Disaster Water: How Citrus Juice Works
In camping and survival handbooks, a means for sterilizing water at high altitudes employs the use of lime juice in water, and then bringing the water to a boil. What the lime juice purportedly does is lower the killing temperature, which is necessary since water boils at lower temperatures as the air pressure lowers with increasing altitude.
This is not, however, a good method is disaster areas since most high-altitude areas are not where lime trees can grow. Take, for example, the Tibetan city of Kathmandu in the Himalayas. It lies near the tree line, and is subject to numerous earthquakes that result in great damage to its infrastructure – including drinking water distribution systems. Yet, perhaps there is a component on lime juice that might be practicable in Kathmandu. Let’s consider the possibilities.
First, it might be something specific to limes and not to any other citrus fruit. Thus lime juice would work, but lemon- or orange juice would not. That should be easily testable.
Let’s say that all citrus juices work, then we turn to a major component of citrus juice – citric acid, which is a strong chelator. You should test some sodium citrate and other solutions of chelators such as EDTA (Na ethylene-diamine tetra-acetate)
If chelators don’t work, then perhaps you should next simply test the effects of weak acids on the killing temperatures in water. Perhaps the most common non-toxic acid that would be safe to add to water would be acetic acid as in vinegar. After all, vinegar is probably available in almost all cultures around the world.
What to do: You first need to get a wide variety of types of bacteria and add them to your water sample. One of the best such bacterial sources is common garden soil, which has zillions of species, many of which are relatives to known pathogens. When you have such a bucket of water, you dope it with your agent, and then slowly raise the temperature of the bucket. Periodically, you take a swab of the water and make a stripe on an agar plate. (One plate can have many stripes!) You’re interested in when the stripes don’t grow up with colonies.
Distribute your results to missionary societies, who will promulgate your discovery around the world, and save many lives the next time a major disaster hits at high altitudes.