Unraveling the radium riddle

Over the last several years, the city of Waukesha, Wis., has become the poster child for requests to divert water from Lake Michigan under the Great Lakes Compact, in part because it’s also the poster child for something else: Communities built on sandstone-based groundwater aquifers with higher-than-normal concentrations of radium, a radioactive contaminant that can increase the incidence of bone cancer. – See more at: http://news.wisc.edu/

We carved Pumpkins!

Jacqueline Mejia Awarded DOE SCGSR Fellowship

Doctoral candidate Jacqueline Mejia was awarded a fellowship from the DOE Office of Science Graduate Student Research to work with Professor Jack Gilbert at Argonne National Laboratory and the University of Chicago.

Congratulations!

Jackie’s project will use model Fe oxide-SOM (denoted Fe-SOM) complexes to study how the chemical nature of SOM and its interaction with Fe oxides shapes SOM metabolism under environmentally relevant conditions. A comparative metagenomic analysis of the communities that arise in these experiments will provide insight into the microbial community structure and the metabolic pathways involved SOM mineralization. Moreover, the information obtained from this study has the potential to improve metabolic models utilized to predict the fate of C in soils and sediments.

New Paper by Elizabeth Tomaszewski!

Elizabeth Tomaszewski’s first paper has been published in Chemical Geology! Congratulations Beth!

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The role of dissolved Fe(II) concentration in the mineralogical evolution of Fe (hydr)oxides during redox cycling

This paper examines the mineralogical evolution of ferrihydrite over eight redox cycles during which it reacts with dissolved Fe(II) in the absence of oxygen (anaerobic conditions) for 48 h and is subsequently exposed to air (oxic conditions) for 18 h. Using X-ray absorption spectroscopy (XAS) and 57Fe Mössbauer spectroscopy, the abundance of each mineral phase present after each anaerobic or oxic period, is quantified. Our results demonstrate that rapid redox cycling limits the extent of ferrihydrite transformation leading to disequilibrium between mineral phases while magnetite stoichiometry increases throughout the study despite periodic exposure to oxygen. A deeper understanding of poorly crystalline Fe (hydr)oxide transformation during multiple, short redox cycles can provide insight into reactions controlling the speciation of redox active nutrients and contaminants in soils and sediments

 

Tomaszewski, E. J.; Cronk, S. S.; Gorski, C. A.; Ginder-Vogel, M., The role of dissolved Fe(II) concentration in the mineralogical evolution of Fe (hydr)oxides during redox cycling. Chemical Geology.

http://dx.doi.org/10.1016/j.chemgeo.2016.06.016

Off to the ACS Meeting in San Diego

Our group has two presentations at the American Chemical Society meeting in sunny San Diego, CA.

Sarah Balgooyen is presenting her research examining the reactivity of Mn oxide minerals with BPA on Sunday, March 13 in the afternoon.

Matt is presenting his research on Wednesday, March 16 also in the  afternoon as part of the Adsorption of Metals of Geomedia.

Professor Remucal’s group also has several presentations at the meeting.

 

Production of high pH leachate from Recycled Concrete Aggregate

Professors Ginder-Vogel and Edil were awarded a grant from the Ready Mix Concrete Research and Education Foundation and the Portland Cement Association to study the production of high pH leachate from recycled concrete aggregate (RCA).

Concrete recycling reduces the need for mining of virgin aggregate, thereby conserving scarce natural resources and often dramatically decreasing transport costs and impacts. Additionally, recycling concrete reduces the need for landfill space, stockpiles and waste concrete, and illegal concrete dumping. During the recycling process, crushing or fracturing of concrete may expose fresh surface area. Due to the solubility of hydroxide-bearing minerals and other chemical reactions, the pH of water that interacts with recycled concrete may become elevated. Here, we propose to couple laboratory leaching studies, utilizing representative saturation and geochemical conditions, with results from a forensic examination of an RCA base course located at the MNROAD test facility to determine mechanisms that may limit the production of high pH of leachate.

Hg Biogeochemistry in St. Louis River Estuary

Matt Ginder-Vogel and a team of researchers from Minnesota and Wisconsin have been awarded a grant to determine the relative bioavailability of Hg in different habitats (e.g., estuary flats, sheltered bays, near-shore wetlands, clay-influenced river mouths, etc.) in the St. Louis River Estuary and what geochemical factors control Hg bioavailability.

Ginder-Vogel will work with Prof. Nathan Johnson at the University of Minnesota – Duluth, Prof. Kris Rolfhus at the University of Wisconsin – La Crosse and Prof. Jeff Jeremiason at Gustavus Adolphus College.

The grant was awarded by the Wisconsin Sea Grant Institute and the Minnesota Sea Grant Institute.

Group trip to SSSA meeting in Minneapolis

The Biogeochemistry group took advantage of the proximity of the Soil Science Society of America annual meeting this year. Every member of the group gave an oral presentation on their research. Videos of the presentations are available below!

Noah Stern - Dual Role of Humic Substances As Electron Donors and Shuttles for Dissimilatory Iron Oxide Reduction

Jacqueline Mejia - Impact of Redox Cycling on Fe (Hydr)oxide Transformations and Organic Matter Degradation

Sarah Balgooyen - Mineral Surface Modification of delta-MnO2 Decreases Bisphenol A Oxidation Rate

Elizabeth Tomaszewski - Iron (Hydr)oxide) Charging and Chromium Fate During Rapid Redox Cycling

Balgooyen Awarded NSF Fellowship

Meet Sarah Balgooyen, a second year Ph.D. student in the University of Wisconsin-Madison’s Environmental Chemistry and Technology program. She has been awarded a National Science Foundation Fellowship to study how filters composed of manganese oxide could prevent pollutants from entering natural waters. Ms. Balgooyen is a student in Professor Ginder-Vogel’s and Professor Remucal’s research groups.27-435-1211-1-2