Skip Navigation
Button that takes you to back to the home page. Button that takes you to the teacher pages. Button that takes you to the modules and activities page. Button that takes you to the related links page. Button that takes you to the references page. Button that takes you to the Problem Based Learning model page. Button that takes you to the glossary page.Image map of some Water Quality puzzle pieces.  Please have someone assist you with this.

Button that takes you to the Overview page.
Button that takes you to the Biological Assessment page.
Button that takes you to the Chemical Assessment page. Button that takes you to the pH page. Button that takes you to the Alkalinity page. Button that takes you to the Nitrates, Nitrites, and Ammonia page. Button that takes you to the Ortho-and Total Phosphate page. Button that takes you to the Dissolved Oxygen and Biochemical Oxygen Demand page. Button that takes you to the Fecal Coliform page. Button that takes you to the Conductivity and Density page. Image that says Hardness.
Button that takes you to the Physical Assessment page.

Water Quality Assessment: Chemical: Hardness
Image of stream water.Stream water hardness is the total concentration of cations, specifically calcium (Ca2+), magnesium (Mg2+), iron (Fe2+), and manganese (Mn2+), in the water. Water rich in these cations is said to be "hard." Stream water hardness reflects the geology of the catchment area. Sometimes it also provides a measure of the influence of human activity in the area. For instance, acid mine drainage often results in the release of iron into a stream. The iron produces extraordinarily high hardness readings. For these reasons, hardness is a useful water quality indicator. Photo 1999 -www.arttoday.com

For the most part, however, hardness is a reflection of the amount of calcium and magnesium entering the stream through the weathering of rock such as limestone (CaCO3). When limestone is weathered, it dissolves into calcium (Ca2+) and carbonate (CO32-). Calcium is an important nutrient that is used by plants and animals. Carbonate buffers the stream's pH . Although these two ions are beneficial to a stream, they can cause problems in a home. Foaming agents such as those in soaps and detergents do not work as well in hard water. Also, hard water tends to leave hard, scaly calcium deposits on faucets. This is why many people install water softener systems in their homes.

 

Overview ..|.. Biological Assessment ..|.. Chemical Assessment ..|.. Physical Assessment.

pH / Alkalinity / Hardness / Nitrates. Nitrites, and Ammonia / Ortho- and Total Phosphate / Dissolved Oxygen and Biochemical Oxygen Demand / Fecal Coliform / Conductivity and Density
Glossary  .|
Related Links  .|.. References ..|.. PBL Model  .|

  Home ..|.. Teacher Pages ..|.. Modules & Activities  

Button that takes you back to the Water Quality main page.

HTML code by Chris Kreger
Maintained by ETE Team
Last updated November 10, 2004

Some images 2004 www.clipart.com

Privacy Statement and Copyright 1997-2004 by Wheeling Jesuit University/NASA-supported Classroom of the Future. All rights reserved.

Center for Educational Technologies, Circuit Board/Apple graphic logo, and COTF Classroom of the Future logo are registered trademarks of Wheeling Jesuit University.