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Identification and Quantification of Cumulative Factors that Increase Environmental Exposures and Impacts
Citation:
Huang, H. AND T. Barzyk. Identification and Quantification of Cumulative Factors that Increase Environmental Exposures and Impacts. ISES 2015 Annual Meeting, Henderson, NV, October 18 - 22, 2015.
Impact/Purpose:
The National Exposure Research Laboratory (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA mission to protect human health and the environment. HEASD research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.
Description:
Evaluating the combined adverse effects of multiple stressors upon human health is an imperative component of cumulative risk assessment (CRA)1. In addition to chemical stressors, other non-chemical factors are also considered. For examples, smoking will elevate the risks of having lung cancer associated with radon exposure2; toluene and noise together will induce higher levels of hearing loss3; children exposed to violence will have higher risks of developing asthma in the presence of air pollution4. Environmental Justice (EJ) indicators, used as a tool to assess and quantify some of these non-chemical factors, include health, economic, and social indicators such as vulnerability and susceptibility5. Vulnerability factors encompass race, ethnicity, behavior, geographic location, etc., while susceptibility factors include life stage, genetic predisposition, pre-existing health condition and others6, although these two categories are not always mutually exclusive. Numerous findings regarding combined effects of EJ indicators and chemical stressors have been identified7-11. However, fewer studies have analyzed the interrelation between multiple stressors that exert combined harmful effects upon individual or population health in the context of exposure assessment within the risk assessment framework12. In this study, we connected EJ indicators to variables in the exposure assessment model, especially the Average Daily Dose (ADD) model13, in order to better understand how the interaction of multiple stressors will affect individual or population level exposure assessment. Specifically, the impacts of multiple EJ indicators upon each main component of the ADD model such as contaminant concentration, intake rate, exposure factor and body weight13 were examined and characterized. Major intention of this method is to quantify what are often considered qualitative EJ indicators to provide a more accurate representation of environmental exposures and impacts.
