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Melanie Edwards, PStat.

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Melanie Edwards, PStat.
Senior Solution Architect

Melanie Edwards, PStat.

Senior Solution Architect (206) 852-5739 Seattle, WA medwards@integral-corp.com

Ms. Melanie Edwards is an accredited statistician who routinely provides insight on the interpretation of analyses and presentation of findings for experts from a variety of backgrounds, including environmental science, ecology, toxicology, and engineering, and for non-scientists. She has provided litigation support in the form of depositions, trial testimony, and expert reports. Her work includes investigations of multichemical and multimedia interactions, environmental forensics, spatial and temporal trend analysis, modeling exposure and effect relationships, probabilistic modeling, and study design considerations. With more than 20 years of experience, Ms. Edwards has provided statistical support for projects involving PCBs, dioxins/furans, PAHs, and metals in soil, sediment, dust, groundwater, surface water, tissue, and air.

Ms. Edwards’ understanding of data workflow includes data management practices, data review and cleansing, statistical analysis methods, and clear presentation and communication of findings. Equally important, she understands the weaknesses and limitations of improper data preparation and statistical techniques to avoid over-interpretation of results. She is familiar with traditional methods such as correlation, regression, analysis of variance, non-linear models, factor analysis, principal component analysis, and non-parametric methods, as well as modern analytics techniques as they apply to environmental data.

Assessing Background Arsenic in Portland Harbor Sediment and Riverbank Soil

Poster

January 30 2025

What Lies Beneath: Exercising Caution when Repurposing Data in Environmental Analytics

Resource

March 05 2024

EPA Revs Up ProUCL: How Will Your Site Be Affected?

Resource

November 04 2022

Data Hub Development for Complex Environmental Litigation Support

Case Study

November 19 2024

Forensics

U.S. Environmental Protection Agency, Ottawa River, Ohio Performed statistical analyses of elevated PCB congener and Aroclor concentrations after a known source area had been capped. Results identified a common composition downstream but variability in the cap area. Individual congeners elevated in some samples suggest seepage from a historical landfill in the area. Data analysis identified laboratory errors with the Aroclor results for a subset of samples.
U.S. Environmental Protection Agency, River Raisin, Michigan Analyzed PCB congener results from an initial sampling event to understand compositional variability relative to potential sources. The identified compositions reflect standard Aroclor compositions with elevated low-chlorinated congeners. Results provided insights to direct a more comprehensive sampling event. Forensic analyses of the congener and Aroclor results from the greater spatial coverage and depth sampling are underway.
DDT Manufacturing Facility, Portland, Oregon Utilized likelihood ratios to combine nondistinct chemical signatures for dioxins/furans and pesticides, which provided evidence to limit the area of influence. Individual forensic analyses of PCBs, dioxins/furans, and pesticides were not sufficient to uniquely distinguish contributions from individual sources.
Massachusetts Department of Environmental Protection, Hudson, Massachusetts Reviewed statistical analyses of per- and polyfluoroalkyl substances (PFAS) results for a variety of sample matrices to distinguish between potential sources and impacts to the surrounding area related to a coating application services plant. Results included visual assessment of bar charts, principal component analysis, and hierarchical cluster analysis of groundwater, surface water, sediment, residuals and sludge, soil, and air emissions and filtrate. Technical comments covered choice of statistical methods, presentation of results, and validity of conclusions.

Site Investigation

Fox River Superfund Site, Wisconsin Evaluated and interpreted spatial and temporal trends in sediment PCB composition and concentration throughout a 25-mile stretch of river, in support of a natural resource damage assessment. Additionally developed a predictive relationship for fish PCB concentrations based on sediment.
Chemical Manufacturing Plant, West Virginia Performed statistical analyses of dioxin and furan concentrations in soil near a former chemical manufacturing plant, which yielded evidence of localized source influences but no broad impacts to the surrounding residential area. Chemical forensic analyses of dioxin and furan levels in blood samples from nearby residents showed that former plant workers were distinct from other residents.
Red Dog Mine, Northern Alaska Assisted with developing a sampling program for metals in multiple tundra environments. Conducted statistical analyses to evaluate the contribution of metals to changes observed in plant communities near road and active mining areas. Analyses encompassed various methods to quantify spatial trends, compare concentrations between potentially impacted and reference locations, evaluate habitat differences in the vegetation community, assess similarities in the benthic invertebrate community, and develop inputs for ecological and human health risk assessment.
Deepwater Horizon Oil Spill, Gulf of Mexico Developed a data assessment and quantification analyses to relate field-collected fluorescence and dissolved oxygen measurements in the water column with laboratory-quantified benzene, ethylbenzene, toluene, xylene (BTEX) and PAH concentrations. Results demonstrated significant biodegradation within the water column. Designed the database and provided oversight for data compilation from multiple diverse sources encompassing three million sample records each with multiple measurements.

Statistical Modeling

Hudson River, New York Modeled relationships between mink mortality and reproduction (decline in fecundity) and PCB concentrations using a generalized linear model. The analyses provided cumulative probability curves and estimates of exceedance probabilities for specified response limits to inform an assessment of potential ecological impacts.
Pesticide Registration Modeled the complex time-dependent dose-response relationships of cholinesterase inhibition across multiple rat exposure studies to estimate the benchmark dose with uncertainty safety limits.  Model results supported sensitivity assessment between adults and pups and across gender.
Berry’s Creek Superfund Site, New Jersey Advised academic scientific researcher on appropriate statistical analyses to assess differences between treatment methods for reducing mercury methylation in sediment.  Results supported modification of the study design and sampling strategy to reduce the confounding effects of tidal changes.
Global Waste Stream Modeling, Petroleum Company, Worldwide Locations Developed a probabilistic model to manage global waste stream volumes for a large petroleum company, including liquid and solid waste from sites ranging in size from local gas stations to major port loading facilities.  Results from the model provided a baseline volume estimate prior to implementation of waste reduction practices.

Data Sufficiency

Department of Natural Resources, Michigan Recommended changes to the fish monitoring program sample design to achieve equivalent monitoring information at lower costs using simulation methods to quantify relative variability in fish tissue concentrations of PCBs and mercury.
Reid Gardner Power Plant, Nevada Demonstrated the limit of available data to explain variability in the spatial distribution of arsenic concentrations that justified measurement of additional parameters in groundwater near the waste ponds.  Predicted most likely source contributions based on groundwater compositions and defended results to responsible parties because conclusions contradicted prior understanding.  Statistical analysis confirmed hydrologic assessment to identify gaining and losing portions of surface water onsite.
Dermal Absorption of Arsenic, New York Determined dermal absorption of arsenic from soil as not different from background levels using analysis of variance (ANOVA) with nested factors.  Evaluated statistical power of the study design and quantified minimum detectable absorption as a recommendation to EPA for updating the human health risk assessment guidance for arsenic.

Aerial Deposition

Wood Treatment Facility, Grenada, Mississippi Demonstrated that historical releases from a wood treatment facility were not a prominent source of dioxin and furan concentrations detected in a nearby residential neighborhood. The chemical fingerprints of residential dust samples did not reflect a consistent gradient away from the claimed source.
Aerial Deposition Analysis, Multiple Locations Quantified the lack of a consistent spatial pattern expected from deposition of aerial emissions of lead, arsenic, and dioxin and furan congeners. Analyses included distance from the claimed source and suggested alternative sources.

Litigation Support

Litigation Support, Nitro, West Virginia Generated upper limit blood concentrations for background levels of exposure to dioxin and furan congeners and toxicity equivalents based on the National Health and Nutrition Examination Survey (NHANES) complex survey study design. Comparisons provided evidence to conclude that there was limited to no excess exposure at residential areas near a chemical manufacturing site.
Litigation Support, Seattle, Washington Estimated the reduction of daylight exposure that would not be sufficient to incur health effects.  Used the American Time Use Survey with location-specific astronomical data to quantify average daylight exposure times.  Compared survey sample demographics with census statistics for the urban area confirmed representativeness of the estimates.

R&D

Dermal Absorption of Arsenic, New York Determined dermal absorption of arsenic from soil as not different from background levels using analysis of variance (ANOVA) with nested factors.  Evaluated statistical power of the study design and quantified minimum detectable absorption as a recommendation to EPA for updating the human health risk assessment guidance for arsenic.

Expert Testimony

New Jersey Department of Environmental Protection v. The Sherwin-Williams Company Docket No. CAM-L-005032-19 in the New Jersey Superior Court, Camden County Provided expert opinions about the plaintiffs’ derivation of background concentrations of lead and arsenic in soils. Expert report submitted June 2024.
Zina G. Bibb, et al. v. Monsanto Company, et al. Civil Action No. 04-C-465 in the Circuit Court of Putnam County, West Virginia Provided demonstration to court of statistical analysis of NHANES data. Responded to questions from the judge and Plaintiffs’ attorney. Affidavits submitted August and September 2011.

Conway, A., S. Pauwels, M. Edwards, L. Fontenot, and R. Palachek. 2024. Red drum salinity tolerance: Comments on Ackerly et al. “Short-term salinity stress during early development impacts the growth and survival of red drum (Sciaenops ocellatus).” Estuaries and Coasts 47:589–599 DOI: 10.1007/s12237-023-01303-w.

Edwards, M. 2024.What lies beneath: Exercising caution when repurposing data in environmental analytics. JDSupra. March 5. https://www.jdsupra.com/legalnews/what-lies-beneath-exercising-caution-3858745.

O’Reilly K., D. Athanasiou, and M. Edwards. 2023. Evaluation of generic PAH profiles commonly used in receptor models: implications for source control policy. Environmental Forensics. DOI: 10.1080/15275922.2023.2172094.

Cook, L., L. Benton, and M. Edwards.  2021.  Beyond data validation – Advanced strategies for assessing data quality for oil spill investigations.  International Oil Spill Conference Proceedings  2021(1):689558.  https://doi.org/10.7901/2169-3358-2021.1.689558.

McGrath, J., G. Getzinger, A. Redman, M. Edwards, A. Martin, and E. Vaiopoulou. 2021. Application of the target lipid model to assess toxicity of heterocyclic aromatic compounds to aquatic organisms. Environmental Toxicology and Chemistry 40(11):3000-3009.

Gard, N., M. Edwards, K. Kulacki, and T. Ginn. 2021. Limitations on development of polychlorinated biphenyl tissue concentration thresholds for survival, growth, and reproduction in fish. Environmental Toxicology and Chemistry 40(8):2085-2097.

Cook, L., B. Drollette, M. Edwards, L. Benton, and P. Boehm. 2020. A data-driven framework for defining stages of oil weathering. Marine Pollution Bulletin 154:111091.

O’Reilly, K., and M. Edwards. 2020. Letter to the Editor: Comment on Norris and Henry (2019). Science of the Total Environment 704:135248.

Edwards, M., J. Pietari, L. Cook, and P. Boehm. 2019. Treatment of non-detects can lead to inaccurate forensic conclusions. pp. 181–191. In: Detection Limits in Air Quality and Environmental Measurements, M.J. Brisson (ed.). ASTM International.

Morrison, A., M. Edwards, J. Buonagurio, L. Cook, K. Murray, and P. Boehm. 2017. Assessing the representativeness and sufficiency of water samples collected during an oil spill. Proceedings, 2017 International Oil Spill Conference, Vol. 2017, No 1.

Shields, W., M. Edwards, C. Monti, and L. Royer. 2016. Examination of PCDD/F outliers in soil background studies provides insights into historic sources. Organohalogen Compounds 78:576–578.

Aldea, M., M. Edwards, J. Pietari, and P. Boehm. 2016. Cautions on the treatment of non-detect results for environmental forensics. Environmental Forensics 17(4):311–318.

Menzie, C., T. Deardorff, J. Ma, and M. Edwards. 2015. Risk factors that contribute to the occurrence of catastrophic wildfires in California. World Environmental and Water Resources Congress. pp. 2617–2626.

Monti, C., W. Shields, M. Edwards, and C. Pozzi. 2014. Fingerprint analysis of PCDD/F in soil samples in the Taranto (Puglia, Italy) area. Organohalogen Compounds 76:830–833.

Aylward, L., C. Monti, M. Edwards, and W. Shields. 2014. Dioxins in sheep and goat liver tissues from Taranto, Italy: Congener pattern. Organohalogen Compounds 76:403–406.

Shields, W., and M. Edwards. 2013. Comparison of dioxin/furan characteristics in different US cities. Abstract 426-2, Water, Food, Energy & Innovation for a Sustainable World, ASA, CSSA, & SSA International Annual Meetings, Tampa, FL, November 3–6. Available at https://scisoc.confex.com/crops/2013am/webprogram/Paper81402.html.

Megson, D., G. O’Sullivan, S. Comber, P. Worsfold, M. Lohan, M. Edwards, W. Shields, C. Sandau, and D. Patterson Jr. 2013. Elucidating the structural properties that influence the persistence of PCBs in humans using the National Health and Nutrition Examination Survey (NHANES) dataset. Science of the Total Environment 461-462:99–107.

Moolgavkar, S., R. McClellan, A. Dewanji, J. Turim, E. Luebeck, and M. Edwards. 2013. Time-series analyses of air pollution and mortality in the United States: a subsampling approach. Environmental Health Perspectives 121(1):73–78.

Shields, W., M. Edwards, J. Abrahams, R. Ferrara, M. Bollinger, and L. Paul. 2012. Source evaluation of dioxins/furans, PAHs, and pentachlorophenol in soil samples near a wood treating site in the southeastern USA. Organohalogen Compounds 74:593–595.

Connor, K., M. Harris, M. Edwards, R. Budinsky, G. Clark, A. Chu, B. Finley, and J. Rowlands. 2008. AH receptor agonist activity in human blood measured with a cell-based bioassay: Evidence for naturally occurring AH receptor ligands in vivo. Journal of Exposure Science and Environmental Epidemiology 18:369–380.

Lowney, Y., R. Wester, R. Schoof, C. Cushing, M. Edwards, and M. Ruby. 2007. Percutaneous absorption of arsenic from soils as measured in the rhesus monkey. Toxicological Sciences 100(2):381−392.

Benton, L., W. Shields, and M. Edwards. 2007. Commentary on O’Connor and Sabrsula (2005): Background dioxins in house dusts. Environmental Forensics 6(3):283–287.

Shields, W., Y. Tondeur, L. Benton, and M. Edwards. 2006. Dioxins and furans. Chapter 14. In: Environmental Forensics: Contaminant Specific Guide. R. Morrison and B. Murphy (eds.), Academic Press, San Diego, CA.

Tsuji, J., P. Williams, M. Edwards, K. Allamneni, M. Kelsh, D. Paustenbach, and P. Sheehan. 2003. Evaluation of mercury in urine as an indicator of exposure to low levels of mercury vapor. Environ. Health Perspect. 111(4):623–630.

Edwards, M., D. Nielsen, K. O’Reilly, and D. Athanasiou. 2023. Ignoring source variability results in misleading allocation of environmental contamination. Conference on Statistical Practice, San Francisco, CA. February 2–4.

O’Reilly, K., M. Edwards, D. Athanasiou, and S. Ahn. 2023. Evaluation of generic PAH profiles used in sediment source characterization modeling. Platform presentation at the Eleventh International Conference on the Remediation and Management of Contaminated Sediments, Austin, TX. January 9–12.

Ridolfi, K., N. Ott, L. Baker, M. Edwards, E. Pendleton, and D. Silva. 2023. Demonstrating sediment recovery in Portland Harbor through PCB temporal trends. Platform presentation at the Eleventh International Conference on the Remediation and Management of Contaminated Sediments, Austin, TX. January 9–12.

Edwards, M., and J. Pietari. 2018. Treatment of non-detects in environmental forensics: incorrect conclusions?! ASTM Symposium on Detection Limits, Washington, DC.

Edwards, M., D. Nielsen, K. O’Reilly, and D. Athanasiou. 2023. Ignoring source variability results in misleading allocation of environmental contamination. Conference on Statistical Practice, San Francisco, CA. February 2–4.

O’Reilly, K., M. Edwards, D. Athanasiou, and S. Ahn. 2023. Evaluation of generic PAH profiles used in sediment source characterization modeling. Platform presentation at the Eleventh International Conference on the Remediation and Management of Contaminated Sediments, Austin, TX. January 9–12.

Ridolfi, K., N. Ott, L. Baker, M. Edwards, E. Pendleton, and D. Silva. 2023. Demonstrating sediment recovery in Portland Harbor through PCB temporal trends. Platform presentation at the Eleventh International Conference on the Remediation and Management of Contaminated Sediments, Austin, TX. January 9–12.

Edwards, M., and J. Pietari. 2018. Treatment of non-detects in environmental forensics: incorrect conclusions?! ASTM Symposium on Detection Limits, Washington, DC.

Edwards, M., T. Sparacio, and W. Shields. 2018. Successful use of visual forensics at a smelter site. INEF Conference, Salt Lake City, UT.

Edwards, M., and M. Aldea. 2015. Effect of data transformations on the interpretability of principal component analysis results. Poster presentation, Joint Statistical Meeting, Seattle, WA.

Aldea, M., M. Edwards, and J. Pietari. 2015. Cautions on the treatment of non-detect results for environmental forensics. Poster presentation, INEF Conference, Toronto, Canada.

Aldea, M., M. Edwards, and J. Buonagurio. 2015. Visualizing the potential of environmental big data. Presentation at the 8th International Conference on Remediation and Management of Contaminated Sediments, New Orleans, LA.

Shields, W., M. Edwards, J. Abrahams, R. Ferrara, M. Bollinger, and L. Paul. 2012. Source evaluation of dioxins/furans, PAHs, and pentachlorophenol in soil samples near a wood treating site in the southeastern USA. Dioxin 2012, 32nd International Symposium on Halogenated Persistent Organic Pollutants, Cairns, Queensland, Australia.

Menzie, C., T. Deardorff, J. Ma, and M. Edwards. 2012. California’s catastrophic wildland fires: Increasing the risks of burning hotter, faster, and higher. Poster presentation, SETAC North America 33rd Annual Meeting, Long Beach, CA.

Johns, M., R. Atlas, and M. Edwards. 2011. Weathering of MC252 oil in the water column of the Gulf of Mexico from May through September 2010: Fluorometry, dissolved oxygen, and quantitative chemistry evaluation. Poster presentation at the Gulf Oil Spill SETAC focused topic meeting, Pensacola, FL.

Edwards, M., E. Maier, D. Reeder, N. Gard, and S. Shock. 2007. Assessment of plant communities exposed to fugitive dust along a mine transportation corridor in Alaska. Poster presentation at the Annual Joint Statistical Meeting, Salt Lake City, UT.

Benton, L., M. Ginevan, and M. Edwards. 2006. Chemical fingerprinting of dioxins using a similarity index. Poster presentation at the 16th Annual AEHS Meeting and West Coast Conference on Soils, Sediments and Water, San Diego, CA.

Kaetzel, R., M. Edwards, Y. Lowney, and J. Tsuji. 2006. Patterns of urinary excretion of arsenic metabolites in a population with low arsenic exposure. Poster presentation at the 45th Annual SOT Meeting, San Diego, CA.

Ginevan, M., M. Edwards, and L. Benton. 2005. Statistical tools for the analysis of PCB and dioxin profile data. Platform presentation at the SETAC 26th Annual Meeting in North America, Baltimore, MD.

Pastorok, R., R. Davis, J. Salatas, and M. Edwards. 2004. Identifying structural and functional indicators for habitat equivalency analysis (HEA) and restoration of submerged vegetation. Interactive platform presentation at the SETAC World Congress and 25th Annual Meeting in North America, Portland, OR.

Booth, P., M. Edwards, and D. Nielsen. 2004. Spatial and temporal trends in PCBs in fish in response to natural recovery in sediments. Poster presentation at the SETAC World Congress and 25th Annual Meeting in North America, Portland, OR.

The significance of statistical significance. DRI Annual Meeting, New Orleans, LA. 2012.

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