Geoffrey Siemering
Soil Contaminant Outreach Specialist/Lecturer
Environmental scientist with a strong record of leading interdisciplinary research and securing competitive funding. Expertise in contaminant behavior, risk assessment, and stakeholder engagement. Proven ability to translate complex science into actionable policy and programmatic outcomes.
Select Achievements
- Regulatory Impact: Led PAH soil background study that informed updated remediation thresholds, reducing redevelopment costs by millions annually.
- Applied Research: Evaluated wastewater land application systems for regulators and industry groups, preserving cost-effective disposal options.
- Funding Success: Initiated and developed proposals which secured over $685,000 in competitive research funding since 2019.
- Program Leadership: Directed statewide aquatic pesticide monitoring and nonchemical weed control research in California ($2.9M total budget).
Professional Experience
Staff Scientist & Lecturer | 2014–Present University of Wisconsin–Madison
Lead investigator on projects addressing legacy mining impacts, PFAS uptake, pesticide contamination, and nutrient dynamics.
International fieldwork in Colombia, Guatemala, Peru, and Namibia.
Coordinator, Wisconsin Fertilizer Research Program ($400K annual budget).
Member, Wisconsin Brownfield Advisory Board (2015–2021).
Co-lead, ITRC Soil Background Guidance; Trainer, ITRC Bioavailability Workgroup.
Frequent invited speaker at conferences, stakeholder meetings, and trainings.
Courses Taught:
- Soil Pollution and Human Health (Soil Sci 430)
- Environmental Impact Assessment (Soil Sci 575)
- Sustainable Food Systems in Italy (InterAg 321/ Nut Sci 421)
Environmental Scientist | 2002–2009 San Francisco Estuary Institute, Oakland, CA
Directed $2.9 million multi-agency statewide aquatic pesticide environmental impact assessment and evaluation of nonchemical aquatic weed control methods.
Authored peer-reviewed publications and technical reports for California environmental agencies.
Contracts & Grants Specialist | 2001–2002 University of California–Berkeley
Negotiated research agreements with government, nonprofit, and industry partners.
Technical Editor, Yucca Mountain Project | 1999–2001 Lawrence Livermore National Laboratory, Livermore, CA
Edited scientific and regulatory documents on nuclear waste storage.
Career Note:
Additional experience at Lawrence Berkeley National Lab, Argonne National Lab, Pacific Northwest National Lab, and Savannah River Ecology Lab.
Education
- B.A. Geochemistry, Pomona College, Claremont, CA
- M.S. Soil Science, University of California-Berkeley, Berkeley, CA
- Ph.D. Civil Engineering, University of Portsmouth, UK
Research and Outreach Overview
Dr. Siemering’s research to date has encompassed contaminant metals, polycyclic aromatic hydrocarbons, pesticides (aquatic and neonicotinoid), radionuclides, nitrogen, phosphorus, and PFAS largely at the interface of science and environmental policy/regulation. He has also worked with communities on soil health issues in Guatemala, Peru, Colombia, and Namibia as a technical expert for the USAID Farmer to Farmer program. Currently he is working on projects involving soil lead in urban areas, PFAS uptake in common garden crops and forages, and soil denitrification of cheese making and vegetable processing wastewater. In addition, Geoff has served as an author and trainer for the ITRC Bioavailability of Contaminants in Soil training and author for the ITRC Soil Background and Risk Assessment.
Contact Information
UW-Madison, Department of Soil and Environmental Sciences
1525 Observatory Drive
Madison, WI 53706-1299, USA
Office: 443 King Hall
Phone: 608.262.9969
Email: gsiemering@wisc.edu
Publications
Oke, O.O., Magzamen, S., Siemering, G.S., Johnson, S.L., Auerbach, J.D., and Carter, E.M. Investigating patterns and sources of variability in children’s blood lead levels in Milwaukee, Wisconsin using a machine learning model. Submitted August 2025 to Environmental Research: Health.
Siemering, G.S. and Thomas A. Background concentration, risk assessment and regulatory threshold development: Metal elements in Milwaukee, Wisconsin surface soils. In preparation.
Siemering, G.S., Read H., Springer, B., Martensson, K., Seibert, R., Barak, P. Comparison of USEPA validated soil PAH extraction methodologies. In preparation.
Siemering G.S., Arriaga F.J., Cagle G.A., Van Beek J.M., Freedman Z.B. Impacts of vegetable processing and cheese making effluent on soil microbial functional diversity, community structure, and denitrification potential of land treatment systems. Water Environment Research. 2024 May;96(5):e11036.
Siemering G.S., Arriaga F.J., VanderLeest C.P., Naatz S.L. Evaluation of nitrogen fate from land-application wastewater treatment for cheese making and vegetable processing facilities. Environmental Science: Advances. 2024;3(1):51-61.
Siemering G.S., Vanderleest C.P., Arriaga F.J. Autonomous high-throughput in situ soil nitrogen flux measurement system. Environmental Monitoring and Assessment. 2022 Oct;194(10):680.
Siemering, G.S. and Thiboldeaux, R., 2021. Background concentration, risk assessment and regulatory threshold development: Polycyclic aromatic hydrocarbons (PAH) in Milwaukee, Wisconsin surface soils. Environmental Pollution, 268, p.115772.
Plunkett, S.A., Wijayawardena, M.A., Naidu, R., Siemering, G.S., Tomaszewski, E.J., Ginder-Vogel, M. and Soldat, D.J., 2018. Use of Routine Soil Tests to Estimate Pb Bioaccessibility. Environmental Science & Technology, 52(21), pp.12556-12562.
Geoffrey S. Siemering, Jennifer D. Hayworth, Ben K. Greenfield. 2008. Assessment of Potential Aquatic Herbicide Impacts to California Aquatic Ecosystems. Archives of Environmental Contamination and Toxicology 55(3): 415-431
Ben K. Greenfield, Geoffrey S. Siemering, Joy C. Andrews, Michael Rajan, Stephen P. Andrews, Jr., and David F. Spencer. 2007. Mechanical Shredding of Water Hyacinth (Eichhornia crassipes): Impacts to Water Quality in the Sacramento-San Joaquin River Delta, California. Estuaries and Coasts30: 627-640.
Siemering, Geoff. 2006. Technical Report for the Interagency Ecological Program (IEP) Pelagic Organism Decline (POD) Workgroup: Tier 1 Risk Assessment of California Department of Boating and Waterways Aquatic Herbicide Use in the Sacramento-San Joaquin River Delta. SFEI Contribution 436. San Francisco Estuary Institute, Oakland, CA.
Siemering, Geoff and Jennifer Hayworth. 2006. Aquatic Herbicides: Overview of Usage, Fate and Transport, Potential Environmental Risk, and Future Recommendations for the Sacramento-San Joaquin Delta and Central Valley. White Paper for the Interagency Ecological Program. SFEI Contribution 414. San Francisco Estuary Institute, Oakland, CA.
Nicole David, Ben K. Greenfield, Geoffrey S. Siemering. 2006. Evaluating Impacts of Lake Maid Plant Control. Journal of Aquatic Plant Management 44: 60-67.
Lingtian Xie, Kelly Thrippleton, Mary Ann Irwin, Geoffrey S. Siemering, David Crane, Kevin Berry, and Daniel Schlenk. 2005. Evaluation of Estrogenic Activities of Aquatic Herbicides and Surfactants Using a Rainbow Trout Vitellogenin Assay. Toxicological Sciences 87: 391-398.
Allen, P.G., G.S. Siemering, D.K. Shuh, J.J. Bucher, N.M. Edelstein, C.A. Langton, S.B. Clark, T. Reich and M.A. Denecke. 1997. Technetium Speciation in Cement Waste Forms Determined by X-ray Absorption Fine Structure Spectroscopy. Radiochimica Acta, 76: 77-86.
University of Wisconsin Extension Publications
The Value of Arbuscular Mycorrhizal Fungi for Field Crops (A414-01)
The Value of Bacillus amyloliquefaciens for Crop Protection (A4114-03)
The Value of Trichoderma for Crop Protection (A4114-02).
Managing Mine-scarred lands in Southwestern Wisconsin (G4173)
Digital Atlas of Historic Mining Features in Southwestern Wisconsin (G4177).
Sampling lawn and garden soils for analysis (A2166).
Lead in home garden soil (A4089).
Reducing exposure to lead in your garden soil (A4088).
Soil contaminants in community gardens (A3905-03).