Drinking Tap Water Disinfected With Chlorine May Harm Fetus?
Chlorine-treated water may increase the risk of having children with heart problems, cleft palate or major brain defects, according to a study published in BioMed Central's open access journal Environmental Health.
Water chlorination is a common and effective way to disinfect drinking water and reduce the risk of waterborne diseases. However, recent research suggests that prenatal exposure to chlorination by-products may increase the risk of birth defects.
The research team led by Jouni Jaakkola from the Institute of Occupational and Environmental Medicine, University of Birmingham, UK looked at almost 400,000 infants born in Taiwan to see if drinking tap water with high, medium or low levels of chlorination by-products increased the risk of 11 common birth defects. The researchers used statistical analyses to see if there was a correlation between chlorination by-product levels and the number of birth defects.
The researchers found no direct link between the prevalence of any birth defect and the level of exposure, but their calculations revealed that exposure to high levels of by-products substantially increased the risk of three common defects: ventricular septal defects (holes in the heart), cleft palate, and anencephalus.
Exposure to total trihalomethanes above 20 ìg/L was associated with an increased risk of 50 to 100% compared with levels below 5 ìg/L. These results were corroborated by additional analyses, using pooled data from a number of similar studies.
The biological mechanism by which disinfection by-products may cause defects is still unknown, says Jaakkola. However, our findings suggest that exposure to chlorination by-products may be responsible for some specific and common defects. Whilst the benefits of water chlorination are quite evident, more research needs to be carried out in order to determine these side-effects.