Chapter 18 Water Pollution
18.1 Water Pollution
• Water pollution is anything that degrades
water quality
– Chemical
– Biological
– Particulate Matter
– Taste
– Esthetics
– Thermal
18.2 Types And Effects Of Water
Pollutants
• Infectious agents remain an important threat to
human health
• Bacteria are detected by measuring oxygen levels
• Coliform Bacteria
– Not Dangerous, but Indicate Fecal Contamination
• Nutrient enrichment leads to cultural
eutrophication
– BOD = Biological Oxygen Demand
• Eutrophication can cause toxic tides and “dead
zones”
18.2 Types And Effects Of Water
Pollutants
• Inorganic pollutants include metals, salts,
acids, and bases (alkalis)
• Organic pollutants include drugs, pesticides,
and other industrial substances
• Sediment also degrades water quality
• Thermal pollution is dangerous for organisms
18.3 Water Quality Today
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The Clean Water Act protects our water
The importance of a single word
Water quality problems remain
Other countries also have serious water
pollution
• Groundwater is hard to monitor and clean
• There are few controls on ocean pollution
– London Dumping Convention 1990
18.4 Water Pollution Control
• Source reduction is often the cheapest and
best way to reduce pollution
• Controlling nonpoint sources requires land
management
• Human waste disposal occurs naturally when
concentrations are low
• Water remediation may involve containment,
extraction, or phytoremediation
18.5 Water Legislation
• The Clean Water Act of 1972 was ambitious,
bipartisan, and largely successful
– “Fishable and Swimmable”
• What Can You Do? Steps You Can Take to Improve
Water Quality
– Don’t Dump Pollutants (Lawn Fertilizer, Motor Oil, Pet
Waste)
• Clean water reauthorization remains contentious
– Unfunded Mandates
• Other important legislation also protects water
quality