| Silver nanoparticles (nAg) are the largest and fastest growing class of nanomaterials, and are a concern when released into aquatic environments even at low microg L-1 levels. Measurement at environmental levels requires extremely sensitive instrumentation, therefore this research developed two passive samplers to track the the concentration of nAg and dissolved silver (Ag+). Diffusive gradient in thin films (DGT) with a thiol-modified resin were used to detect labile silver and carbon nanotubes (CNT-sampler) were used to measure nAg. Laboratory uptake experiments in lake water provided an Ag+ DGT diffusion coefficient of 3.09 x 10-7 cm2s-1 and CNT sampling rates of 24.73, 5.63, 7.31 mL day-1, for Ag+, citrate-nAg and PVP-nAg, respectively. The optimized passive samplers were deployed in mesocosms dosed with nAg. DGT samplers provided estimated Ag + concentrations ranging from 0.15 to 0.98 microg L -1 and CNT-samplers provided nAg concentrations that closely matched measured concentrations in water filtered at 0.22 microm. |
