Friday, October 3, 2008

Plastic Bottle Codes

Do you ever wonder what are those codes found at the bottom of plastics bottles.The symbols used in the code consist of arrows that cycle clockwise to form a rounded triangle and enclosing a number.Well these are the SPI resin identification coding system developed by the Society of the Plastics Industry.The SPI resin identification code (also known as the material container code) system has been developed to provide a consistent national system to facilitate recycling of post-consumer plastics through the normal channels for collecting recyclable materials from household waste. Improper use of the SPI resin identification code can have serious ramifications for individual manufacturers and could jeopardize the integrity of the coding system.

The summarize the meaning of each numbers.

#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.

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