Birth Defects and Disinfection By-Product Exposures and Source Water

Abstract

Previous epidemiological studies suggest that women exposed to disinfection byproducts have an increased risk of delivering babies with neural tube, genitourinary system, and ventricular septal defects. The risk of birth defects (n=3,500) among all live births from 275 towns in Massachusetts was examined relative to different water sources, disinfection types, and disinfection byproduct concentrations using 2000 to 2004 data. Preliminary unadjusted and adjusted results for combined birth defects were largely null among the water source and disinfection exposure metrics. Adjusted odds ratios (aORs) ranged from 1.17 to 1.37 for obstructive urinary defects among births linked to drinking water treated with chlorine, chloramines, and other alternative disinfectants compared to untreated ground water systems. Compared to untreated ground water, increased aORs for cardiac defects were noted for chlorinated surface water (1.14; 95%CI=0.92, 1.41) and chloraminated water (1.08; 95%CI=0.88, 1.33). Increased aORs for hypospadias and epispadias were found for chlorinated surface water (1.19; 95%CI=0.80, 1.78) and chloraminated water (1.17; 95%CI=0.79, 1.72) compared to untreated ground water. Preliminary analyses showed no increased risk of combined birth defects for total trihalomethane or total haloacetic acid exposures compared to the lowest quintiles. Small increased aORs for ventricular septal defects were detected for the upper two brominated trihalomethane quintiles (aOR range=1.15-1.24), while increased risks for obstructive genitourinary defects were detected for the upper three bromodichloromethane (aOR range=1.10-1.51) and brominated trihalomethane (aOR range=1.61-1.91) quintiles. These preliminary data indicate larger risks for birth defects for brominated disinfection byproducts, but further analyses are needed to confirm these results. The views expressed herein are those of the authors only and do not necessarily reflect the views or policies of the USEPA.