According to Martin Wagner and Jörg Oehlmann from the Department of Aquatic Ecotoxicology at Goethe University in Frankfurt am Main, an analysis of 20 bottled water brands found that 60 percent are contaminated with estrogenic chemicals, which can disrupt hormonal systems by mimicking estrogen in the body. (As described in the Miller-McCune magazine story, “NAFTA and the Unmanning of America,” chemicals that mimic estrogen are known as endocrine disruptors, and “scramble the chemical signals used by vertebrates from reptiles to humans to regulate a wide range of functions, including sexual development.”)

The German researchers found evidence that the estrogenic compounds leach out of the bottles’ plastic packaging and into the drinking water itself. The findings, which are the first to show that substances leaching out of plastic food packaging materials act as functional estrogens, appear in the journal Environmental Science and Pollution Research.

The study results appear as some governments have moved to regulate or ban endocrine-disrupting chemicals in the manufacturing of plastic, following media reports and research results focusing on bisphenol A, which can mimic estrogen in the body and cause adverse health effects. A recent study from Canada’s Department of Health found that the majority of canned soft drinks it tested had low but measurable levels of bisphenol A, leading the government to declare it a hazardous substance. After the six largest American companies that sell baby bottles announced they would stop using the chemical in their products, legislation has been proposed in the House and Senate to ban bisphenol A.

“Because bisphenol A and nonylphenols are ubiquitous, we cannot exclude their presence in mineral water,” the German researchers write in their paper.

Wagner and Oehlmann analyzed 20 brands of mineral water available in Germany to determine whether substances in plastic packaging could move into foodstuffs, increasing human exposure to manmade hormones. Nine of the water brands were bottled in glass, nine in plastic, and two were bottled in paperboard boxes coated with an inner plastic film. After taking water samples from the bottles to test for the presence of estrogenic chemicals in vitro, the researchers conducted a reproduction test, breeding New Zealand mud snails in both plastic and glass bottles to determine the strength and source of the chemicals.

The researchers found more than double the number of embryos in plastic bottles as compared with glass. About one in three of the mineral waters in glass bottles showed significant hormonally activity, compared to 78 percent of the waters in plastic and both waters bottled in composite packaging.

The authors conclude: “We must have identified just the tip of the iceberg in that plastic packaging may be a major source of xenohormone contamination of many other edibles. Our findings provide an insight into the potential exposure to endocrine-disrupting chemicals due to unexpected sources of contamination.”

Still, the researchers cautioned that their study was not designed “to evaluate whether the consumption of plastic packed nourishments comprehends the risk of endocrine disruptive effects in humans.”