Adding chemicals to your water to make it cleaner seems to be counter productive. Don't we want to eliminate contaminates? The answer really comes down to choosing the lesser of two evils. Yes, the chemicals used to treat water can do damage to your body with long term exposure. Drinking untreated water, however, can wreak havoc on your body in the short term with very little exposure.
There are numerous chemicals that we can use to treat our drinking water. The most popular are various forms of iodine or chlorine. There are tons of chemicals that can purify water, but if you go to a camping store and look for "water purification tablets" they will most likely be a form of iodine or chlorine. There are actually about a dozen types of iodine and chlorine used for water purification. Each has its own set of pro's and con's. Since I am not a chemist and do not have the background necessary to describe these in depth, we are just going to look at the two in general terms.
Iodine simply works better in most circumstances than chlorine. It is more stable, works faster, is not as easily deactivated, and tastes better (opinion) than chlorine.
No one knows how it kills microorganisms, but we know that it does. It easily kills bacteria and viruses, but struggles with Giardia and Cryptosporidium. In fact, Giardia requires a double dose of iodine and a double the time required to be effective. It basically will not kill all Cryptosporidium, even in a laboratory.
It is best to double the recommended contact time when the water is cold or murky. You can also half the recommended dosage in clear, warm water if you double the contact time. This is a useful trick if you are running low on tablets.
If you do not like the taste, a small amount of vitamin C will neutralize it. Be careful though, if the iodine is not finished working, the vitamin C will prevent the water from being purified.
Do not use iodine daily for more than three months, or if you are pregnant. Also, be careful if you are allergic to shellfish. People that are allergic to shellfish are often allergic to iodine.
Chlorine works great for bacteria and viruses. Like iodine it does poorly with Giardia and does not work at all on Cryptosporidium. It will kill protozoa, but requires a concentration so high, it would damage you too.
It is great for long term water storage. Once water is properly treated it can be stored for long periods of time. You can tell if water is properly treated if it smells like chlorine. If it does not smell like chlorine, you need to add more.
Chlorine has a nasty habit of binding to organic debris in water. If the water is murky it will stick to the dirt and plant matter in the water instead of attacking the bad stuff. Also, it does not work well in water with high PH or in water that is being agitated. Your container has to sit still for it to work.
Chlorine is very safe to use. The chances of it making you sick is very small.
If you have a choice between chlorine and iodine, go with iodine every time. It simply works better.
Here are some general tips when using chemicals to treat water:
- Use the clearest water possible and pick out any debris that you can.
- All chemicals take some time to work. Read the directions and follow them carefully.
- Chemicals become less effective with age. They come with an expiration date on the package, respect it!
- They do not work as well in cold water, so allow more time for them to work.
- Chemicals will not neutralize or remove pollutants.
As you can see, chemical water purifiers have some serious drawbacks. Why use them? Well, they are small, light weight, durable, and very inexpensive. While they are not perfect, they are better than nothing.