During the last few years, considerable attention is given to children as a sensitive subpopulation in chemical risk assessment. Knowledge on the exposure part of the risk assessment is equally important as the toxicological endpoints, but this knowledge is scarce.
A child’s exposure pattern to a consumer product can be very different from that of an adult, due to distinct child-specific behaviors and activities. For this reason, an exposure assessment for a child requires incorporation of these child-specific behaviours and activities when defining exposure scenarios. RIVM has aimed to provide guidance for child-specific exposure assessments for non-food consumer products (Van Engelen et al, 2007). Characteristics of children may influence exposure due to their different behaviour, physiology and activities. Children can be categorized in different age groups based on age-related activities. Default values for children are attached in Appendix 3 of this report. Part of this guidance is based on the Guidelines for Exposure Assessment, US-EPA, 1992 as well as on the US-EPA’s Child Specific Exposure Factors Handbook (US-EPA, 2008). These data are integrated in the general update of the Exposure Factor Handbook that is recently published (US-EPA, 2011).
Hand-to-mouth contact is a child specific behaviour that can lead to a relevant exposure for children. It is defined as all activities in which hands or fingers are touched by the mouth or put into the mouth, except for dietary activities. The extent of oral exposure as a result of hand-to-mouth contact is influenced by the frequency of contacts, insertion of the hand into the mouth and hand surface area which is contacted by the mouth. RIVM has proposed new default values for assessing the degree of exposure of children to chemicals following hand-to-mouth contact in 2007 (Ter Burg, 2007). This behaviour is also described in chapter 4 of the update of the Exposure Factor Handbook (US-EPA, 2011).
Another important source of exposure for children is chemical
substances in toys, for which RIVM has developed a special
risk-based methodology at the request of DG-Enterprise of the
European Commission (Van Engelen et al, 2008). Default values for
estimation of exposure using the ConsExpo model can be found in the
Children’s toys Factsheet (Bremmer et al, 2002).