Confluence at Colfax, Palouse Watershed.  Photo courtesy of Brandee Era-Miller, Ecology Environmental Assessment Program.The Environmental Importance of the Different Pollution Problems

Ammonia | Dissolved Oxygen |Fecal Coliform Bacteria | pH | PCBs and Pesticides | Temperature



Ammonia (NH4+) is one measure of nitrogen, a nutrient that can increase the growth of plants and algae in water. When higher-than-normal levels of nutrients are present, plants and algae can get out of control and lead to changes in the water’s pH, dissolved oxygen and clarity. In addition, increased algae and plants can be ugly, create odor problems when they die, decompose and interfere with recreational activities like boating and swimming.

To learn more about nutrients please see our focus sheet: Focus Sheet: Nutrients in Our Lakes and Streams

Dissolved Oxygen

Like people, fish and other aquatic organisms need oxygen to live. As air or water moves past an animal’s breathing apparatus (gills or lungs), oxygen is transferred to its blood. It is more difficult to transfer oxygen from water to blood than it is to transfer oxygen from air to blood. Therefore, it is critical to maintain an adequate amount of oxygen in the water so this transfer can take place efficiently. In addition to being required by aquatic organisms for respiration, oxygen is necessary to help decompose organic matter in the water and bottom sediments. It also is necessary for other biological and chemical processes.

To learn more about dissolved oxygen please see our focus sheet: Focus Sheet: Dissolved Oxygen and the Water Quality Standards

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Fecal Coliform Bacteria

Fecal coliform is a type of bacteria found in the feces of warm-blooded animals. When found in water bodies it can be an indicator of the presence of other disease-carrying organisms. Fecal coliform bacteria can get into water bodies from failing septic systems and animal waste. High levels of fecal coliform in the water can affect the public health, economy, and environmental quality of a community.

A long history of illness outbreaks and epidemics have demonstrated a relationship between the presence of fecal coliform bacteria and the presence of illness-causing viruses and bacteria, called pathogens. These pathogens can be accidentally swallowed with water. People swimming or playing in water can be exposed to pathogens when they enter the body through small cuts, abrasions or mucus membranes.

Some of the symptoms of illnesses associated with fecal coliform pathogens are minor, such as upset stomach, diarrhea, ear infections, and rashes. However, some pathogens, such as E coli, hepatitis, and Salmonella, can have very severe health effects. Washington State’s water quality standard for fecal coliform bacteria is set to protect public health.

People can help keep bacteria out of the water. Properly collect, bag, and trash dog poop. Check your on-site sewage system to make sure it is maintained and working properly.

For more on fecal coliform check out our focus sheet:

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PCBs and Pesticides

Pesticides and polychlorinated biphenyls (PCBs) can be toxic to fish and wildlife that use a contaminated water body.

In the past, PCBs were used as coolants and lubricants in electrical equipment such as transformers and capacitors. The United States banned the manufacture of PCBs in 1977 because they build up in the environment and can be harmful to humans and wildlife. PCB exposure can occur if you:

The pesticides found in the Palouse River are no longer used, but are still an environmental concern.

Although all these pesticides have not been used for over a decade, they tend to persist in the environment and can be toxic to fish and wildlife and humans when they eat contaminated foods.

To learn more about PCBs and pesticides, see the Agency for Toxic Substances and Disease Registry’s (ATSDR) fact sheets:

If you have pesticides you no longer use check the following website for free pesticide collection events:

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pH is a measure of how acidic or alkaline the water is. The pH is measured on a scale of 0-14, with the lower numbers indicating acidic conditions and higher numbers alkaline conditions. Optimal pH levels to support fish and wildlife should range from 6.5 to 9.0. A pH of 7 is neutral.

pH can affect the solubility of nutrients and metal compounds. By affecting the solubility of nutrients, it can change the amount of nutrients available for plant growth. If too many nutrients are available, aquatic plants can grow out of control. When these plants decompose, they can deplete the water of oxygen. The solubility of many metal compounds also changes greatly with pH. Generally, a reduction in pH (more acidic) increases the solubility of heavy metals. When more metals are dissolved in the water, aquatic animals may absorb them faster. Therefore, a lower pH (more acidic) may make these metals more toxic to aquatic life.


pH Scale Graphic.  Graphic source:  The Stream Scene.
Chart showing various pH levels and effects (click on chart to see full view)

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Elevated water temperature is a common problem in many streams in Washington. When temperatures are too high it can make the streams uninhabitable for fish and other aquatic animals. Many salmon and trout species suffer a variety of ill effects ranging from decreased spawning success to death when waters are too warm. The optimal temperature for most salmon and trout species is between 12-14˚C (54-57˚F) and temperatures in the range of 23-25˚C (73-77˚ F) can be lethal, depending on the species. The temperature of the water can also affect how much oxygen is dissolved in the water. The fish need this dissolved oxygen (DO) to breathe. The warmer the water, the less DO it can hold. Warmer temperatures also tend to speed up the metabolism of the fish so they require more oxygen for biological functions.

One way to cool water temperature is to shade the water body by adding or retaining streamside vegetation.

To learn more about temperature check out our focus sheet:

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Last updated August 2013