The rapid production and application of silver nanoparticles (Ag) has led to significant release of Ag into the terrestrial environments and has increased the possibility of contamination of groundwater resources and soils by nanoparticles (). Once released into soil, Ag could enter into different interactions with soil particles which play key roles in controlling the fate and traort of these nanoparticles. It is crucial to study the fate of in order to evaluate and control their risks to ecosystems and human health. In spite of that, experimental evidences on the retention and traort of Ag in soils are very scarce. Hence, this study was conducted in three parts to: i) investigate the retention behavior of polyvinylpyrrolidone (PVP) stabilized silver nanoparticles (PVP-Ag) and Ag(I) ions in a range of calcareous soils, ii) study the traort and retention of PVP-Ag under saturated and unsaturated conditions in sand and two calcareous soils, and iii) examine the biological effects of PVP-Ag and Ag ions in two calcareous soils. The results revealed that the retention data for both PVP-Ag and Ag(I) ions were well described by the Keywords : Silver nanoparticle, AgNO 3 , Sorption Isotherms, Unsaturated flow, HYDRUS-1D, ED 50 .
