WHAT IS HAPPENING TO HARM OUR WATER SUPPLY? “When the well is dry, we learn the worth of water.” - Benjamin Franklin 1

Water Pollution Water pollution is the addition of any substance that degrades, or lowers the quality of the water for living organisms. Point-source pollution – _____________________________ __________________________________________________ ________________________________________________ Nonpoint-source pollution – _________________________ __________________________________________________ __________________________________________________ As runoff produced by rain and snow melt makes its way across farms, lawns, and streets, it picks up accumulated fertilizers, pesticides, salt, oil and other pollutants. 2

Nutrient Pollution The process of Eutrophication – Eutrophication occurs naturally when ____________ _________________________ _________________________. When nutrients build up, the growth rate of algae and aquatic plants increase. More growth means more decomposition. Decomposition requires oxygen so dissolved oxygen levels decrease. ___________ _________________________ _________________________ _________________________ 3

Cultural Eutrophication Nutrient pollution by humans can dramatically increase the rate at which eutrophication occurs, a situation called cultural eutrophication or artificial eutrophication. Excess phosphorus is the most common cause of cultural eutrophication fresh water. ________________________________ _______________________________________________________ _______________________________________________________ Excess nutrients cause a sudden explosion of algal froth called algal blooms Algae blooms caused by eutrophication______________________ _______________________________________________________. As the plants die, the dissolved oxygen (DO) levels of the water decline. A decline in dissolved oxygen causes the suffocation of large organisms, like fish. 4

Toxic-Chemical Pollution Many freshwater supplies have become polluted with toxic chemical. These chemicals can be organic like pesticides and __________________ _________________________________________ _________________________________________ All of these substances make their way into fresh water from point-source and nonpoint-source pollution _________________________________________ _________________________________________ _________________________________________ _________________________________________ 5

Oil Spills Although oil spills from rigs and tanker ships are not the biggest source of oil in the ocean, ___________________________________ ________________________________________________________ ________________________________________________________ One of the worst spills to ever affect North America was the Exxon Valdez in

Exxon Valdez When the Exxon Valdez ran aground in Alaska, a high volume of oil was spilled. The damage was worsened by a series of other factors: The remoteness of the spill’s location. A delayed cleanup response due to a lack of preparation by the oil companies. 7

Deepwater Horizon The worst oil spill by volume occurred in 2010 when an oil rig in the Gulf of Mexico experienced a blowout. The drilled well at the bottom of the sea gushed nearly 5 million barrels of oil into the sea over a period of four months. 8

Plastic A study by the Environmental Investigation Agency revealed that ________________________________________________________ ________________________________________________________ A gray whale stranded near Seattle was found to have the following in its stomach: Sweatpants Duct tape Surgical gloves Golf ball More than 20 plastic bags 9

Plastic Plastic is non-degradable, __________________________________ ________________________________________________________ Exposure to sunlight will cause it to __________________________ ________________________________________________________, which accumulate in systems of rotating ocean currents called gyres. 10

Great Pacific Trash Vortex The largest collection of plastic pollution in the ocean is the Great Pacific Trash Vortex, located in the South Pacific gyre. Most of the plastic is small and suspended below the surface. The mass of plastic pieces sampled from this area is 6 times greater than the plankton biomass. 11 A sample of the plastic and fishing gear caught by filmmakers of the Garbage Island documentary.

Sediment Pollution Sediment transported by rivers and runoff can harm aquatic ecosystems. Some rivers are naturally rich in sediment and some are not. __________________________ __________________________________________________ __________________________________________________ __________________________________________________ Sediment pollution can be increased by ________________ __________________________________________________ __________________________________________________ 12

Thermal Pollution __________________________________________________ __________________________________________________ Some aquatic organisms may not survive when human activities raise water temperature Recall that one of the most common uses of water is fro cooling industrial processes and power plants. Water used in their way absorbs a lot of heat. When the water is returned to its source, the temperature of the water will be higher than when it was with drawn, resulting in thermal pollution 13

Biological Pollution When disease causing ______________________________ _________________________________________________ make their way into our air, soil and water it is called biological pollution Drinking water supplies can become contaminated with biological pollution ________________________________ _________________________________________________ The best way of decreasing biological water pollution is to _________________________________________________ _________________________________________________ _________________________________________________ 14

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