Are disinfection byproducts (DBPs) in drinking water harmful to an unborn fetus?
According to a study in the November issue of the American Journal of Epidemiology, a team of researchers at the University of North Carolina School of Public Health headed by David A. Savitz, Ph.D., director of the Center of Excellence in Epidemiology, Biostatistics, and Disease Prevention at MSSM, and formerly chair of the Department of Epidemiology at the University of North Carolina at Chapel Hill, have determined that drinking water DBPs—in the range commonly encountered in the U.S.—do not affect fetal survival. This finding is particularly important because previous research has suggested that exposure to elevated levels of drinking water DBPs might cause pregnancy loss.
The interaction of chlorine with organic material in raw water supplies produces chemical DBPs of health concern, including trihalomethanes (THMs) and haloacetic acids (HAAs). Several epidemiological studies have addressed potential reproductive toxicity of DBPs. The strongest support in earlier studies was noted for pregnancy loss, including stillbirth.
Researchers looked at three locations with varying DBP levels and evaluated 2,409 women in early pregnancy to assess tap water DBP concentrations, water use, other risk factors and pregnancy outcome. Tap water concentrations were measured in the distribution system on a weekly or biweekly basis. DBP concentration and ingested amount, bathing/showering and integrated exposure that included ingestion and bathing/showering were considered. Based on 258 pregnancy losses, the finding did not show an increased risk of pregnancy loss in relation to ingested amounts of DBPs.
“Decisions about treating drinking water nationwide rest in part on these health concerns, and our results provide assurance that there is no measurable adverse effect of disinfection byproducts on risk of miscarriage. Given the need to control risk of infection through treatment and the huge expense involved in further reducing DBPs, this is good news for the water utility industry and their customers,” said David A. Savitz, Ph.D., lead investigator and director of the Center of Excellence in Epidemiology, Biostatistics, and Disease Prevention at MSSM.