Chemical and physical properties of water quality

1. Envirothon 2009 Chemical and physical properties of water quality

2. pH • pH ranges from 0-14 • 0 is the most acidic • 14 is the most basic/alkaline • 7 is neutral • Most healthy bodies of water in the U.S. are between 6.5 and 8.5. • Certain macros exist in certain pH ranges

3. alkalinity • Alkalinity is a measure of how well water can neutralize acids that might get added • Should be between 20-200 mg/L • Less than 20 mg/L means the water cannot easily buffer changes in pH • Acids can be added from acid rain and other environmental pollutants • Determined by the geology (rocks) that the water flows through. • Link to Wilkes alkalinity info

4. Dissolved oxygen • D.O. is the amount of oxygen dissolved in a body of water • The more O2 that is dissolved, the more that is available to living organisms • Changes with temperature • Cold water holds more O2 than warm water.

5. Stream velocity • Determined by depth and width of stream • Narrow streams are often faster and colder • Wide streams are slower and warmer • Will have greater velocity if the stream is the same depth all along its route • Certain macros are adapted to live in faster streams while others must live in slow water.

6. Water temperature • Affects the amount of dissolved oxygen • Cooler water holds more oxygen • Affects rate of photosynthesis • Warmer water = faster photosynthesis • Affects organisms’ sensitivity to pollutants • Warmer water = higher sensitivity • Link to temp website

7. Turbidity • Measure of how much suspended matter is in the water • Cloudy water has lots of silt, sand, clay and organic material floating • Certain macros must live in clear water (clogs up gills, for example) • Some macros are adapted to live in more turbid water. • Comes from erosion, runoff, algae blooms and sediment disturbances