Contaminants in backcountry water
Immediate threats:
Pathogenic microorganisms in water sources are the greatest threat to your immediate health. The main source of these pathogens is human and animal fecal waste. When ingested, they can cause gastrointestinal illness which include diarrhea, vomiting, and cramps. At a minimum, treatment techniques should focus on removal of the following pathogens:
Bacteria, examples of which include E-coli and Salmonella. Bacteria typically range in size from 0.2 - 10 microns.
Viruses, examples of which include norovirus and rotavirus. Viruses typically range in size from 0.02 - 0.3 microns.
Protozoa, examples of which include Giardia and Cryptosporidium. Protozoa typically range in size from 1 micron to several millimeters or more.
Other contaminants:
Turbidity is the cloudiness of water, which may be caused by suspended solids, microorganisms, and other particles. Although certain sediments are not necessary harmful, higher levels or turbidity are often associated with higher levels of pathogens.
Inorganic Chemicals may be naturally occurring or caused by anthropogenic activities such as industry and agriculture. Examples include arsenic, mercury, and nitrate.
Organic Chemicals are carbon based compounds which can enter waterways as runoff from agricultural land and through other human activities. Examples include atrazine and benzene.
Natural Organic Matter (NOMs) refers to organic material that comes from the presence of plants and animals. For example, tannins occur in many species of trees and plants. Tannins can leach out of these plants, and as water passes through decaying vegetation it can take on a brown tea-like appearance.
Additional information on contaminants and sanitation of backcountry drinking water sources:
Centers for Disease Control and Prevention