Exploratory study first to quantify TCE in breast milk
By Sarah Wilkinson
A new study funded in part by the NIEHS Superfund Research Program (SRP) (http://tools.niehs.nih.gov/srp/programs/Program_detail.cfm?Project_ID=P42ES4940) at the University of Arizona (UA) reports, for the first time, levels of the environmental contaminant trichloroethylene (TCE) in breast milk.
Published Aug. 21 in Environmental Science and Technology, the study identified the chemical, which the U.S. Environmental Protection Agency (EPA) has identified as a high priority need for risk assessment, in 35 percent of the breast milk samples analyzed.
“The results of this exploratory study suggest that more in-depth studies will be important for understanding the risk to infants of TCE exposure via breast milk intake and how to reduce the mothers’ exposure,” said lead researcher Paloma Beamer, Ph.D., an environmental engineer at the UA Mel and Enid Zuckerman College of Public Health. In the meantime, the authors stress that mothers should continue to breastfeed their children to ensure critical health benefits for both mother and baby.
Bathing water exposes babies to TCE in mothers’ milk
The study sampled breast milk from women in 20 households in Nogales, Ariz., a city known to have TCE-contaminated groundwater. The research team collected samples of water used for drinking, cooking, laundry, and bathing, and administered a risk factor questionnaire. They detected TCE in seven of the 20 breast milk samples, ranging from 1.5 to 6 nanograms per milliliter.
The researchers also found TCE in all water samples collected. The concentration of TCE in breast milk was significantly associated with the concentration of TCE in water used for bathing and laundry, but not drinking and cooking. TCE was more likely to be found in breast milk of mothers whose babies had a body mass index less than 14. Based on average breast milk consumption, the researchers proposed that TCE intake for five percent of infants might exceed the proposed EPA reference dose.
TCE as a public health concern
Used as a solvent, in the past, for many industrial and commercial applications, TCE is the most frequently reported organic contaminant in groundwater and impacts communities across the country. TCE and other chlorinated solvents are the primary contaminants of concern at 31 of 35 state and 13 of 15 federal Superfund sites in Arizona.
In other studies, TCE exposure has been associated with increased risk of a variety of diseases, from autoimmune diseases such as lupus, to blood disorders and cancer. Maternal and early childhood exposures have been associated with increased risk of childhood cancers, such as leukemia.
Nogales, the largest border city in Arizona, is home to a 13-acre TCE plume, and faces a unique potential for additional TCE exposure from rapid growth of industrial production along the US-Mexico border. Nogales was selected as the study site for this project, because of existing TCE contamination and an increased prevalence of lupus and cancers associated with TCE exposure.
In addition to Beamer, the UA SRP research team included Eduardo Sáez, Ph.D., of the UA Department of Chemical and Environmental Engineering; Leif Abrell, Ph.D., of the Arizona Laboratory for Emerging Contaminants; community research partner Swilma Campos, of the Mariposa Community Health Center; María Elena Martínez, Ph.D., of the University of California, San Diego; and Catherine Luik, a recent master of public health graduate of the UA College of Public Health.
The study was also supported by funding from the American Cancer Society, National Cancer Institute, Health Resources and Services Administration, and National Science Foundation.
Citation: Beamer PI, Luik CE, Abrell L, Campos S, Martínez ME, Sáez AE. 2012. Concentration of trichloroethylene in breast milk and household water from Nogales, Arizona. Environ Sci Technol 46(16):9055-9061.
(Sarah Wilkinson, Ph.D., is the research translation coordinator for the Superfund Research Program at the University of Arizona.)