Quantified activity pattern data from 6 to 27-month-old farmworker children for use in exposure assessment
Paloma Beamer1, Maya E Key, Alesia C Ferguson
1Community, Environment and Policy, Mel and Enid Zuckerman College of Public Health, University of Arizona, AZ 85724, USA. pbeamer@email.arizona.edu
Insights
Infants and toddlers in farmworker families exhibit high hand-to-mouth behaviors, exceeding US EPA exposure guidelines. Age and gender influence these contact patterns, crucial for accurate risk assessments.
Area of Science:
- Environmental Health
- Pediatric Exposure Science
- Occupational Health (Farmworker Families)
Background:
- Understanding children's exposure pathways is critical for public health.
- Farmworker communities face unique environmental exposures.
- Infants and toddlers engage in frequent hand-to-mouth behaviors.
Purpose of the Study:
- To characterize exposure-prone behaviors in infants and toddlers within farmworker households.
- To quantify hand-to-mouth and object-to-mouth contact frequencies and durations.
- To identify age- and gender-specific differences in these behaviors.
Main Methods:
- Direct observation via videotaping of 23 children (infants and toddlers) in their homes for 2-6 hours.
- Translation of video footage into micro-level activity time series (MLATS) for hands and mouth.
- Calculation of hourly duration in microenvironments, contact frequency, and median contact durations.
Main Results:
- Median hand-to-mouth frequency was 15.2 events/h; object-to-mouth frequency was 27.2 events/h.
- Median mouthing duration with hands/objects was 2 seconds; overall hand contact frequency was 689.4 events/h.
- Infants mouthed non-dietary objects more; toddlers mouthed pica-associated objects (e.g., paper) more. Boys had higher contact frequencies; girls had longer contact durations.
Conclusions:
- Observed contact frequencies exceed current US Environmental Protection Agency (US EPA) recommendations for infants and toddlers.
- Age and gender are significant factors influencing exposure behaviors, necessitating tailored exposure assessments.
- Current US EPA exposure guidelines may not adequately protect young children in high-exposure environments like farmworker settings.
Abstract:
This study was conducted to describe exposure prone behaviors of infants and toddlers in the farmworker community. Analysis of hand and mouth contact frequencies and durations aids understanding of how children interact with their environment and are exposed via contact with surfaces. All 23 participating children (8 female infants, 5 male infants, 5 female toddlers and 5 male toddlers) lived with at least one farmworker. Children were videotaped at home for 2-6 h. Video footage was translated into micro-level activity time series (MLATS) for both hands and the mouth. MLATS were processed to calculate hourly duration in microenvironments, contact frequency, hourly contact duration and median contact duration. The median hourly duration spent indoors was 53 min/h. The median hand-to-mouth frequency was 15.2 events/h and the median object-to-mouth frequency was 27.2 events/h. The hourly mouthing duration was 1.2 and 2.2 min/h with the hands and objects, respectively. The median mouthing duration with hands and objects was 2 s. The median contact frequency for both hands combined was 689.4 events/h with an hourly contact duration of 100.5 min/h and a median contact duration of 3s. Infants had higher mouthing frequencies with non-dietary objects while toddlers had higher mouthing frequencies with objects associated with pica (i.e., paper). Boys had higher contact frequencies while girls had longer contact durations. These sub-group differences indicate factors such as age and gender should be accounted for when conducting exposure assessments. Contact frequencies in this study are higher than current US EPA recommendations, questioning their protective value for infants and toddlers.
