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Environmental Medicine: Integrating a Missing Element into Medical Education
From an article in your local newspaper, you learn that an underground waste solvent storage tank at a local semiconductor manufacturing plant is leaking toxic chemicals. According to the plant manager, the tank, which contains mostly 1,1,1-trichloroethane (TCA), is located about 2000 feet from a well that supplies drinking water to a nearby residential area. The article also mentions that at the time the leak was discovered, the concentration of TCA in the well was 1700 ppb. The well was immediately removed from service. The newspaper article states that as reporters interviewed residents for the story, they were told about five cases of spontaneous abortion and four cases of cardiac defects in the area.
Two weeks later, TCA levels in the well reached 8800 ppb, and minor amounts of 1,1-dichloroethylene (DCE) were found. Eighteen of your patients received water from the contaminated well, and several of them, including a 30-year-old pregnant patient, have requested consultations with you. After listening to their concerns, you contact the Agency for Toxic Substances and Disease Registry (ATSDR) to request assistance. In the health consultation provided, ATSDR concludes that the levels are far above levels established to protect public health; however, no human epidemiologic studies have been reported that adequately address reproductive effects caused by TCA or DCE. Data from animal studies do not suggest adverse reproductive or developmental outcomes from ingestion of these chemicals.
ATSDR decides to conduct a Public Health Assessment for this site. While collecting information for the health assessment, ATSDR finds that birth certificates for the county do not reveal an excess of adverse pregnancy outcomes in the water-service area compared with the rest of the county. However, because only 20% of all birth defects are typically reported on birth certificates, the agency advises that birth certificate studies alone cannot rule out an increase of birth defects; furthermore, vital records do not provide data on spontaneous abortions.
Currently, ATSDR is developing a protocol for an epidemiologic study to determine whether an association exists between exposure to the contaminated well water and congenital anomalies and spontaneous abortions. Pending the outcome of the epidemiologic study, you must communicate the risk of adverse reproductive and developmental effects due to toxic exposures. How will you address the following questions from your patient who is pregnant and her neighbors?
(a) Can adverse reproductive effects such as spontaneous abortion and birth defects be caused by drinking and using contaminated well water?