"MenzieCura@aol.com" <menziecura@aol.com> 

02/27/2008 03:56 PM	

	To

	Joseph Nash/DC/USEPA/US@EPA

	cc

	Mike Santoro <masantoro@mmm.com>

	Subject

	Charge questions for Peer Consultation

	

	

	

	Dear Joe,

Here are the draft charge questions we developed for the PFOA Peer 

Consultation. Please let us know if you have any objections or 

suggestions for improvement. We will expect your comments within 15 

days, per the MOU, but if you can get them to us sooner that would be 

appreciated.

Did you receive my email regarding your availability for the Peer 

Consultation meeting in Decatur?

If not, please let me know and I will re-send.

Best regards,

Charlie Menzie

PEER CONSULTATION CHARGE QUESTIONS

This Peer Consultation is being conducted pursuant to the October 2004
Memorandum of Understanding (MOU) between the U.S. Environmental
Protection Agency (EPA) and 3M Company and Dyneon LLC (the Companies)
for a Perfluorooctanoic Acid (PFOA) Site-Related Environmental
Assessment Program. According to the MOU, the purpose of the Peer
Consultation Group (PCG) is to provide scientific input on the
Assessment documents produced by the Companies in light of the following
Charge, and in particular, on the recommended data needs. 

THE CHARGE:

Are current PFOA environmental releases and sources of those
environmental releases from the Site and the presence of PFOA in
environmental media on and around the Site sufficiently understood so
that pathways of migration and exposure to PFOA associated with that
Site are adequately characterized and assessed on a screening level
basis?

The three Assessment documents that are the subject of the Peer
Consultation are:

Data Assessment Report;

Screening Level Human Exposure Assessment Report;

Future Data Needs Assessment Report.

The PCG is expected to evaluate the Assessments for technical accuracy,
proper documentation and satisfaction of established specifications. We
refer you to Section V.D. of the MOU for the specifications for each
assessment document. Clarifying questions, mentioned below, will also
call attention to these specifications. The PCG should also determine if
the Assessments adequately present assumptions, calculations, supporting
documentation, extrapolations, alternative interpretations, methodology,
acceptance criteria, as well as other conclusions.

 

For the purpose of facilitating and focusing the Peer Consultation
Group’s discussion, Menzie-Cura is providing the following technical
and scientific questions that clarify and relate directly to the Charge
set forth in Section V.A. of the MOU and to each of the three Assessment
documents.  Individual PCG members will be given responsibility for
specific charge questions. However, every member of the PCG is
encouraged to review and comment on all the charge questions. Leads for
each charge question will be expected to prepare an overview of initial
comments from their fellow Group members and be prepared to contribute
significantly to those discussions during the meting in Decatur.

EPA and the Companies have reviewed these clarifying questions to ensure
that they are consistent with the scope of the MOU. EPA and the
Companies have agreed upon terminology to establish the general scope of
the PFOA Site-Related Environmental Assessment Program (see MOU Section
V.A.2.a-d). The following terminology is important in the peer
consultation process, because it governs interpretation of the Charge:

“Associated With The Site,” as used in the Charge, includes any
current environmental release or presence in Environmental Media of PFOA
on and off the site resulting from Current or Past Manufacturing
Activities at the site. “Current or Past Manufacturing Activities”
at the site refers to all activities that may have resulted in the
current presence of PFOA in environmental media both on and off the site
without regard to distance from the site, including but not limited to
waste disposal activities that occurred off-site, such as landfills that
received materials from the site; land application materials originating
from the site; off-site treatment facilities receiving waste material
from the site; and air emissions that may have deposited off the site,
except that “Current or Past Manufacturing Activities” does not
encompass commercial products manufactured at the site and distributed
in commerce.

“Environmental media,” as used in the Charge, refers to air, surface
water, groundwater, soil, sediment, biota, wastewater, waste streams,
landfills, landfarms, water discharges and offsite disposal of all
types.

“Pathways of Migration,” as used in the Charge, refers to the routes
by which PFOA moves from any Current or Past Manufacturing Activity
through Environmental Media, and includes but is not limited to,
leaching to surface water or groundwater from land-applied materials;
discharge from areas with contaminated groundwater to surface waters or
wells; releases from landfills to air, groundwater and surface water;
and air deposition to soils and migration to groundwater.

“Exposure to PFOA Associated With The Site,” as used in the Charge,
refers to current exposures and the potential for future exposures from
the presence of PFOA in Environmental Media as a result of Current or
Past Manufacturing Activities at the site, but does not include an
assessment of exposures that may have occurred in the past. The
Screening Level Exposure Assessment of current human Exposure to PFOA
Associated With The Site shall include a quantitative assessment for any
exposure pathway for which the data allow quantitative assessment, and a
qualitative or semi-quantitative description of exposure where the data
do not allow quantitative assessment. The Screening Level Exposure
Assessment will be based on data necessary to understand sources of
release associated with the site and Pathways of Migration of those
releases. Although the Screening Level Exposure Assessment will focus
primarily on human exposure, it will characterize the presence of PFOA
in Environmental Media, including biota, on and off the site as a result
of Current or Past Manufacturing Activities.

CLARIFYING QUESTIONS RELATED TO THE Data Assessment Report

Is the data and information presented in this report relevant to the
Screening Level Exposure Assessment and of sufficient quality,
objectivity, utility, and integrity?

 Are the characteristics of the on-site and off-site locations evaluated
in this assessment described in a sufficient level of detail to
understand potential human exposure pathways?  These characteristics
include, for example, current and possible future land use patterns,
characteristics of the local population, habitats, and general physical
conditions. 

Have the nature of the soil, sub-surface geological, sedimentary, and
hydrological conditions been adequately described for the purposes of
assessing pathways of migration through and/or into environmental media?


Have the pathways of migration of PFOA from soils to other environmental
media been adequately considered and represented? Please identify any
major limitations in the assessment or data gaps that have not been
identified.

Have the pathways of migration of PFOA in the groundwater been
adequately considered and represented? Please identify any major
limitations in the assessment or data gaps that have not been
identified.

Have the pathways of migration of PFOA in surface water and sediment
been adequately considered and represented? Please identify any major
limitations in the assessment or data gaps that have not been
identified.

Have the pathways of migration of PFOA in air been adequately considered
and represented? Please identify any major limitations in the assessment
or data gaps that have not been identified.

Has the potential for bioaccumulation into aquatic or other biota been
adequately considered and represented? Please identify any major
limitations in the assessment or data gaps that have not been
identified.

CLARIFYING QUESTIONS RELATED TO THE Screening Level Human Exposure
Assessment Report

Hazard Identification

Does the site conceptual model adequately characterize sources and
exposure pathways linking these sources to on-site and off-site human
receptors under current conditions and possible future conditions? 

Have appropriate receptors been identified? Do they include potentially
highly exposed populations? Do they include potentially sensitive
populations?

Do the selected exposure scenarios sufficiently cover the situations,
behaviors, and conditions under which receptors are likely to be
exposed? 

Elements of Exposure Analysis and Utilization of Data

Of the data available to the authors, did they select the right data
sets to quantify exposure?  Should they have considered any of the data
excluded from the analysis?

Are these data sufficient to support the exposures that were quantified
in the assessment?

Were the data used appropriately to calculate exposure point
concentrations? 

Did the authors define reasonable exposure points (in three-dimensional
space) that represent locations associated with current and possible
future exposure?  

Are the data sufficient to understand patterns of contamination at each
exposure point?  

Were EPC calculations and other statistical manipulations (e.g.,
treatment of results below detection limits, field duplicates, and
qualified data) of these data performed accurately and appropriately? 

Other than the EPCs, were the assumptions and exposure input parameters
for each combination of pathway and receptor appropriate? 

Was bioavailability of PFOA in the various exposure media (e.g., soil)
addressed appropriately?

Have the appropriate age groupings been defined to assess exposure given
any variability in sensitivity to the effects of PFOA? 

Are the selected receptor characteristics and exposure patterns (i.e.,
duration, frequency, and intensity) the most appropriate for use in this
assessment?

Were the doses averaged over the appropriate time interval to account
for sensitive life stages and relevant health outcomes? 

Overall, are the input data and assumptions valid and appropriate for
current and possible future receptors?

Were the appropriate exposure pathways selected for quantifying dose?
Was the justification for excluding exposure pathways from dose
estimation reasonable?

For exposure pathways for which the data did not allow quantitative
assessment, did the authors present a qualitative or semi-quantitative
description of exposure?

Uncertainty Analysis and Data Needs to Remedy Uncertainty

The authors describe data needs for exposure pathways that were not
quantified in this assessment.  Do you agree with recommendations for
further sampling and analysis designed to facilitate quantification of
these other exposure pathways?  Do you have other recommendations for
data collection, modeling and other analyses, and exposure pathway
quantification? 

Were all the significant sources of uncertainty identified and
characterized? Are the authors’ conclusions regarding the significance
and impact of the uncertainties on the resulting assessment conclusions
appropriate (See Table 9-1)?  Given uncertainties, what is the
likelihood that actual exposures have been over- or under-estimated?

CLARIFYING QUESTIONS RELATED TO THE Future Data Needs Assessment Report

Does the Future Data Needs Assessment Report assess the sufficiency of
the Data Assessment and the Screening Level Exposure Assessment with
reference to the Charge?

Does this Assessment identify additional data and/or other appropriate
information necessary to fully address the Charge? Please identify any
critical data gaps or potential pathways for exposure you feel have not
been identified.

Does the Phase 3 Work Plan Outline contain all of the technical elements
required for gathering the proposed additional data to fully address the
Charge?

