We know we want to have clean water, but how can we know?
* An easy way to know that our water is not clean is to see if it is turbid. Turbid means cloudy which is caused by bits of sediment (solids) in the water.
* Another thing that decreases water quality is the temperature. Warm water contains less dissolved water than cold water. (faster moving particles have more chance for gas to escape) Therefore, when industries (such as nuclear power plants) cool down machinery with water and then release it back into the water, it increases the temperature which can be harmful to our drinking water.
* Acidity- a pH of 7 is what we call neutral. If it has a pH below 7, it is an acid and if it is above 7 it is known as a base. * Fresh water is between 6.5 and 8.5. Lucky for us we have the ability to test for acidity with lots of different things. One such thing is called litmus paper that will turn red or blue depending on if it is an acid or a base.
* Salt- Pure water doesn't actually conduct electricity, but salt water conducts electricity very well. Therefore if you can run a current though water, you can test to see if there is salt in it.
* Other substances such as chlorine, nitrates, iron, copper, calcium and magnesium can be tested through various paper test strips, similar to litmus paper.
* Continental divides- high regions that divide North America so that water drains towards the large bodies of water. See page 298.
* These regions are call watersheds. The Great Lakes Basin is a watershed that flows into the great lakes. This means these large bodies of water will get all runoff from lots of different places. Therefore contaminants could come from very far away.
* The great lakes are a large source of fresh water, so when they were getting polluted, the Canadian and American governments signed an agreement to stop pollution from getting into the great lakes.
* One way to reduce pollutants is to introduce specific organisms that feed on the pollutants. This is called bioremediation. Bacteria can convert spilled oil into carbon dioxide and water. Certain plants can take in metals, thus removing them from water.
* Certain areas called wetlands act as natural filters and rid the water of bacteria, waste solids and excess nutrients. It is possible for us to conserve these wetlands and then use them to help clean water. In Europe they are using wetlands to help treat wastewater.