A modular Human Exposure Model (HEM) framework to characterize near-field chemical exposure in LCIA and CAA
Citation:
Dionisio, K., D. Vallero, P. Egeghy, K. Isaacs, K. Thomas, AND P. Price. A modular Human Exposure Model (HEM) framework to characterize near-field chemical exposure in LCIA and CAA. 2016 Annual International Society of Exposure Science Meeting, Utrecht, NETHERLANDS, October 09 - 13, 2016.
Impact/Purpose:
Presented at the 2016 Annual ISES Meeting held in Utrecht, The Netherlands, from 9-13 October 2016.
Description:
Life Cycle Impact Analysis (LCIA) has proven to be a valuable tool for systematically comparing processes and products, and has been proposed for use in Chemical Alternatives Analysis (CAA). The exposure assessment portion of the human health impact scores of LCIA has historically focused on far-field sources (environmentally mediated exposures) while research has shown that use related exposures, (near-field exposures) typically dominate population exposure. Characterizing the human health impacts of chemicals in consumer products over the life cycle of these products requires an evaluation of both near-field as well far-field sources. Assessing the impacts of the near-field exposures requires bridging the scientific and technical gaps that currently prevent the harmonious use of the best available methods and tools from the fields of LCIA and human health exposure and risk assessment. The U.S. EPA’s Chemical Safety and Sustainability LC-HEM project is developing the Human Exposure Model (HEM) to assess near-field exposures to chemicals that occur to various populations over the life cycle of a commercial product. The HEM will be a publically available, web-based, modular system which will allow for the evaluation of chemical/product impacts in a LCIA framework to support CAA. We present here an overview of the framework for the modular HEM system. The framework includes a data flow diagram of in-progress and future planned modules, the definition of each module including required inputs and outputs, and interactions between modules (as inputs/outputs, and via feedback loops). Planned modules for the HEM include: 1) Population generator module, simulating a population with associated family structures, age, race, and physiologic characteristics representative of the U.S. population; 2) Housing/residential characteristics module, assigning characteristics of the home such as housing type, air exchange rates, heating fuel type, etc.; 3) Product composition module, containing information on the chemical composition and associated functional use and weight fractions for products; 4) Occupational exposure module, characterizing exposures during occupational use of a product; 5) Agent-based model for simulating human behavior; 6) Dose intake module, to bring together the personal characteristics, human behaviors, housing characteristics, and product composition data to calculate population intake dose; and 7) Dosimetry module, to translate intake doses into blood concentrations.
