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Water Pollution
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Point Source Pollution Nonpoint Source Pollution
vs. Nonpoint Source Pollution What’s the difference?
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Point and Nonpoint Sources
Urban streets Suburban development Wastewater treatment plant Rural homes Cropland Factory Animal feedlot POINT SOURCES
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Point Source Pollution
comes from a specific source, like a pipe factories, industry, municipal treatment plants can be monitored and controlled by a permit system
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What is nonpoint source pollution?
Nonpoint Source (NPS) Pollution is pollution associated with stormwater or runoff NPS pollution cannot be traced to a direct discharge point such as a wastewater treatment facility
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Examples of NPS oil & grease from cars fertilizers animal waste
grass clippings septic systems sewage & cleaners from boats household cleaning products litter
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Pollutant Transport Mechanisms
NPS pollutants build up on land surfaces during dry weather Atmospheric deposition Fertilizer applications Animal waste Automotive exhaust/fluid leaks Pollutants are washed off land surfaces during precipitation events (stormwater runoff) Stormwater runoff will flow to lakes and streams
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More Coverings= More Water
Linking Land Use to Water Quality More Coverings= More Water
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What do we mean by cover? roads, rooftops, parking lots, and other hard surfaces that do not allow stormwater to soak into the ground “predominant American vegetation”
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Cover provides a surface for accumulation of pollutants
leads to increased polluted runoff and flooding inhibits recharge of groundwater
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Impact of Nonpoint Source Pollution
fish and wildlife recreational water activities commercial fishing tourism drinking water quality
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Pollutants Found in Runoff
Sediment Soil particles transported from their source Biochemical Oxygen Demand (BOD) ● Oxygen depleting material Leaves Organic material Toxics ● Pesticides Herbicides Fungicides Insecticides ● Metals (naturally occurring in soil, automotive emissions/ tires) Lead Zinc Mercury ● Petroleum Hydrocarbons (automotive exhaust and fuel/oil) Nutrients ● Various types of materials that become dissolved and suspended in water (commonly found in fertilizer and plant material): Nitrogen (N) Phosphorus (P) Bacteria/ Pathogens Originating from: ● Pets ● Waterfowl ● Failing septic systems Thermal Stress Heated runoff, removal of streamside vegetation Debris Litter and illegal dumping
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Potential Sources of Pollutants Found in Residential Areas
Nutrients: Fertilizers and septic systems Pathogens: Pet waste and septic systems Sediment: Construction, road sand, soil erosion Toxic: Pesticides, household products Debris: Litter and illegal dumping Thermal: heated runoff, removal of streamside vegetation
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Pollutants from Agriculture
Sediment Nutrients Pathogens Pesticides
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Why are these pollutants important?
Sediment reduces light penetration in stream, clogs gills of fish and aquatic invertebrates. Nutrients act as fertilizer for algae & aquatic plants which can cause highly varying dissolved oxygen levels. At low DO levels, the aquatic life has the potential to be harmed. Toxics can impact life and contaminate drinking water supplies. Bacteria/Pathogens are an indicator of possible viruses present in the system.
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Biological Magnification
Rainbow smelt 1.04 ppm Zooplankton 0.123 ppm Phytoplankton ppm Water ppm Herring gull 124 ppm Lake trout 4.83 ppm Herring gull eggs Why we need good water quality. Higher in food chain means more concentrated is contamination. Where are we on the food chain. Why Audobuan society devotes money to water quality. To protect birds.
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Pollution of Streams Oxygen sag curve Fig. 20-5
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Mississippi River Basin Ohio River Missouri River Mississippi River LOUISIANA Mississippi River Depleted Oxygen Gulf of Mexico
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Pollution of Lakes Eutrophication
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Groundwater Pollution: Causes
Low flow rates Few bacteria Low oxygen Cold temperatures Hazardous waste injection well Pesticides Coal strip mine runoff De-icing road salt Buried gasoline and solvent tank Pumping well Cesspool septic tank Gasoline station Waste lagoon Water pumping well Sewer Landfill Leakage from faulty casing Accidental spills Discharge Unconfined freshwater aquifer Confined aquifer Confined freshwater aquifer Groundwater flow
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Solutions: Preventing and Reducing Surface Water Pollution
Nonpoint Sources Point Sources Reduce runoff Clean Water Act Buffer zone vegetation Water Quality Act Reduce soil erosion
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Groundwater Pollution Prevention
Monitor aquifers Find less hazardous substitutes Leak detection systems Strictly regulating hazardous waste disposal Store hazardous materials above ground
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Case Study: Chesapeake Bay
Largest US estuary Relatively shallow Slow “flushing” action to Atlantic Major problems with dissolved O2
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Ocean Pollution
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Coastal Water Pollution
Solutions Coastal Water Pollution Prevention Cleanup Reduce input of toxic pollutants Improve oil-spill cleanup capabilities Separate sewage and storm lines Ban dumping of wastes and sewage by maritime and cruise ships in coastal waters Sprinkle nanoparticles over an oil or sewage spill to dissolve the oil or sewage without creating harmful byproducts (still under development) Ban ocean dumping of sludge and hazardous dredged material Protect sensitive areas from development, oil drilling, and oil shipping Require at least secondary treatment of coastal sewage Regulate coastal development Use wetlands, solar-aquatic, or other methods to treat sewage Recycle used oil Require double hulls for oil tankers
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Technological Approach: Septic Systems
Require suitable soils and maintenance
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Sewage Treatment Physical and biological treatment Fig p. 511
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Technological Approach: Using Wetlands to Treat Sewage
Fig p. 513
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Prevent groundwater contamination Greatly reduce nonpoint runoff
Solutions Water Pollution Prevent groundwater contamination Greatly reduce nonpoint runoff Reuse treated wastewater for irrigation Find substitutes for toxic pollutants Work with nature to treat sewage Practice four R's of resource use (refuse, reduce, recycle, reuse) Reduce resource waste Reduce air pollution Reduce poverty Reduce birth rates
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Wetlands Home to ~33% of nation’s threatened and endangered species
Statistics— 50% loss since 1900 in US; cities on filled wetlands; rising sea level Mitigation banking—Nat’l Academy: ~half of attempts to build a wetland fail. More than 500 wetland restoration banks in US
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Virtues of Wetlands Home to wildlife and flora Flood protection
Cycling and storage of chemical and biological substances Found at heads of rivers Remove toxins from sewage
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How Wetlands are Destroyed
Mostly by draining for development or farming. To ‘reclaim’ land along coastlines
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The Everglades ~77,000 sq km; 3 sub-basins
Thin sheet of water miles wide Formed ~5000 yrs ago--how Human influences: late 1880’s—first dredging 1907 and 1928: canals—saltwater; draining south of Lake O. : Kissimee River channelized 65% now drained Plants and animals depend on water level timing—seriously disturbed Number of species of wading birds—dropped 95% since 1947
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Protecting, Sustaining, and Restoring Wetlands
Regulations Wetlands protection Mitigation banking Wetlands restoration Control of invasive species
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Supply of Water Resources
Freshwater Readily accessible freshwater Biota 0.0001% Rivers Atmospheric water vapor Lakes 0.0007% Soil moisture 0.0005% Groundwater 0.592% Ice caps and glaciers 0.014%
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Use of Water Resources Humans use about 54% of reliable runoff
United States Industry 11% Public 10% Power cooling 38% Agriculture Agriculture Industry Domestic Power plants
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Evaporation and transpiration
Ground Water Evaporation and transpiration Evaporation Stream Infiltration Water table Unconfined aquifer Confined aquifer Lake Well requiring a pump Flowing artesian well Runoff Precipitation Confined Recharge Area Aquifer Less permeable material such as clay Confirming permeable rock layer
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Problems with Using Groundwater
Water table lowering Depletion Subsidence Saltwater intrusion Chemical contamination Reduced stream flows
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Groundwater Pollution: Causes
Hazardous waste injection well Pesticides Coal strip mine runoff De-icing road salt Buried gasoline and solvent tank Pumping well Cesspool septic tank Gasoline station Waste lagoon Water pumping well Sewer Landfill Leakage from faulty casing Accidental spills Discharge Unconfined freshwater aquifer Confined aquifer Confined freshwater aquifer Groundwater flow Fig
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Contaminant plume moves with the groundwater
Leaking tank Aquifer Water table Bedrock Figure 21.8 Natural capital degradation: groundwater contamination from a leaking gasoline tank. As the contaminated water spreads from its source in a widening plume, it can be extracted by wells used to provide water for drinking and irrigation. Groundwater flow Free gasoline dissolves in groundwater (dissolved phase) Gasoline leakage plume (liquid phase) Migrating vapor phase Water well Contaminant plume moves with the groundwater Fig
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Too Little Water Dry climate Drought Desiccation Water stress
Acute shortage Adequate supply Shortage Metropolitan regions with population greater than 1 million Water stress
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$23 billion/year for 8-10 years to bring clean drinking water to those who don’t have it
Consequences of a warmer world Pollution of freshwater streams Dilution and biodegradatoin Breakdown of pollutants by bacteria—oxygen sag curve
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Developing countries: half of world’s 500 major rivers are heavily polluted
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Global Outlook: Stream Pollution in Developing Countries
Water in many of central China's rivers are greenish black from uncontrolled pollution by thousands of factories. Figure 20-7
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Case Study: India’s Ganges River: Religion, Poverty, and Health
Religious beliefs, cultural traditions, poverty, and a large population interact to cause severe pollution of the Ganges River in India. Very little of the sewage is treated. Hindu believe in cremating the dead to free the soul and throwing the ashes in the holy Ganges. Some are too poor to afford the wood to fully cremate. Decomposing bodies promote disease and depletes DO.
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Case Study: India’s Ganges River: Religion, Poverty, and Health
Daily, more than 1 million Hindus in India bathe, drink from, or carry out religious ceremonies in the highly polluted Ganges River. Stop 1:00
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Is Bottled Water the Answer?
Some bottled water is not as pure as tap water and costs much more. 1.4 million metric tons of plastic bottles are thrown away. Fossil fuels are used to make plastic bottles. The oil used to produce plastic bottles in the U.S. each year would fuel 100,000 cars.
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Using Laws to Protect Drinking Water
The U.N. estimates that 5.6 million Americans drink water that does not meet EPA standards. 1 in 5 Americans drinks water from a treatment plant that violated one or more safety standard.
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• Minimize your use of pesticides.
What Can You Do? Water Pollution • Fertilize garden and yard plants with manure or compost instead of commercial inorganic fertilizer. • Minimize your use of pesticides. • Do not apply fertilizer or pesticides near a body of water. • Grow or buy organic foods. • Do not drink bottled water unless tests show that your tap water is contaminated. Merely refill and reuse plastic bottles with tap water. Figure 21.19 Individuals matter: ways to help reduce water pollution. QUESTION: Which three of these actions do you think are the most important? • Compost your food wastes. • Do not use water fresheners in toilets. • Do not flush unwanted medicines down the toilet. • Do not pour pesticides, paints, solvents, oil, antifreeze, or other products containing harmful chemicals down the drain or onto the ground.
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