Gradient

Senior Scientists

Gradient is proud to have a diverse, skilled, and well-trained technical staff who work collaboratively to manage our projects, perform research, and deliver innovative solutions with superior quality.

Lisa A. Bailey, Ph.D.

Senior Toxicologist

Expertise

  • Molecular Biology & Toxicology
  • Carcinogenesis
  • Mode-of-action Analyses
  • Human Exposure
  • Risk Assessment
  • DNA Damage, Repair and Mutagenesis
  • Weight of Evidence

Ali Boroumand, Ph.D.

Senior Environmental Engineer

Expertise

  • Contaminant Fate & Transport
  • Groundwater Hydrology
  • Remedial Investigation & Design
  • Groundwater Modeling
  • Multiphase Flow and Reactive Transport
  • "Green and Sustainable Remediation"

Joel M. Cohen, Sc.D., DABT

Senior Toxicologist

Expertise

  • Inhalation Toxicology
  • Human Health Risk Assessment
  • Product Safety
  • Alternative Assessment
  • Nanotechnology
  • Skin Sensitization

Amy L. Dale, Ph.D.

Senior Environmental Engineer

Expertise

  • Contaminant Fate & Transport
  • Risk Assessment
  • Numerical Modeling
  • Computational Fluid Dynamics
  • Quantitative Policy Analysis
  • Climate Impact Assessment
  • Nanomaterials

David G. Dodge, M.S., DABT, CIH

Senior Toxicologist

Expertise

  • Risk Communication
  • Human Health Risk Assessment
  • Applied Toxicology
  • Occupational Exposure Assessment
  • Industrial Hygiene

Grace I. Greenberg, M.P.H.

Senior Environmental Toxicologist

Expertise

  • Exposure Modeling
  • Human Health Risk Assessment
  • Ecological Risk Assessment
  • Database Construction and Management
  • Data Analysis and Interpretation

Mary L. Hixon, Ph.D.

Senior Toxicologist

Expertise

  • Reproductive and Developmental Toxicology
  • Toxicogenomics
  • Mode of Action Analyses
  • Human Exposure

Laura E. Kerper, Ph.D.

Senior Toxicologist

Expertise

  • Risk Assessment
  • General and Molecular Biology
  • Heavy Metals Toxicity
  • Solvent Toxicity
  • Toxicology
  • Perfluorinated Chemicals

Jessie M. Kneeland, Ph.D.

Senior Environmental Chemist

Expertise

  • Chemical Fingerprinting
  • Organic Geochemistry
  • Oceanography
  • Climate Change Science
  • Chemical Registrations
  • Environmental Forensics
  • Fate and Transport

John M. Kondziolka, M.S., E.I.T.

Senior Environmental Engineer

Expertise

  • Contaminant Fate and Transport
  • Risk Assessment
  • Fluid Dynamics
  • Numerical Modeling

Cynthia J. Langlois, M.S.

Senior Health Scientist

Expertise

  • Risk Communication
  • Exposure Assessment
  • Data Quality
  • Toxicology

Julie C. Lemay, M.P.H.

Senior Environmental Health Scientist

Expertise

  • Risk Communication
  • Human Health Risk Assessment
  • Exposure Assessment
  • Epidemiology
  • Public Health
  • Data Analysis and Interpretation

Tamara D. Lunsman, Ph.D.

Senior Environmental Toxicologist

Expertise

  • Ecological Risk Assessment
  • Chemical Hazard Assessment
  • Environmental Toxicology
  • Hydrophobic Organic Chemicals
  • Marine Ecology
  • Environmental Compliance
  • Product Environmental Safety Assessment

Rosemary Mattuck, M.S.

Senior Environmental Engineer

Expertise

  • Exposure Assessment
  • Blood Lead Modeling
  • Product Safety
  • Risk Assessment
  • Proposition 65

David B. Mayfield, M.S., DABT, BCES

Senior Toxicologist

Expertise

  • Metals Toxicology
  • Human Health Risk Assessment
  • Exposure Analysis
  • Toxicology
  • Ecological Risk Assessment
  • Dose-Response Analysis
  • Environmental Site Investigation

Matthew J. Mayo, M.S., GISP, CPG, PG

Senior GIS/Environmental Scientist

Expertise

  • Hydrogeology
  • GIS Management
  • 2D and 3D Geospatial Modeling
  • Remote Sensing and Aerial Imagery Analysis
  • Database Construction and Management
  • Geospatial Data Acquisition and Visualization

Isaac Mohar, Ph.D., DABT

Senior Toxicologist

Expertise

  • Risk Assessment
  • Toxicology
  • Immunology
  • Liver Pathology

Margaret C. Pollock, M.S.

Senior Environmental Scientist

Expertise

  • Statistical Methods
  • Exposure Assessment
  • Database Development
  • Cost Estimation and Allocation

Robyn Prueitt, Ph.D., DABT

Senior Toxicologist

Expertise

  • Molecular Biology & Toxicology
  • Carcinogenesis
  • Mode-of-action Analyses
  • Human Genetics
  • Molecular Epidemiology

Kathleen A. Radloff, Ph.D.

Senior Environmental Engineer

Expertise

  • Contaminant Fate & Transport
  • Aqueous Geochemistry
  • Lead, Arsenic, and Metals
  • Groundwater Hydrology
  • Risk-based Remediation

James W. Rice, Ph.D.

Senior Environmental Scientist

Expertise

  • Contaminant Fate & Transport
  • Polycyclic Aromatic Hydrocarbons (PAH)
  • Read-Across Assessment
  • Environmental Sampling and Data Interpretation

Jeffrey T. Rominger, Ph.D.

Senior Environmental Engineer

Expertise

  • Contaminant Fate & Transport
  • Environmental Forensics
  • Fluid Dynamics
  • Solid Mechanics
  • Numerical Modeling

Meghna H. Swamy, M.S.

Senior Environmental Engineer

Expertise

  • Contaminant Fate & Transport
  • NAPL Transport
  • Remedial Investigation & Design
  • Risk-based Remediation

Caroline B. Tuit, Ph.D.

Senior Environmental Chemist

Expertise

  • Chemical Fate/Transport
  • Rare Earth and Minor Metals
  • Sediment Management
  • Cost Allocation
  • Chemistry/Forensics

Matthew P. Tymchak, M.S.

Senior Hydrologist

Expertise

  • Remedial Investigation & Design
  • Hydraulic Fracturing
  • NAPL
  • Contaminant Fate and Transport
  • Environmental Cost Analysis
  • Groundwater-Surface Water Hydrology

Jiaru Zhang, M.P.H.

Senior Toxicologist

Expertise

  • Product Safety Evaluation
  • Product Stewardship
  • Medical Device and Pharmaceutical Safety Assessments
  • GHS hazard assessment, SDS, and Label