1. Water Quality

2. Water Quality • Water quality is a term used to describe the chemical, physical, and biological characteristics of water. • Factors that affect water quality are broken down into two categories: biotic and abiotic.

3. Water Quality • Biotic Factors: Living factors affecting water quality • Abiotic Factors: Non-living factors affecting water quality

4. Water Quality • Water quality is also described in terms of the water’s intended use. • Water that is drinkable is called potable. • Water than can be used for swimming or bathing is referred to as safe.

5. Water Quality • Water quality standards outline the water pollution control program that is mandated by local, state and federal government agencies. • Primary among these is the Environmental Protection Agency (EPA)

6. Water Quality • Environmental Protection Agency (EPA) • Acts as a Steward of the environment • Sets maximum levels for the 90 most common water contaminants

7. Water Quality • Water quality standards are based on the following questions: • What is the intended use of the body of water? • How can we protect that use? • What long term dangers might the body of water face?

8. Abiotic Factors • Temperature – the temperature of water in rivers and lakes determine the kinds of organisms that can survive there. • Certain species have preferred water temperature ranges. • The temperature of water affects what solids and gasses are dissolved within it. • Warm Water = Less Oxygen • Colder Water = More Oxygen

9. Abiotic Factors • Dissolved Oxygen – (DO) Oxygen that is dissolved in water. • DO is a measure of the amount of oxygen in water that is available for chemical reactions and for use by aquatic organisms. • DO is vital for the survival of micro-organisms, and higher organisms such as zooplankton and fish. • Dissolved Oxygen gets into the water through diffusion with the air (the higher concentration of oxygen in the air causes oxygen to move from the air to the water) and as a by-product of photosynthesis by water plants. • High DO levels in potable water make it taste better

10. Major affects that adjust DO • Water temperature increases and DO goes down. • Increased eutrophication. • Eutrophication: Decreased amount of DO in a body of water due to increased algae and plant growth.

11. Abiotic Factors • pH • A measure of how acidic or basic the water is • On a scale of 0 to 14 – 7 is neutral, below 7 is acidic, above 7 is basic • The pH of pure water is 7 • Water that is too acidic may cause other elements that are always present to become toxic to organisms living there

12. Abiotic Factors • Turbidity – A measure of how clear water is • Higher turbidity in potable can mean pathogens are present • Higher turbidity in lakes and rivers can lead to increased temperatures, lower DO, and bad conditions for aquatic organisms

13. Abiotic Factors • Phosphates and Nitrates • If these levels are too high they pose a risk to humans in potable water. • The major sources of phosphates are: humans and animal waste, detergents, cleaning and industrial waste. • The major sources of nitrates: runoff contaminated with fertilizers, animals waste and septic waste.

14. Biotic Factors • Bioindicators – living things whose presence, condition, and numbers are indicators of the health of a body of water

15. Thinking Question • On the left hand side of your notes: What are some connections between water quality factors? • Right hand side: Look back in your notes and try to find as many connects between the abiotic factors just discussed.