Regret the Error

A story about wilderness survival in the Arts & Life section Nov. 22 stated that chemicals were just as good as boiling to purify drinking water. According to the Ohio Department of Health and NSF International, a non-profit group that tests water filtering systems, chemicals such as iodine and chlorine will work on many but not all contaminants. Both say water must be brought to a full boil for one minute to kill cryptosporidium, a parasite that can occur in the fecal contamination of water. Some filters also will remove the parasite. Link