Of all the hazards you might encounter while recreating in Tahoe, you probably never worried about ingesting chemicals from your plastic water bottle. But if your bottle is made of the durable, transparent, Number 7 plastic known as polycarbonate, it could be leaching small amounts of a harmful chemical called Bisphenyl-A into your liquids.
Though Bisphenyl-A (BPA) is the building block of polycarbonate, it wasn’t synthesized with sports bottles in mind. In the 1930s, BPA was studied as a synthetic estrogen, but was abandoned for medical purposes because it was weaker than the favored estrogen at the time: DES, or diethylstilbestrol. Chemists later strung molecules of BPA together in chains and created polycarbonate plastic.
Hard, clear, lightweight and possessing such desirable properties as heat and electrical resistance, polycarbonate plastic is widely used for digital media (CDs, DVDs,) sports safety equipment, eyeglasses, dental sealants and bulletproof glass. Manufacturers found polycarbonate’s durable, shatterproof nature ideal for sports bottles, baby bottles, sippy cups, plastic cutlery, and food storage containers for the fridge and microwave. But it’s in the kitchen that polycarbonate creates a problem; when the plastic comes in contact with food or liquids, Bisphenyl-A can leach out. The epoxy resins that line food and soda cans are also made of Bisphenyl-A, exposing us to even more of the chemical.
According to the National Institute of Environmental Health Sciences (NIEHS,) virtually all of our exposure to BPA is the result of food and beverages coming in contact with polycarbonate containers or the linings of food and soda cans. Though you can’t taste it or smell it, you’re almost guaranteed to have Bisphenyl-A in your bloodstream; almost every American does. And weak though it may be, BPA is nevertheless estrogenic, belonging to a class of chemicals known as endocrine, or hormone, disruptors. Once in the bloodstream, hormone disruptors mimic your body’s own hormones, interfering with the complex endocrine system in ways that are little understood by scientists.
Animal studies have clearly shown that BPA is harmful, causing chromosomal abnormalities that result in birth defects, miscarriage, mental retardation and reduced sperm count. But research on humans has yielded baffling and inconsistent results. Last year, the NIEHS convened two panels of experts to examine the research. The first panel concluded that low levels of BPA exposure in animals caused abnormalities ‘of great concern’ that the scientists believe could be connected to the human population’s rise in breast and prostate cancer, early onset of puberty in girls, obesity, urogenital defects in male babies, diabetes and ADHD.
The second panel disagreed with many of the first panel’s conclusions, finding fault with some of the studies’ methodologies, including how the chemical reached the animals’ bloodstreams (injected or given in food), though once in the blood, the chemical reacted the same way.
Research is always open to interpretation, so some disagreement is to be expected, Still, it’s impossible to ignore the fact that virtually every study funded by the plastics industry concludes that any amount of BPA is harmless. The second panel apparently used more industry-funded studies when forming their conclusions. Yet both panels could not ignore research showing that Bisphenyl-A caused brain and behavioral abnormalities in young rats and mice.
This news is particularly worrisome, because during the fetal, infant and youth stages of development – whether in animals or humans – the neurological system is growing in leaps and bounds, and any disruption during this time, even if it’s subtle, may damage the brain. Researchers observed that in mice, BPA caused changes in the number and density of nerve cells in the parts of the brain that interact with hormones. Young mice were more anxious, less playful and less likely to explore new environments. The females were more sexual, the males less.
When pregnant mice were exposed to BPA, the grandchildren suffered chromosomal abnormalities. This is because, in mammals, a female fetus is already forming eggs that will become her children. Other animal research shows that the fetus tends to concentrate BPA in its blood because its system for ridding the body of chemicals is not fully developed. (The same inability to detoxify the body has been measured in human children.)
In a study of adult women, those with a history of recurrent miscarriages were shown to have high levels of BPA in their systems. In female fetuses, exposure to BPA while in the womb was linked to uterine diseases – such as fibroids and cystic ovaries – later in the women’s lives.
Though scientists still consider human research inconclusive, many strongly suggest limiting BPA exposure, especially in infants, children and pregnant women. Since most of our exposure comes from food and beverages, there are a number of actions you can take to reduce the amount of Bisphenyl-A entering your body.
First, determine whether the plastics you use are made of polycarbonate. If stamped with the recycling logo, polycarbonates will carry the number 7. However, number 7 is a miscellaneous category, and includes plastics that either do not fit into categories 1 through 6 or are a blend of plastics. (Corn-based compostible plastic containers, for example, fall under the number 7 category, but contain no polycarbonate.)
Wide-mouth, transparent Lexan sports bottles are made of polycarbonate. A safer alternative is to use a number 4 bike bottle or a stainless steel bottle, available at New Moon Natural Foods, or online at kleankanteen.com and newwaveenviro.com. Never, ever put boiling water in a polycarbonate bottle; doing so can release BPA up to 55 times faster than when cool or temperate water is used, regardless of the bottle’s age.
In the kitchen, replace any number 7 products if they are hard and transparent (and therefore probably polycarbonate). Most Tupperware is number 5, which is generally considered safe, but some experts caution against using these for hot foods or microwaving. (Hands-down, the safest containers for food storage and microwaving are glass or porcelain.) If you can’t part with your polycarbonate containers, you can at least take steps to minimize BPA leakage. Wash the containers by hand, since dishwashers and harsh scrubbers release BPA. And don’t use polycarbonates in the microwave, as heat accelerates leakage.
Use baby bottles and sippy cups free of BPA. New Moon Natural Foods carries ThinkBaby bottles, or you can find numerous products on the web (thinkbabybottles.com, newbornfree.com, and safesippy.com). These bottles are also free of harmful PVC and phthalates.
Look for alternatives to canned products – including fresh or frozen foods – and products bottled in glass, such as pasta sauces. The only food manufacturer that currently uses BPA-free linings in their food cans is Eden, a brand commonly found in health food stores. Many soups are now available in shelf-stable cartons, and often have the advantage of containing healthier ingredients those in cans. Two companies that make soup in these cartons are Imagine and Trader Joe’s. Look for tuna and salmon in pouches instead of cans.
If you drink soda, opt for bottled versions. Glass is the least-reactive option, but number 1 and 2 plastic bottles are generally considered safe. Just don’t reuse them too many times, or the plastic starts to break down.
If your dentist recommends dental sealants, ask for the newer kind, free of Bisphenyl-A.
Plastic By the Numbers
1 PETE: Polyethylene Terephthalate
Bottled water, soda bottles, vinegar bottles, medicine containers.
2 HDPE: High Density Polyethylene
Milk bottles, containers for laundry detergent, dishsoap, bleach, shampoo and conditioners, motor oil.
3 PVC: Polyvinyl Chloride
Some cooking oil bottles and meat wraps, baby bottle nipples, shrink-wrap, sticky cling-wrap, coffee containers. Avoid: contains phthalates to soften the plastic.
4 LDPE: Low Density Polyethylene
Bicycle bottles, some food wraps, grocery bags, sandwich bags.
5 PP: Polypropylene
Tupperware and similar food storage containers, yogurt and margarine tubs. Do not microwave yogurt or margarine tubs.
6 PS: Polystyrene
Most ‘Styrofoam’ take-out containers and cups, disposable cutlery, bakery clamshells, meat trays, packaging ‘peanuts.’ Avoid: can leach styrene into food.
7 Other
Includes polycarbonate (PC) and mixtures of plastics Food can liners, Nalgene-type widemouth sports bottles, baby bottles, sippy cups, dental sealant, 5-gallon jugs, corn-based compostible containers. Avoid if polycarbonate: Bisphenyl-A can leach out, especially if heated.
