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Water Quality
Water quality testing determines whether water is safe for different types of use such as swimming, fishing, drinking, and irrigation. Knowledge of the water quality within your watershed provides understanding about human activities and our role in the ecological processes. Typically, tests for water quality identify several indicators that can be used to determine the health of a watershed. Key indicators include alkalinity, dissolved oxygen, nitrates, pH, temperature, and turbidity.

Alkalinity measures the ability of the water to neutralize (or buffer) acids and keep the pH from changing. Sources: Rocks, soils, salts, plant activities, and certain wastewater discharges. Effects and Hazards: High water alkalinity causes higher algae and plant growth; while low alkalinity indicates that the water's ability to buffer acids is poor. If there are drastic changes in alkalinity, many chemical and biological processes will be affected.

Dissolved oxygen
Dissolved oxygen measures the presence of oxygen gas molecules in water. These oxygen molecules keep organ- isms living, sustain species reproduction, and support many chemical processes that occur in water. Water that maintains high dissolved oxygen levels is generally considered environmentally healthy; although saltwater, warm water, and water at high altitudes can contain less dissolved oxygen and still be part of a health-sustaining ecosystem. Effects and Hazards: Low dissolved oxygen levels stress fish and other aquatic organisms.

Nitrates are essential for plant growth, although too much nitrate may indicate a pollution problem. Sources: Soil, animal wastes, and decomposing plants; sewage, fertilizers, and animal waste. Effects and Hazards: High levels of nitrates affect dissolved oxygen levels and lead to excessive plant growth, affecting the types of plants and animals that can live in the water. Infant blood poisoning, cancer, and genetic changes have been attributed to high levels of nitrates.

PH measures the acidity of a solution as an "index" of the amount of hydrogen ions present in a substance and affects many chemical and biological processes. Sources: Acidity increases due to mine draining, industrial waste, and acid precipitation.

- PH is measured on a scale of 0-14, with a neutral pH at 7
- A pH less than 7 is an acid, with more hydrogen ions
- A pH greater than 7 is basic and has more hydroxide ions
- Most natural water has a pH value between 5.0 and 8.5. Rainwater has a pH between 5.5 and 6.0. Salt water has a pH between 8.0 and 8.5
- Most aquatic animals prefer a range of 6.5 to 8.0
- All water with a pH of less than 5.0 or greater than 8.5 should be viewed as suspicious.

Temperature measures the degree of heat in the water, which affects the rate of many of the waterways' biological and chemical processes and the amount of dissolved oxygen. Sources: Air temperature, the amount of runoff, the temperature of water running into the waterway, amount of sunlight, and water cloudiness. Effects and Hazards: Temperature affects the rate of photosynthesis and decomposition in plants. High temperatures may be a sign of pollution from industrial sites.

Turbidity is the clarity of the water. Clear water has a low turbidity while murky water has a high turbidity. Sources: Small particles suspended in water such as algae, clay, microorganisms, silt, organic chemicals, decaying vegetation, or chemical wastes. Effects and Hazards: Turbidity can interfere with the process of disinfecting water.

From top to bottom:
Liquids used to measure water for how much Alkalinity it has

A meter called the D.O. meter that is used to measure how dissolved oxygen is in water

A diagram that shows how nitrates are circulated in the nitrogen cycle

The strips Adnan and Dave used to measure the PH level of the water they tested

An instrument used to measure temperature called a thermometer

A scientific instrument used to measure turbidity called a turbidity meter

Profeser Dillan Jackson is testing water in a Loiusiana town