1. Oregon Health & Science University Oregon Child Development Coalition
Assessment of Exposure to Organophosphate Pesticides in Migrant Farm Workers and Their Children
Linda McCauley, Rachelle Mann-Gaytan, William Lambert, Juan Muniz, Michael Lasarev & Caren Ebbert
Oregon Health & Science University
Oregon Child Development Coalition
Presented by Rachelle Mann-Gaytan

2. Migrant Farm Workers

3. Purpose of this analysis
To characterize the extent of exposure to organophosphate (OP) pesticides for children of migrant farm workers
To identify factors influencing residential levels of these pesticides
To compare the level of exposure in farm worker families with a reference group of grower families

4. Methods
With the Oregon Child Development Coalition (OCDC), we recruited families through the Migrant HeadStart Program and the growers association
OCDC and OHSU teams conducted interviews and collected environmental samples in homes in summers of 1998 and 1999
Carpets were sampled with HSV3 vacuum
Pesticide residues were analyzed by GC/MS
Urinary metabolites were analyzed by GC with flame photometric detection

5. Results of Floor Dust Samples
Azinphos methyl (AZM) was found in carpet dust from 22 of 25 farm worker homes
Few other pesticides detected
Median = ppm (range 0.3 – 12.0)
AZM levels decreased with greater distance from the orchards
AZM levels increased with number of household members working in agriculture

6. Floor Dust AZM Levels by Distance to Orchard
10.0
p-value = 0.04
5.0 o o
Azinphos Methyl (ppm) o o o o o o o o o o o o
1.0 o o o o o
0.5 o o 5 10 50
100
Meters

7. Home AZM Levels by Number of Workers in Household
10.0
p-value = 0.002
5.0 o o
Azinphos Methyl (ppm) o o o o o o o o o o o o
1.0 o o o o o
0.5 o o 1 2 3 4 5
Number of persons working in agriculture

8. Differences in Homes of Workers and Owners

9. AZM in Floor Dust of Worker and Owner Homes
Max
75%
Median
25%
Min

10. Characteristics of Households
Farm Workers
n = 25
Farm Owners
n = 24
Area of home (m2)**
62 (+3.6)
212 (+17.0)
Number of persons*
5.2 (+0.3)
4.3 (+0.2)
Area per person (m2/person)**
12.6 (+0.9)
51.9 (+5.1)
* p = ** p < 0.001

11. Other factors influence indoor levels
Lower indoor AZM levels were observed when male farm workers or owners reported that they:
Removed shoes before entering home
Changed out of work clothes before entering home
Changed out of work clothes within 30 minutes after arriving home
Washed up within 30 minutes of arriving home

12. Workers: Do you take off your boots before entering your home?
Response (n)
AZM (ppm)
Range
Median
Mean
Never (5)
6.90
6.72
Sometimes (1)
3.20
---
Yes (7)
1.00
4.10
p = 0.27, Wilcoxon rank sum test

13. Owners: Do you take off your boots before entering your home?
Response (n)
AZM (ppm)
Range
Median
Mean
Never (1)
7.34
---
Sometimes (13)
0.37
1.10
Yes (10)
0.89
1.56
p = 0.28, Wilcoxon rank sum test

14. Urinary Metabolites in Adults
Max
75%
Median
25%
Min

15. Urinary metabolite concentrations in younger vs. older children
250
0 – 6 years old
200
150
Median DMTP  g/ g Cr
100
7 – 11 years old 50 F M A M J J A S O
Month

16. Urinary metabolite concentrations in adult thinners vs. non-thinners
150
Thinners
100
Median DMTP  g/ g Cr
Non-thinners 50 F M A M J J A S O
Month

17. Urinary metabolites in children of migrant farm workers

18. Implications
Dissemination of video to educate farm workers on practical ways to reduce exposures for their children
“Deep cleaning” of homes to remove accumulated dust and pesticide residues

19. Acknowledgments
This research is supported by a grant from the National Institute of Environmental Health Sciences (RO1 ES08707)