days) was studied. Depending on the enzyme and soil type tested, an inhibitory or a stimulating effect of NPs on the activity of the enzymes was observed. The absence of the dose-effect relationship made it difficult to compare the effects among the individual NPs. It could be clearly noted, however, that relatively the most frequent negative effect was observed for CuO NPs. The levels of inhibition/stimulation of the NPs varied notably also in relation to the soil type, duration of contact between NPs and the soil, and particle size (nano, bulk).