# Math of plastic water bottles

By Murray Bourne, 22 Apr 2009

Today is Earth Day. I have become somewhat cynical of these one-off "environmental awareness" events, since they cause a flurry of activity for a short time, then fade away. But at least it's a start and if we manage to convince a few people to look after the planet a bit better, I guess it's worth it.

## The Plastic Water Bottle Scourge

In many countries, there is no tap water at all, so clean bottled water is a valuable resource. In certain other countries, the tap water is so polluted that many people will use bottled water if they can afford it (I always do so when I am traveling around Asia).

But in the countries where tap water is abundant and (reasonably) clean, why is there such a love affair with plastic bottles?

In the US, sales of bottled water have skyrocketed, to around 30 billion plastic bottles sold during 2005.

The environmental cost of this is huge:

• The plastic is a petroleum product and its manufacture pollutes air and water
• Transport of the bottles uses up more gasoline
• The water may have been pumped from river systems that are already fragile, disturbing wildlife and livelihoods downstream
• A large proportion of plastic bottles are not recycled (or cannot be recycled) so they go into landfill, or end up in waterways and the oceans, ready to be consumed by wildlife
• Re-using plastic water bottles can mean ingesting toxins - they are normally intended to be one-use affairs (of course, to increase sales).

The dollar cost: Tap water typically costs around 1/20 of 1 cent per litre, but consumers spend between 240 and 10,000 times as much on bottled water. (Bottled water is $500–$1,000 per cubic meter, compared with 50¢ per cubic meter for tap water in California. One cubic meter of water is 1000 L, so 1 liter costs 0.05¢. That's not 5¢, it's 0.05 of 1 cent.)

This is yet another example of consumerism gone mad. It's ridiculously expensive, it's polluting, it's toxic and in many cases, it's unnecessary.

When you need to carry water with you, do yourself, and the Earth, a favor — use a re-usable bottle and be happy with tap water (filter it if you must).

[Image sources: Kiki and Quinn.anya.]

### 3 Comments on “Math of plastic water bottles”

1. zb says:

Down here (Aus) just recently they had segment on the topic during 60minutes (or something like that). There is 1000+ different options of bottled water - you name a condition, and they have specialised water for it; even dogs are included! Unsurprising, independent research showed no truth in the claims of the tested sample. Though, manufacturer is using nutrition scientifically found to help the cause, the concentration of it in the 'water' is negligible to make any difference. justMarketing...!

Ps: not taking the placebo into consideration :p

2. Joeseph says:

I think that we all should turn to water purifiers cause there are bad things in our tap water. My water quality in the area that I live in has a grade of D.

3. Crystal Beverage Co. says:

Yes, I totally agree with what you said. I think that it is better to stop buying bottled water to reduced the waste in the environment that harms the animals. I also think that we can save a lot money when we switch to tap water. Thanks for sharing this article.

### Comment Preview

HTML: You can use simple tags like <b>, <a href="...">, etc.

To enter math, you can can either:

1. Use simple calculator-like input in the following format (surround your math in backticks, or qq on tablet or phone):
a^2 = sqrt(b^2 + c^2)
(See more on ASCIIMath syntax); or
2. Use simple LaTeX in the following format. Surround your math with $$ and $$.
$$\int g dx = \sqrt{\frac{a}{b}}$$
(This is standard simple LaTeX.)

NOTE: You can mix both types of math entry in your comment.

## Subscribe

* indicates required

From Math Blogs