Harmful Types of Plastic Water Bottles

Most of us know we should be drinking a lot of water. However, since faucets (or pristine mountain streams) aren't always in easy reach, we usually carry our water around in some kind of bottle. Unfortunately, scientific reports have raised the alarm about some of the chemicals used to make common plastic water bottles. The situation is continually changing, as new products come on the market and scientific knowledge increases. However, some basic information will help you choose the safest bottles possible.

Types of Plastic

• Have you ever wondered about the little numbers on the bottom of plastic products, usually surrounded by arrows? These are called the resin identification codes and were introduced in 1988 by the Society of the Plastics Industry, Inc. to help with recycling (Reference 1). Today, most single-use plastic water bottles are made out of Polyethylene Terephthalate (PET or PETE), which is marked with a 1. Reusable plastic water bottles are usually made from High-Density Polyethylene (HDPE), which is marked with a 2; Polypropylene (PP), which is marked with a 5; or Polycarbonate (marked with a 7 or the letters "PC").

Single-Use Water Bottles

• While it's tempting to just re-use that water bottle you bought at the gas station or drugstore, you may want to toss it in the recycling bin instead. Chances are the bottle is made out of PET. While manufacturers such as the American Plastics Council have said that washing PET bottles with soap and water will keep the bottle safe (Reference 2), health and environmental groups are concerned that re-using these bottles leaches phthalates, specifically DEHP (also called BEHP), into the water. Among other concerns, an October 2008 study published in Environmental Research found that pregnant women exposed to high levels of DEHP gave birth to baby boys with smaller penises and undescended testes. Other studies have found that degraded PET bottles leach DEHA, which is known to cause liver problems and may be a carcinogen.

Bisphenol A, or BPA

• BPA is used to make polycarbonate plastics, which are usually rigid, transparent, and marked with the number "7" or the letters "PC." For instance, the 3- and 5-gallon reusable water bottles purchased at grocery stores are usually made from polycarbonate (Reference 1).

  BPA may pose health risks to humans. Studies on lab animals have shown that BPA causes genetic damage, and that pregnant rodents gave birth to stunted offspring with a reduced chance of survival. Other animal studies have linked BPA to cancer, obesity and diabetes. However, the scientific research on the effects of BPA on humans is unclear, and industry groups say levels of human exposure are far too low to pose any health risks. However, according to Environment California, "More than 130 studies suggest that BPA exposure at very low doses is linked to a staggering number of health problems, including prostate and breast cancer, obesity, attention deficit and hyperactivity disorder, brain damage, altered immune system, lowered sperm counts, and early puberty."

  Many sources agree that exposing polycarbonate bottles to heat, bleach or scrubbing may make them more likely to leak BPA. Therefore, if you plan on cleaning your water bottle, it's best to avoid polycarbonate.

Safe Plastic Types

• If you plan on washing and re-using your plastic water bottle, your best bet is to go for polyethylene (marked with a 2) or polypropylene (marked with a 5). However, you may want to consider foregoing a plastic bottle entirely, and choosing one made from glass, stainless steel or enamel-lined aluminum.

Other Plastic Tips

• In general, avoid exposing plastics to extreme heat, like in the dishwasher or microwave. Even if the plastic claims to be dishwasher or microwave safe, heating it to extreme levels will cause it to degrade, and could release chemicals into your food and drink. And don't fill your plastic water bottles with hot liquids, like tea or coffee, for the same reason. Remember not to re-use single-use plastic products, like water bottles, because they will quickly degrade.