WATER QUALITY

Water Quality Describes the health of a water system Is determined by the balance between physical, chemical, and biological variable.

Indicators of Water Quality Physical Indicators: temperature, turbidity, water movement Chemical Indicators: dissolved oxygen pH nitrates & phosphates salinity Biological Indicators: macroinvertebrates

POTABLE WATER VS. SAFE WATER Potable Water is drinkable!!!! Safe water is only good for bathing, cleaning, etc…

TEMPERATURE Determines the kind of organisms that can live there Aquatic species have preferred water temperature ranges within which they will survive Cannot tolerate water temperatures below 32°F Very few can handle temperatures above 97°F

Changes in Temperature CAUSES source of water time of year suspended sediment depth of water shade from shoreline vegetation EFFECTS Aquatic life may become susceptible to disease Extreme changes can result in death

TURBIDITY Measure of how clear the water is The more suspended solids there are in a water sample, the less transparent it is

CHANGES IN TURBIDITY CAUSES EFFECTS Increased levels of phytoplankton Sediment from erosion Sediments stirred up by bottom dwellers Waste discharge Algae growth Urban runoff EFFECTS Increases the absorption of sunlight Makes the water temperatures warmer Dissolved Oxygen levels decrease Fish may die

The rate and amount of water flow WATER MOVEMENT The rate and amount of water flow

Changes in Water Movement CAUSES: Rainstorms Droughts Seasons Shoreline vegetation Irrigation Industry dams EFFECTS: Faster moving water can dissolve pollution better Determines the type of aquatic life Determines the amount of sediment Determines the amount of dissolved oxygen (DO)

DISSOLVED OXYGEN (DO) Amount of oxygen dissolved in water that is available for chemical reactions and for use by aquatic organisms

DISSOLVED OXYGEN (DO) DO balance in water is important for the survival of certain microorganisms and higher organisms such as zooplankton and fish DO enters water during photosynthesis by aquatic plants DO also enters the water through diffusion from the air around the water

LEVELS OF DISSOLVED OXYGEN (DO) DO levels vary throughout the day as well as throughout the year Average DO level is 9.0 ppm Must be 4-5 ppm to support a diverse population of fish

CHANGES IN Dissolved Oxygen LEVELS EFFECTS If DO levels get low, sensitive animals may move away, weaken, or die If DO level is high in potable water, it usually tastes better CAUSES Turbulent actions such as waves, rapids, etc… Water depth Plant growth

pH How acidic or basic water is Controls many chemical & biological processes Impacts other materials in the water such as iron, aluminum, ammonia or mercury (acidic water can make some these poisonous)

pH Scale pH scale goes from 0 to 14 Substances with a pH from 0 to 6 are ACIDIC Substances with a pH from 8 to 14 are BASIC Substances with a pH of 7 are NEUTRAL Surface freshwater: 6.0-9.0 Swamps: as low as 4.3 Salt Water: 7.7 to 8.1

CHANGES IN pH CAUSES EFFECTS Natural conditions Fertilizers Farm runoff Dumping of waste EFFECTS Most aquatic life will die if the pH changes to a level outside of their optimal range

NITRATES AND PHOSPHATES Major sources of nitrates in surface water include runoff contaminated with fertilizers, septic tank leakage, sewage, and erosion of natural deposits. Phosphates usually come from human and animal waste, laundry, cleaning, and industrial effluents.

LEVELS OF NITRATES Potable Water = 10 mg/L Fish = below 90 mg/L

CHANGES IN LEVELS OF NITRATES CAUSES Fertilizer runoff Manure pits Leaks in septic systems Animal waste Car exhaust EFFECTS Increase in plant production Increase in fish population Overcrowding Decrease in Dissolved Oxygen Death in fish

BIOINDICATORS Macroinvertebrates found living in water Macroinvertebrates are easy to collect & identify Macroinvertebrates are sensitive to pollution Variety of macroinvertebrates= GOOD QUALITY Very few and no variety of macroinvertebrates= POOR QUALITY

CHANGES IN BIO-INDICATORS CAUSES Change in pH Change in temperature Change in Dissolved Oxygen Change in nitrate levels EFFECTS Change in the variety of macroinvertebrates Change in the number of macroinvertebrates