Hiking Tech Notes

Water Impurities

The two major types of water impurities are biological and chemical. Most wilderness areas and hiking terrain are at higher elevations and above or up stream of any outposts of "civilization". So in most wilderness areas chemical contamination is not a real problem. The primary exception to this rule of thumb is in some desert areas where dissolved chemicals may reach toxic levels through evaporation.

Biological impurities on the other hand potentially exist in almost any water source except possibly right at a spring because they are carried not only by other hikers but also by animals. Biological contaminates may be microorganisms, bacteria, or viruses.

The two most common microorganisms to contaminate a hiker's water sources are Giardia and Cryptosporidiosis. Chemical treatments are typically less effective against these than boiling or filters.

Many different forms of bacteria and viruses may also cause discomfort if ingested from contaminated water sources. Coliform and E coli are bacteria sometimes found in water that may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. Boiling and chemical treatments are typically more effective against bacteria and viruses than are filters.

Related Information:

Water Purification

Chemical Purification

Related Information from other Web Sites:

• Giardius Fact Sheet
• Cryptosporidiosis: Sources of Infection and Guidelines for Prevention
• Cryptosporidiosis: Fact Sheet
• Cryptosporidium: A Waterborne Pathogen