Effect of soil properties on Zn availability for plant plant uptake in soils amended with ZnO nanoparticles

There is a need to understand processes regulating fate of NPs in natural media like soil. Recent studies, however, show that the solubility and plant uptake of NPs in soil cannot be fully explained on the basis of common... [ view full abstract ]

There is a need to understand processes regulating fate of NPs in natural media like soil. Recent studies, however, show that the solubility and plant uptake of NPs in soil cannot be fully explained on the basis of common soil-solution partition processes as for ionic metals.

To identify the degree to which Zn from ZnONPs added to well-aerated soils was available for plant uptake, a pot experiment with 3 natural soils of variable properties (pH=4.8-7.0; OC=1.1-2.2 %; clay=3-17 %) was performed. Each pot was equipped with solution samplers to extract in-situ pore water samples.
Pots were amended with a suspension of ZnONPs (at 10 or 100 mg Zn kg-1 soil) and kept for 30 days at constant moisture (70 % of WHC). After this, seeds of Lactuca sativa were planted. Plants were observed for 21 days after 50 % emergence of the seedlings in control pots (OECD 208 guideline). Finally, emerged plants were harvested, dried and shoots were analysed for Zn total concentration.

The soil-pore water distribution of dispersed ZnONPs as well as dissolved Zn released from NPs was monitored throughout the experiment. At the end of the experiment, soils from pots were separated in 2 sub-samples (0-5 and 5-10 cm depth) and dried. Subsequently extraction tests were applied to quantify the geochemically reactive and bioavailable pool of Zn that remained in soil.

In this presentation the effect of soil properties on the solubility of ZnO NPs and availability of Zn for plant uptake will be discussed in detail.