Presentation on theme: "Chapter 21 Water Pollution. Vocabulary Water pollution- any chemical, biological, or physical change in water quality that has a harmful effect on living."— Presentation transcript:
Vocabulary 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.
Vocabulary Point sources- discharge pollutants at specific locations through drain pipes, ditches, or sewer lines into bodies of surface water.
Vocabulary 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…
Vocabulary 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.
Vocabulary 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.
Vocabulary 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.
Objectives 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.
Objectives 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.
Objectives 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.
Objectives Causes of groundwater pollution? – Improper on-site disposal of wastewater from domestic holds as well as from industries – Over extraction of ground water in coastal areas causing intrusion of sea water into ground water aquifer – Removal of top soil for construction activities, quarrying of minerals, etc. – Improper sealing of wastewater treatment plants without properly determining the permeability of soil stratification – runoff
Objectives Major water pollution problems affecting oceans? – Toxic wastes – Boating pollution – Garbage dumping – Wastewater (runoff from rainwater) – Runoff from urban areas
Objectives Prevention and reduction of surface water pollution? – Limits on the amount of water you are allowed to remove from aquifers – Limits on construction
Objectives 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.