A recent study, published in the journal 'Environmental Science & Technology,' says if you're drinking water from a recyclable plastic bottle, you may also be ingesting thousands of plastic particles. Those nanoparticles are so small, they're absorbed throughout the gastrointestinal tract and enter our tissues where they can trigger an immune reaction, or release toxic substances, including heavy metals.
Dr. James Diaz, Director of the School of Public Health at LSU Health New Orleans, says the full impact on our health isn't known.
"But, there are some plastics in water bottles that we're very interested in. These are components of plastic, and the most toxic one that we're concerned about is called BPA or bisphenol A. And, we know that recyclable plastic bottles with the recycling numbers 3 and 7 are most likely to contain BPA."
He says BPA is a concern because of possible effects on the brain and prostate gland of fetuses, infants and children. It can also affect children's behavior. And, research suggests a possible link to high blood pressure. Bisphenol A can imitate the body's hormones, and it can interfere with the production, secretion, transport, action, function, and elimination of natural hormones. BPA can behave in a similar way to estrogen and other hormones in the human body.
"Some people are very sensitive to certain plastics and can have allergic reactions to the plastic," says Diaz. And, he says the most danger comes from the plastic bottles being heated. The National Institutes of Health advises against microwaving polycarbonate plastics or putting them in the dishwasher, because the plastic may break down over time and allow BPA to leach into foods.
"You never want to leave bottled water in your car when your car is over-heating because that's probably the most dangerous situation for getting plastic components in the body. If you're drinking bottled water that is left in your car and it becomes very hot, then you can leach out of the plastic all kinds of particles."
We normally ingest microscopic pieces of plastic with our food, beverages and the air we breathe. But, the study says those who drink bottled water exclusively, rather than tap water, can take in an additional 90,000 plastic particles a year.
Dr. Diaz says you may have to pick your poison.
"Tap water out of the faucet may have pathogens in it...bacteria, or parasites or amoeba or whatever. Bottled water is not going to have parasites in it, but it could have plastics in it. So, you need to pick and choose your plastic bottles very carefully and you need to filter your tap water."
"You should look for bottles that are labeled 'BPA Free.' And, if you're buying water battles, look at the base and make sure that little recycling label has a number that's not 3 or 7 in it."
The National Institute of Environmental Health Sciences says you may want use alternatives like glass, porcelain or stainless steel containers for hot foods and liquids instead of plastic containers. And, reduce your use of canned foods since most cans are lined with BPA-containing resin.
The FDA is continuing its review of BPA, including supporting ongoing research.