Gradient

Senior Scientists

Daniel G. Skall, M.S.
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Education

M.S., Aquatic Toxicology, University of Maine

B.S., Marine Science, Mathematics minor, University of Maine

Expertise

  • Exposure Analysis
  • Ecological Risk Assessment
  • Aquatic Toxicology
  • Hazard Assessment

    Daniel G. Skall, M.S.

    Senior Environmental Health Scientist

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    Mr. Skall is an environmental health scientist with a background in aquatic toxicology.  His experience is in ecological risk assessment and exposure analysis.  His primary responsibilities at Gradient include reviewing and interpreting toxicity literature and data, assessing environmental hazards, and evaluating risk to ecological receptors.  Prior to joining Gradient, Mr. Skall investigated biomarker induction in scales from fish exposed to surface water contaminants, including organics, synthetic hormones, and pharmaceuticals.  He received his B.S. in Marine Biology and M.S. in Aquatic Toxicology from the University of Maine. 

    Education

    M.S., Aquatic Toxicology, University of Maine

    B.S., Marine Science, Mathematics minor, University of Maine

    Expertise

    • Exposure Analysis
    • Ecological Risk Assessment
    • Aquatic Toxicology
    • Hazard Assessment

      Representative Projects

      Toxicological Information Review: Reviewed and summarized ecotoxicological information on chemicals identified by client for use in environment.

      Literature Review: Reviewed and summarized plaintiff depositions to establish exposure parameters of plaintiffs for client. Reviewed and summarized literature describing similar exposures to those claimed by plaintiffs for client.

      Literature Review: Reviewed and summarized literature regarding birth defects in Latin America to establish background occurrence of birth defects in that region for client.

      Technical Comments Summary: Reviewed and summarized technical comments regarding US EPA’s proposed amendment to the secondary ozone NAAQS.

      Literature Review: Reviewed and summarized sample chains of custody. Reviewed and summarized literature regarding aquatic toxicology reports from past National Resource Damage Assessment (NRDA) oil spills.

      Hazard Classification: Identified and assessed ecotoxicological data for hydraulic fracturing chemicals to classify their ecological hazards based on Globally Harmonized System regulations.

      Chemical Registration Summary: Researched and summarized chemical registration procedures in countries where hydraulic fracturing is being considered.

      Chemical Hazard Assessment: Performed chemical hazard assessments for several chemicals using Clean Production Action’s GreenScreen® for Safer Chemicals method.

      Ecological Risk Assessment: Prepared screening-level and baseline ecological risk assessments for client, to determine potential risks of ecological receptors (aquatic organisms, fish, plants, soil invertebrates, amphibians, birds, and mammals) exposed to chemicals associated with site activities.

      Selected Publications

      Skall, DG; Reid, KR; Cohen, JM; Lewandowski, TA.  2016. "IC2 Level 1 Alternative Assessment for Refrigerants in Domestic Refrigerators." Presented at SETAC North America 37th Annual Meeting, Orlando, FL, November 6-10

      Skall, DG; Mayfield, DB; Johnson, MS.  2015. "Refining Ecological Soil Screening Levels Using Benchmark Dose Analysis." Presented at SETAC North America 36th Annual Meeting, Salt Lake City, UT, November 1-5

      Mayfield, DB; Skall, DG.  2014. "Characterizing Wildlife Exposure-Response Relationships Using Benchmark Dose Analysis: Exploring Effect Endpoints and Dose-Metrics." Presented at the Society of Environmental Toxicology and Chemistry (SETAC) North America 35th Annual Meeting, Vancouver, BC, 17p.