Web Date: August 3, 2012
Carcinogenic Solvent Measured In Breast Milk
For the first time, researchers have reported levels of the industrial solvent trichloroethylene in human milk (Environ. Sci. Technol., DOI: 10.1021/es301380d). The solvent is the most frequently reported organic contaminant in groundwater in the U.S. Experts say the levels found in the research don’t raise immediate concerns, but that the results warrant further study.
U.S. manufacturers produce over 300 million pounds of trichloroethylene (TCE) per year, which often is used to strip grease from metal parts. The Environmental Protection Agency classifies TCE as a carcinogen. Previous studies have linked exposure to the solvent to a range of health problems, including multiple myeloma and lupus, says Paloma Beamer, an environmental engineer at the University of Arizona, Tucson, and lead author of the new study.
Between 1988 and 2008, factories cut TCE releases to the environment from 49 million to 3.6 million pounds annually. But from the 1950s until the early 1990s, workers at plants commonly dumped waste TCE on the ground or in unlined holding ponds, where it leached into groundwater. As a result, about 60% of hazardous waste sites across the nation contain TCE, according to the Agency for Toxic Substances and Disease Registry.
Researchers detected TCE in breast milk in the 1980s, but did not report the levels of the solvent.
So Beamer and her team recruited 20 breast-feeding mothers from Nogales, Ariz., which has groundwater contaminated by TCE. Mothers provided breast milk samples and the researchers measured concentration of TCE in the milk using gas chromatography and tandem mass spectrometry.
The team found TCE in just seven of the 20 breast milk samples, at concentrations from 1.5 to 6 ng per mL of milk.
James Bruckner, a toxicologist at the University of Georgia, Athens, notes that these breast milk concentrations could expose infants to roughly the maximum safe daily oral dose for TCE set by the EPA. Because the levels could approach and sometimes exceed this limit, he thinks researchers should further study TCE levels in breast milk and their effects on mothers and babies’ health.
Bruckner cautions that because the results are based on only 20 women and because the EPA limit is quite low, breast-feeding mothers should not be concerned.
Beamer agrees and notes that breast-feeding provides benefits for babies’ health.
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