title: One-Time Addition of Nano-TiO2 Triggers Short-Term Responses in Benthic Bacterial Communities in Artificial Streams.
abstract: Nano-TiO2 is an engineered nanomaterial whose production and use are increasing rapidly. Hence, aquatic habitats are at risk for nano-TiO2 contamination due to potential inputs from urban and suburban runoff and domestic wastewater. Nano-TiO2 has been shown to be toxic to a wide range of aquatic organisms, but little is known about the effects of nano-TiO2 on benthic microbial communities. This study used artificial stream mesocosms to assess the effects of a single addition of nano-TiO2 (P25 at a final concentration of 1 mg l(-1)) on the abundance, activity, and community composition of sediment-associated bacterial communities. The addition of nano-TiO2 resulted in a rapid (within 1 day) decrease in bacterial abundance in artificial stream sediments, but bacterial abundance returned to control levels within 3 weeks. Pyrosequencing of partial 16S rRNA genes did not indicate any significant changes in the relative abundance of any bacterial taxa with nano-TiO2 treatment, indicating that nano-TiO2 was toxic to a broad range of bacterial taxa and that recovery of the bacterial communities was not driven by changes in community composition. Addition of nano-TiO2 also resulted in short-term increases in respiration rates and denitrification enzyme activity, with both returning to control levels within 3 weeks. The results of this study demonstrate that single-pulse additions of nano-TiO2 to aquatic habitats have the potential to significantly affect the abundance and activity of benthic microbial communities and suggest that interactions of TiO2 nanoparticles with environmental matrices may limit the duration of their toxicity.
authors.affiliation: Department of Biology, Loyola University Chicago, 1032 West Sheridan Road, Chicago, IL, 60660, USA.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Ozaki
authors.affiliation: Department of Biology, Loyola University Chicago, 1032 West Sheridan Road, Chicago, IL, 60660, USA.
authors.forename: Erin
authors.initials: E
authors.lastname: Adams
authors.affiliation: Department of Biology, Loyola University Chicago, 1032 West Sheridan Road, Chicago, IL, 60660, USA.
authors.forename: Chu Thi Thanh
authors.initials: CT
authors.lastname: Binh
authors.affiliation: Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
authors.forename: Tiezheng
authors.initials: T
authors.lastname: Tong
authors.affiliation: Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Gaillard
authors.affiliation: Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Gray
authors.affiliation: Department of Biology, Loyola University Chicago, 1032 West Sheridan Road, Chicago, IL, 60660, USA. jkelly7@luc.edu.
authors.forename: John J
authors.initials: JJ
authors.lastname: Kelly
mesh_terms: D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D017753:Ecosystem; D053758:Nanoparticles / Q000633:toxicity*; D045483:Rivers / Q000382:microbiology*; D014025:Titanium / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D014025:Titanium
keywords: Bacteria; Benthic; Community; Nano-TiO2; Sediment; Stream; Toxicity