Document ID: EPA-HQ-OPP-2006-0856-0043
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2007-01-08T05:00Z

FIFRA SCIENTIFIC ADVISORY PANEL (SAP) 

OPEN MEETING

JANUARY 9 - 12, 2007

FIFRA SAP WEB SITE http://www.epa.gov/scipoly/sap/

OPP Docket Telephone: (703) 305-5805

Docket No.: EPA-HQ-OPP-2006-0856

TUESDAY, JANUARY 9, 2007

U.S. Environmental Protection Agency, One Potomac Yard, South Building

Conference Center, Lobby Level

2777 S. Crystal Drive, Arlington, Virginia 22202

REVIEW OF WORKER EXPOSURE ASSESSMENT METHODS

8:30 a.m.	Introduction and Identification of Panel Members – Steven
Heeringa, Ph.D., FIFRA SAP Chair

8:40 a.m.	Administrative Procedures by Designated Federal Official –
Myrta R. Christian

8:45 a.m.	Opening Remarks – Tina Levine, Ph.D., Director, Health
Effects Division, Office of Pesticide Programs, EPA

8:55 a.m.	Introduction and Overview – Jeff Evans, Health Effects
Division, Office of Pesticide Programs, EPA

9:20 a.m.	Historical Perspective – John Worgan, Health Canada, Pest
Management Regulatory Agency

10:00 a.m.	BREAK

10:15 a.m.	Case Study – Jeff Dawson, Health Effects Division, Office
of Pesticide Programs, EPA

11:45 a.m.	Issues Related to Antimicrobial Pesticides – Cassi Walls,
Ph.D., Antimicrobial Division, Office of Pesticide Programs, EPA

12:00 noon	LUNCH

1:00 p.m.	AHETF Overview and Approach – AHETF Representatives Richard
H. Collier, Ph.D., Victor Canez, Ph.D., and Curt Lunchick

2:40 p.m.	AEATF Overview and Approach – AEATF Representative Ryan
Williams, Ph.D.

3:00 p.m.	BREAK

3:15 p.m.	Public comments

5:00 p.m.	ADJOURNMENT

FIFRA SCIENTIFIC ADVISORY PANEL (SAP) 

 OPEN MEETING

JANUARY 9 - 12, 2007

FIFRA SAP WEB SITE http://www.epa.gov/scipoly/sap/

OPP Docket Telephone: (703) 305-5805

Docket No.: EPA-HQ-OPP-2006-0856

WEDNESDAY, JANUARY 10, 2007

U.S. Environmental Protection Agency, One Potomac Yard, South Building

Conference Center, Lobby Level

2777 S. Crystal Drive, Arlington, Virginia 22202

REVIEW OF WORKER EXPOSURE ASSESSMENT METHODS

8:30 a.m.	Introduction and Identification of Panel Members – Steven
Heeringa, Ph.D., FIFRA SAP Chair

8:35 a.m.	Administrative Procedures by Designated Federal Official –
Myrta R. Christian

8:40 a.m.	Follow-up from Previous Day’s Discussion – Jeff Dawson,
Jeff Evans, Health Effects Division, Office of Pesticide Programs, EPA

9:00 a.m.	Agency – Biological Monitoring/Passive Dosimetry Comparison
– Sheryl Beauvais Ph.D., California EPA, Department of Pesticide
Regulation

9:45 a.m. 	Agency Methods for Measuring Hand Exposure – Jeff Dawson,
Jeff Evans, Health Effects Division, Office of Pesticide Programs, EPA

10:15 a.m.	BREAK

10:30 a.m.	AHETF Comparison of Passive Dosimetry and Biological
Monitoring – AHETF Representatives John Ross, Ph.D. Graham Chester,
Doug Baugher, Ph.D., Bruce Houtman and Curt Lunchick

12:00 noon	LUNCH

1:00 p.m.	Questions to the Panel

1) Data Needs

EPA believes that many studies within our current database have
limitations.  In some

cases, the Agency is lacking data to address modern pesticide
application equipment and techniques.  EPA believes that additional data
could significantly improve our ability to estimate and better
characterize the range of worker exposure with greater certainty. 

Please comment on these limitations and EPA’s conclusion that
additional data could improve significantly the Agency’s ability to
assess worker exposure.  Also, please comment on the selection criteria
proposed by the AHETF and AEATF in their respective submissions for
evaluating the extent to which existing data would meet EPA’s exposure
assessment needs.

2:30 p.m.	BREAK

2:45 p.m.	Panel Discussion (continued)

2) Passive Dosimetry Performance

The common approach for conducting dermal exposure monitoring studies
relies on the use of whole-body dosimetry, handwashing, and facial/neck
wipes.  In some cases, biological monitoring is also used as an
alternative method.  Exposure estimates in Agency risk assessments,
however, typically rely on “to the skin” measurements (i.e.,
potential dose) coupled with dermal absorption data or dermal toxicity
studies in order to calculate risks.  The Agency believes that these
methods are complementary and that they can provide appropriate
estimates for exposure assessment but that the results directly relate
to the reliability of the inputs used.  Please comment on the Agency’s
conclusion regarding passive dosimetry and biological monitoring,
including whether a systematic bias exists in either approach.

Based on the information presented, the Agency has particular concerns
over three specific aspects of how these studies are conducted including
(1) the possible need to correct for the efficiency of the handwashing
technique; (2) compensating for absorption of residues through the skin
during sample collection periods; and (3) the breakthrough of residues
under whole-body dosimeter garments. Please comment on the need to
systematically account for residue losses due to these potential method
biases.  If there is a need, please describe how these corrections
should be accomplished in a way that could reduce uncertainties in the
resulting exposure estimates.

4:15 p.m.	Panel Discussion (continued)

3) Passive Dosimetry vs. Biomonitoring

EPA believes that a comparison of exposure estimates derived from data
collected through biomonitoring with data collected through passive
dosimetry is the most appropriate way to assess the predictive nature of
a passive dosimetry-based approach for estimating worker exposure. 
Please comment on the strengths and limitations of this kind of
comparison for judging the potential utility of passive dosimetry data
in conducting exposure assessments.

EPA has conducted such a comparison using available data and believes
that the

comparison shows sufficient concordance of estimates based on
biomonitoring data and passive dosimetry data to support the conclusion
that a passive dosimetry-based approach can generate data that can be
used to develop relatively predictive estimates of worker exposure for a
wide variety of scenarios and activities.  Please comment on the
adequacy of the analysis to support EPA’s conclusion.

5:30 p.m.	ADJOURNMENT

FIFRA SCIENTIFIC ADVISORY PANEL (SAP) 

 OPEN MEETING

JANUARY 9 - 12, 2007

FIFRA SAP WEB SITE http://www.epa.gov/scipoly/sap/

OPP Docket Telephone: (703) 305-5805

Docket No.: EPA-HQ-OPP-2006-0856

THURSDAY, JANUARY 11, 2007

U.S. Environmental Protection Agency, One Potomac Yard, South Building

Conference Center, Lobby Level

2777 S. Crystal Drive, Arlington, Virginia 22202

REVIEW OF WORKER EXPOSURE ASSESSMENT METHODS

8:30 a.m.	Introduction and Identification of Panel Members – Steven
Heeringa, Ph.D., FIFRA SAP Chair

8:35 a.m.	Follow-up from Previous Day’s Discussion – Jeff Dawson,
Jeff Evans, Health Effects Division, Office of Pesticide Programs, EPA 

8:50 a.m.	Proportionality Between Exposure and Amount of Active
Ingredient Handled – Matthew Crowley, David J. Miller, Health Effects
Division, Office of Pesticide Programs, EPA

10:00 a.m.	BREAK

10:15 a.m.	Statistical Basis for AHETF Data Development Program –
AHETF representatives Bryce Landenberger, Curt Lunchick and Larry
Holden, Ph.D.

12:00 noon	LUNCH

1:00 p.m.	Questions to the Panel

4) Normalization of Exposure by Amount of Active Ingredient Handled
(AaiH)

The normalization of exposure by AaiH – the unit exposure – has,
since the mid-1980s, been the principle relationship underlying the use
of exposure data in the Agency's pesticide handler exposure assessments.
 It is based on the assumption that the two variables are proportional. 
That is, if one doubles the amount of pesticide they handled or applied,
the resultant exposure will be doubled as well.

The Agency is unsure whether the results of our exploratory work showing
that proportionality between exposure and AaiH is reasonable in some but
not all cases, is a function of limitations of the data within PHED or
whether this relationship is in fact not a reasonable assumption for all
scenarios.  It may be the case that an additional ancillary variable
(e.g., boom length, # of tank mixes, or # de-couplings in a closed
loading system), in addition to or in place of AaiH, may improve the
predictive capabilities of our exposure model.

Though it is recognized that neither the studies in our current database
nor the proposed studies by the AHETF were designed for the primary
purpose of examining proportionality between exposure and AaiH or to
determine the extent to which other parameters influence exposure,
compared with our current database, the Agency believes that the
proposed AHETF studies will generate data that will reinforce the
assumption of proportionality between exposure and AaiH or,
alternatively, inform the applicability of another variable as a more
appropriate predictor of exposure.

Based on the themes presented on this topic including its historical
precedent, its application in risk assessment and subsequent risk
management decisions, the Agency’s exploratory work using the six PHED
scenarios in the case study, and the study design and objectives of the
AHETF, please comment on the assumption of proportionality between
exposure and AaiH, as a default.   Also, please provide comments on
whether the proposed AHETF study design is adequate to evaluate
proportionality between exposure and AaiH?  What other parameters should
AHETF study designs measure in order to improve the prediction
capabilities of our exposure model?

2:30 p.m.	BREAK

2:45 p.m.	Panel Discussion (continued)

5) Within-worker and Between-worker Variability

The proposed AHETF study design does not include true worker replicates
and is not intended to examine the issue of variability within workers. 
The AHETF notes that to appropriately investigate this issue would
require significantly more sampling and resources.  They propose,
however, that their single-day exposure distribution results can be used
to evaluate longer term multiple day exposures by placing reasonable
limits on expected intra-class correlation coefficients (ICC):  they
indicate that, from their own research and review of the literature, the
ICC is likely to be between 0.3 and 0.5 over relatively short periods of
time (e.g., seasonal), and likely to be even lower over longer periods
of time.

Please comment on the AHETF’s approach to estimating the number of
samples (MU) needed to determine within worker variability and their
conclusion on the importance of measuring such variability in their
proposed studies.

4:15 p.m.	Defining the Scope of a Research Plan Designed to Quantify
Occupational Handler Exposures – David J Miller, Jeff Evans, Health
Effects Division, Office of Pesticide Programs, EPA

5:30 p.m.	ADJOURNMENT

FIFRA SCIENTIFIC ADVISORY PANEL (SAP) 

 OPEN MEETING

JANUARY 9 - 12, 2007

FIFRA SAP WEB SITE http://www.epa.gov/scipoly/sap/

OPP Docket Telephone: (703) 305-5805

Docket No.: EPA-HQ-OPP-2006-0856

FRIDAY, JANUARY 12, 2007

U.S. Environmental Protection Agency, One Potomac Yard, South Building

Conference Center, Lobby Level

2777 S. Crystal Drive, Arlington, Virginia 22202

REVIEW OF WORKER EXPOSURE ASSESSMENT METHODS

8:30 a.m.	Introduction and Identification of Panel Members – Steven
Heeringa, Ph.D., FIFRA SAP Chair

8:35 a.m.	Follow-up from Previous Day’s Discussion – Matthew
Crowley, David J Miller, Health Effects Division, Office of Pesticide
Programs, EPA

8:50 a.m.	AHETF Research Plan Development and Considerations – AHETF
representatives Victor Canez, Ph.D., Richard Collier, Ph.D., Bruce
Houtman, Curt Lunchick and Larry Holden, Ph.D.

10:00 a.m.	BREAK

10:15 a.m.	Questions to the Panel

6) Sample Size: Number of Sites and Subjects per Scenario/Activity

The Agency’s goal is to ensure that monitoring studies rely on sample
sizes that adequately represent the range of exposure of people who
engage in a particular handler scenario and activity.  It is also
recognized that occupational monitoring studies are costly and have many
logistical obstacles.  The Agency is also concerned about limiting the
numbers of participants in these types of studies in accordance with the
ethical requirements described in Subpart K (40CFR26) and the recent
criteria outlined by the Agency’s Human Studies Review Board.  The
Agency’s current guidelines recommend 15 monitoring units for each
scenario.  In addition, the AHETF has provided a rationale for the
number of samples in their study design.

Please comment on the uncertainties associated with the Agency’s and
AHETF’s recommended number of monitoring units.  In your comments,
please include any recommendations you may have regarding specific
statistical analyses that may assist the Agency in developing better
understanding of these uncertainties and characterizing them in a
complete and transparent manner in Agency assessments based on these
data.

12:00 noon	ADJOURNMENT

Please be advised that agenda times are approximate; when the discussion
for one topic is completed, discussions for the next topic will begin.
For further information, please contact the Designated Federal Official
for this meeting, Ms. Myrta Christian, via telephone: (202) 564-8450;
fax: (202) 564-8382; or email: christian.myrta@epa.gov

  PAGE  6  of   NUMPAGES  6