Contaminated Drinking Water Linked to Birth Defects
Exposure to drinking water contaminated with the solvent perchloroethylene (PCE) during pregnancy increases the risk of neural tube defects and oral clefts in her newborn, according to research reported in the online journal Environmental Health.
PCE, also known as tetrachloroethylene, is a chemical used in both dry cleaning and in metal products. It has been observed in animal studies to be linked with several malformations, including that of the cardiovascular system, the musculoskeletal system, the central nervous system, and defects in the eyes. Epidemiological studies have also found prenatal exposure to solvents resulted in a 60% increased risk of major birth defects.
Ann Aschengrau, PhD, of Boston University’s Department of Epidemiology, and colleagues studied children born to almost 2200 mothers living in the Cape Cod, Massachusetts area between the years 1969 and 1983. PCE was found to be leaching into the public drinking water from the inner lining of the asbestos cement water pipes. The liner was painted onto the pipe surface using a vinyl resin and PCE in order to control taste and odor problems. 1492 mothers were believed to be exposed to the chemicals during their pregnancies.
The follow-up was conducted during the years 2002 and 2003, where the mothers were given questionnaires regarding their reproductive and prenatal history and the presence of congenital anomalies among their birth children.
Overall, a total of 4657 children were evaluated in the final study with 1658 of those having had prenatal exposure to PCE. 61 children with exposure had congenital defects, with a significant increased risk of neural tube defects (particularly anencephaly) and an increased risk of oral clefts. Those with higher estimated exposure, greater than 1.136 grams per month over the course of the nine-month pregnancy, were more likely to develop the conditions.
Additional malformations observed included those of the genitourinary tracts presenting as hypospadias, but these findings were less significant. There also was no significant increased risk observed for cardiac and musculoskeletal malformations, and there were too few exposed cases to estimate risk for ocular (eye) and other anomalies.
Other studies have also found the presence of birth defects linked to public drinking water supplies. A Tucson AZ study found that children born to parents with contact with PCE-contaminated drinking water were three times more likely to have cardiac defects. A separate New Jersey study found that drinking water containing PCE was associated with a 3.5 fold increase in oral clefts and a 2.5 fold increased risk of neural tube defects.
Back in Cape Cod, city officials discovered the water line problems in 1980, when the contaminant levels ranged from 80 micrograms per liter to up to 7750 mcg/L. However, the pipes were not replaced due to the expense of the project, and instead were flushed so that the water contained what was then considered to be a safe level for consumption -- 40 mcg/L. Today, the U.S. EPA's maximum acceptable contaminant level for PCE is 5 mcg/L.
Symptoms of excessive PCE exposure include dizziness, headache, sleepiness, confusion, nausea, difficulty speaking and walking, and death, according to the Agency for Toxic Substances and Disease Registry. In addition to birth defects, the Department of Health and Human Services has linked the chemical to liver and kidney cancers in rats.
Sources: Environmental Health, Agency for Toxic Substances and Disease Registry