Unit 13: PollutionSECTION 1: WHAT IS WATER POLLUTION?

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.)

Leading Causes of Water Pollution1. Agricultural Activities – sediment

erosion = #1; others include fertilizer, pesticide, fecal bacteria, salts, etc.

2. Industrial Facilities – emit harmful inorganic and organic chemicals

3. Mining – surface = erosion, toxic metal runoff; also, acid drainage

Types of Water PollutionType/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

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!!!!

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

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

Clean Water PoliciesClean 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

ofClean 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.

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