I Left a Plastic Water Bottle in a Hot Car. Is It Safe to Drink?

New York Times

5 days ago

Q: If I leave a plastic water bottle in my car for a few days, is it safe to drink the water when I come back?
It's important to stay hydrated in the heat, but high temperatures and UV rays can influence what goes on in single-use plastic water bottles — especially when they have been sitting in cars, where windows can trap extra heat.
Scientists warn that chemical additives and microplastics could leach into the water, and that bacteria or mold could grow in the bottle.
Does that make the water unsafe to drink? We asked experts to help us sort it out.
Microbes in the Water
One potential concern is that if you've already opened a plastic bottle and have consumed water from it, bacteria from your mouth, your hands or the air can get in and multiply, said Jaime Ross, a neuroscientist at the University of Rhode Island who studies how exposures to microplastics and other substances affect the body.
Beizhan Yan, a geochemist who researches environmental contamination at Columbia University, said he wasn't aware of any studies that have looked into exactly what happens if you leave a plastic water bottle in a hot car. But scientists can make inferences from relevant research.
In one peer-reviewed study published in 2013, for instance, researchers analyzed which microbes grew in various partly consumed beverages — including plastic bottled sodas, teas, juices, sports drinks and water — left at 77 degrees for two weeks. They found that bacteria, mold and yeast grew in many of them.
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