Researchers from Oregon State University Report on Findings in Nitrosomonas europaea (Influence of Water Hardness on Silver Ion and Silver Nanoparticle Fate and Toxicity Toward Nitrosomonas europaea)
By a News Reporter-Staff News Editor at Ecology, Environment & Conservation -- Investigators publish new report on Proteobacteria. According to news reporting from Corvallis, Oregon, by VerticalNews journalists, research stated, "This study investigated the influence of water hardness (Mg2+ and Ca2+) on the fate and toxicity of 20 nm citrate silver nanoparticles (AgNPs) and Ag+ toward Nitrosomonas europaea, a model ammonia-oxidizing bacterium. Nitrification inhibition of N. europaea by 1 ppm AgNPs and 0.5 ppm Ag+ was reduced from 80% and 83%, respectively, in the absence of Mg2+ to 2% and 33%, respectively, in the presence of 730 mu M Mg2+."
The news correspondents obtained a quote from the research from Oregon State University, "Introduction of Mg2+ resulted in the rapid aggregation of the AgNP suspensions and reduced the 3 h Ag+ dissolution rates from 30%, in the absence of Mg2+, to 9%, in the presence of 730 mu M Mg2+. Reduced AgNP dissolution rates resulted in decreased concentrations of silver that were found adsorbed to N. europaea cells. Increasing AgNP concentrations in the presence of Mg2+ increased the observed inhibition of nitrification, but was always less than what was observed in the absence of Mg2+. The presence of Mg2+ also reduced the adsorption of Ag+ to cells, possibly due to multiple mechanisms, including a reduction in the negative surface charge of the N. europaea membrane and a competition between Mg2+ and Ag+ for membrane binding sites and transport into the cells. Ca2+ demonstrated similar protection mechanisms, as Ag+ toxicity was reduced and AgNP suspensions aggregated and decreased their dissolution rates."
According to the news reporters, the research concluded: "These results indicate that the toxicity of Ag+ and AgNPs to nitrifying bacteria in wastewater treatment would be less pronounced in systems with hard water."
For more information on this research see: Influence of Water Hardness on Silver Ion and Silver Nanoparticle Fate and Toxicity Toward Nitrosomonas europaea. Environmental Engineering Science, 2014;31(7):403-409. Environmental Engineering Science can be contacted at: Mary Ann Liebert, Inc, 140 Huguenot Street, 3RD Fl, New Rochelle, NY 10801, USA. (Mary Ann Liebert, Inc. - www.liebertpub.com; Environmental Engineering Science - www.liebertpub.com/overview/environmental-engineering-science/15/)
Our news journalists report that additional information may be obtained by contacting J.W. Anderson, Oregon State University, Sch Chem Biol & Environm Engn, Corvallis, OR 97331, United States. Additional authors for this research include L. Semprini and T.S. Radniecki.
Keywords for this news article include: Oregon, Corvallis, United States, Proteobacteria, Nitrosomonadaceae, Nitrosomonas europaea, Gram-Negative Bacteria, North and Central America, Gram-Negative Aerobic Bacteria, Gram-Negative Aerobic Rods and Cocci
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