Research

Characterizing Mn(II) attenuation mechanisms in the subsurface

Chapman University

Co-principal investigators: Prof. Chris Kim

Undergraduate Mentees: Thao Vy Le and James Hazen

Lead in incubation and flow-through experiments to investigate the abiotic attenuation and re-mobilization of Mn(II) from clay and Fe-oxide minerals under diverse but environmental conditions. Involves mentorship with undergraduate researchers as part of their capstone project.

Impact of the spatial distribution and speciation of arsenic in mine tailings on future bioaccessibility

Chapman University

Primary Investigator: Prof. Chris Kim

Undergraduate Researchers: Jackie Dall, Manual Vejar

Analysis of X-ray absorption spectroscopy (XAS) and microscopic X-ray fluorescence data (µXRF) to determine the spatial distribution and speciation of As from mine tailing mineral samples from the Empire Gold Mine in Northern California before and after mechanical weather. Data was used in tandem with synthetic gastric fluid extractions to determine the impact of measured speciation and spatial distribution on bioaccessibility.

Manganese in drinking water during pregnancy and adverse birth outcomes in California

Co-principal investigators:

University of California Riverside

Prof. Samantha Ying (Environmental Sciences)

Investigating the association between high drinking water manganese and adverse birth outcomes in California’s San Joaquin Valley. Includes incorporation of socio-economic factors of communities impacted by high drinking water manganese and possible avoidance behaviors. Uses data from the Safe Drinking Water Information System, National Birth Defect Prevention Study, and California Birth Data.

Biogeochemical controls on trace metal contamination of groundwater during aquifer recharge

Co-principal investigators and collaborators:

University of California Riverside

Prof. Samantha Ying (Environmental Sciences) and Ben Maki (Graduate student)

University of California Santa Cruz

Prof. Chad Saltikov (Microbiology and Environmental Toxicology) and Prof. Andrew Fisher (Earth Sciences)

Lead collaborator to design and execute geochemical experiments (including leading X-ray based solid phases C and metal analyses) to determine the role of redox processes as a function of organic carbon input (i.e. wood mulch) and flood frequency in metal release from sediments at flood MAR sites throughout California. Trained 2nd year graduate student from UC Santa Cruz in XRF and solid phase sequential extractions. Contributed text to USDA NIFA Foundational and NSF Low-Temperature Geobiology and Geochemistry proposals.