Dose–response effects of silver nanoparticles and silver nitrate on microbial and enzyme activities in calcareous soils

The extensive use of silver nanoparticles (AgNPs) in consumer and medical products leads inevitably to release of such particles into environment and soil resources. This study was conducted to provide evidences for biological effects of AgNPs in two calcareous soils with different textures and salinity levels. Basal respiration (BR) and substrate-induced respiration (SIR), as indicators of soil microbial activity and biomass, respectively, were determined in the calcareous soils spiked with a dilution series of AgNPs and AgNO₃. Urease and alkaline phosphatase activities were also measured in the spiked and control soils. Finally, dose–response approach was used to model the sensitivity of the soil biological properties to AgNPs and AgNO₃ contamination. The results revealed that the effects of AgNPs and AgNO₃ on the soil respiration and enzyme activities depended on Ag dose and soil type. For instance, soil …