Plastic containers for water and food.

Consumers tend to buy bottled water under the impression that it is healthier than tap water. However, studies by the Natural Resources Defense Council and University of Geneva have found that, in general, bottled water is not necessarily any safer; nor is bottled spring water necessarily better than bottled water from other sources. In 2003, tests by the Centre for Science and Environment in India found high pesticides levels in some bottled waters.

Before paying for water that you can get for free from a drinking fountain, or for vastly less cost from a faucet, consider that bottled water may also pose a threat from toxic chemicals that have leached into the water from the plastic. Because leaching can be increased by heat, exercisers who gulp from a water bottle on a hot day may notice a certain plastic taste. But it's infants and children, whose bodies are rapidly growing, who are most vulnerable to potential developmental harm from chemicals that have been found to leach from certain plastics, including polycarbonate, the most common plastic used in baby bottles. Similar harm may come from food packaged in certain plastics.

The good news is that one can easily avoid plastics leaching by nursing rather than bottle-feeding infants, by using--and reusing--containers made of glass, metal and lead-free ceramic, and by taking water from the tap. Such measures will help reduce demand--and therefore supply--of plastics, which are made from petroleum, a nonrenewable resource. And, because not all plastics are created equal, safer plastic containers for food and water can be used in a pinch. One way to tell the kind of plastic a container is made of is to check its international plastics coding number in the chasing-arrows triangle embossed in its surface.

Bad Plastics

#7 Polycarbonate: Most baby bottles and some baby drinking cups are made from clear, rigid polycarbonate plastic, as are five-gallon and some one-gallon water jugs. The problem: Polycarbonate plastics contain bisphenol-A, an estrogenic chemical and known hormone disruptor in lab animals, meaning that it can interfere with the way that hormones guide fetal development. As reported in Current Biology on April 1, 2003, bisphenol-A exposure in pregnant mice resulted in errors in fetal cell division. In another study, male lab rats exposed in the womb to bisphenol-A at low levels showed reproductive abnormalities. Several studies have reported that bisphenol-A can leach from plastic when heated or exposed to acidic solutions, or after prolonged use. The potential for leaching provides yet one more reason to choose breastfeeding, which delivers preheated milk from a safe, natural container. At times when bottles must be used, alternatives include tempered glass or opaque plastic baby bottles made of polypropylene (#5) or polyethylene (#1), which do not contain bisphenol A.

#3 Polyvinyl Chloride (PVC): This virtually unrecyclable plastic's manufacture and incineration release dioxins, which are carcinogens and hormone disruptors. In contact with hot and/or fatty foods, PVC can also leach chemicals such as adipates and phthalates, which have been shown in mice to cause birth defects and damage to the liver, kidneys, lungs and reproductive systems. Unfortunately, PVC cling wrap is used in most supermarkets and delis to wrap cheeses and meats.

#6 Polystyrene can leach styrene, a possible human carcinogen which may also disrupt hormones. It's easy to dodge by imbibing hot drinks from glass or ceramic rather than foam cups, rejecting plastic cutlery, and never heating food in polystyrene containers (they'll not only leach but melt into your food, as well as give off toxic fumes).

Better Plastics

Most 1-, 1.5-, 2-liter and smaller beverage bottles are made from #1 PETE/PET or #2 HDPE. Although PET has generally been considered the safest plastic bottle choice, a recent Italian study found that the amount of DEHP, an endocrine-disrupting phthalate and a probable human carcinogen, in bottled water increased after 9 months' storage in a PET bottle. So, while PET isn't one of the worst offenders, next time you or your child get thirsty in the park, save your money and look for a drinking water fountain.

Finally, the following plastics have not been shown to leach any carcinogens or endocrine disruptors.

#2 HDPE: includes many reusable food storage containers, pitchers, etc.

#4 LDPE: includes some plastic wraps, baggies, and baby bottle liners.

#5 Polypropylene: includes some drinking cups for children, some reusable athletic squeeze bottles, reusable food containers, yogurt and margarine tubs.

For more information and lists of specific brands of bad/better plastics, see Product Reports on "Plastics for Kitchen Use" and "Bottled Water" at www.thegreenguide.com.

Mindy Pennybacker is editor of Green Guide, published by The Green Guide Institute, which provides the research for this department.