Plastics are everywhere. They have a lot of good uses. However, not all plastics are created equal, and some are downright harmful.
The most pressing problem addressed recently is the fact plastics can poison our food. Of particular concern is the BPA that is used in many plastics.
Bisphenol-A (BPA) is a class of chemicals known as endocrine-disruptors, mimicking the naturally occurring hormone estrogen. These chemicals can duplicate, block or exaggerate hormonal responses that control development of the brain, the reproductive system and other functions. Studies on animals have linked BPA to low sperm count, hyperactivity, early puberty, obesity, small testes size, and enlarged prostates.
Just recently a study published in the Journal of the American Medical Association revealed even more alarming problems with BPA. In a large population study of individuals between the ages of 18 and 74, it was found that people with higher levels of bisphenol-A in their urine also had higher rates of cardiovascular disease and diabetes.
Interestingly enough, it was an accident that problems with BPA were even discovered in the first place. For instance, in 1998, researchers at Case Western University were studying chromosome abnormalities in mice when they noticed an eightfold increase in the abnormality in eggs. Investigation revealed that a lab technician had washed the water bottles with an unusually strong detergent, causing them to degrade and BPA to leach into the mice’s drinking water. Follow-up research confirmed that the chromosomal abnormalities were related to low-level BPA exposure.
“No, it doesn’t take washing the bottle with floor soap,” researcher Patricia Hunt said. “As these products get reused, they start to leach BPA. The part that will make your hair stand on end is baby bottles. They are made of polycarbonate plastic. People who use them say that after just washing them in the dishwasher they see these same changes in the bottles. When we see bottles start to turn cloudy, they are leaching. And when they get sticky, they are giving off a lot of this stuff.”
High temperatures cause BPA to leach out much faster. In one study, BPA was released 15 to 55 times faster when exposed to boiling water. This concern led Canadian retailers to pull all baby bottles made with BPA from the shelves. In the United States, many manufacturers and retailers are beginning to do the same.
There is a split in research results on BPA safety but it’s important to note that although studies funded by the plastic industry find no harmful effects, 90 percent of government-funded low-dose studies found harmful effects from BPA.
In August 2007, thirty-eight of the world’s leading scientific experts on BPA concluded that, “Commonly reported circulating levels in humans exceed the circulating levels extrapolated from acute exposure studies in laboratory animals.”
This is a key finding: levels causing adverse effects in animals are lower than what is already in people. The use of this chemical is so widespread that it was detected in the urine in 93% of the population over 6 years of age (it’s unknown what levels are for children under 6 years of age as they weren’t tested).
It’s not hard to see why when you realize more than 6 million pounds of BPA are used each year to make polycarbonate plastics and epoxy resins. It’s been used for decades in the linings of canned foods, in plastic and baby bottles, in polymers of some dental fillings and in other plastic products.
Polycarbonate plastics are typically hard and clear and are marked with the resin identification code number 7. These numbers indicate the type of plastic used to make the item, with number 7 being considered the “other” category, and includes not only BPS, but other chemicals not listed in the previous 6 identification numbers.
Although plastic is so commonly used, there are still ways to protect yourself. Professor Fredrick S. vom Saal, a professor of biology at the University of Missouri, recommends using plastic items made with identification code number 2 (high-density polyethylene) or 5 (polypropylene).
And keep to these two rules when using plastics:
- Recycle, do not reuse: Use the product only for what it was intended for. Do not reuse bottles or microwave trays if they were not made to be reused.
- Keep the heat away from BPA: Do not warm bottles made with BPA in the stove or microwave, don’t put boiling water in them, and do not place them in the dishwasher.
Plastic has some good uses, but the wrong kind of plastic leaching BPA into our food and drinks isn’t one of them.
Environmental Working Group
Green Living Online
Journal of the American Medical Association
