1. Section 1: What is Water Pollution?
Unit 12: Water Pollution
Section 1: What is Water Pollution?

2. What is Water Pollution?
Water pollution is any change in the quality of water that can cause harm to organisms or make the water unusable to humans
Types of Pollution:
Point-source – drain pipes (usually) discharge pollutant directly into bodies of surface or underground water
Nonpoint-source – broad, diffuse areas of pollution where rainfall runs pollutants into water from land (ex. Agricultural fields, parking lots, logged forests, livestock pens, lawns, etc.)

3. Leading Causes of Water Pollution
Agricultural Activities – sediment erosion = #1; others include fertilizer, pesticide, fecal bacteria, salts, etc.
Industrial Facilities – emit harmful inorganic and organic chemicals
Mining – surface = erosion, toxic metal runoff; also, acid drainage

4. Types of Water Pollution
Type/Effects
Examples
Major Sources
Infectious agents – cause diseases
Bacteria, Viruses, Parasites
Human/Animal Waste
Oxygen-demanding waste – Deplete DO needed by aquatic organisms
Animal waste and plant debris
Sewage, animal feedlots, food processing plants, paper mills
Plant nutrients – cause excessive growth of algae
Nitrates (NO3-) and Phosphates (PO43-)
Sewage, animal waste, inorganic fertilizers
Organic chemicals – Add toxins to water
Oil, gasoline, plastic, pesticides, cleaning solutions
Industry, farms, homes
Inorganic chemicals – Add toxins to water
Acids, bases, salts, metal compounds (oxides, etc.)
Industry, homes, surface runoff, mining
Sediments – Disrupt photosynthesis, food webs, etc.
Soil, silt
Land erosion (mostly agricultural)
Heavy metals - Cause cancer, disrupt immune, nervous, and endocrine systems
Lead, Mercury, Arsenic, etc.
Unlined landfills, households, mining, industries
Thermal – Increase vulnerability to disease and decrease DO
Heat
Industrial and Power plants

5. Oxygen-Demanding Wastes
Flowing streams and rivers can recover from moderate levels of oxygen-demanding waste through dilution and bacterial biodegradation
Leads to depletion of oxygen
Oxygen sag curve!!!!

6. Plant Nutrient Pollution
Leads to eutrophication (and subsequent decrease in DO)
In marine ecosystems, can lead to harmful algal blooms (Red/Green/Brown Tides)
Release water and air poisons and can deplete DO, leading to oceanic dead zones

7. Groundwater Pollution
Pollution can leak from landfills, agricultural land, industry, and other sources into groundwater.
Must be purified prior to use and in some cases, it is permanently contaminated and the aquifer is abandoned

8. Clean Water Policies Preservation of Clean water
Clean Water Act (1972, 1977) established the basic structure for regulating direct discharges of pollutants into the waters of the United States. It gave EPA the authority to implement pollution control programs such as setting wastewater standards for industry.
Preservation of
Clean water
Safe Drinking Water Act of 1974 established to protect the quality of drinking water in the U.S. This law focuses on all waters actually or potentially designed for drinking use, whether from above ground or underground sources. Allowed EPA to set tap water standards.
Originally, Congress enacted the Soil Conservation Act of 1935 on April 27, 1935 in an attempt to address farm erosion problems by bringing within its policy and purposes, the improvements and preservation of national soil resources.
Dust Bowl
The CRP program originally began in the 1950s as the conservation branch of the Soil Bank Program which was enacted by the Agriculture Act of 1956.

9. Oceans: The Ultimate Destination
Most pollutants ultimately end up in the ocean
Ocean currents can transport this pollution all around the planet
Currents are driven by:
Density differences
Temperature differences
Gravity
Or, Wind

11. Ocean Gyres
Warm and cool currents can influence climate along the coasts
Sections of the oceans’ currents create circular, clockwise (Northern) or counter-clockwise (Southern) patterns
These are called gyres
Pollutants (especially garbage and plastics) can collect in the middle of them

16. Currents Drive Water Movement
Water has the property of cohesion
So when currents diverge in an area, water beneath is drawn up
This is known as upwelling and generally brings cool, nutrient-rich water to the surface
Upwelling can also occur when wind blows across the surface, parallel to a coastline
Water can also converge, or sink in an area
This is referred to as downwelling and transports surface water rich in dissolved gases such as Oxygen and Carbon dioxide
These areas of differing movement of water leads to the earth’s thermohaline circulation
Warm, fresher water moves along surface, sinks/cools, and cool, saltier water moves deeper beneath the surface