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Residential/ Non- occupational Exposure Assessment
Jeff Evans Biologist Health Effects
Division Office of Pesticide Programs
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Purpose

• To present our use of a calendar based model
  (Calendex), to address the temporal aspects of
  OP pesticide use
• Approach is similar to the OP case study
  presented to SAP (12/7-8/00)
• To discuss the data used in our cumulative
  residential exposure assessment
• To discuss with the Panel
• Use of distributions of the available data
• Additional ways to incorporate survey data and
  other pesticide use in future assessments

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Residential OP Assessment Uses

• Indoor use DDVP (crack and crevice, pest strips)
• Pet use DDVP and Tetrachlorvinphos (spray/dip,
  collars) currently only qualitatively
  assessed
• Home Lawns Bensulide, Malathion, Trichlorfon
• Golf Course Acephate, Bensulide, Fenamiphos,
  Malathion, Trichlorfon
• Home Garden Acephate and Disulfoton
  (ornamental) , Malathion (ornamental and
  edible food)
• Public Health Fenthion, Malathion, Naled

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Expression of Residential Risk
MOE POD (mg/kg/day) Exposure (mg/kg/day)

• Routes considered, as appropriate
• Oral, Dermal, Inhalation

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Age Groups

• Assessment performed for the following age
  groups
• Children 1-2 years old
• Children 3-5 years old
• Adults 20

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Scope

• Assessments conducted for 12 distinct
  geographical regions, reflecting climate pest
  pressure differences
• One region split into two residential assessments
• Includes remaining residential OPs that have
  significant exposure and appropriate exposure
  data
• Pet products not quantified
• Only screening level SOPs available at this time

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Regional Framework
Source USDA ERS
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Region 5 Eastern Uplands

• Lawn DDVP, Malathion, Trichlorfon
• Golf Course Acephate, Bensulide, Fenamiphos,
  Malathion, Trichlorfon
• Ornamental Gardens Acephate, Disulfoton,
  Malathion
• Home Garden Malathion
• Indoor DDVP (pest strips and crack and crevice
  treatments)

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Road Map

• Key Data Used (distributions selected)
• Lawn
• Golf Courses
• Public Health
• Home Garden
• Characterization
• Future Consideration of Survey Data

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Lawns Use Information

• National Home Garden Pesticide Use Survey
  (NHGPUS 1991)
• percent of households using a given pesticide
  regional distinctions
• Treated lawns based on regions using the National
  Garden Survey 1996-1997
• Percent of population hiring lawn care services
• Lawn Size (Vinlove and Torla 1995 and ORETF
  Survey)

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Lawn Size

• Uniform Distribution 500 15,000 ft2
• Difficult to quantify
• Only considers lot size minus footprint
• Does not consider other structures/green space

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Lawns Use Information

• Label
• site/pest relationships
• application rates
• State Cooperative Extension services
• Timing of applications to control common pests
• Comparative Insecticide Effectiveness for Major
  Pest Insects of Turf in the United States

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Lawn Applicator Exposure Data

• Data source ORETF
• Application Type
• Granular push-type rotary spreaders
• Hose-end sprayer ready to use and one requiring
  the user to add the concentrate
• Clothing types
• Range of clothing
• Short-sleeved shirt, short pants and long-sleeved
  shirt, long pants

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Lawn Applicator Exposure

• Unit Exposure (UE)
• mg of exposure/amount of active ingredient (a.i.)
  used
• UE x ai/sq ft x area treated
• Divided by body weight

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Lawn Applicator Exposure Data

• Hose-end Sprayer
• Uniform Distribution 0.017 49 mg/lb ai
• Granular Applicator
• Uniform Distribution 0.02 7.6 mg/lb ai

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Lawn Applicator Exposure Data

• Well understood activity pattern
• Easy to measure and develop distributions
• However, selected a uniform distribution that
• Reflects range of clothing that can be worn
• Survey data suggest that clothing worn while
  applying pesticides changes as growing season
  progresses
• seasonal changes are only based on formulation
  type not equipment used
• Hose-end includes both mix you own and ready
  to use

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Lawn Post- Application Exposure Data

• Difficult activity pattern to determine what is
  representative
• Residue transfer to skin (transfer coefficient)
• Choreographed Activities of Adults Measured Using
  Biological Monitoring, (Vacarro 1996)
• Crawling, football, Frisbee
• Non-Scripted Activities of Children Measured
  Using Fluorescent Tracers, (Black 1993)
• Mostly solitary play with toys and books. Also
  activities such as cartwheels

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Lawn Post- Application Exposure Data

• Duration up to 2 and 3.5 hrs for adults and
  children respectively (Cumulative, EFH)
• Adult TC 1,930 13,200 cm2/hr
• Uniform distribution (n 16 Vacarro)
• Child TC 700 16,000 cm2/hr
• Uniform distribution Vacarro (n 16) and Black
  (n 14)

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Lawn Post- Application Exposure Data

• Turf Transferable Residues (TTR)
• Chemical specific dissipation data (mg/cm2)
• Uniform distribution selected for each days
  residues
• Each day includes a range of values instead of
  mean
• First day values include as soon as dry up to 8
  hours after application
• Watering in and not watering in
• Other days include potential for rainfall

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Lawn Post- Application Exposure Data

• Non-Dietary Ingestion (Hand-to-Mouth)
• Most challenging activity pattern to assess
• Hand-to-mouth frequency of events, (Reed 1999)
• Adjust lawn residue data (TTR) to account for
  saliva wetted hands, (Clothier 2000)
• Saliva extraction e.g., (Camann 1995)

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Lawn Post- Application Exposure Data

• Hand-to-mouth frequency of events (Reed 1999)
• Children in day-care (n-20) at home (n-10)
• Uniform distribution 0.4 to 26 events/hr
• Mean 9.5, median 8.5, 90th percentile 20
• Issue indoors vs. outdoors, active vs. quiet
  play
• Freeman et al., 2001 outdoors (2-3x less than
  indoors)
• Small subset (4 out of 19)

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Lawn Post- Application Exposure Data

• Lawn residue data to account for saliva wetted
  hands (Clothier 2000)
• Compared wet hand efficiency vs. dry hand
  efficiency (cyfluthrin, chlorthalonil and
  chlorpyrifos)
• Dry hand transfer efficiency is similar to TTR
  measurements (0.9 to 3) for 2 chemicals
• Chlorpyrifos much lower overall (0.05 - 0.15)
• Wet palms uniform distribution 1.4-3x higher
  than TTRs

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Lawn Post- Application Exposure Data

• Saliva extraction (uniform 10 to 50)
• 50 removal by saliva wetted sponges vigorous
  (Camann et al., 1995)
• 20 40 hands rinsed with water/Ethanol and
  water/Isopropanol (Fenske and Lu, 1994)
• 10 22 soil removal from hands to account for
  possible residue/soil matrix (Kissel et al., 1998)

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Golf Courses Post- Application Exposure Data

• Percent of individuals participating in golf,
  1992 Golf Course Operations by the Center for
  Golf Course Management
• Number of hours playing golf
• Percent of Golf Courses Applying Selected
  Pesticides (Doane GolfTrak, 1998-1999)
• An activity pattern that is easy to understand
  and measure

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Golf Courses Post- Application Exposure Data

• Residue transfer to skin (transfer coefficient)
• Uniform distribution 200 to 760 cm2/hr
• Small data set (less than 10) includes walking
  and using a cart.
• Chemical-specific turf residue data

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Public Health Post- Application

• Range of residues that deposit onto lawns is
  based on a percent of public health use
  application rate (3.8 to 30) using values
  presented in Tietze et al., 1994 and the Spray
  drift model, AgDrift
• Once an estimate of deposition is made the post
  application is assessed in the same way that lawn
  chemicals are
• Estimates of population based on percent of
  homes having lawns
• Timing and pesticide used based on personal
  communication and publications prepared by
  organizations such as the Florida Coordinating
  Council of Mosquito Control

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Garden Applicator Exposure Data

• An activity pattern that is easy to understand
  and measure
• Shaker Can (n-20) uniform, 0.0034-0.356 mg/lb ai
• Garden Duster (n-20) uniform, 7.99-1375.4 mg/lb
  ai
• Small Tank Sprayer (n-20), uniform, 7.99-354.4
  mg/lb ai
• Similar issues regarding clothing as in lawn
  applications

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Garden Applicator Exposure Data

• Area Treated
• Ornamental Gardens uniform, 500 to 2,000 ft2
• No data. Defined in the assessment as the area
  consisting of the perimeter around a median home
  area 2,250 sq ft2., with a 2.5 to 8 ft border
• Vegetable gardens log-normal, 135 to 8,000 ft2
• May be easier for people to estimate than lawns

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Garden Post- Application Exposure

• Post-application dermal exposure
• An easily defined activity in agriculture
• Home gardens are more difficult due to wide
  variety of crops grown (fruits and vegetables)
  and a wide variety of activities
• Uniform distribution of 100 to 5,000 cm2/hr
• Duration of garden activities uniform, 5 to 60
  min.
• Chemical/regional specific residue data

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Indoor Inhalation Exposure Data

• Applicator uniform range of inhalation exposure
  values for pressurized aerosol can (PHED)
• 0.72 2.499 mg/lb ai
• Post application inhalation exposure (adults and
  children)
• Pest Strips 0.005 0.11 mg/m3
• (Collins et al., 1973)
• Crack and Crevice 0.075 0.548 mg/m3
• (Gold et al., 1983)
• Duration of time spent indoors, and breathing
  rates
• Up to 24 hours, at rest to moderate

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Methods Summary

• All available data considered
• e.g.,Lawn residue data available for all
  compounds and made regional adjustments where
  feasible
• Addressed a variety of activity patterns
• Some more straight forward Application
• Some more difficult Hand-to-Mouth
• Tended to use uniform distributions when
  presented with scenarios that had confounding
  variables

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Characterization
over estimate - under estimate neutral
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Characterization
over estimate - under estimate neutral
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Characterization
over estimate - under estimate neutral
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Characterization
over estimate - under estimate neutral
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Survey Data

• Overview of our use of survey data to address use
  and co-occurrence
• Future considerations
• Use of existing macro activity pattern data
• SHEDS example
• Upcoming pesticide use survey

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Survey Data Macro Activity Patterns

• Human Activity Patterns
• Calendar based models present an opportunity to
  consider an individuals macro activity patterns
  that can lead to exposure to one or more
  chemicals
• Macro Activity Patterns are broadly defined as
  where individuals spend their time
• In the garden
• Driving to work

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Survey Data Macro Activity Patterns

• Our Basic Approach (Independence/Dependence)
• Identify households based on reported use of an
  OP for a given scenario (e.g., NHGPUS)
• 6 of households in Region 5 use lawn chemical A
• Identify the time individuals spend on lawns or
  other locations
• In the Exposure Factors Handbook, there are
  recommended values taken from surveys such as the
  National Human Activity Pattern Survey (NHAPS)

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Survey Data Macro Activity Patterns

• STEP 1 Calculate Exposure from Food for
  Individual 1 on a given day (Food Exposure(from
  DEEM))
• STEP 2 Select Residential Treatments for
  Individual 1 on a given day
• Specific to region, time and demographics of
  individual
• Were pesticides applied in/around home?
• If so, which treatments?
• And how much, how often, during what time frame,
  with what frequency, and by whom?
• Repeat Step 2 until all relevant residential uses
  are addressed

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Survey Data Macro Activity Patterns

• Co-occurrence is driven by random probabilities
  ( households being treated)
• (6 lawn use) x (10 crack and crevice) 0.6
• However, once a household is selected, the
  probability of being on the lawn is 1 because
• We used a distribution of time spent on the lawn
  based only on individuals who were actually on
  lawns
• Does not account for individual responses
  indicating they did not spend time on lawns

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Survey Data Macro Activity Patterns

• Consolidated Human Activity Database (CHAD)
  hhtp//www.epa.gov/chadnet1
• Compilation of pre-existing human activity
  surveys collected at the national, state and city
  level
• Review questionnaires and individual responses
• Develop daily activity patterns for an individual
  based on responses to the questionnaires
• Most surveys are cross-sectional rather than
  longitudinal

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Survey Data Macro Activity Patterns

• Stochastic Human Exposure and Dose Simulation
  model - SHEDS
• Developed by
• Valerie Zartarian
• Jianping Xue
• Haluk Ozkaynak

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Exposure Rate ug/min
etc...
living room playing
lawn playing
car In-transit
daycare learning
bedroom sleeping
Time (min)
Macro-activities
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Winter Weekday
Winter Weekend
Spring Weekday
Spring Weekend
Summer Weekday
Summer Weekend
Fall Weekday
Fall Weekend
1
360
90
180
270
Day of Year

• 8 CHAD diaries simulate a persons year in
  specified age-gender cohort
• 1 person from each of 4 seasons
• 1 person from each of 2 day categories (weekend
  and weekday)
• Fix 5 weekday diaries and 2 weekend diaries
• Repeat 7 day activity patterns within each season

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Survey Data Macro Activity Patterns

• Residential Exposure Joint Venture (REJV)
• Longitudinal survey data addressing the
  application pesticides in and around households
• When and where applications are made
• Multiple applications made in one day
• What they wore while making those applications
• Demographic information (children)

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• EXTRA SLIDES From other presentations FOLLOW

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Region 11 had an applicator residue where a
residue for a child should be
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Questions for the SAP on Residential Exposure
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Question 1

• Historically, the Agency has relied on means
  (primarily arithmetic or geometric) from residue
  and exposure studies for key input variables in
  exposure assessments. The recent development of
  calendar based models and others having features
  to incorporate distributions of exposure values
  has presented the Agency an opportunity to
  consider using all available data points from
  existing exposure and residue studies. In the
  Cumulative Risk Assessment Case study presented
  to the FIFRA Scientific Advisory Panel in
  September, 2000, most of the exposure variables
  were presented as uniform distributions. The
  exceptions were for variables that are reasonably
  well established , such as exposure durations
  taken from the Agencys Exposure Factors
  Handbook. The data used in the Case Study and
  in the preliminary CRA, are believed to be from
  well conducted studies of generally high quality.
  However, these data sets tend to be small (e.g.,
  n 10 - 30) and are being used to address wide
  variety of exposure situations. The uniform
  distribution appears to be most appropriate for
  these relatively small data sets because it
  relies on easily established values such as the
  minimum and maximum and provides the most
  conservative estimate of the standard deviation
  (riskanalal_at_lyris.pnl.gov).

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Question 1 (continued)
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Question 2

• The use of calendar based models also allows
  exposure assessors to consider exposure from a
  variety of sources from the same or from
  different chemicals. Longitudinal survey data
  such as the National Human Activity Pattern
  Survey (NHAPS) are available for consideration by
  HED for use in future assessments. In addition,
  from a practical standpoint, the use of such
  survey data ensures combinations of exposure do
  not come from unrealistic random combinations
  that current models may produce (e.g., activities
  adding up more than 24 hours in a day).

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Question 2 (continued)

• The use of calendar based models provides an
  opportunity to explore the potential for the
  co-occurrence of multiple sources of exposures
  from residential pathways. In the cumulative
  assessment, OPP used summary statistics from
  sources such as the Exposure Factors Handbook
  (EFH) regarding the time spent indoors, time
  spent on lawns and time spent at other outdoor
  locations. In the preliminary assessment, we
  assumed these activities were stochastically
  independent. OPP is currently evaluating data in
  the EFH such as data from the National Human
  Activity Pattern Survey (NHAPS) to determine if
  it can directly incorporate (i.e., empirically)
  information on an individuals activity patterns
  over a full day from this database to account for
  the likelihood and duration that an individual
  might be exposed to a pesticide through various
  activities over the course of a day.

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