Plastics Numbering System Demystified: Go Green

Ever look at the base of your plastic water bottle and wonder what that little number means? You’d be smart to know those numbers since some of them can be detrimental to your health. Look for the number enclosed in the recycle symbol (arrows that form a triangle) at the bottom of your plastic container.

#1 Polyethylene Terephthalate:Used for most clear beverage bottles, this is the number you’ll likely see at the bottom of your plastic water bottle.
#2 High Density Polyethylene: Used for white plastic milk jugs and opaque food bottles.
#3 Polyvinyl Chloride: Used in some cling wraps and “soft” bottles. Vinyl chloride, the chemical used to make PVC, is a known human carcinogen, according to the World Health Organization’s International Agency for Research on Cancer.
#4 Low Density Polyethylene: Used in food storage bags.
#5 Polypropylene: Used in hard containers, such as the “throwaway types” you buy in the store, some baby bottles, cups and bowls.
#6 Polystyrene: Used in foam “to-go”-type containers, meat and bakery trays, clear take-out containers, some plastic cutlery and cups. According to The Green Guide, “Polystyrene may leach styrene into food it comes into contact with. A recent study in Environmental Health Perspectives concluded that some styrene compounds leaching from food containers are estrogenic (meaning they can disrupt normal hormonal functioning).” Styrene is also considered a possible human carcinogen by the World Health Organization’s International Agency for Research on Cancer.
#7 Other (usually polycarbonate): Used in 5-gallon water bottles, some baby bottles. Polycarbonate is another suspected hormone disruptor.

Takeaway: Avoid number 3, 6 and 7 whenever possible. Because leaching is most prevalent at higher temperatures, pay special attention to microwaveable food containers.

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    Catherine Brock

    As a Southern California transplant now living in the Midwest, Catherine has turned layering into an art form and accepted that UGGs actually do have a place in the stylish lady's wardrobe. She's been featured in Woman's World Magazine,, Refinery29, and has made appearances on ABC7 Chicago, FOX2News St. Louis, KCAL9 Los Angeles, Fox19 Cincinnati, WGN TV Chicago and WCPO TV Cincinnati.

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