Harmful substances in soil and dust may enter into human body through direct inhalation, digestion, and dermal contact causing adverse health effects. Owing to the difference in physical and physiological behaviors, infants and toddlers are less tolerant to toxic substances than adults and the toxic substances will pose higher risk to the children. Soil and dust ingestion thus becomes a critical exposure factor to determine the risk to children. We have already gotten the soil/dust ingestion data of 0~6 years old children and some other parameters of dermal contact in the past programs and established a good communication channel with USEPA. This year, the
program will focus on supplement the data of localized exposure parameters and use the localized parameters to estimate the health risk of a soil and groundwater containment site on the children under 6 years old.
The objectives of this project are as follows:
1. Expending the former investigation on the effects of soil types and properties on the exposure of dermal contact of the soil containments to children.
We will investigate the soil loading of four body parts (i.e., hands, arms, feet, and legs) of 54 children (27 boys and 27 girls) in three scenarios (without contact, direct contact, and indirect contact activities) in summer. Considering the seasonal dependence, the soil loading of hands of another 18 children (9 boys and 9 girls) will be further investigated in winter. The surface of each body part of children will be measured and the soil characteristics and size distribution will be analyzed. Moreover,
the hand-to-mouth transfer ratio will be obtained by a laboratory-based examination reported by Kissel et al. in 1998.
2. Establishing the local exposure parameters of the tier one health risk assessment
of the soil and groundwater containment sites for the children under six years old.
We will summarize the data collected during the past two years and this year to establish the local exposure parameters of soil ingestion rate (IRoral-soil), adherence (AF), exposure frequency (EV), and projective hand surface (HSA). Moreover, the indoor dust loading, activities record of children and daily water intake of children will be investigate in this year.
3. Estimating the exposure dose of the children under six years old from soil by the local exposure parameters on one soil and groundwater containment site. After the local exposure parameters are established, these parameters will be used to estimate the exposure dose of the containments and health risk from a chosen
soil and groundwater containment site.
4. Compiling and summarizing the results of the past programs and exchanging the experiences with US EPA by academic meeting. We will visit Washington DC and NCEA/ORD/USEPA to share our result with the senior scientists of US EPA and other researchers in US.