Hydrogeology / Geohydrology Expert Witnesses

Paul E. Rosenfeld, M.S., Ph.D., is the Founder and Principal Scientist of RoseyFields LLC and a nationally recognized forensic environmental scientist and plaintiff expert witness. Over 25 years, his work has spanned complex toxic-tort and class-action litigation — including MTBE, PFOA/PFAS, asbestos, FELA railroad exposure, air-dispersion modeling, epidemiology, toxicology, industrial contamination, and pesticide exposure matters — with an aggregate case value of approximately $14 billion, and he has been deposed approximately 150 times in 31 states.

Litigation Support

Dr. Rosenfeld's opinions are based on established scientific methodologies, quantitative exposure models, peer-reviewed scientific literature, published technical methods, and reproducible calculations that can be independently evaluated and tested, providing a rigorous scientific foundation for expert opinions under Daubert and related standards for the admissibility of scientific evidence. He has authored and contributed to books and technical publications concerning environmental contamination, exposure assessment, and risk evaluation and has applied these scientific methods in expert reports, litigation, depositions, regulatory proceedings, and trial testimony.

Methodologies & Scientific Approach

Dr. Rosenfeld's air dispersion modeling work applies EPA-approved and peer-reviewed models, including AERMOD, CALPUFF, and ALOHA, to reconstruct historical emissions, source attribution, and community-level exposure pathways. His exposure and dose reconstruction methods integrate environmental sampling data, regulatory exposure factors, and published toxicological and epidemiological literature to quantify human exposure to chemicals including benzene, PFAS/PFOA, TCE, hexavalent chromium, and crystalline silica, among others. Each methodology is applied transparently, allowing the underlying calculations, data inputs, and modeling assumptions to support general cuasation opinions. 

Publications & Court Qualifications

Dr. Rosenfeld has authored six books and dozens of peer-reviewed publications on environmental contamination and risk assessment. He has been qualified as an expert under Daubert and analogous standards in federal and state courts nationwide reflecting consistent application of scientifically defensible methodologies under prevailing standards for expert testimony admissibility.

Areas of Expertise:

Mayotte Design & Engineering, PC (MD&E) is a Civil and Environmental Engineering Design Firm based in East Lansing, Michigan.  Since 2003, MD&E has proved itself a highly responsive design, advocate and risk management partner for clients in the energy, automotive, commercial printing, textile, pharmaceutical, chemical, real estate, and legal industries.  MD&E offers a variety of services, specializing in the design and engineering of treatment solutions for wastewater, groundwater, stormwater and contaminated soil, sediment, and air.

MD&E personnel assist clientele across the US and have completed projects in: Alabama; Arizona; California; Colorado; Connecticut; Illinois; Indiana; Iowa; Kansas, Massachusetts; Michigan; Missouri, Mississippi; Nevada; New Jersey; New York; Ohio; Oregon; Tennessee; Texas; Vermont; Virginia; West Virginia; Washington, Wisconsin; Wyoming; British Columbia; Ontario; Quebec; Brazil; China; Czech Republic; Italy; and Mexico.

Timothy J. Mayotte, PhD, CPG, PE, President at MD&E, is an Environmental Engineer with over 35 years of experience in his field. He has provided litigation support and served as an expert witness on over a dozen cases dating back to the mid-1980s. Dr. Mayotte's experience includes providing testimony during numerous depositions and in open court. He has offered expertise in the following areas:

• Hydrodynamics of natural and engineered systems.
• Contaminant fate and transport in the environment.
• Biological and physicochemical process design for the treatment/remediation of water, wastewater, soil, and sludge.
• Industrial wastewater treatment.
• Management and inspection of commercial and residential construction and demolition projects, including due diligence services for property transactions.