In emergencies, which method can be used to disinfect small quantities of water?

Using tincture of iodine is an effective method for disinfecting small quantities of water in emergencies. Iodine has strong antimicrobial properties and can inactivate bacteria, viruses, and some protozoa present in contaminated water. When using tincture of iodine, a typical guideline is to add 5-10 drops of the tincture to one quart of clear water, allowing it to sit for at least 30 minutes before consumption. This method is valuable in emergency scenarios where access to safe drinking water is limited.

In contrast, while the other methods may have specific uses or benefits in particular contexts, they are less suitable or effective for immediate disinfection of drinking water. Salt tablets, for instance, do not provide a disinfecting effect and may even lead to dehydration if consumed in large quantities. Direct exposure to sunlight can be helpful for disinfection in some cases, but it typically requires exposure for a longer duration than specified, usually around 6 hours under optimal conditions. Aluminum salts can be used for water treatment in other contexts but are not a practical or effective choice for disinfecting small quantities of water in emergencies.