HE+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? 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. 2.) Why are water hardness levels important to the ecosystem? 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. 3.) What important ion do fish need to survive? 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. 4.) What are some potential sources for Magnesium and Calcium ions? 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. 5.) Predict: If you have high levels of hard water, how would the pH of the water be affected. 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. So, the pH of the water would be affected by how the dissolved minerals would act as a buffer and would then reduce the amount of acid in the water.

Procedure See attached procedure and safety information below. 1.) What are the safety concerns for the chemicals in this lab? With the potassium sodium tatrate the vapors and the liquid can cause irritation to the eyes, skin, and respiratory system. It is also harmful if swallowed. With the magnesium chloride it can cause severe eye and skin irritation and it is harmful is swallowed. 2.) How do you calculated Magnesium Hardness Subtract the mean calcium hardness from the mean total hardness.

Data The first trial that we did the hardness came out to a little over 200 parts per million and then the second trial the calcium was 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!) The average concentration of calcium in river water is between 13.4 and 14 mg/L. The recommended upper limit in public water supplies is 0.05 mg/L. Manganese is often present to the extent of more than 1 mg/L in streams that have received acid drainage from coalmines. http://www.leo.lehigh.edu/projects/hydroprobe/wqdef.html

Conclusion 1.) What were the challenges of this particular water test? That we added the whole amount of the hard #7 for the first test which we were only supposed to add one drop at a time. 2.) What might you do differently next time? Be more careful and make sure that were just adding one drop at a time.