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
This retrospective cohort study is testing the hypothesis that perchloroethylene (PCE) found in public drinking water supplies in Cape Cod, Massachusetts is associated with reproductive and developmental disorders, including sperm and menstrual abnormalities, impaired fecundity, secondary infertility, spontaneous abortion, low birth weight, intrauterine growth retardation, pre-term delivery, congenital malformations, and developmental disorders of learning and attention. The source of the contamination was a vinyl liner that was applied to the inner surface of certain asbestos cement water distribution pipes in eight Cape Cod towns. The study population is comprised of families who were exposed to PCE-contaminated drinking water during 1969-1983, and a comparable group of unexposed families. All study families experienced the birth of at least one child during this period. Progress during the past year has occurred in the areas of subject tracing, survey data collection, geocoding, dose model development and testing, and exposure validation.
Birth records of Cape Cod families from the period 1969-1983 were reviewed, and 1,910 exposed children and their families and 1,928 unexposed children and their families were identified for the study population. Recent addresses were found for 95% of the children's mothers or, if the mother was deceased, the children's fathers. Self-administered questionnaires were sent to study parents who were successfully traced, and completed surveys were received from 67% of parents. Another 9% refused to participate, and 19% received a survey but never responded. In addition, 4% of surveys were unable to be delivered by the post office. All survey data have been computerized and 98% of Cape Cod addresses reported by participants were geocoded to the parcel level. Survey data cleaning and PCE exposure assessments are currently underway.
During the past year, project investigators completed two activities aimed at reducing exposure misclassification. First, a dose model was developed that estimates a subject's personal dose from ingestion, inhalation and dermal absorption using physical properties of PCE and survey data on bathing, water consumption, and residency time. In addition, the dose model was applied to epidemiological data from the investigators' prior case-control study of PCE-contaminated drinking water and breast cancer risk. They found that the personal dose model was more heavily influenced by known parameters such as residency time, PCE water concentration, and shower duration than by unknown parameters such as air ventilation rates. In addition, the results of the breast cancer analysis using the personal dose model did not differ greatly from the results of the original analysis.
Second, a corroboration study was conducted that compared PCE concentrations in historical tap water samples with concentrations predicted by the exposure assessment model. In general, the investigators found good agreement between actual and predicted water concentrations. Manuscripts describing both of these activities have been prepared for publication.