Influence of Suwannee River humic acid on particle properties and toxicity of silver nanoparticles

► Adsorption of humic acid on silver nanoparticles had a Langmuir adsorption isotherm at neutral pH. ► Dispersion of nano-Ag particles increased with SRHA amount and started decreasing at TOC > 10 mg L−1. ► Equilibrium concentration of ionic Ag remained constant at all SRHA concentrations. ► There was a linear decrease in toxicity within a certain nano-Ag concentration range.