Following the Occurrence and Origin of Titanium Dioxide Nanoparticles in the Sava River by Single Particle ICP-MS

Titanium dioxide nanoparticles (TiO2NPs) are widely produced and used NPs in different applications. To evaluate the risk from anthropogenic TiO2NPs, more information is needed on their occurrence in the environment. For the first time, this study reports the levels of TiO2NPs in waters and sediments at selected sampling sites along the Sava River using inductively coupled plasma mass spectrometry in single particle mode (spICP-MS). The highest concentrations of TiO2NPs were determined in river water at Vrhovo (VRH), Jasenovac (JAS), and Slavonski Brod (SLB) sampling locations impacted by urban, agricultural, and/or industrial activities, suggesting that these NPs are likely of anthropogenic origin. The results further showed that hydrological conditions and sediment composition significantly influence the levels of TiO2NPs in river water at most locations. Moreover, the Ti/Al elemental concentration ratios of NPs in water and sediments at JAS were higher than the natural background ratios, further confirming their anthropogenic origin. The outcome of this study provides first information on the presence of (anthropogenic) TiO2NPs in different environmental compartments of the Sava River, contributing to more reliable risk assessments and better regulation of TiO2NPs emissions in the future.