ABOUT THE STUDY

This project focuses on collecting new data for soil/dust ingestion for children within their homes. In addition, the study will conduct modeling and meta-analysis for soil/dust ingestion data across various environments where children spend time. Children are exposed to soil and dust ingestion via primarily four mechanisms, where this study focuses on 1, 2, and 4:

1. Soil/dust found on objects/surfaces placed in the mouth

2. Soil/dust placed directly into the mouth

3. Soil/dust found on food placed in the mouth, and

4. Soil/dust found on hands (on other body) placed in the mouth from hand contact with soil/dust

The frequency and duration of these activities, efficiencies of removal (hand/surfaces), and contact surface area are key variables in the estimation of soil/dust ingestion. Based on the current limited data available, US EPA estimates in the Exposure Factors Handbook, that children ingest close to 80 mg/day of soil or dust though ingestion rates vary by children's activities, housing dynamics, dust loading rates and particular scenarios (e.g., outdoor settings). These estimates are considered to have high degree of uncertainty due to limitations in the current data and how the rates were estimated. Newer methodologies are needed to collect soil/ingestion rates and current data sets that enhance diverse geographic regions.

Study Objectives

1. Deliver a household dust survey to families (n=450) of young children (aged 6 months - 6 years) for analysis of key variables influencing dust loading on children's hands and in homes and ingestion rates

2. Conduct a field study (sampling from the above 450 families that complete the survey)

i. Perform studies to quantify dust loading on children's hands (n=100) and indoor home surfaces
(8 surfaces per home; n=800) to include innovative surface sampling, and hand rinse methodologies.

ii. Collect children's (n=100) hand contact and mouthing activities in homes through improved video capture and video translation methods in order to expand the current database of children's micro-activities

iii. Collect information from activity bands to support collection of activity data (activity level and location of child)

3. Enhance an existing validated model to capture additional soil/dust pathways for children's dermal and non-dietary ingestion and use to estimate soil and dust ingestion exposure factor distributions for children aged 6 months to 6 years, across multiple geographical locations and from diverse sociodemographic backgrounds based on newly collected and existing datasets

Because these studies are collected across 3 locations (cities: Greensboro, Miami and Tucson), we are able to look at geographical differences

This study observes children in their natural environment

Funded by the Environmental Protection Agency #84020101-0