Ask A Scientist Chemistry Archive

name         Frank R.
status       educator
age          50s

Question -   I am often asked what is the appropriate plastic
container to store water in for drinking purposes. When using water
machines in stores, various plastic containers are for sale.
Please provide which codes (1through7) are not toxic to your health.
Certain plastics will leach chemicals into the water contained
within.  Which are the good and bad codes?
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The Food and Drug Administration (FDA) determines what materials, and how
much, is allowed to come into contact with foods. Food packagers, and I
assume bottled water falls under these regulations, must supply data showing
how much (if any) of the components of the packaging migrates into the food
contained therein.
There are different categories, for example, dry food, fatty foods (meats,
potato chips, etc.), aqueous foods and so on. There are also different
regulations for "direct" and "indirect" contact, that is, packaging that
actually touches the contents, and packaging (for example the outer
container of a cereal box) that "might" come into incidental short-term
contact with the contents. If I remember the number correctly the
regulations and prescribed test methods are published in the Code of Federal
Regulations (CFR--21). I think you can be fairly certain that any food
substances you find on the grocery shelf has been rather thoroughly tested
(or is "grandfathered") to conform with these regulations. A much higher
risk is posed by consumers who wrap or store foods in container materials
not intended for food contact-- for example putting homemade cookies on
newspaper to cool off.

Vince Calder
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All the plastics coded 1 through 7 can be made in grades that are approved
for use as food containers.  You do not really need to worry about the
leaching of chemicals from the plastics.  Even the plastics that can exude
some components upon prolonged content do so in such low amounts that it is
not a health issue.  The chance of being injured by a car as you are on your
way to the store to buy bottled water is much, much greater than the chance
that your health will be impaired by drinking water from a plastic
container.

Richard E. Barrans Jr., Ph.D.
PG Research Foundation, Darien, Illinois
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