TEST 7: TURBIDITY
Brief Summary The measure of water's cloudiness. This test measures turbidity by comparing a turbid sample with a clear sample, then adding drops of a special clouding solution to the clear sample until it appears as cloudy as the turbid sample. The results are measured in Jackson Turbidity Units (JTUs). Background Turbidity is a measurement of how cloudy water appears. Technically, it is a measure of how much light passes through water, and it is caused by suspended solid particles that scatter light. These particles may be microscopic plankton, stirred up sediment or organic materials, eroded soil, clay, silt, sand, industrial waste, or sewage. Bottom sediment may be stirred up by such actions as waves or currents, bottom-feeding fish, people swimming, or wading, or storm runoff. Clear water may appear cleaner than turbid water, but it is not necessarily healthier. Water may be clear because it has too little dissolved oxygen, too much acidity or too many contaminants to support aquatic life. Water that is turbid from plankton has both the food and oxygen to support fish and plant life. However, high turbidity may be a symptom of other water quality problems.
Effects of Turbidity
• Turbidity diffuses sunlight and slows photosynthesis. Plants begin to die, reducing the amount of dissolved oxygen and increasing the acidity (decaying organic material produces carbonic acid, which lowers the pH level). Both of these effects harm aquatic animals. • Turbidity raises water temperature because the suspended particles absorb the sun's heat. Warmer water holds less oxygen, thus increasing, the effects of reduced photosynthesis. In addition, some aquatic