Molybdenum Availability Is Key to Nitrate Removal in Contaminated Groundwater Environments

• DOI: 10.1128/aem.00917-15
• Publication Date: 2015-05-16T02:56:15Z
• Authors: Michael P. Thorge...; W. Andrew Lancaster; Brian J. Vaccaro; Farris L. Poole; Andrea M. Rocha; Tonia Mehlhorn; Angelica Pettenato; Jayashree Ray; R. Jordan Waters; Ryan A. Melnyk; Romy Chakraborty; Terry C. Hazen; Adam M. Deutschbauer; Adam P. Arkin; Michael W. W. Adams
• Keywords: Pseudomonas stutzeri; Maximum Contaminant Level

The concentrations of molybdenum (Mo) and 25 other metals were measured in groundwater samples from 80 wells on the Oak Ridge Reservation (ORR) (Oak Ridge, TN), many which are contaminated with nitrate, as well uranium various metals. nitrate ranges 0.1 μM to 230 mM <0.2 nM 580 μM, respectively. Almost all examined had significantly greater median a subset that highly (≥126 nM). They included cadmium, manganese, cobalt, 1,300- 2,700-fold higher. A notable exception, however, was Mo, lower concentration uranium-contaminated wells. This is significant, because Mo essential dissimilatory reduction branch global nitrogen cycle. It required at catalytic site reductase, enzyme reduces nitrite. Moreover, more than 85% contained less 10 whereas 100 for efficient growth by two Pseudomonas strains isolated ORR model denitrifier, stutzeri RCH2. Higher tended inhibit these due accumulation toxic nitrite, this effect exacerbated high concentrations. relevance results Mo-based removal strategy potential community-driving role plays environments discussed.