Water Quality IndicatorsWater Quality Indicators

A selectionA selection

pHpH

Relative concentration of (in water)Relative concentration of (in water)– Hydrogen ions H+ Hydrogen ions H+ – Hydroxide ions OH-Hydroxide ions OH-

pH Scale is pH Scale is logarithmiclogarithmic (as you go up on (as you go up on the scale, it increases by a factor of 10)the scale, it increases by a factor of 10)– Acid – pH less than 7Acid – pH less than 7– Alkaline – pH more than 7Alkaline – pH more than 7– Neutral is 7Neutral is 7

pH and Water QualitypH and Water Quality

Very high or low pH values are toxic to life in the Very high or low pH values are toxic to life in the streamstream

6.5 to 8.2 is optimal for most organisms6.5 to 8.2 is optimal for most organisms

Factors that affect pH Factors that affect pH – Acid Rain (magnitude and frequency)Acid Rain (magnitude and frequency)– Area geology – Dissolved Minerals (limestone)Area geology – Dissolved Minerals (limestone)– Algal BloomsAlgal Blooms– Industrial or Commercial SourcesIndustrial or Commercial Sources– Carbonic Acids from Respiration and DecompositionCarbonic Acids from Respiration and Decomposition

Base Line pHBase Line pH

Dissolved OxygenDissolved Oxygen

Oxygen gas dissolved in the waterOxygen gas dissolved in the waterVital for the existence of aquatic organismVital for the existence of aquatic organismKey component in cellular respiration for both Key component in cellular respiration for both aquatic and terrestrial life.aquatic and terrestrial life.Factors to affect DO levelsFactors to affect DO levels– Aquatic plant populations (diversity and volume)Aquatic plant populations (diversity and volume)– Decaying organic matterDecaying organic matter– Current velocityCurrent velocity– Atmospheric PressureAtmospheric Pressure– Human ActivityHuman Activity

DO and Water QualityDO and Water Quality

The larger the organism, the more DO it The larger the organism, the more DO it requires.requires.– Trout need 6.5 mg/LTrout need 6.5 mg/L– Mosquito Larvae need 1.0 mg/LMosquito Larvae need 1.0 mg/L

Sources of DOSources of DO– Atmospheric Diffusion (air touching the water)Atmospheric Diffusion (air touching the water)– Aeration of water (white water)Aeration of water (white water)– Photosynthesis of primary producers (plants)Photosynthesis of primary producers (plants)– Higher in the day or night??Higher in the day or night??

Fish KillsFish Kills

Nitrates and PhosphatesNitrates and Phosphates

Necessary nutrients for aquatic plants and Necessary nutrients for aquatic plants and algae (only small amounts needed)algae (only small amounts needed)

Excessive amounts = eutrophicationExcessive amounts = eutrophication

Two types – Organic and InorganicTwo types – Organic and Inorganic– Organic (human or animal waste)Organic (human or animal waste)– Inorganic (fertilizers and detergents)Inorganic (fertilizers and detergents)

Nutrients and Water QualityNutrients and Water Quality

High levelsHigh levels– Eutrophication of aquatic ecosystemEutrophication of aquatic ecosystem– Increased algal bloomsIncreased algal blooms– Decreased DODecreased DO

Nitrates and Phosphates easily dissolve in Nitrates and Phosphates easily dissolve in water (percolation and runoff enable this)water (percolation and runoff enable this)Common sources – Factories, urban Common sources – Factories, urban runoff, farms, decomposition of plants and runoff, farms, decomposition of plants and animalsanimals

Nitrogen CycleNitrogen Cycle

Algal BloomAlgal Bloom

Water TemperatureWater Temperature

How warm or cool the water isHow warm or cool the water is

Abnormal temperatures are toxic to Abnormal temperatures are toxic to aquatic life (too warm or cold)aquatic life (too warm or cold)

Small changes can have a huge impact Small changes can have a huge impact (even 1 degree)(even 1 degree)

Temperature affects DO levels Temperature affects DO levels (warm=less and cool=more)(warm=less and cool=more)

Temperature and Water QualityTemperature and Water Quality

Warm Temps – Thermal Pollution – will kill fish Warm Temps – Thermal Pollution – will kill fish and increase photosynthesis (algal blooms)and increase photosynthesis (algal blooms)Example: Trout 5-20 degrees C, Caddisfly Example: Trout 5-20 degrees C, Caddisfly Larvae 10 to 25 degrees CLarvae 10 to 25 degrees CFactors to Affect TemperatureFactors to Affect Temperature– Air tempAir temp– Amount of ShadeAmount of Shade– Soil erosion (too much sediment)Soil erosion (too much sediment)– Human Activity (power plants)Human Activity (power plants)– Where streams meetWhere streams meet

Human ActivityHuman Activity

Others Parameters Not DiscussedOthers Parameters Not Discussed

BOD – Biological Oxygen DemandBOD – Biological Oxygen Demand

TDS – Total Dissolved SolidsTDS – Total Dissolved Solids

Specific ConductivitySpecific Conductivity

TurbidityTurbidity

Homework ProjectHomework Project

Each group should pick one factor and Each group should pick one factor and research it thoroughlyresearch it thoroughly

Discuss examples of how that factor Discuss examples of how that factor affected a stream, lake or pond.affected a stream, lake or pond.

Next Tuesday, May 10, you will present Next Tuesday, May 10, you will present your findings to the class (powerpoint or your findings to the class (powerpoint or posterboard)posterboard)