Superfund Research Program
Early Life Exposure to Tetrachloroethylene (PCE)-Contaminated Drinking Water and Social Stressors may Interact to Increase the Risk of Substance Use Later in Life
Dr. Ann Aschengrau’s group is conducting a population-based retrospective cohort study to test the hypothesis that tetrachloroethylene (also known as PCE) found in the public drinking water supplies in Cape Cod, Massachusetts, is associated with an increased risk of nervous system abnormalities among men and women exposed during gestation and childhood. The source of the water contamination was a vinyl liner that was applied to hundreds of miles of asbestos cement water distribution pipes in eight towns in the
Over the past year, Dr. Aschengrau and her team have made progress in the areas of project staffing; obtaining necessary approvals to conduct the study; identifying study subjects; developing a self-administered questionnaire and other data collection forms; developing data entry systems and linked data bases; finalizing tracing protocols; assessing PCE exposure levels; designing an exposure validation study; conducting epidemiological and statistical analyses; and drafting manuscripts for publication.
To date, the researchers have identified 4,508 subjects—3,838 individuals who were included in a prior study of reproductive and developmental abnormalities and 670 newly identified older siblings. The investigators have drafted a self-administered questionnaire to gather information on indicators and diagnoses of learning, attention, and vision disorders; confounding variables such as other sources of solvent exposures; effect modifying variables such as alcohol consumption; and residential histories. The questionnaire has also been designed to screen subjects who are appropriate for follow-up neuropsychological and vision testing and neuroimaging studies.
Project researchers also used EPANET, a software package developed by the Environmental Protection Agency, to model the complex interconnected geometries of each town’s entire water distribution system, and hence assess more accurately a subject’s exposure to PCE. The method used previously by the researchers was based on a visual assessment of only the portion of the distribution network near a subject’s residence. To date, project investigators have used EPANET to assess PCE exposure levels of the 2,490 individuals whose mothers participated in the prior study of PCE exposure and reproductive and developmental abnormalities. Initial comparisons of the prior and new exposure designations suggest that the prior designations were somewhat misclassified. While 77% of the designations were in agreement, 23% were not. Most subjects with discrepant designations were considered exposed using EPANET and unexposed using the prior method. This difference likely results from EPANET’s ability to model a town’s entire distribution system. A validation study has been designed to compare the EPANET assessments with historical records of PCE concentrations in drinking water samples.
Epidemiological and statistical analyses have been completed that examine the relationship between PCE exposures that took place pre-pregnancy, during pregnancy, and pre-birth and the occurrence of several reproductive abnormalities, including low birth weight, prematurity and intrauterine growth retardation. Analyses examining congenital anomalies and spontaneous abortion are currently underway. A manuscript describing the completed analyses has been drafted.