Water Pollution

Distribution of Water ReservoirsOceans

97%

Atmosphere 0.01%

Rivers, Lakes, and Inland Seas

0.141%Soil Moisture 0.0012%

Ground Water 0.4 – 1.7%

Ice Caps and Glaciers 1.725%

World Water Supply

97.200% salt water in the oceans 02.014% ice caps and glaciers 00.600% groundwater 00.009% surface water 00.005% soil moisture 00.001% atmospheric moisture

Water Cycle

• Atm. -Ocean - Land

• Evap. - PPT - Runoff

Water Pollution

Two major classifications• Point Source • Non-point Source

• Single large source

• Can localize it to one spot

– Industrial Plants

- Sewage pipes

Diffuse source or many smaller point sources

• Automobiles

• Fertilizer on fields

Water Pollution: Many Forms

• Disease: In developing nations, 80% of diseases are water-related.

• Synthetic Organic Compounds• Inorganic Compounds & Mineral Substances such as

Acids, etc.• Radioactive substances• Oxygen-demanding wastes• Plant Nutrients• Sediments• Thermal Discharges

Acid Precipitation: When Air Pollution

Becomes Water Pollution

Acid Rain Effects – Aquatic Systems

When the pH drops below 6.0 species start to die off.When one species dies, others that depend on it may as well

Oxygen and Water

• Biochemical Oxygen Demand – What does this mean?– Anything in the water that bacteria can

break down. – Bacteria will use up oxygen in the water– Other aerobic organisms will die

• What else can affect the amount of O2 in the water?– Temperature– Speed of water flow– Roughness of surface

over which water flows

Stories about particular pollutant forms: Oil• Both Point and Nonpoint Sources• Largest source of oil pollution is pipeline leaks and runoff

– 61% ocean oil pollution river & urban runoff– 30% intentional discharges from tankers– 5% accidental spills

from tankers

The nitrates in fertilizers promote excessive growth of algae and larger aquatic plants, causing offensive algae blooms and driving out sport fish.

Phosphates are often thought to culprit, nitrogen is the “limiting factor” in most aquatic systems.

Stories about particular pollutant forms: Detergents

Stories about particular pollutant forms: Sediments

• THE largest form of water pollution

• Erosion is source – we’ve sped up rate of erosion, e.g. during urban construction can lose up to 43 tons of topsoil/acre/year

• Natural rates of erosion: leads to aquatic succession

Succession in Aquatic Habitats

Stories about particular pollutant forms: thermal pollution

• 26% of all water in U.S. is affected by this

• Up to a point of adding heated water, you can get thermal enrichment

• Adding more heat,

you get

thermal pollution

A special case: Groundwater

• What forms of pollution can affect groundwater?

• All of them except thermal pollution!

• Renewal time of groundwater is important

– Rivers: 12-20 days

– Soil Moisture: 280 days

– Groundwater: 300 years

Groundwater doesn’t stay in one place