The Influence of Soil Organic Matter on the Uptake of Silver Nanoparticles in a Terrestrial System (original) (raw)

— The uptake of silver from silver nanoparticles in soil was investigated in the presence of increasing concentrations of soil organic matter. Especially, the effect of Humus component of soil organic matter on the uptake of Ag from silver nanoparticles was studied. Two insect species, Acheta domesticus and Tenebrio molitor, and two plant species, Helianthus annuus and Sorghum vulgare, were exposed to silver nanoparticles(25 ppm in the presence of increasing concentrations of Humus (0, 1, 5, 10, 15, and 20% Humus) in soil (by weight). The techniques of transmission electron microscopy, dynamic light scattering, and powder X-ray diffraction were used to characterize the silver nanoparticles used in the study. An inductively coupled plasma-optical emission spectrometer was used to measure the levels of silver in test samples. Increasing concentrations of Humus in soil has resulted in an increase in the sulfur content and cation exchange capacity of the soil. A general decrease in the concentrations of silver was observed in Acheta domesticus and both the plant species, as a function of increasing concentrations of Humus in soil. In the case of plant species, the accumulation of silver nanoparticles was predominantly observed in the root tissue. Additionally, the translocation of silver from the roots to other plant tissues was observed in the case of Helianthus annuus. Results from this study suggest that the presence of Humus in soil could possibly decrease the uptake of silver from silver nanoparticles by insect and plant species.