title: The influence of multiwalled carbon nanotubes on polycyclic aromatic hydrocarbon (PAH) bioavailability and toxicity to soil microbial communities in alfalfa rhizosphere.
abstract: Carbon nanotubes (CNTs) may affect bioavailability and toxicity of organic contaminants due to their adsorption properties. Recent studies have observed the influence of multiwalled carbon nanotubes (MWNTs) on the fate of polycyclic aromatic hydrocarbons (PAHs) and other organic contaminants. Greenhouse studies (49 d) were conducted with alfalfa plants in two different soil types. Four treatment conditions (0, 25, 50, or 100 mg/kg MWNTs+100 mg/kg PAHs mixture-pyrene and phenanthrene) were tested in order to determine their effects on soil microbial community composition and PAH residues. Microbial community structure in the two highest treatments (50 mg/kg and 100 mg/kg MWNTs) showed a dramatic shift in the presence of MWNTs in sandy loam soil (1% organic matter) in comparison to the control (0 mg/kg MWNTs). Many microbial fatty acid methyl ester (FAMEs) markers (i15:0, 16:1ω5c, 10Me17:0, 10Me16:0) were missing in the control soil. However, there was a lower abundance of these FAMEs in the 25 mg/kg MWNT treatment (except 10Me17:0) and a higher presence of these FAMEs in the 50 mg/kg and 100 mg/kg MWNT treatments compared to control. In contrast, microbial community composition was not influenced by the MWNT treatments in sandy clay loam soil (5.9% organic matter). However, pyrene degradation in sandy clay loam soil significantly increased by 21% in the highest MWNT treatment group (100 mg/kg) and 9.34% in 50 mg/kg MWNT treatment. Under the conditions tested in this study, MWNTs significantly impacted the soil microbial community distribution and PAH degradation and effects were dependent on soil types, specifically organic matter content.
authors: Department of Environmental Toxicology, The Institute of Environmental and Human Health (TIEHH), Texas Tech University, Lubbock, TX, United States; Pegasus Technical Services Inc., Cincinnati, OH, United States. Electronic address: shrestha.babina@epa.gov.
authors: Babina
authors: B
authors: Shrestha
authors: Department of Environmental Toxicology, The Institute of Environmental and Human Health (TIEHH), Texas Tech University, Lubbock, TX, United States.
authors: Todd A
authors: TA
authors: Anderson
authors: USDA-ARS, Cropping Systems Research Laboratory, Lubbock, TX, United States.
authors: Veronica
authors: V
authors: Acosta-Martinez
authors: USDA-ARS, Cropping Systems Research Laboratory, Lubbock, TX, United States.
authors: Paxton
authors: P
authors: Payton
authors: Department of Environmental Toxicology, The Institute of Environmental and Human Health (TIEHH), Texas Tech University, Lubbock, TX, United States.
authors: Jaclyn E
authors: JE
authors: Cañas-Carrell
mesh_terms: D001682:Biological Availability; D005227:Fatty Acids / Q000032:analysis; D000455:Medicago sativa / Q000378:metabolism; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity*; D010616:Phenanthrenes / Q000032:analysis; D010944:Plants / Q000378:metabolism; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000493:pharmacokinetics* / Q000633:toxicity; D011721:Pyrenes / Q000032:analysis; D058441:Rhizosphere; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000633:toxicity*
chemical_list: D005227:Fatty Acids; D037742:Nanotubes, Carbon; D010616:Phenanthrenes; D011084:Polycyclic Aromatic Hydrocarbons; D011721:Pyrenes; D012989:Soil Pollutants; C031181:phenanthrene; C030984:pyrene
keywords: Carbon nanotubes; Microbial toxicity; Nanomaterials; Polycyclic aromatic hydrocarbons