Assessing the impact of nano- and micro-scale zerovalent iron particles on soil microbial activities: particle reactivity interferes with assay conditions and interpretation of genuine microbial effects.
The effects of nano-scale and micro-scale zerovalent iron (nZVI and mZVI) particles on general (dehydrogenase and hydrolase) and specific (ammonia oxidation potential, AOP) activities mediated by the microbial community in an uncontaminated soil were examined. nZVI (diameter 12.5 nm; 10 mg g⁻¹ soil) apparently inhibited AOP and nZVI and mZVI apparently stimulated dehydrogenase activity but had minimal influence on hydrolase activity. Sterile experiments revealed that the apparent inhibition of AOP could not be interpreted as such due to the confounding action of the particles, whereas, the nZVI-enhanced dehydrogenase activity could represent the genuine response of a stimulated microbial population or an artifact of ZVI reactivity. Overall, there was no evidence for negative effects of nZVI or mZVI on the processes studied. When examining the impact of redox active particles such as ZVI on microbial oxidation-reduction reactions, potential confounding effects of the test particles on assay conditions should be considered.
Soil Research Centre, Department of Geography and Environmental Science, School of Human and Environmental Sciences, The University of Reading, Reading RG6 6DW, UK.
Laurence G
LG
Cullen
Emma L
EL
Tilston
Geoff R
GR
Mitchell
Chris D
CD
Collins
Liz J
LJ
Shaw
D000180:Acrylic Resins / Q000737:chemistry / Q000633:toxicity; D000641:Ammonia / Q000032:analysis / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000633:toxicity; D006867:Hydrolases / Q000032:analysis / Q000378:metabolism; D007501:Iron / Q000737:chemistry / Q000633:toxicity*; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity* / Q000648:ultrastructure; D058465:Nitrification / Q000187:drug effects; D010084:Oxidation-Reduction / Q000187:drug effects; D010088:Oxidoreductases / Q000032:analysis / Q000378:metabolism; D010316:Particle Size; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology
D000180:Acrylic Resins; D004791:Enzyme Inhibitors; D012987:Soil; C006903:carbopol 940; D000641:Ammonia; D007501:Iron; D010088:Oxidoreductases; D006867:Hydrolases