Antimony and Microplastics
Even though drinking water past its best-by date isn’t considered an issue to regulators, storing bottled water for an extended period of time could in some cases pose potential risks.
Researchers have focused in particular on the potential for antimony, a chemical in many plastic bottles, to be released into the water—if the bottle is exposed to high enough temperatures long enough. A silvery metal, antimony is a potential carcinogen that has been tied to lung and heart problems.
Most of the studies found that the hotter it gets, the more of a concern this becomes. For example, one 2007 study found that at 150° F, it took 38 days for the water to show antimony levels above FDA limits. But at 167° F, it took just five days. And while that may seem like a lot, in the summer and in direct sun, temperatures can easily get higher than that. So water left in the trunk of your car for a week or so could produce dangerous levels.
Responding to a separate 2014 study on the same issue, the IBWA said PET plastic bottles have been demonstrated to be safe for use.
That study, published in the journal Environmental Pollution, looked at bottled water brands sold in China that were stored at 158° F for four weeks. Just one of the brands exceeded limits for antimony as a result of being stored in such circ*mstances, the study notes, and the IBWA says these levels were minimal and “well below the FDA’s health-based regulatory limit.”
“In most cases, antimony is not even detected in migration tests using protocols that represent common ‘real world’ conditions,” the IBWA said at the time.
Ultimately, the levels shown in the studies wouldn’t be likely to put someone at risk if they were ingested once. But researchers say that people who drink water bottled in plastic should be more cognizant about where, and how long, they’re storing it.
“Clearly, only a small fraction of the antimony in PET plastic bottles is released into the water,” the 2007 study says. “Still, the use of alternative types of plastics that do not leach antimony should be considered, especially for climates where exposure to extreme conditions can promote antimony release from PET plastics.”
Concerns about the presence of microscopic pieces of plastic leaching from bottles into water has also been a high-profile issue as of late, an issue that could pose health risks.
But the best-by-date on bottled water isn’t related to microplastics, says Sheri Mason, Ph.D., sustainability coordinator at Penn State Behrend and a chemist who has studied the presence of plastic in tap water, beer, sea salt, and bottled water.
“To our knowledge, there is no data with regard to increased shedding of plastics from water bottles due to the influence of time,” Mason tells CR.
The IBWA says on its website that it’s possible for algae or mold to develop in bottled water if it’s exposed to extended periods of direct sunlight or heat. But the association says that happens infrequently and consumers can alleviate any potential issue by storing water in a cool place.
The group also recommends that consumers store bottled water away from household chemicals, noting that plastic containers are slightly permeable, which may allow ambient air gases to affect the taste and odor of the product.
