Chapter 11-3 Water Pollution
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Water Pollution
• Introduction of chemical, physical or biological agents that adversely affect the organisms that depend upon that water
Point-source versus Nonpoint-source pollution
• Point-source can be traced to a source
• Nonpoint –source comes from many different sources that are often hard to identify
Pathogens
• Parasites, bacteria and viruses that cause illness in living things
• Many spend part of their life cycle in water
• Pathogens carried by water cause more human deaths than any other environmental problem
Cholera
• Acute diarrhea• Caused by bacteria• Infected food water,
shellfish• Heat kills cholera
bacteria
Dysentery
• Several bacteria and protozoa responsible
• Vomiting, severe diarrhea
• Cause water contamination
• Heat kills most of these
Typhoid Fever
• Salmonella Thyphi• Only people carry the
bacteria• Shed in feces• Vaccination available• Boil it , cook it, peel it
or forget it
Schistosomiasis
• Caused by microscopic worms
• Enters through the skin of people who walk in infected water
• Attacks liver, urinary bladder, and intestines
Schistosomiasis
• Africa, Middle East, Egypt
• 100 million people affected
• 1 million deaths annually
• Aswan Dam
Malaria
• Protozoan• Transmitted by
mosquito• The mosquitoes breed
in standing water• 800 million affected• 1 million deaths
annually
Organic Matter
• Animal and plant remains, feces etc.
Organic Chemicals
• Pesticides, fertilizer, gasoline, oil etc..
• Runoff from farmlands
• Organic pesticides, herbicides and fertilizers
Inorganic chemicals
• Acids, bases, salts, etc..
Heavy Metals
• Dangerous heavy metals include: Mercury, lead, cadmium, nickel, chromium and Slipknot.
Physical Agents
• Heat and suspended solids
Wastewater
• Contains waste from homes or industry
Treatment
• Primary – filtration and settling. Gets the big stuff out
Secondary
• Aeration
• Second settling tank
• Chlorination to kill pathogens
Artificial eutrophication
• Caused by fertilizer run-off or other organic wastes
Thermal Pollution
• Heat can be a type of water pollution
• Power Plants
• Reservoirs
Groundwater Pollution
• Any polluted surface water can become polluted groundwater
• Very hard to clean up
Ocean Pollution
• Oil spills – Exxon Valdez 1989
• Plastics
Cleaning up water pollution
• Clean Water Act of 1972
• Safe Drinking water act of 1996
