water pollution chapter 20. point sources of pollution water discharged from industry water...
DESCRIPTION
Nonpoint Sources of Pollution Nonpoint sources – pollutants that come from many different sources and are difficult to identify; diffuse into soil (or air) and the plume seeps into bodies of water or runoff into bodies of waterTRANSCRIPT
Water Pollution
Chapter 20
Point Sources of Pollution
Water discharged from industry
Water dischargeof treatedsewage
Point sources – pollutants directly discharged into bodies of water
Nonpoint Sources of Pollution
Nonpoint sources – pollutants that come from many different sources and are difficult to identify; diffuse into soil (or air) and the plume seeps into bodies of water or runoff into bodies of water
Fig. 20-11, p. 542
Hazardous waste injection well
10Pumping well
Gasoline station
Water pumping well
Discharge
Unconfined freshwater aquifer
Confined freshwater aquiferConfined aquifer
Principal Sources of Groundwater
Contamination in the U.S.
2
46
3 5
11
19
87
Principle Sources of Groundwater Contamination
1. Pesticides and fertilizers2. Buried gasoline and solvent tanks3. Accidental industrial spills4. Industrial waste lagoons and reservoirs5. Hazardous waste wells6. Landfills7. Cesspools and septic tanks8. Sewer9. Salt for de-icing roads10. Coal strip-mining11. Polluted air12. Saltwater intrusion
Groundwater Contamination Groundwater cannot cleanse itself of degradable
wastes as quickly as surface water because:1. Slower flow (less than 0.3 meters per day)2. Lower DO-dissolved oxygen (O2 promotes
decomposition)3. Smaller populations of decomposing bacteria4. Colder temperatures slow down reactions
Non-degradable wastes, such as lead, DDT, MTBE and arsenic, remain permanently.
Contamination of Rivers, Lakes, and Streams
• Polluted rivers and streams recover rapidly; lakes recover slowly.
• Sources of pollution in rivers, lakes, and streams:1. Industry and mines2. Agriculture and feedlots3. Human sewage and garbage4. Drought and warm weather
Contamination of Rivers, Lakes, and Streams
• Problems caused by excess pollution:1. Contaminated drinking water2. Health hazards and disease3. Biomagnification of harmful chemicals4. Habitat destruction5. Fish kills6. Algal blooms (cultural eutrophication)
• Even though it is vast, the ocean still has pollution problems:1. Dead Zones – O2 depleted (hypoxic) areas
caused by algal blooms
Polluting Oceans - Coastal areas are affected most by ocean pollution; deeper waters, oceans can dilute, disperse, and degrade large amounts of pollutants
• Even though it is vast, the ocean still has pollution problems:1. Dead Zones – O2 depleted (hypoxic) areas
caused by algal blooms2. Oil pollution – caused by runoff and tanker
accidents/spills
Polluting Oceans - Coastal areas are affected most by ocean pollution; deeper waters, oceans can dilute, disperse, and degrade large amounts of pollutants
MAJOR OIL SPILLS 1989: Exxon-Valdez (oil tanker)• Hit rocks and released 10.8 million gallons of oil into
Prince William Sound, Alaska
MAJOR OIL SPILLS 2010: Deepwater Horizon (drilling platform)• Explosion damaged underwater pipes and caused sea-
floor gusher to flow into ocean for 3 months, spilling 210 million gallons of oil (into the Gulf of Mexico.)
Polluting Oceans
Major environmental problems - • VOC’s: (volatile organic compounds) kill aquatic
organisms & larvae• Floating tar globs: kill seabirds and marine mammals
(coat feathers and fur)• Heavy oil components: sink to floor and harm bottom
dwellers
Polluting Oceans
Economic impact - • Damages to: fishing and tourism industries• Clean-up costs:• $4 billion Exxon-Valdez• $20 billion Deepwater (estimated)
Polluting Oceans Cleaning up oil spills:
1. Floating booms2. Skimmers3. Absorbent materials4. Chemicals5. Fires6. Bacteria that degrade oil
Polluting Oceans
Prevention of oil spills is the key:• Use tankers with double hulls
Major Water Pollutants Have Harmful Effects - Pathogens
BACTERIA• Sources: Human and animal wastes• Human effects: Examples – typhoid fever, cholera,
bacterial dysentery
VIRUSES• Sources: Human and animal wastes• Human effects: Examples – Hepatitis B
Diarrhea, vomiting, etc.
Enlarged liver, jaundice
Major Water Pollutants Have Harmful Effects - Pathogens
PROTOZOANS• Sources: Human and animal wastes• Human effects: Examples – Amoebic dysentery
PARASITIC WORMS• Sources: Human and animal wastes• Human effects: Examples – Schistosomiasis
Diarrhea, vomiting, etc.
Anemia, chronic fatigue
Major Water Pollutants Have Harmful Effects
BIODEGRADABLE ANIMAL WASTES• Sources: Sewage and feedlots• Environmental effects: Deplete DO
BIODEGRADABLE PLANT WASTES• Sources: Pulp mills, food processing plants• Environmental effects: Deplete DO
Major Water Pollutants Have Harmful Effects
NITRATES and PHOSPHATES• Sources: Fertilizer runoff, sewage treatment• Environmental effects: Excessive algal growth
(decreased photosynthesis & DO)• Human effects: cancers, blue baby syndrome
Major Water Pollutants Have Harmful Effects
OIL, GAS, and ORGANIC SOLVENTS• Sources: Industry, households• Environmental effects: Toxic to aquatic systems• Human effects: Toxic, carcinogenic• Example: MTBE (methyl tertiary butyl ether)• Gasoline additive used since 1977• Carcinogen• Has been phased out since 2005, but has already
contaminated aquifers across the country
Major Water Pollutants Have Harmful Effects
PESTICIDES• Sources: Farms, households• Environmental effects: Toxic to aquatic organisms
and wildlife• Human effects: poisonous, possible lethal
ACIDS and BASES• Sources: Agriculture, industry, households• Environmental effects: Alters pH
Major Water Pollutants Have Harmful Effects
SALINE• Sources: Saltwater intrusion, salt for de-icing roads,
salinization runoff• Environmental effects: Harmful to aquatic species
and plants• Human effects: Gastrointestinal issues
SOIL and SILT• Sources: Runoff from agriculture and mining• Environmental effects: Disrupts photosynthesis
Major Water Pollutants Have Harmful Effects
LEAD, MERCURY, ARSENIC• Sources: Mining, industry, landfills• Environmental effects: Toxic to aquatic organisms• Human effects: Toxic, lethal, carcinogens
PLASTICS• Sources: Garbage• Environmental effects: Harmful to aquatic animals
Major Water Pollutants Have Harmful Effects
HEAT• Sources: Power and industrial plants• Environmental effects: Harmful to aquatic organisms,
decreases DO
PCB’s (polychlorinated biphenyl)• Sources: Used from 1929-1977 in lubricants, hydraulic
fluids, insulation, paints, fire retardant fabrics, adhesives, etc.
• Human effects: Carcinogen
Using Laws to Protect Drinking Water Quality
1. 1972: Clean Water Act Set water quality standards for allowed levels of
pollutants in surface water Established monitoring, enforcement and
management plans
2. 1974: Safe Drinking Water Act Sets maximum contaminant levels for pollutants in
drinking water that affect human health
Major Water Pollutants Have Harmful Effects
10% of world’s population lacks access to clean drinking water
3.4 million people (mostly children) die each year from water-related diseases
Drinking Water Treatment
Wastewater Sewage Treatment
Wastewater Sewage Treatment
effluent
Sludge is disposed of in landfill, ocean,
cropland, pasture, rangeland
Solutions: Septic Tank System
1 2
3
4
5 6
1. Sewage is discharged into a septic tank2. Grease and oil rise to the top3. Solids fall to the bottom - decomposed by bacteria
Solutions: Septic Tank System
1 2
3
4
5 64. Wastewater is discharged into a field through small
holes in pipes5. Soil filters out some pollutants6. Soil bacteria decompose biodegradable materials