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Questions to SAP: LifeLineT -
System Operation Review
Model Operation

FIFRA Scientific Advisory Panel (SAP)


  1. The LifeLineT - CD includes model documentation in the form of a Users' Manual, Technical Manual, and Demonstration Case. Is this documentation sufficient to understand and operate the model?

  2. The LifeLineT - CD includes "pre-packaged" data files for use in conjunction with the Demonstration Case as well as Knowledge base files which are used by the model to estimate potential exposure and risk. Were panel members able to generate a risk assessment report and identify routes of exposure and populations at risk, using the "pre-packaged" data files provided on the CD? Were panel members able to identify exposure contributors, and the data/assumptions used in the exposure/risk calculation by examination of output reports, output files (e.g. Exposure.bdf, Lives.dbf, Ractiv.dbf)and knowledge base files (e.g. Rtrecipe.dbf, Rtfoodit.dbf, Rtcgrac.dbf)? Please note these files are located in C:/HRI/RTL.

  3. LifeLineT reports are based on seasonal maximums and means of exposure. From the standpoint of producing a comprehensive risk assessment, what are the strengths and weaknesses of the reports generated by LifeLineT? Which reports are particularly useful for risk assessment and are there other types of reports that the Panel would suggest?

  4. LifeLineT contains more than 90,000 lines of C++ computer code. The panel was provided annotated code for the risk assessment algorithms used in LifeLineT . Do the algorithms in the annotated code perform the functions defined in the LifeLineT Technical Manual? Model Architecture

  5. LifeLineT relies heavily on survey data and EPA SOPs to estimate exposure and the frequency of exposure. These include:

    1. Natality data ((Birth records) National Center for Health Statistics [NCHS]),

    2. Residential patterns (Current Population Statistics, US Census),

    3. The Third National Health and Nutrition Examination Survey ((NHANES III), also maintained by NCHS)

    4. American Housing Survey (US Census and Department of Housing and Urban Development),

    5. Nation Home and Garden Pesticide Use Survey (US EPA, 1992b)

    6. National Human Activity Pattern Survey (US EPA, 1994),

    7. The Continuing Survey of Food Intake by Individuals (CSFII), US Department of Agriculture (USDA,),

    8. Residential Exposure SOPs (US EPA, 1998), and

    9. Exposure Factors Handbook (US EPA, 1997)

    Would the Panel please comment on the appropriateness of using these surveys/SOPs in the LifeLineT model to estimate exposure and frequency of exposure to pesticides?

  6. LifeLineT uses the USDA CSFII survey (a 24 hour dietary recall for 2 or 3 days) to estimate daily dietary exposure over an individual's hypothetical life-time (ca. 85 years). This is done by matching criteria (age, gender, etc...) from CSFII with the individual being modeled by LifeLineT. Would the Panel please comment on this feature of the model?

  7. LifeLineT estimates route specific risk via a route specific toxicological endpoint, but estimates the systemic or aggregate risk by route to route extrapolation using absorption factors. Would the Panel please comment on the appropriateness of this approach to estimating aggregate risk in this model?

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