Assessment of TiO2 Nanoparticles on Maize Seedlings and Terrestrial Isopods Under Greenhouse Conditions

Abstract

This study aims to evaluate the TiO 2 nanoparticles (NPs) and soil type effect on Zea mays L. seedlings and to assess the effect of the TiO 2 NPs retained in organic matter on terrestrial isopods (Armadillidium vulgare, Latreille). It was hypothesized that (i) the combined effect of soil pH and minerals, and the addition of TiO 2 NPs harm maize plants, and (ii) increasing Ti's content in organic matter (OM) causes mortality in the isopods. Under greenhouse conditions, the effects of TiO 2 NPs (300 and 600 mg kg −1 dry soil) were assessed during 21 days in acid or alkaline soils, with an organic matter layer above the soil surface (3 cm). An inhibitory effect of TiO 2 NPs on plant length and root size was clearly shown at 21 days in alkaline soil but not in acid soils. Besides, a higher amount of Ti was accumulated on maize tissues in alkaline soil than those grown on acid soil. An increase in TiO 2 NPs caused higher Ti concentrations in the soil organic matter (SOM), which harmed the survival and weight of the terrestrial isopods when the OM is consumed. Isopods limit the consumption of NPs at high concentrations while the NPs leached toward soil deeper layers allowing a reduction in plant height and root size in Z. mays plants grown in alkaline soil. Nevertheless, further investigations on the effect of TiO 2 NPs in the association of plants and terrestrial isopods in natural conditions are required.