MM+Task+3

=__**Water Test: Total, Calcium and Magnesium Hardness**__=

Hard water is a term that is often used when referring to level of dissolved minerals that are present in the water. Water that is considered to be hard, has a high concentration of these minerals. Water that is soft, has a low concentration of minerals. Water hardness is caused by the dissolving of minerals to form ions in the water. Two minerals, calcium and magnesium, typically come from limestone rock that had dissolved into the water. Areas that have high levels of limestone will tend to have high levels of calcium and magnesium.

Water hardness is an important biochemical aspect in the ecosystem. Calcium is one of the minerals that we measure when we detect water hardness. Fish and other species need this important mineral in their daily lives. Some of the reasons they need it is for bone formation and proper blood clotting. This is why it is important that safe levels of these mineral ions are present in the water.

Hard water is also linked to pH levels. Water that has a high levels of hardness, tend to be high in pH as well. This is because the dissolved minerals act as a buffer and can reduce the amount of acid in the water. Water that is low in levels of hardness, tend to be low in pH because there are not as many minerals to help buffer the acid.

Please refer to these and other resources to help you with your research.

Resources [|Understanding Water Hardness] [|USGS - Water Hardness and Alkalinity]

1.) What does it mean when your water is considered to be hard? When water is considered to be hard that means it has a high concentration of the minerals. 2.) Why are water hardness levels important to the ecosystem? Water hardness levels are important to the ecosystem because it affects fish and other species that need that mineral in their daily lives. 3.) What important ion do fish need to survive? Calcium is an important ion fish need to survive. 4.) What are some potential sources for Magnesium and Calcium ions? Calcium and magnesium are typically from limestone rock that has dissolved into the water. 5.) Predict: If you have high levels of hard water, how would the pH of the water be affected. If there are high levels of hard water, the pH would raise as well. If the pH level is too high or low it might not be at a safe level anymore for the fish and other species living in the area.

Procedure See attached procedure and safety information below. 1.) What are the safety concerns for the chemicals in this lab? Some safety concerns for the chemicals in this lab are irritation to eyes, skin and respiratory system.

2.) How do you calculated Magnesium Hardness? You calculate Magnesium hardness by calculating the mean total hardness and mean calcium hardness from your 3 (or more) replicates. Subtract the mean calcium hardness from the mean total hardness. Record magnesium hardness as mg/l CaCO3. Mg Hardness (mg/l CaCO3) = Mean Total Hardness - Mean Ca Hardness.

Data The first test we added too much Hardness #7 and we had over 200 Parts Per Million. The Second test we only needed to add 48 Parts Per Million.

Analysis Using the internet and other resources, determine what levels of calcium and magnesium hardness are safe for aquatic organisms. (BE SURE TO CITE YOUR SOURCE!)

Aquatic animals can tolerate a broad range of calcium hardness concentrations. A desirable range would lie between 75 and 200 mg/L CaCO3.

Conclusion 1.) What were the challenges of this particular water test? Some challenges of this water test was that we added too much Hardness #7 because we didn't see the blue as blue, we saw it more purple when it was really a blue. 2.) What might you do differently next time? Next time I would be more careful with watching the color change.

__Cites__

http://www.ca.uky.edu/wkrec/AlkHardness.htm