Water Pollution Chapter 18

What is Water Pollution? Water pollution is anything that degrades water quality! Pollution is spread from: Point sources: Sources of pollution that come from specific locations (drain pipes, sewer outfalls, ditches) Nonpoint sources: Sources of pollution that are scattered or diffuse such as runoff from farm fields.

Water Pollution  Infectious agents, organic and inorganic chemicals from industrial effluents, natural sources of radioactive materials all effect human health  Sediment from erosion, plant nutrients from fertilizers and sewage, thermal pollution from power plant and industrial cooling are all reasons of ecosystem disruption.

Water Pollution con’t  Bacterial diseases are found in many water sources mainly in poorer countries.  Sediments can also be found in water and can greatly degrade water quality.  The amount of oxygen dissolved in water is used as an indicator of its quality (page 407)  Biochemical oxygen demand (BOD): test measuring the amount of dissolved oxygen in water

Water Pollution Control  Source reduction is often the cheapest and best way to reduce pollution. (avoid producing pollution to reduce it).  In order to control nonpoint sources, land contaminating agriculture, urban runoff, construction, and waste disposal must be managed and regulated  Effluent sewage: a tank collects and digests solid waste. Liquid waste is filtered into a central treatment plant.

Water Pollution Control cont  Wetlands: after days of exposure to sun, air, and aquatic plants, pathogens in the polluted water are destroyed. Effluent is used for crop irrigation or to raise fish for human consumption  Municipal sewage treatment:  Primary treatment: separates large solids from waste and filters liquid through a screen. The effluent is not yet safe to discharge  Secondary treatment: effluent from primary treatment moves to a sewage lagoon where it aerobically decomposes

Water Quality Today  Due to The Clean Water Act only 10% of water pollution in the US is due to industrial waste.  However, the Act only protects “navigable” water sources, so areas such as wetlands are excluded and are not protected by the act.  Around 117 million Americans get their drinking water from sources that are not protected by the clean water act.

Water Quality Today cont  Although some countries, such as Sweden, serve water that receives sewage treatment twice, many countries are served water that isn’t treated at all.  In Greece, only 1% of water served is even treated once prior to distribution.  There is little control on ocean pollution throughout the world.

Water Legislation  Federal Water Pollution Control Act (1972): nationwide controls for major polluting industries  Clean Water Act (1985): point sources of pollution were required to have discharge permits and best possible control technology. Set national goal for all surface waters to be “fishable and swimmable”  Safe Drinking Water Act (1974): regulates water quality in commercial and municipal systems.

What Can You Do?  Compost yard and pet waste  Don’t fertilize lawn or apply lawn chemicals  Make sure your car doesn’t leak fluids  Create a “rain garden” to capture and filter surface runoff  Avoid buying two-cycle engines (i.e. lawnmowers, snowmobiles)  Keep informed about water policy debates at local and federal levels. Input is important!!

Fun Facts  The World Bank estimates that if everyone had pure water and satisfactory sanitation, 200 million fewer episodes of diarrheal illness would occur each year  14 billion pounds of garbage are dumped into the ocean annually  Over 1 million seabirds and 100,000 sea mammals are killed by pollution annually  46% of US lakes are too polluted for human activity or aquatic life