ALAN SIRULNIKOFF / SCIENCE PHOTO LIBRARY ALAN SIRULNIKOFF / SCIENCE PHOTO LIBRARY
Drinking from a stream. Man using a cup to drink water from a glacial stream. There are many diseases that can be transmitted through contaminated water, but fast-running glacial water will be safer than still (standing) water. Glacial water (which has melted from glacial ice) contains glacial flour (small particles of rock ground up by the weight of the glacier) that should be left to settle to the bottom of a container before the water is drunk. Filters and chemical treatments can be used to remove or kill protozoa, bacteria and viruses, if it is thought that the water is contaminated. This is Cesna Creek in Elaho Valley, British Columbia, Canada.
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