Managing waste also uses up a lot of energy, so recycling is a good second choice to reuse. HDPE is therefore a better option than gable-top cartons, as long as you actually place it in the blue bin rather than tossing it in the trash.
Given its high costs and third-place environmental finish, you might wonder why the gable-top carton is still hanging around the dairy case. It's probably because ultraviolet light, which can penetrate clear glass bottles (PDF) and HDPE (PDF), degrades vitamins A and D and riboflavin. That's no small matter, considering between one-third and one-half of American adults are vitamin D deficient.
There are other choices out there. Manufacturers have experimented with refillable HDPE containers on a small scale. Plastic pouches for milk, though neither recyclable nor refillable, require fewer environmental resources than even reusable glass bottles. While the Lantern remembers when his elementary school cafeteria flirted with this approach, American consumers, so far, seem a little uneasy with the amorphous sacks. And maybe we just don't want another option.
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