A comparison of in-residence aggregate risks from population exposures in two geographic regions of Arizona.

摘要

This thesis assesses risks from residential exposures to ten target pollutants from multiple routes of the two geographically distinct populations, using aggregate risk assessment method that improves the weakness of the traditional exposure and risk assessment method. One is the AZ State population, denoting the total Arizona population. The other is the AZ border population at the U.S. Arizona-Mexico border, which may be subject of environmental justice concerns potentially due to predominantly low-income population as well as its proximity to Mexico. The major objectives of this thesis are to assess whether risks from exposures to pollutants of the AZ border population are different from those of the AZ State population and to investigate that pollutant concentration comparison used most frequently can predict risk differences between the two geographic regions from environmental justice point of view.; Ten target pollutants are four metals, two pesticides, and four volatile organic compounds. The multiple routes of exposure in this study are inhalation, dietary ingestion, non-dietary ingestion, and dermal absorption. Two databases are used to estimate exposure and the resulting risk of the two geographic populations: NHEXAS-AZ and BORDER-AZ databases. The selection of exposure scenarios and development of exposure, dose, and risk models are based on the studies for assessing multiple route exposures. The indirect approach is used to estimate exposures and doses to multiple pollutants by multiple routes utilizing measured concentrations in multi-media and questionnaire information for activity patterns, food consumption and other necessary subject information. Aggregate risk values are estimated using potential dose values and other pertinent information for carcinogens and non-carcinogens with the deterministic and probabilistic approaches to analyze uncertainty associated with risk estimates.; Differences of specific pollutant concentrations between the two regions are observed, but these differences do not provide patterns with consistent direction of magnitude differences. Differences of aggregate risk to specific pollutants between the two geographic populations are investigated in magnitude and direction. Exposure to two metals lead to higher aggregate risk at the AZ border population, therefore, the AZ border region may be subject of environmental justice issues.