1. PESTICIDES AND CHILDREN as a Susceptible Population
J. Routt Reigart, MD
Professor of Pediatrics
Medical University of South Carolina

2. Children Are Different
1. Exposure patterns are different
Diet
Skin
Air
Behaviour
2. Susceptibility is different
Critical periods of development
Lifelong alteration of function and structure

3. DIET Caloric intake of children less than one year of age 100 Cal/Kg
Equivalent for 70 Kg adult is 7000 Calorie diet
Fluid intake of children less than one year of age Ml/Kg
Equivalent for 70 Kg adult is liters per day

4. DIET
NAS Report “Pesticides in the Diets of Infants and Children” (1993)
Children differ quantitatively and qualitatively in dietary consumption patterns
Simulation of food and juice exposure to organophosphates 4.1% of children each day exceeded reference dose

5. FOOD QUALITY PROTECTION ACT
“Aggregate” is risk from all exposures: dietary, water, residential
“Cumulative” adds risk from all chemicals with common mechanism of toxicity
Application of this law illustrated that non-dietary exposures often overwhelm dietary exposures

6. SKIN Children’s skin is often more exposed
Children are lower to the ground and low-growing plants
Children spend more time actually on the ground
Ratio of skin surface area to body weight very high in children
Ability of skin to protect a developmental task

7. SKIN SURFACE AREA

8. AIR LUNG CAPACITIES

9. Air Breathing Rates By Age

10. BEHAVIOUR Hand-to-mouth and object to mouth Floor and ground play
High activity levels
Low to the ground
Variable diet and food choices

11. Diethylstilbesterol DES
Before million Americans exposed via pregnancy use
Major reported effects on fetus
1:1000 females estimated to get clear cell adenocarcinoma relatively early in life

12. DES
Multiple structural abnormalities in female and probably in male offspring. Estimates up to 69% of an exposed female cohort
Dose related risk but no consensus opinion on threshold
Mode of action for cancer clearly different for fetus vs. adult. Not mutagenic.

13. DES
Mortality and morbidity from cancer clearly unacceptable on public health basis.
Morbidity from malformations also unacceptable.
Mechanism of carcinogenesis most likely different in fetus from adult.
Must consider mode of action for fetus in risk assessment process.

14. Atrazine Breast tumors in Sprague-Dawley rats
Mode of action thought to be hypothalamic suppression of gonadotrophin releasing hormone
Decreased GnRH leads to decreased LH, resulting in prolonged secretion of estrogen and prolactin
Persistent estrus

15. Atrazine
Humans- weak possible association between triazines and cancer
Ovary, Breast, Prostate
Atrazine likely alters hypothalamic function in primates and humans
Mode of action less plausible in primates and humans

16. Atrazine
In children atrazine may lead to a variety of non-cancer human health effects, but not a cancer risk
Most likely effect is delayed puberty

17. MIREX Very persistent though production ceased 1976
Bioaccumulated and biomagnified in aquatic and terrestrial food chains
Though not observed in humans, cataracts can be produced in rats and mice by exposure between one and eight days postpartum

18. METHOXYCHLOR
Relatively short lived in the environment though is an organochlorine
Rapidly metabolized in human and animals
In animals adversely affects development of female reproductive system, early onset of estrus, uterotrophic, mammary gland hyperplasia.
In male animals, testicular and prostatic atrophy. Decreased sperm counts.

19. PCB’s Highly persistent organic pollutants
Behavioral abnormalities observed in young children over a wide range of exposure
Effect from intrauterine and perhaps breast fed infants
Widespread contamination, very variable levels
Bioaccumulate, particularly in fish
Effects seen with wide range of species, including primate models

20. TOXAPHENE
ATSDR list fetus, nursing babies, and very young children as particularly susceptible
Potential for alteration of reproductive physiology
Immature enzyme detoxification
Placental and milk transfer
Adverse behavioral response in offspring exposed in utero (animal)
Histopathology in fetal liver, thyroid, and kidneys (animal)