Toxics Release Inventory Sites and Population Health across Rural and Urban Areas

Research center:
Lead researcher:
Project funded:
September 2009
Project completed:
August 2010
Rural populations are exposed to a variety of environmental risks from point and non-point pollution sources. Our preliminary analysis in Year 1 found significant associations between air and water pollution discharge sources and population mortality rates in rural areas. However, an analysis of the number of Toxics Release Inventory (TRI) sites showed no association to mortality. This may be due to the imprecision of the measure - we counted TRI sites but did not investigate the volume or type of chemical release. Some TRI sites report zero releases.

Project Goals: The current project will conduct two mini-studies to examine discharges in more detail by refining the TRI exposure measure and investigating variability in exposure across population subgroups; the first study will focus on mortality rates and the second on low-birth weight and preterm delivery rates.

Methods: The study will utilize and supplement the previously developed environmental hazards inventory from Year 1 to conduct a county-level analysis of mortality rates and birth outcomes in association with TRI sites. We have already linked existing county-level databases to assess potential pollution sources and corresponding health outcomes, with particular attention to rural settings but including analyses for both urban and rural locations. Data were drawn from the Environmental Protection Agency, Department of Agriculture, National Land Cover Dataset, Energy Information Administration, Centers for Disease Control and Prevention (CDC), US Census, and other sources. We will refine this dataset with additional mortality rates specific to race and ethnic minority groups, and will continue to update other data sources as data become available. We will also incorporate natality data from the CDC on low birth weight and preterm births. Analysis will include calculation of descriptive and inferential statistics. We will examine the statistical associations between population health outcomes and TRI pollution sources separately in rural and urban counties. This will be done using Poisson regression models (for mortality rates) or ordinary least squares models (for birth outcomes) that adjust for population characteristics. Subgroup analyses will be conducted for race/ethnic minority populations and for counties stratified by socioeconomic indicators, comparing rural to urban locations. Anticipated publications or products: The study will result in at least one final report and one policy brief to HRSA, and at least one academic peer reviewed publication. We may also present the findings of this study at a national conference relevant to rural and/or environmental health.