Farm family exposure to 2,4-D
DuPont, DowU Minn Public HealthAmerican Chemistry
Published in Environmental Health Perspectives
2,4-D characteristics
• Moderate acute oral LD50 (~ 350 mg/kg)• Not considered to cause mutagens, not
likely to be a carcinogen, no likely effect on reproductive system or development at human exposure rates
• Dermal penetration about 7% of skin dose
Study Purpose
• Identify real-world pesticide exposure and factors before, during, and after application
• 2, 4-D widely used in ag and non-ag applications
• Ranked 5th in ag uses – 2001• #1 in home, garden uses
Participants
• Certified pesticide applicators – South Carolina & Minnesota
• Farmer, spouse, 1+ child 4 to 17 years old• Live on farm• Farm at least 10 acres within 1 mi of home• Both amine and ester forms used
• Answer questions and allow observation• Collect all urine for 5 consecutive days –
day before, application day, 3 consecutive days after
• Allow field observer to document weather, application practices, family activities
Participants
Characteristics
• 34 families – 17 MN 17 SC• Average age - farmer 43.6y, spouse 40.2y• 53 children – 10.2y (4-17)• Applications during spring and early
summer
Practices – survey responses
• None had applied 2,4-D within 7 days before study• No spouses had mixed pesticides within
1 week of study• 2,4-D detectable in 70% of applicators,
62% of children, and 41% of spouses in pre-application urine samples
Practices
• 44% used enclosed cab tractors• 26% < 25 ac; 30% - 25 to 74 ac;
44% > 75 ac• 26% - 1 to 2 loads; 41% - 3 to 5 loads;
33% - 6 or more loads
Spray day observations
• 71% wore rubber gloves – during mixing /loading/ application• 47% had some contact w/ 2,4-D• 24% spouses & 38% (20) children present during
some of mix/load/ spray• 1 spouse & 8 children had chance for direct pesticide
contact
Spray day observations
• 11% ate during application• 32% used tobacco during application• 35% had spills during mixing and /or loading• 62% repaired equipment during the application• 65% spouses washed spray clothing
Results – Applicator
2,4-D in urine (ugm/L)
Peak urine concentration 1 day after applicationBiological half-life 17 hrs
2,4-D in urine (ugm/L)
Yes NoWore rubber gloves 43.8 236.2Closed cab 61.4 81.5Spill or accident 115.4 55.6Observed skin contact 188.8 30.5Equipment repair 184.1 40.2Used tobacco 106.7 59.6Ate while spraying 140.1 65.8
2,4-D in urine (ugm/L)
Acres <25 25-50 50-75 >75treated 57.0 12.9 100.9 99.7
No. of loads 1-2 3-5 >5 53.0 50.5 144.8
Factors associated with INCREASE in urinary 2,4-D concentrations
• Did not wear gloves• Treated more acres • Repaired equipment
2,4-D doses (mg/kg body wt)
Group Average dose
Maximum dose
Applicators 2.46 58.5Spouses 0.08 1.14
Children 4 – 11 0.22 7.2
Children > 11 0.32 31.1Spouses and children present at some time during mixing / loading/ spraying received greater doses than those not present
Limits of study
• Only one application evaluated per family• All were tractor boom sprayer
applications• Participation in study may have
affected behavior of applicators
Some lessons
• Application of 2,4-D resulted in exposure of applicator and family members \
• Amount of exposure was determined by potential for direct contact with the pesticide
• Use of rubber gloves when mixing, loading, and applying 2,4-D and repairing equipment was associated with greatly reduced urinary concentrations of 2,4-D
• Reduce children’s potential for contact
Reminders
• 2,4-D metabolism in the body is very different than that for other pesticides
• Actions that reduce exposure result in lower absorption of 2,4-D