WATER POLLUTION Chapter 11

Where does the pollution come from? Point source = single, identifiable source -can you point your finger at the polluter? Nonpoint source = many sources, hard to identify -the pollution could be from many sources – hard to point your finger at the culprit

Point Sources of Pollution 1.Septic tank systems 2. Storage lagoons for polluted water (mines) 3. Municipal landfills 4. Underground storage tanks of pollutants 5. Public and industrial wastewater treatment plants

Non-Point Sources of Pollution 1. Soil runoff from construction sites and farms 2. Storm-water runoff (oil, dog poop, litter, gas) 3. Pesticides, herbicides, and fertilizers 4. Agricultural feces and chemicals 5. Salt for snow and ice

Which is a bigger problem? Which is easier to eliminate? Point source water pollution Non-point source water pollution

Impaired U.S. Waters

Types of Pollution Thermal Artificial Eutrophication Genetic Ocean Groundwater Wastewater

Thermal pollution Factories use water in cooling systems, then discharge warm water into streams Fish and other organisms need very specific temperatures Too hot = lower dissolved O2

Artificial Eutrophication Algal blooms caused by too much Nitrate and Phosphate in the water Reaches the water by runoff from farms 2. lawns 3. sewage treatment plants

Remember why runoff is bad… Too much nutrient leads to LOTS of plant growth –mostly algae Eventually block out sun Ultimately die  increase decomposers  use up O 2  kill fish

Gulf of Mexico Dead Zone

Genetic Pollution Invasive species hitch a ride on boats Get into the water and take over –Zebra mussels causing native mussels to die clog up intake pipes

Ocean Pollution Trash Oil Spills –Exxon Valdez –BP Deepwater Horizon Sewage - Combined Sewer Overflows

Combined Sewer Overflow

Percolation and seepage

Which is harder to clean up, surface water or groundwater?

Groundwater pollution sticks around... Very cold, no bacterial breakdown Very slow water movement: recharge can take 100’s or 1000’s of years Pollutants can stick to rocks in aquifer and pollute new water

Case Study: Natural Gas Drilling Marcellus Shale Fracking - Hydraulic Fracturing Loophole in Safe Water Drinking Act –natural gas companies don’t have to disclose chemicals being used

How can we protect groundwater? Prevention is the key… –Monitor aquifers & landfills –Requirements for old fuel tanks Leak detection system Liability insurance –Stricter regulations on toxic waste disposal Above-ground storage of toxic waste...but then you have toxic mud spills!

Water pollution laws 1.Recreation: Water fit for fishing and swimming, cleaned up locally (1972 Clean Water Act) 2.Oceans: Controlled dumping of waste and required double hulled tankers to prevent oil spills (Oil Pollution Act) 3.Drinking Water: Protect groundwater and surface water from pollution (1975 Safe Drinking Water Act)