Team Number: 072
School Name: To'hajiilee Community School
Area of Science: Environmental Science
Project Title: Water Contamination
Our community's water system has been experiencing water problems with hard water and contaminants such as bacteria and alkali. The contamination of the water was considered hazardous to the health of community members, and in fear of fatal illnesses, they did not use or mainly drink the water. Instead, they were forced to haul water from nearby cities such as Albuquerque and Gallup. We decided that instead of sitting around and doing nothing that something needed to be done. So we are currently holding a series of investigations to determine the leading contaminant of the water system.
The purposes of our investigations are to:
Water is a great solvent that can easily pick up impurities. Pure water is tasteless, odorless and colorless, and is often referred to as the universal solvent. When pure water is mixed with carbon dioxide a very weak carbonic acid it produced, resulting in an even better solvent. As the water moves through soil and rock, it dissolves very small amounts of minerals and holds them in solution. The calcium and magnesium dissolved in the water are the two most common minerals that are known to make the water "hard."
Hard water interferes with almost every cleaning task from laundering and dishwashing to bathing and personal grooming. Clothes laundered in hard water may look dingy and feel harsh and scratchy. Dishes and glasses may be spotted when dry. Hard water may cause a film on glass shower doors, shower walls, bathtubs, sinks, faucets, etc. Hair washed in hard water may feel sticky and look dull. Deposits in pipes may reduce water flow.
Dealing with hard water problems in the home can be a nuisance. The amount of hardness minerals in water affects the amount of soap and detergent necessary for cleaning. Soap used in hard water combines with the minerals to form a sticky soap curd. Some synthetic detergents are less effective in hard water because the active ingredient is partially inactivated by hardness, even though it stays dissolved. Bathing with soap in hard water leaves a film of sticky soap curd on the skin. The film may prevent removal of soil and bacteria. Soap curd interferes with the return of skin to its normal, slightly acid condition, and may lead to irritation. Soap curd on hair may leave it dull, lifeless, and difficult to manage.
Hard water also contributes to inefficient and costly operation of water- using appliances. Heated hard water forms a scale of calcium and magnesium minerals that cab contribute to the inefficient operation or failure of water-using appliances. Pipes can become clogged with scale that reduces water flow and ultimately requires pipe replacement.
Hard water is not a health hazard. In fact, the National Research Council (National Academy of Sciences) states that hard drinking water generally contributes a small amount toward total calcium and magnesium to the diet.
Researchers have studied water hardness and cardiovascular disease mortality. Such studies have been "epidemiological studies," which are statistical relationship studies.
While some studies suggest a correlation between hard water and lower cardiovascular disease mortality, other studies deny a correlation. The National Research Council states that results at this time are inconclusive and recommends that further studies should be conducted.
The hardness of our water will be reported in grains per gallon, milligrams per liter (mg/l) or parts per million. One grain of hardness equals 17.1 mg/l or ppm of hardness.
The Navajo Environmental Protection Agency establishes standards for drinking water, which fall into two categories - Primary Standards and Secondary Standards. Primary standards are based on health considerations and Secondary Standards are based on taste, odor, color, foaming and staining properties of water. There is no Primary or Secondary standard for water hardness. Water hardness is classifies by the U.S. Department of Interior and the Water Quality Association as follows:
Classification mg/l or ppm grains/gal Soft 0 - 17.1 0 -1 Slightly Hard 17.1 - 60 1 -3.5 Moderately Hard 60 - 120 3.5 - 7.0 Hard 120 - 180 7.0 - 10.5 Very Hard 180 & Over 10.5 & Over NOTE: Other organizations may use slightly different classifications.
The purposes of our investigations are to: