US EPA

In 1989, the U.S. EPA published an Exposure Factors Handbook which contains a summary of the available statistical data on various factors used in assessing human exposure and health risk. Updated in 1997, this Handbook is addressed to exposure assessors, both inside and outside the EPA, who need to obtain data on standard factors used to calculate human exposure to toxic chemicals. These factors include:

• drinking water consumption,
• soil ingestion,
• inhalation rates,
• dermal factors including skin surface area and soil adherence factors,
• consumption of fruits and vegetables, fish, meats, dairy products, homegrown foods,
• human activity factors,
• consumer product use, and
• residential characteristics.

Although the handbook includes factors specific to all age groups, the EPA has identified the need for additional detail on exposure factors for potentially susceptible populations, including children and older adults. To this end, EPA developed a Child-Specific Exposure Factors Handbook in 2002 to focus on factors used in assessing exposure of children 0-21 years of age. Similarly, older adults may be more susceptible to the adverse effects of environmental contaminants due to differential exposures arising from physiological and behavioral changes with age, as well as the body’s decreased capacity to defend against toxic stressors. To address these issues and discuss practical considerations of the utility of an Exposure Factors Handbook for the Aging in conducting exposure assessments, a panel of experts in the fields of exposure assessment, risk assessment, physiology, and behavioral science were convened at a national workshop in February of 2007. This report summarizes the discussions held during the workshop, highlights several sources of existing data, and provides recommendations for additional research.

This is the final report. Portions of this report may be published in the peer-reviewed literature.

Contacts:

Douglas Johns
(919) 541-5596
johns.doug@epa.gov

Jacqueline Moya
(202) 564-3245
moya.jacqueline@epa.gov