Influences of water properties on the aggregation and deposition of engineered titanium dioxide nanoparticles in natural waters.
With the increasing usage of titanium dioxide nanoparticles (NPs), their release into the environment makes it important to understand their transport, fate and behaviour in natural waters. In this study, aggregation and deposition of TiO2NPs were studied during a 3-h period by using a dynamic light scattering instrument and a UV-vis spectrophotometer, respectively. TiO2NPs were spiked in 34 lake and 5 brackish water samples at an initial concentration of 10 mg L-1. Depending on the physicochemical properties of the natural waters, TiO2NPs exhibited different colloidal stability. In brackish waters with high salinity, TiO2NPs were prone to aggregate and settled rapidly. Whereas under conditions of humic and humus-poor lake waters, TiO2NPs were suspended in water column for a longer time without remarkable change in particle size and concentration. Deposition likely occurred in nutrient-rich lakes which had high amount of nitrogen and phosphorus accompanied by high values of conductivity, alkalinity, pH and turbidity. Linear regression analysis revealed the statistically significant relationships (p ≤ 0.008) between the TiO2NPs stability and these water properties. Our study makes a better understanding of the water properties that control the aggregation and deposition of TiO2NPs in complex natural waters.
Finnish Environment Institute, Laboratory Centre, Ecotoxicology and Risk Assessment, Hakuninmaantie 6, FI-00430 Helsinki, Finland. Electronic address: ling.li@helsinki.fi.
Ling
L
Li
Finnish Environment Institute, Laboratory Centre, Ecotoxicology and Risk Assessment, Hakuninmaantie 6, FI-00430 Helsinki, Finland.
Markus
M
Sillanpää
Finnish Environment Institute, Laboratory Centre, Environmental Chemistry Research, Hakuninmaantie 6, FI-00430 Helsinki, Finland.
Maarit
M
Risto
D000327:Adsorption; D006801:Humans; D060106:Lakes / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D012542:Scattering, Radiation; D014025:Titanium / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification
D014874:Water Pollutants, Chemical; D014867:Water; C009495:titanium dioxide; D014025:Titanium
Aggregation; Deposition; Linear regression analysis; Natural water properties; Titanium dioxide nanoparticles