Aqueous and Terrestrial Geochemistry Laboratory

Current and future research focuses on:
  • Determining the nutrient and carbon distribution in agricultural soils subjected to different best management practices.
  • Investigate the role of drainage water management systems on nutrient losses. 
  • Investigate transport and fate of nutrients and carbon in agricultural soils that have been restored as wetlands. 
  • Determine the parameters that enhance nitrate and phosphate removal from agriculture tile drainage employing edge-of-field practices (e.g., woodchip bioreactors and steel slag filters).


Dr. Angélica Vázquez-Ortega | Assistant Professor of Geochemistry | Click image for CV

Undergraduate Researcher

Adam Joseph Swint | Undergraduate Researcher, BS in Environmental Science
Emily Manner | BS in Environmental Science
Sara Honeck | Pre-Philosophy, Politics, Economics, Law
Hannah Bebinger | BS in Environmental Science

Graduate Students

Matthew Franks | MS in Geology
Russell Brigham | MS in Geology
Melissa Wyderka | MS in Geology


Samuel Jefferson | Alumnus, BS in Psychology
Madison Brown | Alumna, BS in Environmental Science
Lydia Archambo | Alumna, BS in Environmental Science


Dredged Material Benefits for Crop Production and Environmental Implications
Dr. Angélica Vázquez-Ortega (PI) and Shannon Pelini (Co-PI)

Greenhouse experiments

This study proposes to identify the effects of dredged material on crop yield, metal bioaccumulation and ecological dynamics in crops and their invertebrate consumers and mutualists, and water quality in Lake Erie watershed soils.

The overall research objectives of the study are to: 1) identify the appropriate native soil to dredged material ratio to achieve the best crop yield, 2) use dredged material as a phosphate fertilizer source, 3) determine nutrient and metal release into soil solution, 4) determine metal bioaccumulation in crops and invertebrates in farm soils amended with dredged material, and 5) determine microcystin persistent in soils and bioaccumulation in corn grains. The ultimate goal of this project is to identify the optimal level of supplementation that achieves benefits of dredged material in agricultural systems surrounding Lake Erie.

Dredged material supplies essential plant nutrients and provide organic matter to agricultural soils that can further reduce fertilizer application costs. However, in order to achieve these benefits, we need to determine the appropriate quantity and quality of added dredged material in such a way that minimizes negative environmental impacts while maximizing benefits to crop management.

Enhancing nutrient removal from agricultural tile drainage by understanding the role of organic carbon quality
Dr. Angélica Vázquez-Ortega (PI) and Margaret Kalcic (Collaborator)

Enhancing nutrient removalThe overall objectives of the study are: 1) to determine the efficiency of nutrient removal from agricultural tile drainage using steel slag filters and denitrifying bioreactors in field conditions and 2) characterize the biogeochemical processes governing the removal of phosphate and nitrate from agricultural tile drainage treated with steel slag filters and denitrifying bioreactors in order to increase their application in agricultural fields in northwest Ohio.

The proposed study will focus on the role of dissolved organic matter (DOM) on P sorption onto steel slag filters and on nitrate removal in denitrifying bioreactors. In-field management practices (e.g., cover crops, no-till, manure application, and crop rotation) will directly influence the quality of DOM; therefore, affecting DOM composition in agricultural tile drainage. DOM quality refers to the degree of aromaticity and recalcitrance of the organic compounds, as well as the presence of carboxyl and phenol groups.

We hypothesize that DOM with high content of carboxyl and phenol functional groups will affect phosphate sorption into the steel slag filter as DOM can compete for active sites; therefore, decreasing phosphate sorption. In addition, DOM release from the woodchip substrate can either enhance or decrease denitrification depending on the degree of DOM recalcitrance. Results from this study will establish how DOM quality affects the lifespan of steel slag filters and the effectiveness of nitrate removal in denitrifying bioreactors as different woodchip substrates leach distinctive aromatic and recalcitrant DOM compounds.

Nutrient and carbon distribution in agricultural soils subjected to different best management practices in Northwest Ohio
Dr. Angélica Vázquez-Ortega (PI)

Nutrient and carbon distributionAgricultural tile drainage in midwestern Ohio has significantly contributed to degrading water quality in Lake Erie. High loads of the nutrients phosphorus and nitrogen exported primarily by the Maumee River into the Western Lake Erie Basin have induced large, toxic, and long lasting harmful algal blooms (HABs) for nearly two decades.

In early August 2014, the Western Lake Erie Basin experienced a toxic bloom that left 500,000 people in Toledo without potable water service for nearly three days; this crisis further fueled public concerns about the health of the lake and brought the Great Lakes HABs into the national and international spotlight. The overall goal of my research is to investigate the nutrient distribution (nitrogen, phosphorus, and carbon) on agricultural soils subjected to different best management practices in NW Ohio. The specific objective is to perform a physico-chemical characterization of agricultural soils and relate nutrient retention to the soil mineralogical composition.

We hypothesize that nutrients will be retained to a higher extend in soils participating in BMPs versus those that are manage under conventional practices. Multiple biogeochemical processes such as 1) spatial inaccessibility, 2) aqueous complexation, 3) solid-solution partitioning, and 4) bio-uptake are involved in controlling the release of nutrients from soils. This study will provide information on nutrient partitioning into organic and inorganic mineral phases.

Analytical balance
pH meter probe
Fluorescence Ultraviolet-Visible Spectrometer
Inductively coupled plasma optimal emission spectroscopy (ICP-OES)
Carbon analyzer
Water bath
Ultra pure water system
EC Meter
Top balance
Vacuum Pump
Uranium speciation in acid waste-weathered sediments: The role of aging and phosphate amendments.
Perdrial, N., Vazquez-Ortega, A., Wang, G., Kanematsu, M., Mueller, K.T., Um, W., Steefel, C.I., O'Day, P.A., Chorover, J., 2018.  Applied Geochemistry 89, 109-120.
A net ecosystem carbon budget for snow dominated forested headwater catchments: linking water and carbon fluxes to critical zone carbon storage.
Perdrial, J., Brooks, P.D., Swetnam, T., Lohse, K.A., Rasmussen, C., Litvak, M., Harpold, A.A., Zapata-Rios, X., Broxton, P., Mitra, B., Meixner, T., Condon, K., Huckle, D., Stielstra, C., Vazquez-Ortega, A., Lybrand, R., Holleran, M., Orem, C., Pelletier, J., Chorover, J., 2018.  Biogeochemistry 138 (3), 225-243.
Thermodynamic modeling of Mn(II) adsorption onto manganese oxidizing bacteria.
Vazquez-Ortega, A.
, Fein, J.B., 2017. Chemical Geology 464, 147-154.

Geochemical evolution of the Critical Zone across variable time scales informs concentration-discharge relationships: Jemez River Basin Critical Zone Observatory.
McIntosh, J.C., Schaumberg, C., Perdrial, J., Harpold, A., Vazquez-Ortega, A., Rasmussen, C., Vinson, D., Zapata-Rios, X., Brooks, P.D., Meixner, T., Pelletier, J., Derry, L., Chorover, J., 2017.  Water Resources Research 53 (5), 4169-4196.

U-series isotopic signatures of soils and headwater streams in a semi-arid complex volcanic terrain.
Huckle, D., Ma, L., McIntosh, J., Vazquez-Ortega, A., Rasmussen, C., Chorover, J., 2016. Chemical Geology 445, 68-83.

Solid-phase redistribution of rare earth elements in hillslope pedons subjected to different hydrologic fluxes.
Vazquez-Ortega, A.
, Huckle, D., Perdrial, J., Amistadi, M.K., Durcik, M., Rasmussen, C., McIntosh, J., Chorover, J., 2016. Chemical Geology 426, 1-18.
Rare earth elements as reactive tracers of biogeochemical weathering in forested rhyolitic terrain.
Vazquez-Ortega, A.
, Perdrial, J., Harpold, A., Zapata-Rios, X., Rasmussen, C., McIntosh, J., Schaap, M., Pelletier, J.D., Brooks, P.D., Amistadi, M.K., Chorover, J., 2015.  Chemical Geology 391, 19-32.
Fractionation of Dissolved Organic Matter by (Oxy)Hydroxide-Coated Sands: Competitive Sorbate Displacement during Reactive Transport.
Vazquez-Ortega, A.
, Hernandez-Ruiz, S., Amistadi, M.K., Rasmussen, C., Chorover, J., 2014.  Vadose Zone Journal 13 (7).
Experimental Assessment of Passive Capillary Wick Sampler Suitability for Inorganic Soil Solution Constituents.
Perdrial, J.N., Perdrial, N., Vazquez-Ortega, A., Porter, C., Leedy, J., Chorover, J., 2014.  Soil Science Society of America Journal 78 (2), 486-495.

The influence of goethite and gibbsite on soluble nutrient dynamics and microbial community composition.
Heckman, K., Welty-Bernard, A., Vazquez-Ortega, A., Schwartz, E., Chorover, J., Rasmussen, C., 2013.  Biogeochemistry 112 (1-3), 179-195.

Heckman, K., Vazquez-Ortega, A., Gao, X., Chorover, J., Rasmussen, C., 2011. Geochimica et Cosmochimica Acta 75 (15), 4295-4309.  


ENVS 1010 Introduction to Environmental Studies
ENVS 3040 Water Quality in the Environment
SEES 4800/5800: Introduction to Biogeochemistry
SEES 4800/5800: Soil
Students participating in service learning field trip.
Students learning about water quality in environmental studies class.
Students measuring water quality parameters in the Geochemistry Lab.
Students designing prototypes to clean an oil spill.
Students sharing their environmental issues research during poster session.
During some hands-on activities with second graders from Crim Elementary School, Bowling Green, Ohio.