Other Resources ¦ Ice Storm and Safety Info

WATER PURIFICATION

Montreal water purification plants lost power briefly during the ice storm. Fortunately, there was still water available to flush toilets. The population was instructed to boil drinking water, cooking water and water used to brush teeth, for five to 10 minutes due to the contamination which passed into the water supply. This is an effective method of killing bacteria and viruses if the degree of contamination is not too great. In some areas, the water was too contaminated and people were asked not to use the tap water at all.

In some regions outside of Montreal people still do not have a good water supply (day 12) and they may have no water at all where it must be pumped with electric motors. Micropore filtration of water effectively removes bacteria and parasites but not viruses (such as those which cause hepatitis). Chlorine is not to be relied upon except as used in municipal water treatment plants. Bleach (Javel; Javex) must not be added to water used for drinking or cooking. Do not use iodine when pregnant or if you have iodine sensitivity or thyroid disease. Some water purification techniques which individuals can use are described below (there are also other products on the market which you should check out):

• Diatomic iodine reliably disinfects water, destroying bacteria, viruses, parasites and parasitic cysts. A concentration of 0.5 mg/L (0.5 parts per million) is adequate if parasites are not a problem, otherwise 8 mg/L (8 parts per million) should be used. Water containing 8 mg/L of iodine has a definite brown colour. Cloudy, heavily contaminated water may require 16 mg/L of iodine to effectively disinfect the water for drinking and cooking purposes. Contact time must be 10 minutes in warm water (23 C) or 20 minutes in cold water. Daily consumption of one to two litres of water disinfected with 8 mg/L of iodine would provide thirty to eighty times the amount of iodine required by the average adult, but such quantities would not affect most individuals with normal thyroid function. Most people who have developed iodide goiter after consuming excess iodide have consumed far larger amounts for six months or more. As a comparison, the recommended dose of potassium iodide for asthmatics is 1.2 to 8.0 gm daily (equivalent to 0.9 to 6.0 gm of iodine).

• One fresh tablet of tetraglycine hydroperiodide (Globaline; Potable-Aqua) dissolved in one litre of water will provide an iodine concentration of 8 mg/L. Sealed tablets can be stored for months with little loss of iodine whereas tablets exposed to air at 23 C and 100% humidity lose 33% of their iodine after four days. Members of the U.S. Army are supplied with tetraglycine hydroperiodide tablets individually packaged in metal foil.

• Concentrated alcoholic iodine solutions can also be used. They are reliable, compact and resist freezing. If a solution contains 8 gm of iodine in 100 mL (100 cc) of 95% ethanol, then only 0.1 mL needs to be added to each litre of water to be disinfected. A volume of 100 mL of concentrated alcoholic iodine solution will disinfect 1000 litres of water. These solutions are not readily available, they require an accurate measuring device and they must be stored in a glass container.

• Tincture of iodine (2% iodine and 2.4% sodium iodide in 50% alcohol) is reliable, easily available and resistant to freezing. However, it imparts a strong taste to the water, causes unnecessary consumption of extra iodine due to the presence of the salt, is bulky and must be stored in a glass container.

• Quaternary ammonium anion exchange resins combined with iodine (Mini Water Purifier; Walbro Water Purifier; Water Tech Travelmate Water Purifier) are convenient, effective and leave no iodine taste, but they are tedious to use and there is no indicator that the resin has been exhausted and is no longer able to purify the water.

• Crystalline iodine (Kahn-Visscher method) is reliable and compact, but it is not readily available, there is the possibility of ingesting iodine crystals and it must be stored in glass containers.

• A carbon filter can be used to remove the chemical taste of treated water.

CC Austin, PhD

© 1998 SAREC - All rights reserved (Updated 98/01/21) http://www.sarec.ca/ice
Contact CC Austin, PhD, to obtain special permission to reproduce and distribute this safety bulletin (at no cost) within the context of the current ice storm disaster.
This copyright notice must be included with all reproductions of this safety bulletin. Telephone: (514) 989-3720 Email: caustin@sarec.ca