Drinking mineral water from a plastic bottle may mean you are also drinking a sex hormone that affects your reproductive system.
Researchers have found evidence of chemicals containing the hormone oestrogen leaching out of the packaging into the water.
Oestrogen is the main female sex hormone, and taking it unwittingly may interfere with the reproductive process. These findings by researchers in Germany show for the first time that substances leaching out of plastic food packaging materials act as the hormone oestrogen.
Besides interfering with the reproductive process, oestrogens may reduce the flow of breast milk. The effects of oestrogen on nursing infants are not known.
Martin Wagner and J?rg Oehlmann from Department of Aquatic Ecotoxicology, Goethe University, in Frankfurt, looked at whether the migration of substances from packaging material into foodstuffs contributes to human exposure to man-made hormones.
They analysed 20 brands of mineral water available in Germany - nine bottled in glass, nine bottled in plastic and two bottled in composite packaging (paperboard boxes coated with an inner plastic film).
They took samples from the bottles and tested them for the presence of oestrogen-containing chemicals. They then carried out a reproduction test with the New Zealand mud snail to determine the source and potency of the hormones.
The researchers found that these chemicals are potent in living organisms and are causing an increased development of embryos in the snails.
They detected oestrogen contamination in 60 percent of the samples (12 of the 20 brands) analysed. Mineral waters in glass bottles had less oestrogen than waters in plastic bottles.
Specifically, 33 percent of all mineral waters bottled in glass compared with 78 percent of waters in plastic bottles and waters bottled in composite packaging showed significant hormonal activity.
By breeding the New Zealand mud snail in both plastic and glass water bottles, the researchers found more than double the number of embryos in plastic bottles compared with glass bottles, said a Goethe University release.
Taken together, these results demonstrate widespread contamination of mineral water with the potent man-made chemical that partly originate from compounds leaching out of the plastic packaging material.
These findings were published in Environmental Science and Pollution Research.