Results from theResults from theAgricultural Health StudyAgricultural Health StudyPesticide Exposure StudyPesticide Exposure Study

Linda Sheldona, Kent Thomasa, Guadalupe Chapaa, Sydney Gordonb Martin Jonesc, James Raymerd, Dale Sandlere, Jane Hoppine

Mustafa Dosemecif, Aaron Blairf, and Michael Alavanjaf

aNational Exposure Research Laboratory, U.S. Environmental Protection Agency bBattelle Memorial Institute, cUniversity of Iowa, dRTI International; eNational Institute of Environmental Health Sciences, fNational Cancer Institute

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PRESENTATION OVERVIEW

Background of the Agricultural Health Study

Purpose of the Pesticide Exposure Study

Exposure Study Procedures

Applicator Exposure Measurement Results

Spouse and Child Measurement Results

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AGRICULTURAL HEALTH STUDY RESEARCHERS• NCI and NIEHS are leading the epidemiological study and investigations of cancer and non-cancer health outcomes

• University of Iowa Department of Epidemiology operates the Iowa AHS Field Station

• Battelle Center for Public Health Research and Evaluation operates the North Carolina AHS Field Station

• Westat operates the AHS Coordinating Center

• EPA and NIOSH are leading AHS exposure sub-studies

• Battelle, University of Iowa, and RTI International conducted the AHS Pesticide Exposure Study

4

AHS BACKGROUNDAHS BACKGROUND

The epidemiological study is designed to: 

• Measure cancer and non-cancer health risks in the agricultural community

• Examine associations between use of agricultural chemicals, other exposures, and disease 

• Determine factors that promote good health

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AHS PHASE I (1993 – 1997)AHS PHASE I (1993 – 1997)

Prospective cohort enrolled in Iowa and North Carolina:

• 52,395 private licensed pesticide applicators

• 32,347 spouses of private pesticide applicators

• 4,916 commercial applicators (IA only)

Questionnaires collected information about pesticide use, work practices, other exposures, lifestyle factors, and health.

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AHS PHASE II (1998 – 2004)

Follow-up through cancer registries and vital records linkage

5-year follow-up questionnaire via computer assisted telephone interview (CATI)

Update health status, exposures, and lifestyle

Buccal Cell Collection and Dietary Health Questionnaire

Nested studies of exposure and specific health outcomes

AHS PHASE III (2005 - 2008)

Continued cancer and mortality follow-upFollow-up telephone interviewCross sectional and panel studies, nested case-control studies

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AHS RESULTS DISSEMINATION

AHS Web Site

• www.aghealth.org

Direct communication to study participants

Fact sheets and other information distributed to and through Iowa and North Carolina Cooperative Extension Services

Scientific and Informational Presentations

Journal Publications

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The AHS is examining possible links between pesticide use and health risks

Information on use of up to 50 common insecticides, herbicides, fungicides, and fumigants obtained from AHS enrollment and take-home questionnaires – current and historical uses

Information on work practices collected from questionnaires

AHS PESTICIDE EXPOSURECLASSIFICATION

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2) Cumulative Exposure

Years Used x Days/Year

AHS EXPOSURE CLASSIFICATION

3) Adjusted Cumulative Exposure

Years Used x Days/Year x Intensity Score

1) Ever/Never Use of a Pesticide

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Dosemeci et al., Ann Occ Hyg, 46:2, 2002

Intensity Score

= (Mix + Appl + Repair) * PPE

where,

Mix : Mixing Frequency of Pesticides (0, 3, 9)

Appl

: Application Method (0 - 9)

Repair : Repair of Application Equipment (0, 2)

PPE : Personal Protective Equipment (0.1 - 1.0)

AHS EXPOSURE INTENSITY AHS EXPOSURE INTENSITY ALGORITHMALGORITHM

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AHS PESTICIDE EXPOSURE STUDY

Overall Goal

Measure exposure to applied pesticides for a subset of AHS applicators to evaluate and improve the AHS exposure algorithm

Specific Objectives

Measure exposure to target applied pesticides

Compare measurements to algorithm exposure intensity scores

Identify key exposure factors

Assess potential spouse/child exposure to farm- applied pesticides

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STUDY DESIGN OVERVIEWSTUDY DESIGN OVERVIEW 

• Target pesticides 2,4-D and Chlorpyrifos

•  Eight exposure strata based on application method and PPE

• Applicators monitored on one day while using their normal procedures

• Observation of activities

• Dermal, personal air, urine samples

• Questionnaires after use

• Spouse and child biomarker measurement

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PARTICIPANT SELECTION AND RECRUITMENT

Sample Frame• AHS cohort members; completed AHS Phase I & II• Reside in one of 22 Iowa or 22 NC counties• Previous use of a target chemical

Eligibility Screening•Telephone screening• Eligible with planned use of a target chemical

Recruitment• In-home visit to discuss study• Applicator, spouse, child consent/assent• Schedule monitoring visits

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OVERALL MONITORING TOTALSOVERALL MONITORING TOTALS

IA NC Total

Pesticide Applicators 84a 24 108

Spouses (urine) 38b 11 49

Children (urine) 9 3 12

a Includes 24 repeat monitoring visits for applicators

b Includes 8 repeat monitoring visits for spouses

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NUMBER OF OBSERVATIONS IN EXPOSURE STRATA

Broadcast Spray – Liquid 2,4-D or Chlorpyrifos No gloves, no enclosed cab 9 No gloves, enclosed cab 9 Gloves, no enclosed cab 14 Gloves, enclosed cab 21

In-Furrow – Granular Chlorpyrifos No enclosed cab 7 Enclosed cab 6

Hand Spray – Liquid 2,4-D No gloves 22 Gloves 20

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Visit 1 • Provide urine sample containers; discuss

scheduling

Visit 2 • Sample collection (dermal, air, urine)• Observe activities• Application questionnaire

Visit 3• Sample collection (urine pick-up)• Activity questionnaire

MONITORING SCHEDULE SCHEDULE

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MEASUREMENTSDermal Patches

10 Patches, sized proportionally to body area, under PPE and over clothing, combined for analysis

Hand WipeCombined wipes from 12 small areas on each hand

Personal Air Personal monitor (pump and filter)

Applicator UrinePre-Application morning void Post-Application Composite (start of pesticide use

through the following morning)

Spouse and Child UrinePre-Application morning voidPost-Application morning void (2 days later)

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APPLICATOR MEASUREMENT RESULTS

Comparison of exposure measurements across eight exposure strata

Assessment of the relative contribution of hand loading, body loading, and air exposures to urinary biomarker levels

Bivariate analyses for >80 pesticide use, work, and hygiene factor variables – selected results shown here

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0

10

20

30

40

50

60

70

S1 S2 S3 S4 S6 S5 S7 S8

CONCENTRATIONS IN URINEGEOMETRIC MEAN (ug/L)

Pre-Application

Post-Application

Boom Spray In-Furrow Hand Spray

No GlovesNo Cab

No GlovesCab

GlovesNo Cab

GlovesCab

No Cab Cab

No Gloves

Gloves

Preliminary Results

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0

500

1000

1500

2000

2500

S1 S2 S3 S4 S6 S5 S7 S8

ESTIMATED HAND LOADING GEOMETRIC MEAN (ug)

Boom Spray In-Furrow Hand Spray

No GlovesNo Cab

No GlovesCab

GlovesNo Cab

GlovesCab CabNo Cab

No Gloves

Gloves

Preliminary Results

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0

5000

10000

15000

20000

S1 S2 S3 S4 S6 S5 S7 S8

ESTIMATED BODY LOADING GEOMETRIC MEAN (ug)

Boom Spray In-Furrow Hand Spray

No GlovesNo Cab

No GlovesCab

GlovesNo Cab

GlovesCab CabNo Cab

No GlovesGloves

Preliminary Results

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0

0.5

1

1.5

2

S1 S2 S3 S4 S6 S5 S7 S8

AIR CONCENTRATION

GEOMETRIC MEAN (ug/m3)

Boom Spray In-Furrow Hand Spray

No GlovesNo Cab

No GlovesCab Gloves

No Cab

GlovesCab

Cab

No Cab

No Gloves

Gloves

Preliminary Results

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SolidN = 13

LiquidN = 5

RatioL/S

Urine (post-application) ug/La 10b 32 3.2

Hand loading ug 19 360 18.9

Body loading ug 460 2100 4.6

Personal air ug/m3 0.7 0.7 1.0

a Measured as 3,5,6-trichloro-2-pyridinol (TCP) metabolite

b Near average pre-application background levels of 9.8 g/L

Applicator Chlorpyrifos Levels (Geometric Means) By Physical State (as applied)

Preliminary Results

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Urine = β1Hand + β2 Body + β3 Air + Intercept + Error

2,4-D Chlorpyrifos

N 86 18

R2 0.56 0.35

p <0.0001 0.1015

Independent Variables

ParameterEstimate p

ParameterEstimate p

Intercept 1.21 0.0213 1.34 0.1045

HAND 0.48 <0.0001 0.12 0.3327

BODY -0.08 0.2343 0.15 0.4183

AIR 0.20 0.0121 0.12 0.4936

Exposure Pathway Model Results

Preliminary Results

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Hand Loading vs. Post-Application Urine Concentration (For liquid products only)

2,4-D y = 0.48x + 0.39 R2 = 0.53

Chlorpyrifos y = 0.79x - 1.3 R2 = 0.63

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

0.00 2.00 4.00 6.00 8.00 10.00 12.00

Ln Hand Loading (ug)

Ln

Uri

ne

Co

nce

ntr

atio

n (

ug

/L)

2,4-D

Chlorpyrifos

Linear (2,4-D)

Linear(Chlorpyrifos)Linear (2,4-D)

Linear(Chlorpyrifos)

Preliminary Results

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Broadcast SprayN = 49

Hand SprayN = 40

RatioH/B

Urine (post-application) ug/L 22* 43* 1.9

Hand loading ug 230** 1200** 5.2

Body loading ug 1200** 19000** 15.8

Personal air ug/m3 0.26** 1.1** 4.2

Applicator 2,4-D Levels (Geometric Means) By Application Method

* 0.05 > p > 0.001 or **p ≤ 0.001 for significance of difference

Preliminary Results

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Broadcast Spray Hand Spray

Significance Significance

Amount of active ingredient used *Hours active ingredient used ***Average wind speed **Average temperature *

Applicator Post-Application 2,4-D Urine Levels Regression with Selected Variables

* 0.1 > p > 0.05

** 0.05 > p > 0.001

*** p ≤ 0.001

Preliminary Results

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Broadcast Spray Hand Spray

Yes No Yes No

Additive used (most often spreader or surfactant)

26 19 126** 31**

Contact with sprayed vegetation n/a n/a 165** 30**

Adjust nozzles during application 27 20 58 31

Repair equipment 19 23 101 34

Visible wind drift 25 18 56 32

Minor spills, splashes, leaks, drips during mix/load

30 18 63 40

Minor spills, splashes, leaks, drips during application

-a 20 67 33

Applicator Post-Application 2,4-D Urine Levels (Geometric Mean ug/L) for Selected Variablesa

a Minimum number in any cell = 5

**p ≤ 0.01 for significance of difference

Preliminary Results

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Broadcast Spray Hand Spray

No Yes No Yes

Gloves worn during mix/load 51** 16** 82* 25*

Gloves worn during application 26** 7.8** 71* 22*

Respiratory protection used, application 24* 6.7* 43 -a

Long sleeves worn, application 30 17 55 26

Head cover worn, application 40 18 47 43

Applicator Post-Application 2,4-D Urine Levels (Geometric Mean ug/L) for Selected Variablesa

a Minimum number in any cell = 5

* 0.05 > p > 0.01 or **p ≤ 0.01 for significance of difference

Preliminary Results

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Type of Footwear UsedDuring Application

UrineHand

LoadingBody

Loading

N ug/L ug ug

Chemically resistant 10 34 1800 49000

Leather 26 40 800 14000

Fabric or other 6 155 2900 18000

Hand-Spray Applicator 2,4-D Levels (Geometric Means) by Footwear Type

Preliminary Results

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Cab Variable N UrineHand

LoadingBody

LoadingPersonal

Air

Unadjusted ug/L ug ug ug/m3

Open cab 18 21 390 1300 0.23

Enclosed cab 25 26 210 1100 0.25

Adjusted for AIa ug/L/kg ug/kg ug/kg ug/m3/kg

Open cab 18 3.8 150 480 0.086

Enclosed cab 25 2.2 35 180 0.043

Broadcast Spray Applicator 2,4-D Levels (Geometric Means) by Tractor Cab Type

a Measurement result divided by kg of pesticide active ingredient used

Preliminary Results

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Cab Variable

UrineHand

LoadingBody

LoadingPersonal

Air

N ug/L ug ug ug/m3

Windows open 7 25 270 1900 0.42

Windows closed 19 23 170 860 0.20

No filter 19 26 190 1500 0.29

Filter 6 25 300 400 0.14

Broadcast Spray Applicator 2,4-D Levels (Geometric Means) by Enclosed Cab Variable

Preliminary Results

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FAMILY MEASUREMENT RESULTS

Measurement of urinary biomarkers for participating applicator family members

Relationships between spouse and applicator urinary biomarkers

Relationship between spouse 2,4-D urine levels and applicator work practices or household factors

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SPOUSE AND CHILD URINARY BIOMARKER MEASUREMENT RESULTS

Geometric Means Ranges

N

Pre-App.

Urine

ug/L

Post-App.

Urine

ug/L

Post-App.

Urine

ug/L

2,4-D

Spouse 39 - 41 1.3 1.8 < QL – 59a

Child 9 1.6 2.0 < QL – 5.9

Chlorpyrifos (TCP)

Spouse 6 - 8 7.6 4.3 1.1 – 8.3

Child 3 5.5 3.1 1.3 – 5.3

aSpouse with highest measurement reported handling 2,4-D on monitoring day.

Preliminary Results

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0.1

1

10

100

1000

0.1 1 10 100 1000

Applicator Urine (ug/L)

Sp

ou

se U

rin

e (u

g/L

)Spearman Correlation is 0.64, p < 0.0001

SPOUSE AND APPLICATOR POST-APPLICATION URINE 2,4-D CONCENTRATIONS

Preliminary Results

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Observed Applicator Work N

Median Spouse Urine

2,4-D ug/L p-valuea

Glove use during HML No 10 3.2 0.03

Yes 31 1.0

Minor spills, splashes, leaks, drips

Yes 8 3.9 0.01

No 33 1.2

Adjust nozzles during application

Yes 10 3.8 0.01

No 29 1.0

a Mann-Whitney U Non parametric comparison test

Spouse’s Post-Application 2,4-D Levels based on Selected Applicator’s Work Practices

Preliminary Results

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Reported Household Activities N

Median Spouse Urine

2,4-D ug/L p-valuea

Applicator’s removal of boots/shoes before entering home

Yes 23 2.1 0.11

No 18 0.9

Spouse washed the applicator’s clothing in past week

Yes 29 1.7 0.56

No 7 1.8

2,4-D use in the lawn or garden during past year

Yes 5 2.4 0.50

No 36 1.7

a Mann-Whitney U Non parametric comparison test

Spouse’s Post-Application 2,4-D Levels Based on Selected Household Activities

Preliminary Results

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Home Distance From N

Median Spouse Urine

2,4-D ug/L p-valuea

Area where 2,4-D was mixed/loaded today

<200 ft 21 2.4 0.61

>200 ft 18 1.7

Nearest area where 2,4-D was applied today

<200 ft 8 1.8 0.96

>200 ft 32 1.9

Nearest area where 2,4-D was ever applied

<200 ft 32 1.9 0.73

>200 ft 8 1.9

a Mann-Whitney U Non parametric comparison test

Spouse’s Post-Application 2,4-D Levels Based on Home’s Distance from Pesticide Use

Preliminary Results

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APPLICATOR MEASUREMENTS PRELIMINARY FINDINGS

Large range in exposures for spray 2,4-D applicators in this study

Lower exposures and range of exposures for chlorpyrifos applicators in this study

Chlorpyrifos exposures for users of liquid products were much higher than those for users of granular products

Significant differences in exposure were found between many exposure strata

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APPLICATOR MEASUREMENTSPRELIMINARY FINDINGS

Differences in exposure for different application methods (hand spray > broadcast > in-furrow)

Glove use was an important factor – wearing protective gloves reduced urine levels ~70%

Role of enclosed tractor cabs in reducing exposures is less clear for mixer/loader/applicators

Significant associations between urine and dermal or air measures – strongest for hand loading

Several other factors appear to be important in increasing or decreasing exposures to 2,4-D

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SPOUSE AND CHILD PRELIMINARY FINDINGS

Urinary 2,4-D levels were low but measurable for a majority of the spouses and children of 2,4-D applicators (geometric means 2 ug/L)

One spouse reported directly handling a product containing 2,4-D and had the highest urine level (59 ug/L)

Urinary TCP levels were measurable for the spouses and children of chlorpyrifos applicators – but these levels were similar to those found in non-farm populations

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SPOUSE AND CHILD PRELIMINARY FINDINGS

Spouse and applicator post-application urine 2,4-D levels were significantly associated

Some pesticide applicator work practices were significantly associated with spouse urine 2,4-D levels

Some hygiene and household (laundering work clothing, removal of work boots, distance to fields) were not associated with significantly higher exposures to family members in this study

Further study is needed with more people and for different chemicals

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COMMUNICATION OF RESULTS

Journal articles in preparation

Plan for development of AHS/PES outreach materials (brochure and slide sets)

Audience

• AHS participants

• Pesticide safety educators

• Cooperative Extension Services

• Pesticide users

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ACKNOWLEDGEMENTS

Researchers at several organizations provided key contributions to the AHS Pesticide Exposure Study design and implementation:

EPA: Ruth Allen (OPP), Carry Croghan, Paul Jones

AHS Federal Investigators: Cynthia Hines (NIOSH)

NC AHS Field Station: Charles Knott and Joy Pierce (Battelle CPHRE)

IA AHS Field Station: Charles Lynch and Ellen Heywood (University of Iowa)

Field Study: Steven Reynolds (Colorado St. University), Gerald Akland (RTI International), Craig Hayes (North Carolina Department of Agriculture and Statistical Services)

Sample Analysis: Marcia Nishioka (Battelle Columbus), Robin Helburn (RTI International), and David Camann (Southwest Research Institute)

DISCLAIMER

Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.