Chapter 21 Water Pollution. Vocabulary Water pollution- any chemical, biological, or physical change in water quality that has a harmful effect on living.

Chapter 21Chapter 21

Water Water PollutionPollution

VocabularyVocabulary

• Water pollution- any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired uses.

VocabularyVocabulary

• Point sources- discharge pollutants at specific locations through drain pipes, ditches, or sewer lines into bodies of surface water.

VocabularyVocabulary• Nonpoint sources- scattered and diffuse and

cannot be traced to any single site of discharge.

• EX: deposition from the atmosphere, runoff chemicals and sediments into surface water from cropland, livestock, feedlots, logged forests, surface mines and urban streets, lawns, golf courses, etc…

VocabularyVocabulary• Eutophication- the name given to the natural

nutrient enrichment of a shallow lake, estuary, or slow moving stream, mostly from runoff pf plant nutrients such as nitrates and phosphates from surrounding land.

VocabularyVocabulary• Primary sewage treatment- a physical

process that uses screens and a grit tank to remove large floating objects and allow solids such as sand and rock to settle out.

• Secondary sewage tratment- a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen-demanding organic wastes.

VocabularyVocabulary• Advances/tertiary sewage treatment- uses a

series f specialized chemical and physical processes to remove specific pollutants left in the water after primary and secondary treatment.

ObjectivesObjectives• Water is polluted by disease causing agents,

oxygen demanding wastes, plant nutrients, organic and inorganic chemicals. It can come from point and nonpoint sources.

• Pollution can cause disease, deplete oxygen, disrupt photosynthesis, and add toxins to aquatic systems.

ObjectivesObjectives• What pollutes water?– Water is polluted by disease-causing agents,

oxygen demanding wastes, oxygen-demanding wastes, plant nutrients, organic and inorganic chemicals, sediment, and excess heat.

ObjectivesObjectives• Major water pollution problems?– Exposure to infectious disease organisms

(pathogens)– Scientists have identified more than 500 types of

disease-causing bacteria, viruses, and parasites that can be transferred into water from waste.

ObjectivesObjectives• Causes of groundwater pollution?– Improper on-site disposal of wastewater from Improper on-site disposal of wastewater from

domestic holds as well as from industries domestic holds as well as from industries – Over extraction of ground water in coastal areas Over extraction of ground water in coastal areas

causing intrusion of sea water into ground water causing intrusion of sea water into ground water aquifer aquifer

– Removal of top soil for construction activities, Removal of top soil for construction activities, quarrying of minerals, etc. quarrying of minerals, etc.

– Improper sealing of wastewater treatment plants Improper sealing of wastewater treatment plants without properly determining the permeability of soil without properly determining the permeability of soil stratificationstratification

– runoffrunoff

ObjectivesObjectives• Major water pollution problems affecting

oceans?– Toxic wastes– Boating pollution– Garbage dumping– Wastewater (runoff from rainwater)– Runoff from urban areas

ObjectivesObjectives• Prevention and reduction of surface water

pollution?– Limits on the amount of water you are allowed to

remove from aquifers– Limits on construction

ObjectivesObjectives• How safe is drinking water?– Most developed countries have laws establishing

drinking water standards.– Developing countries, however, do not.– Generally water is stored in a reservoir for a few

days(improves clarity and taste) then it’s pumped to a purification plant and treated to government drinking standards.