Work

Open Source Tools

CompToxR

R package for accessing EPA’s CompTox Chemistry Dashboard API. Enables programmatic retrieval of chemical properties, hazard data, and exposure predictions for risk evaluation workflows.

GitHub

THREAT

R Shiny application for comparing observational water quality data against toxicological benchmarks. Integrates CompToxR and curated reference datasets to support environmental risk screening.

GitHub

Curation

R scripts and workflows for aggregating chemical and toxicological data from public sources into analysis-ready datasets.

GitHub

Research Focus

My EPA research spans risk characterization for water reuse, chemical safety data curation, and cross-disciplinary integration for chemical safety decision-making.

Technical Support

  • Region 8 RARE project: Evaluation of Produced Water Intended for Beneficial Reuse in Multiple Oil and Gas Basins. Stakeholders include EPA’s Region 3 and 6, US Department of Energy’s National Energy Technology Laboratory, and US EPA ORD-CCTE/CEMM

    • Front-end R Shiny application development for site prioritization utilizing field and experimental data for acute, chronic, and cumulative toxicological evaluation.

  • New Mexico Produced Water Research Consortium’s Risk and Toxicology work group (workgroup lead), the Multi-State Coordination Counsel, and the Water-Portal and Data Management work group.

    • Development of risk-based workflow to assess acute and chronic potential across human and ecological receptors and determine potential for fit-for-purpose usage of treated produced water.

  • Potable Water Reuse in Protein Production and Processing, Collaborative partnership of Tyson Foods, University of Nebraska, and the United States Department of Agriculture

  • Evaluating the Microbial and Chemical Quality of Air Handler Unit Condensate, US EPA project

  • Integrated Performance Framework for Emerging Contaminants in Wastewater Treatment Plants, US EPA project

  • Technical support for New Mexico State University’s Non-Targeted Analysis and Whole Effluent Toxicity testing efforts for produced water to assess acute and chronic effects of exposure.

  • Technical support for SSWR.411.3 : BIL/IIJA Funded Technical Assistance Projects to Support the Drinking Water State Revolving Fund

    • Front-end R Shiny application development utilizing EJScreen and machine-learning models for site prioritization

Selected Awards and Professional Experience

  • New Mexico Produced Water Research Consortium
  • US EPA Shooting Star Award: “Region 8 is grateful for your work organizing and analyzing our produced water data”

Publications

Delanka-Pedige, Himali M. K., Robert B. Young, Maha T. Abutokaikah, Lin Chen, Huiyao Wang, Kanchana A. B. I. Imihamillage, Sean Thimons, et al. 2024. “Non-Targeted Analysis and Toxicity Prediction for Evaluation of Photocatalytic Membrane Distillation Removing Organic Contaminants from Hypersaline Oil and Gas Field-Produced Water.” Journal of Hazardous Materials 471 (June): 134436. https://doi.org/10.1016/j.jhazmat.2024.134436.
Schoen, Mary E., Jay Garland, Jeffrey A. Soller, Sean X. Thimons, and Michael A. Jahne. 2023. “Onsite Nonpotable Water Systems Pathogen Treatment Targets: A Comparison of Infection and Disability-Adjusted Life Years (DALYs) Risk Benchmark Approaches.” Environmental Science & Technology 57 (26): 9559–66. https://doi.org/10.1021/acs.est.3c01152.
Thimons, Sean. 2021. “Treatment of Produced Water Using Ferrate (VI) and Directional Solvent Extraction,” 101.
Thimons, Sean, Shray Saxena, and Walter Den. 2022. “Ferrate-Pretreated Directional Solvent Extraction for Hydraulic Fracturing Produced Water: Technical and Economic Feasibility Studies.” Journal of Water Process Engineering 49 (October): 103053. https://doi.org/10.1016/j.jwpe.2022.103053.

Presentations, Posters, and Panels

Davis, C., Butler, J., Redman, A., Danforth, C., Thimons, S., Jahne, M., Xu, P. “Towards a Transparent Framework for Risk-based Evaluation of Treated Produced Water in the Permian.” SETAC North America 44th Annual Meeting, November 12–16, 2023, Louisville, KY.

Jahne, M., King, D., Kovalcik, K., Donohue, M., Pfaller, S., Helmick, K., Eades, G., Pait, M., Nye, M., Thimons, S., and Garland, J. “Water Quality Assessment of AC Condensate for Onsite Collection and Use.” 2023 WateReuse Symposium, March 5–8, 2023, Atlanta, GA.

Schoen, M., Jahne, M., Soller, J., Garland, J., and Thimons, S. “Updated Pathogen Log-Reduction Targets for Onsite Non-Potable Water Reuse.” 2023 WateReuse Symposium, March 5–8, 2023, Atlanta, GA.

Thimons, S., Danforth, C., Xu, P., Butler, J., and Jahne, M. “Risk-Based Guidance for Treated Produced Water Reuse - Progress and Opportunities.” 2023 WateReuse Symposium, March 5–8, 2023, Atlanta, GA.

Hightower, M., Reible, D., Rosenblum, J., Stringfellow, W., and Thimons, S. Panel on State Produced Water Treatment and Reuse Approaches, 2023 WateReuse Symposium, March 5–8, 2023

Thimons, S.. Development and Implementation of a Quantitative Hazard, Risk, and Toxicological Evaluation Tool (QHRTET) for Regionally Focused Issues. Presented at Annual Meeting of the New Mexico Produced Water Research Consortium, Las Cruces, NM, USA, Dec 6-7, 2022.

Thimons, S., Saxena, S., Den, W., Treatment and desalination of hydraulic fracturing produced water using ferrate and directional solvent extraction. Presented at ACS Fall 2021, Atlanta, GA, August 22-26, 2021

Thimons, S.X., K.R. Cradock, and M.M.F. Lutnesky, Preliminary Characterization of Fish Survivorship in Backwater Pools on the Pecos River, NM USA. Joint meeting of Ichthyologists and Herpetologists (American Society of Ichthyologists and Herpetologists), Snowbird, UT, 2019