Characterization of Exposures of Urban and Rural Cohorts to Airborne PCBs
The AESOP Study (Airborne Exposures to Semi-volatile Organic Pollutants) seeks to answer key questions about what are the determinants of PCB exposures among children and their mothers, what are the exposure levels indoors and out, and how to best monitor exposures and metabolites.
Aim 1: Gather demographic, residential, occupational, activity, diet history and baseline health data from residents in East Chicago, Indiana and Columbus Junction, Iowa. Researchers enroll participants to study their exposure to PCBs. Demographic, occupational, and activity questionnaires are administered and extensive dietary health data ascertained from the NCI Dietary History Questionnaire (DHQ-II). Researchers will report back data in both communities as they become available.
Aim 2: Collect air samples inside and outside at homes and schools and measure congener-specific concentrations of atmospheric PCBs. Air sampling continues at homes and schools, indoors and outdoors in Columbus Junction.
Aim 3: Collect blood annually from all subjects and measure PCB congeners and congener-specific metabolites in serum samples and report these values to participants. Researchers continue to analyze collected blood specimens for PCBs, OH-PCBs and PCB sulfates as well as biomarkers of effect.
Aim 4: Collect urine from all subjects and measure congener-specific PCB sulfate metabolites and evaluate the efficacy of urine as a biomarker for exposure to lower-chlorinated congeners. Urine collection has been ongoing and researchers have quantified creatinine levels in collected samples. Analytical methods for extraction and analysis of PCB-sulfates from urine are under development.
Aim 5: Model exposures and body burdens for the atmospheric PCB Congeners from the East Chicago and Columbus Junction cohorts and compare modeled and measured data. The goal for 2019 is to have complete air, blood, urine, and dietary PCB data for year 9 of the AESOP Study from mother-child participants. This will facilitate more sophisticated and inclusive models using new statistical tools to deal with left censoring to address this aim.
The AESOP Study has enrolled and followed 421 subjects. Data from those subjects has been provided for research in Projects 1, 3, 4, and 7 and to the Analytical Core. In addition, AESOP researchers, field staff, and trainees have worked closely with the Community Engagement Core to ensure community members are actively involved in the research process and receive the results.
The AESOP study has provided new insight into airborne exposures and resulting body burdens. It has changed prevailing views on how most Americans are exposed to PCBs. Researchers have demonstrated that subjects have substantial exposure to PCB congeners from inhalation in addition to ingestion and their blood shows enrichment with lower-chlorinated congeners. This has important implications for children's environmental health.
Jones, M.P., Linear regression with left-censored covariates and outcome using a pseudolikelihood approach. Environmetrics, 2018. 29(8): p. e2536. PMID: 30686916, PMCID: PMC6344928, DOI:10.1002/env.2536.
Project Leader: Peter S. Thorne, PhD
Dr. Thorne is Chair of (and a Professor of Toxicology) in the Department of Occupational and Environmental Health at the University of Iowa with a secondary appointment in the Department of Civil and Environmental Engineering. He is serving as a principal investigator for this study. He has worked successfully with the community advisory boards and schools in Columbus Junction and East Chicago, and will oversee the enrollment of the cohorts for the project.
Keri C. Hornbuckle, PhD
Dr. Hornbuckle, ISRP Director and Project 4 Leader, will provide advice on fabrication and deployment of the passive monitors and high volume samplers, and will provide guidance in the analysis of PCB congener-specific data. Her experience in measuring and modeling PCBs in urban and rural settings will be drawn upon in the interpretation of exposure data.
Michael Jones, PhD
Dr. Jones is a Professor of Biostatistics in the University of Iowa College of Public Health and has extensive experience developing and using statistical methods for the analysis of multiple PCB-congener measures, many of which fall below the limit of quantification resulting in left censored data.