title: Effects of fullerene (C60), multi-wall carbon nanotubes (MWCNT), single wall carbon nanotubes (SWCNT) and hydroxyl and carboxyl modified single wall carbon nanotubes on riverine microbial communities.
abstract: Commercial production of nanoparticles (NP) has created a need for research to support regulation of nanotechnology. In the current study, microbial biofilm communities were developed in rotating annular reactors during continuous exposure to 500 μg L(-1) of each nanomaterial and subjected to multimetric analyses. Scanning transmission X-ray spectromicroscopy (STXM) was used to detect and estimate the presence of the carbon nanomaterials in the biofilm communities. Microscopy observations indicated that the communities were visibly different in appearance with changes in abundance of filamentous cyanobacteria in particular. Microscale analyses indicated that fullerene (C60) did not significantly (p < 0.05) impact algal, cyanobacterial or bacterial biomass. In contrast, MWCNT exposure resulted in a significant decline in algal and bacteria biomass. Interestingly, the presence of SWCNT products increased algal biomass, significantly in the case of SWCNT-COOH (p < 0.05) but had no significant impact on cyanobacterial or bacterial biomass. Thymidine incorporation indicated that bacterial production was significantly reduced (p < 0.05) by all nanomaterials with the exception of fullerene. Biolog assessment of carbon utilization revealed few significant effects with the exception of the utilization of carboxylic acids. PCA and ANOSIM analyses of denaturing gradient gel electrophoresis (DGGE) results indicated that the bacterial communities exposed to fullerene were not different from the control, the MWCNT and SWNT-OH differed from the control but not each other, whereas the SWCNT and SWCNT-COOH both differed from all other treatments and were significantly different from the control (p < 0.05). Fluorescent lectin binding analyses also indicated significant (p < 0.05) changes in the nature and quantities of exopolymer consistent with changes in microbial community structure during exposure to all nanomaterials. Enumeration of protozoan grazers showed declines in communities exposed to fullerene or MWCNT but a trend for increases in all SWCNT exposures. Observations indicated that at 500 μg L(-1), carbon nanomaterials significantly alter aspects of microbial community structure and function supporting the need for further evaluation of their effects in aquatic habitats.
authors: Environment Canada, National Hydrology Research Centre, 11 Innovation Blvd., Saskatoon, SK, Canada, S7N 3H5. John.Lawrence@ec.gc.ca.
authors: J R
authors: JR
authors: Lawrence
authors: Environment Canada, National Hydrology Research Centre, 11 Innovation Blvd., Saskatoon, SK, Canada, S7N 3H5.
authors: M J
authors: MJ
authors: Waiser
authors: Environment Canada, National Hydrology Research Centre, 11 Innovation Blvd., Saskatoon, SK, Canada, S7N 3H5.
authors: G D W
authors: GD
authors: Swerhone
authors: Environment Canada, National Hydrology Research Centre, 11 Innovation Blvd., Saskatoon, SK, Canada, S7N 3H5.
authors: J
authors: J
authors: Roy
authors: Environment Canada, National Hydrology Research Centre, 11 Innovation Blvd., Saskatoon, SK, Canada, S7N 3H5.
authors: V
authors: V
authors: Tumber
authors: Global Institute for Water Security, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada.
authors: A
authors: A
authors: Paule
authors: Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, L8S 4M1, Canada.
authors: A P
authors: AP
authors: Hitchcock
authors: Canadian Light Source, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada.
authors: J J
authors: JJ
authors: Dynes
authors: Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada.
authors: D R
authors: DR
authors: Korber
mesh_terms: D001419:Bacteria / Q000187:drug effects; D018533:Biomass; D002245:Carbon Dioxide / Q000737:chemistry; D000460:Chlorophyta / Q000187:drug effects; D037741:Fullerenes / Q000633:toxicity*; D017665:Hydroxyl Radical / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity*; D045483:Rivers / Q000382:microbiology; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*
chemical_list: D037741:Fullerenes; D037742:Nanotubes, Carbon; D014874:Water Pollutants, Chemical; D002245:Carbon Dioxide; C041069:carboxyl radical; D017665:Hydroxyl Radical; C069837:fullerene C60
keywords: Carbon nanotubes; Diversity; Effects; Fullerenes; Metabolism; Microbial activity