Melanie Edwards
Melanie R. Edwards, PStat
Managing Statistician
Environmental & Earth Sciences
  • Seattle

Ms. Edwards is an accredited statistician and has testified on the use of statistical methods. She regularly performs and critiques aspects of data analytics of lab chemistry concentrations, toxicity tests, field screening results, and background or reference comparisons. She is called upon frequently to provide understandable descriptions of statistical methods used by testifying experts, and to assist with deposition questioning. Her areas of application are expansive, including chemical forensics, pesticide registration, and injury quantification. With over 20 years of experience, Ms. Edwards has provided statistical support on projects involving metals, PCBs, PAHs, and dioxins/furans in soil, sediment, dust, groundwater, and surface water.

She routinely provides insight on data presentation and interpretation of statistical analyses for experts from a variety of backgrounds, including environmental science, ecology, toxicology, and engineering. She is also familiar with public data sources such as NHANES and SEER data repositories as well as chemistry datasets representing background concentrations in soil and water. She has maintained all aspects of databases used for data validation, compilation, and storage, including transfer of data from multiple formats. Ms. Edwards has provided statistical support on a wide range of projects including chemical fingerprint analyses, model fitting and predictions, comparisons with background and reference populations, probabilistic model development for quantification of uncertainties, and evaluation of toxicity test results. Methods used include regression, analysis of variance, non-linear models, factor analysis, principal component analysis, non-parametric methods, and sampling design and evaluation. She routinely provides insight on data presentation and interpretation of statistical analyses for experts from a variety of backgrounds, including environmental science, ecology, toxicology, and engineering. She is also familiar with NHANES and SEER data repositories as well as chemistry datasets representing background concentrations in soil and water. She has maintained all aspects of databases used for data validation, compilation, and storage, including transfer of data from multiple formats.

CREDENTIALS & PROFESSIONAL HONORS

  • M.S., Statistics, University of Wisconsin, Madison, 1998
  • B.S., Mathematical Science, University of Washington, 1991

LICENSES & CERTIFICATIONS

Accredited Professional Statistician, PStat®, American Statistical Association

Publications

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

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

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

Shields W, Edwards M. 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, 2013. Available at https://scisoc.confex.com/crops/2013am/webprogram/Paper81402.html.

Megson D, O’Sullivan G, Comber S, Worsfold PJ, Lohan MC, Edwards MR, Shields WJ, Sandau CD, Patterson DG Jr. 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 2013; (461–462):99–107.

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

Shields WJ, Edwards MR, Abrahams JA, Ferrara RA, Bollinger M, Paul LS. Source evaluation of dioxins/furans, PAHs, and pentachlorophenol in soil samples near a wood treating site in the Southeastern USA. Organohalogen Compounds 2012; 74:593–595.

Connor KT, Harris MA, Edwards MR, Budinsky RA, Clark GC, Chu AC, Finley BL, Rowlands JC. 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 2008; 18:369–380.

Lowney YW, Wester RC, Schoof RA, Cushing CA, Edwards MR, Ruby MV. Percutaneous absorption of arsenic from soils as measured in the Rhesus Monkey. Toxicological Sciences 2007; 100(2):381–392.

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

Tsuji JS, Williams PRD, Edwards MR, Allamneni KP, Kelsh MA, Paustenbach DJ, Sheehan PJ. Evaluation of mercury in urine as an indicator of exposure to low levels of mercury vapor. Environ Health Perspect 2003; 111(4):623-630.

Book Chapters

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

Presentations


Edwards, M, Aldea M. Effect of data transformations on the interpretability of principal component analysis results. Poster presentation, Joint Statistical Meeting, Seattle, WA, August 8–13, 2015.

Aldea, M, Edwards M, Pietari J. Cautions on the treatment of non-detect results for environmental forensics. Poster presentation, INEF conference, Toronto, Canada, August 3–6, 2015.

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

Edwards M. The significance of statistical significance. Presentation at the DRI Annual Meeting, New Orleans, LA, 2012.

Shields WJ, Edwards, MR, Abrahams JA, Ferrara, RA, Bollinger M, Paul LS. 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, 2012.

Menzie C, Deardorff T, Ma J, Edwards M. 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, November 11–15, 2012.

Johns M, Atlas R, Edwards M. 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, 2011.

Edwards M, Maier E, Reeder D, Gard N, Shock S. 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, 2007.

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

Kaetzel R., Edwards M, Lowney Y, Tsuji J. 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, 2006.

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

Pastorok R, Davis R, Salatas J, Edwards M. 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, 2004.

Booth, P, Edwards M, Nielsen D. 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, 2004.

Professional Affiliations

American Statistical Association

Project Experience

Used principal component analysis of dioxin and furan concentrations from multiple locations and sources to determine if historic releases from a wood treatment facility were the source of these compounds found in a nearby neighborhood in Mississippi. Used diagnostic ratio method to evaluate sources of PAHs. Assisted in preparation of expert report.

Generated upper tolerance limits for concentrations of PCB congeners, dioxin and furan congeners, and toxicity equivalents (TEQ) based on the NHANES complex survey study design. These values represent the upper range of background levels in blood samples from the U.S. population. Several age groups were evaluated separately.

Quantified temporal trends in concentrations measured in groundwater monitoring wells surrounding historical holding ponds used by an electric power generating facility.

Used profile comparisons and principal component analysis to evaluate dioxin and furan fingerprints in water, sediment, and fish tissue samples downstream and upstream of a former pesticide manufacturing facility.

Used simulation methods to evaluate sources of variability in fish tissue PCB concentrations and evaluate state of Michigan’s current sample design for monitoring PCB and mercury concentrations in fish tissue throughout the state.

Developed 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 and more detailed record keeping.

Evaluated the relationship between PCB congener concentrations and total PCB concentrations in sediment and several fish species from the Fox River, 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 NRDA for a Superfund site in Wisconsin.

Assisted with developing a sampling program for metals in fugitive dust in multiple tundra environments. Conducted statistical analyses to evaluate the contribution of metals in fugitive dust to changes observed in plant communities near the road and facility areas. Analyses included hypothesis testing, regression analyses, cluster analysis, principal component analysis, and non-parametric methods to quantify spatial trends in the vicinity of a mine, haul road, and port; compared concentrations between potentially impacted and reference locations; and summarized berry, caribou tissue, invertebrate, soil, sediment, and water chemical concentrations for ecological and human health risk assessment. Factor analysis highlighted habitat differences within the vegetation community. Cluster analysis quantified location similarities in the benthic invertebrate community.

Analyzed chemical endpoint data from surrogate species for human and wildlife receptors to quantify the relative uptake of metals from environmental media, following exposure via dermal or oral contact. Final analyses quantified the relative bioavailability of various treatments against a control. Additionally the sample design was evaluated with respect to the minimum detectable uptake.

Used a generalized linear model (with Poisson link function) and regression analyses to model dose-response relationships for response endpoints for mink. The endpoints evaluated were percent mortality and percent decline in fecundity. Calculated cumulative PCB dose probability curves and exceedance probabilities for percent decline in litter size.

Developed data assessment and quantification analysis to determine whether field collected fluorescence and dissolved oxygen measurements in the water column were associated with lab quantified benzene, ethylbenzene, toluene, xylene (BTEX) and polycyclic aromatic hydrocarbons (PAH) concentrations. Complications overcome included multiple instruments and data processing techniques. Designed the database and provided oversight for data compilation from multiple diverse sources encompassing three million sample records each with multiple measurements.

Calculated multiple benthic metrics (abundance, richness, diversity, and dominance) and assessed statistically significant differences between site stations and the reference area to support a weight-of-evidence approach to assessing biological effects, and to support the calculation of Apparent Effects Threshold values.

Compiled data from multiple studies of mercury in air and urine to assess common relationships using regression analysis. Adjustments of slopes and intercepts allowed for assessing similarity of sample design among studies. Confidence and prediction intervals were used to band the resulting relationships.

Developed regression analyses used to estimate concentration in worms from soil with confidence and prediction upper limits. Estimated worm concentrations were used in various scenarios for calculation of ecological risk to short-tailed shrew.

Used logistic regression to characterize the relationship between PAH concentration and average mortality of Hyalella azteca.

Analyzed mercury concentrations in homes using discriminant analysis to characterize and differentiate between different sources of mercury, including natural gas pressure regulators, thermometers, and other residential sources of mercury.

Evaluated temporal trends in landfill groundwater monitoring concentration data using summary statistics, boxplots, probability plots and distance weighted least squares regression. Standardized concentrations were used to equate the varying magnitude and variation of multiple chemicals.

Used regression analysis to evaluate the results of two analysis methods used to measure mercury concentration in sediment and soil. Results provided statistical support for using both methods, thereby increasing the quantity and precision of data used for site characterization.

Calculated the minimum number of samples necessary to meet statistical performance objectives of sampling plan in accordance with EPA guidance, including multiple levels of confidence, power, and minimum detectable differences.

Managed large environmental databases of chemistry, toxicity, and ecological data for multiple projects (Brunswick, Georgia; Saginaw River, Michigan; Onondaga Lake, New York; and Anaconda, Montana).


Knowledge

News & Events

CREDENTIALS & PROFESSIONAL HONORS

  • M.S., Statistics, University of Wisconsin, Madison, 1998
  • B.S., Mathematical Science, University of Washington, 1991

LICENSES & CERTIFICATIONS

Accredited Professional Statistician, PStat®, American Statistical Association