Titanium nanoparticles fate in small-sized watersheds under different land-uses.

Surface waters from three catchments having contrasting land-uses (forested, agricultural, and urban) were sampled monthly and analysed for nanoparticulate titanium dioxide (NPs-TiO 2) by single particle ICPMS and electron microscopy. We report one-year of data for NPs-TiO 2 having average number and mass concentrations of 9.1 × 108 NPs-TiO 2 particles L-1 and 11 µg NPs-TiO 2 L-1 respectively. An increase in concentration during warmer months is observed in the forested and agricultural catchments. Both concentrations of NPs-TiO 2 are within the range of recently reported values using similar analytical approaches. The positive correlations for NPs-TiO 2 mass concentration or particle number with the concentration of some trace elements and DOC in the forested and agricultural catchments suggest the detected NPs-TiO 2 in these two systems are mostly from geogenic origin. Additionally, microscopy imaging confirmed the presence of NPs in the three catchments. Furthermore, the land-area normalized annual flux of NPs-TiO 2 (1.65 kg TiO 2 year-1 km-2) was highest for the agricultural catchment, suggesting that agricultural practices have a different impact on the NPs-TiO 2 dynamics and exports than other land-uses (urban or forestry). A similar trend is also found by the reanalysis of recent literature data. [Display omitted] • The land-use has an impact on the TiO 2 nanoparticle concentrations, biogeochemistry, dynamics and exports rates. • Higher amounts of small sized TiO 2 nanoparticles are detected by sp-ICPMS. • Ti speciation varies with the type of soils and land-use. • DOM controls the number of TiO 2 nanoparticles in surface water samples. • Land-use impacts TiO 2 nanoparticles concentrations, dynamics and exports rates. [ABSTRACT FROM AUTHOR]