YOUNG CHILDRENʼS HAND ACTIVITIES: AN OBSERVATIONAL STUDY VIA VIDEOTAPING IN A PRIMARILY OUTDOOR RESIDENTIAL SETTING

Abstract

ISEE-361 Introduction: The dermal route is an important route of exposure for children because infants and children can incur a significant portion of their total pesticide exposure from dermal contacts with residential dust, soil, and dislodged surface residues. The micro-activity approach models dermal exposure and dose as a series of transfers and removals resulting from discrete contact events (e.g., right hand contacting toy for 10 seconds). The resulting exposure and dose profiles provide various metrics of toxicological interest (e.g., peaks, averages, and instantaneous values) and yield information on how exposures and doses occur and how they can be mitigated. Micro-activity data on hand contacts is a crucial input needed to implement the micro-activity approach for estimating dermal exposure and dose. This paper presents the results of an analysis on micro-activity data gathered on young children's hand-to-surface contact frequency, duration per contact, and hourly contact duration. Methods: Micro-activity data on 38 children aged 14 to 82 months were collected by videotaping the children during natural play in a primarily outdoor residential environment. The videotape recordings were then translated into ASCII computer files with second-by-second detail through the use of a specialized software called Virtual Timing Device. Results: Significant differences in contact behaviour (p<0.05) were found between the right and left hands, boys and girls, and indoor and outdoor environments. In addition, hourly contact durations for outdoor contacts with non-dietary objects were found to increase linearly with age (p=0.03) while outdoor contact frequencies with wood were found to decrease linearly with age (p=0.01). Furthermore, from studying children who had the highest contact frequencies, we found that children playing on play structures had the highest outdoor contact frequencies with wood, plastic, and metal. Discussion: While it is uncertain how variable hand activities are between different children or between the same child on different days, the results of this study provide valuable estimations of hand contact behaviours for dermal exposure and dose assessments. The results of this study also provide insights into how children's hand contact activities may differ between locations, genders, ages, and right/left hands.