Consumers thought they were safe when they ditched their polycarbonate plastic water bottles and switched over to metal bottles in hopes of avoiding bisphenol A, a chemical so similar to estrogen that it might affect human hormone systems. But a new study shows that some metal bottles can leach BPA, too in one case, even more than plastic bottles. While the industry and U.S. agencies continue to back the use of bisphenol A (BPA), a growing number of lab animal studies have linked exposure to wide-ranging health concerns, including developmental issues, cancers and cardiovascular disease.
We talked to Scott Belcher, professor of pharmacology at the University of Cincinnati College of Medicine, and an author of the new study, published this week in Chemosphere. His team compared six reusable water bottles, three types of aluminum, two types of plastic and one stainless steel water bottle. The bottles tested include: old Nalgene polycarbonate bottles and new Nalgene Everyday "Tritan" copolyester bottles; old Sigg aluminum bottles, new Sigg aluminum bottles with "Eco-Care" lining and Sigg stainless steel bottles; and New Balance aluminum bottles.
In 2008, due to consumer demand for BPA-free products, Sigg switched to "Eco-Care" copolyester-lined bottles and Nalgene switched to "Tritan" copolyester plastics, and both advertised their bottles as "BPA-free". Aluminum water bottles require an inner lining, since the metal is susceptible to corrosion, and epoxy-resin linings may include BPA. Stainless steel, on the other hand, typically does not have a lining. Belcher's study was designed to test the "BPA-free" claims of the well-known manufacturers, and see whether different types of water bottles leached different amounts of the chemical.
Based on the research, here is what you should know:
> BPA can leach from polycarbonate plastics, including pre-2008 Nalgene bottles. That finding confirms the results of previous studies.
> It can also leach from epoxy-resin lined aluminum bottles, including pre-2008 Sigg bottles and the New Balance bottles.
> New Balance aluminum bottles leached 12-times more BPA than pre-2008 Sigg aluminum bottles, and five-times more than pre-2008 polycarbonate Nalgene bottles.
> Hot water increased leaching from these epoxy resin-lined aluminum bottles, in some cases quadrupling the concentration of BPA in water.
> BPA did not leach from stainless steel Sigg bottles, from Sigg "Eco-Care" aluminum bottles or from Nalgene "Tritan" copolyester bottles. The "BPA-free" claims on these bottles appear to be accurate.
> "If you're concerned about BPA, open up the bottle and look at it," Belcher said. The gold-orange lining visible inside aluminum bottles is usually an indicator of a epoxy resin lining, and should be easy to detect and avoid. If unsure, lean on the safe side and purchase name brands you can trust.
> If you need to replace your aluminum bottle, try recycling it with your other aluminum items. Replace it with unlined stainless steel, copolyster plastic or copolyster-lined aluminum.
> The study tested the six bottles described here, in response to consumer concerns about the veracity of new "BPA-free" labels. While both the Nalgene and Sigg "BPA-free" labels appear trustworthy, Belcher said, "I can't be responsible for making a recommendation on all labels."
Related: See which BPA-free Water Bottles Good Housekeeping recommends.
> Sigg unlined stainless steel bottles, 800 ml ($10 at amazon.com)
> Sigg "Eco-Care" aluminum bottles, 20 oz. ($12.15 at amazon.com)
> Nalgene "Tritan" copolyster bottles, 16 oz. ($6.50-$14 at amazon.com)
> Nalgene "Tritan" copolyster bottles, 32 oz. ($8.95-17.20 at amazon.com)
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