Superfund Research Program
Project Leader: Ellen B. Gold
Grant Number: P42ES004699
Funding Period: 2000-2010
Dr. Ellen Gold’s research provides epidemiologic evaluation of human health effects associated with exposure to environmental contaminants in residents adjacent to a Superfund site in Sacramento, California. Her research team accomplishes this by evaluating physiologic dysfunction, specifically reproductive and other hormone-related health effects, in female adults (aged 20-50 years during the likely exposure period of 1988-96) residing downwind or in the groundwater plume of the Sacramento Superfund site and comparing the rates of these health effects to a non-exposed but similar population nearby and relating these rates to likelihood of exposure. In addition to interviewing women residing in these areas and in a comparison area, they will use serum and urine biomarkers of exposure and of health effects that have been developed at UC Davis.
The researchers have identified over 5260 households, screened over 1460 women in the three study areas for eligibility in the study, interviewed 814 women and obtained blood from the first 450 eligible women and daily urine samples for two menstrual cycles from 274 women who were still menstruating in the three areas. They suspended blood collection a few years ago, having found no significant differences in serum parameters they were measuring among the three study sites. They have now also suspended enrollment and data collection due to inadequate funds. The three study areas appear comparable on a number of socioeconomic indicators, as well as on general community and women's health concerns (none of the top four of which include the Superfund site or endocrine/reproductive concerns, respectively).
Further, the research group observed no notable differences in thyroid hormone levels among the first 450 women examined in the three study areas, as expected, since the relevant exposure that might have affected thyroid function ended in 1996, and no prolonged adverse effect on the thyroid would be expected. They have detected no evidence of environmental estrogens in any of the first 250 urine samples tested and thus suspended this testing several years ago as well. Largely, no notable differences are seen in reproductive health or endocrine effects, but further analyses with additional data are required from this ongoing project to determine any differences in health effects that might have occurred during the times of likely exposure.
Finally, Dr. Gold established several collaborations. First, her team is collaborating with UC-Davis project "Transport, Transformation, and Remediation of Contaminants in the Environment: Exposure Assessment in Heterogeneous Environmental Media" in assessing likelihood (realizations) of exposure in each of the households using GIS techniques and analyzing the findings in relation to outcomes ascertained in the study interviews, which should result in a publication in the next year or so. Second, the group has been collaborating with the UC-Davis project "Assessing the Adverse Effects of Environmental Hazards on Reproductive Health", by having laboratory assays of the urine samples conducted to assess ovarian function, which will be examined in relation to study area and likelihood of exposure. This should result in a publication in the next year or so. Third, they have collaborated with CDC, which provided funds for the researchers to have the CDC assay urine samples taken during the study for perchlorate, iodide, nitrate and thiocyanate, and Dr. Gold is using those values to assess the relation of those assay results to the endocrine and reproductive outcomes of interest, which should result in a publication or two in the next year or so. The analyses thus far indicate no differences in urinary perchlorate concentrations or computed perchlorate dose among the three study sites. Fourth, junior faculty have become involved and will analyze the data in relation to fast food consumption, the built environment and opportunities for physical activity, lifetime physical activity and are investigating the relation of thyroid hormones to premenstrual and menopausal symtpoms. These analyses should result in several publications in the next year or two. Last, toxicology investigators at the University of Arkansas have submitted proposals to fund a collaboration with Dr. Gold to investigate trichloroethylene exposure in relation to autoimmune changes, and that collaboration awaits funding.
Applications of epidemiologic techniques in this project have not only facilitated applications of the biomarkers in humans in the exposed population and assessment of the relation of exposure to environmental contaminants to human health effects, but will also help to elucidate modification of these effects by host and lifestyle factors. In turn, this research has and will continue to contribute to the other projects within the grant by providing epidemiologic expertise for developing further field applications of techniques developed in the UC-Davis laboratories in the future. In this effort, these researchers have and will continue to interact with the Cores mentioned above to evaluate exposures to endocrine disruptors as a result of residing downwind or in the groundwater plume of a Superfund site, to assess the likely routes of exposure, and to assess the relation of such exposures to adverse reproductive and other endocrine health effects.