The Influence of Soil pH on the Uptake of Silver Nanoparticles in a Terrestrial System

The production and use of silver nanoparticles (Ag NPs) are increasing in the United States and across the globe. The Ag NPs may enter the terrestrial ecosystem with the application of sewage sludge as a fertilizer on agricultural farms. The present study investigated the influence of soil pH on the uptake of Ag NPs by insects. Two insects A. domesticus and T. molitor were selected for the experiment. The insects were exposed to Ag NPs under different soil pH including: 5, 6, 7, 8 (control), and 9. The Ag NPs were characterized prior to the study with transmission electron microscopy, dynamic light scattering, and powder X-ray diffraction techniques. The concentration of silver in insects was measured with inductively coupled plasma-optical emission spectroscopy. Increased levels of silver in insects was observed in normal and alkaline soil as compared to acidic soil treatment groups. Additionally, there was no significant difference due to insect species in the silver uptake.