Water Quality

- Environment- Climate- Landscape- Land use- Local Population

(animals and humans)

Water QualityDepends on…

We all need oxygen!

Oxygen mixes with water in streams, rivers and oceans◦ Waterfalls, rapids,

waves

High Oxygen = Healthy Ecosystem

Dissolved Oxygen

Fertilizer Run-off Sewage Decaying plants Temperature

Increase

Tumbling over rocks, rapids and waterfalls

Water mixed by waves and wind

Aquatic plants and algae

Temperature decrease

Decrease Increase

Dissolved oxygen

Measurement of relative acidity

Ranges from 0 to 14◦ Below 7 are acidic◦ Above 7 are basic◦ At 7 are neutral

Influenced by:◦ Type of rocks and soil that it

flows through◦ Reacts with alkaline soils and

minerals

pH

Acid Precipitation Mine Drainage Industrial Waste Decaying Plants

Water flowing through alkaline soils and minerals

Rapidly growing plants and algae

Industrial wastes

Decrease Increase

pH

Form of Nitrogen= fertilizer for plants Streams normally have low levels of Nitrates Elevated Nitrate levels can cause:

◦ Excessive plant growth-> Large amounts of decay use up oxygen -> Fish and animals suffocate

EUTROPHICATION ◦ Unsafe drinking water

Nitrate

Natural water has very low levels

Fertilizer run-off Wastewater from

sewage treatment plants

Decrease Increase

Nitrates

Salinity is the amount of dissolved salts in water

Distribution of plants and animals depends on salinity◦ Freshwater life= low/no

salt 0.5ppt◦ Brackish water= mix of

salt and fresh◦ Saltwater life= higher

levels of salt 35 ppt

Salinity

Fresh water has very low levels

Sea water Tides mix salt

water with freshwater

Run-off from road salt

Decrease Increase

Salinity

Affects:◦ Amount of Dissolved

Oxygen◦ Rate of photosynthesis◦ Sensitivity of

organisms- small changes can cause death for some animals

Thermal pollution- adding warm water to river◦ Industries use water

to cool machines and warm water goes back into river

Temperature

Ground water Shade

Sunlight reaches the water

Industry and power plants Run-off from warm

buildings and parking lots

Decrease Increase

Temperature

Chemical testing:◦ Dissolved oxygen◦ pH◦ Nitrate◦ Salinity

How to measure Water Quality?

Take a Sample

Add Testing Tabs

Compare Results

Macroinvertebrates= aquatic insects, worms and crustaceans

Can be used to determine water quality◦ Some can only live

in clean water◦ Some can live in

polluted water

How to measure Water Quality?

Now it’s your turn…

The Macroinvertebrate Game