Introduction to Water Pollution

Target:Describe sources of water pollution the effects of different pollutants in the water.

What are the major categories of water pollutants? Provide examples, major human sources, and harmful effects.

Infectious AgentsComponents

Examples Bacteria, viruses, protozoa, and parasitic worms

Major Human Sources

Human and animal waste

Harmful Effects

Disease

Oxygen-Demanding WastesComponents

Examples Organic waste that can be decomposed by aerobic bacteria

Major Human Sources

Sewage, animal feedlots, paper mills, and food processing plants

Harmful Effects

Dramatic increase in BOD resulting in a crash in DO

Inorganic ChemicalsComponents

Examples Water-soluble acids; toxic chemicals such as lead, arsenic and selenium; salts and fluorides

Major Human Sources

Surface runoff, industrial effluences, and household cleaners

Harmful Effects

Unusable water for drinking and irrigation; fluoride can cause skin cancers and spinal/neck damage; lead and arsenic can damage nervous system, liver, and kidneys; harm aquatic life; lower crop yields; increase metal corrosion

Organic ChemicalsComponents

Examples Oil, gasoline, plastics, pesticides, cleaning solvents, detergents

Major Human Sources

Industrial effluents, household cleansers, surface runoff from farms and yards

Harmful Effects

Some pesticides can cause nervous system damage; some solvents can cause reproductive disorders and some cancers; fish and aquatic life

Plant NutrientsComponents

Examples Water-soluble compounds containing nitrates, phosphates and ammonium ions

Major Human Sources

Sewage, manure and runoff of agricultural and urban fertilizers

Harmful Effects

Algae blooms – high BOD resulting in low DO; excessive levels of nitrates – blue baby syndrome

SedimentComponents

Examples Soil and silt

Major Human Sources

Land erosion

Harmful Effects

Increase turbidity and decreases GPP; disrupt food webs, carry harmful substances such as pesticides and bacteria; destroy critical feeding and spawning grounds for fish; clog and fill lakes; artificial reservoirs, stream channels and harbors

Radioactive MaterialsComponents

Examples Radioactive isotopes of iodine, radon, uranium, cesium and thorium

Major Human Sources

Nuclear and coal-burning power plants, mining and processing of uranium and other ores, nuclear weapon production; natural sources

Harmful Effects

Genetic mutation, miscarriages, birth defects, and certain cancers

Heat- Thermal PollutionComponents

Examples Excessive heatMajor Human Sources

Water cooling of electric power plants and some industrial plants

Harmful Effects

Decreased DO levels – makes aquatic organisms more vulnerable to disease, parasites, and toxic chemicals; thermal shock

How do we measure water quality?WQI –TemperaturepHDOBODTurbidityNitratesPhosphatesFecal coliform bacteriaMacroinvertebrates

Healthy Ranges for Fecal Coliform and DODrinking water: 0 colonies/ 100 mLSwimming: 200 colonies/ 100 mLRaw sewage: several million colonies/ 100 mL

Good: 8-9 ppm at 20 degrees CModerately polluted: 4.5-6.7 ppm at 20

degrees CGravely polluted: below 4 ppm at 20 degrees

C

What is the difference between point and nonpoint source pollution?Point: pollutants discharged at specific

locations through drain pipes, ditches or sewer lines. Example: factories, sewage treatment plants,

underground mines, and oil tankersNonpoint: pollutants scattered and diffused

which cannot be traced to any single site of discharge.Example: acid deposition and runoff from

croplands, feedlots, logged forests, urban streets, lawns, golf courses, and parking lots.