Just when you thought you were reducing your BPA (Bisphenol A) exposure by making the switch from plastic to metal water bottles, new research finds that some metal bottles leach even more BPA than the plastic ones. The problem isn’t the metal itself but certain epoxy-resin linings used in some metal bottles that leach BPA.

The researchers, led by toxicologist Scott Belcher of the University of Cincinnati College of Medicine tested five types of bottles under various conditions: polycarbonate and resin-lined aluminum bottles BPA-free plastic bottles, stainless steel bottles, and aluminum bottles.

The scientists stored room-temperature water in three bottles of each type for five days. In an additional set of experiments, they filled the bottles with boiling water (which tests by others had shown could increase BPA leaching) and then let the water cool to room temperature..

Levels of BPA were below the limit of detection for the stainless steel bottles, the “BPA-free” labeled plastic bottles and one brand of epoxy-resin lined aluminum bottles.

By contrast, the polycarbonate bottles leached 0.17 to 0.3 nanograms of BPA per milliliter of water during the room temperature tests. The aluminum bottles with an epoxy-resin liner (which looked golden orange) leached 0.59 to 0.14 nanograms per milliliter. Another epoxy-resin-lined aluminum water bottle leached substantially more — up to six times more BPA than the worst-leaching polycarbonate-plastic bottle and more than 10 times as much BPA as the polycarbonate-plastic bottle that had leached the least.

The hot-water test quadrupled BPA leaching compared to the test where water had been kept at or below room temperature.

While the researchers did not find BPA leaching from the bottle labeled, “BPA-free” the researchers caution consumers that at present, “BPA-free doesn’t really have a meaning, other than being a marketing tag.” There are no regulations to limit which products can make that claim, Belcher explained. And, some resins don’t contain BPA as a direct ingredient, but during breakdown might release the chemical or a biologically similar cousin.

Tips for Choosing a BPA-free Bottle

So, with some epoxy-resin liners leaching BPA and others not, how do you choose a metal water bottle with confidence?

• If you want to avoid any possibility of BPA exposure, choose a food-grade stainless steel water bottle without a liner. Look for the designation #304 or 18/8 stainless steel. You can also look for bottles with a stainless steel cap and medical grade silicone seals so the contents of the bottle have no contact with plastic.
• If you do purchase a metal (stainless or aluminum) bottle with a liner, the color of the liner seems to be an indicator of BPA. A golden-orange coating points to a material that can shed BPA, a white coating doesn't, says Belcher.
• Un-lined aluminum containers are not a good option due to potential toxicity and reactive issues with raw aluminum.

Why Should I Limit BPA Exposure?

BPA is one of the highest volume chemicals produced worldwide and is used in the production of many plastic products, from plastic food containers and liners to water pipes and sporting equipment. Exposure to BPA is widespread in the US and has been detected in the blood, urine and breast milk of up to 95% of study participants. BPA, which binds to estrogen receptor sites, has been linked to a variety of health problems including breast and prostate cancer, infertility, heart disease, insulin resistance and Type 2 Diabetes, as well as altered gender-specific behaviors. Tolearn more about this issue, read The Lowdown on BPA: The Facts You Need to Know.

Sources:

Science News

Environmental Working Group