water pollution miller chapter 21. water resources water is a renewable but finite resource clean...
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“Water Planet” About 70% of Earth’s surface is water 97.5% of that is ocean water 2.5% is fresh water 1.5% is frozen in ice caps & glaciers 0.5% is inaccessible/brackish Only about 0.02% of the Earth’s water supply is available as liquid freshwaterTRANSCRIPT
Water PollutionMiller Chapter 21
Water ResourcesWater is a “renewable” but finite
resourceClean water is essential to
human/animal health – humans can only live about 3 days without water
“Water Planet”About 70% of Earth’s surface is
water97.5% of that is ocean water2.5% is fresh water
1.5% is frozen in ice caps & glaciers0.5% is inaccessible/brackish
Only about 0.02% of the Earth’s water supply is available as liquid freshwater
Who is using Earth’s water resources?
What 2 conclusions
can you draw from this data?
Hydrological Cycle
Hydrological CycleTranspiration – from plantsEvaporation – from rivers, lakes,
ponds, oceansPrecipitation – rainRunoff – to rivers, lakes, etcInfiltration/Seepage – to aquifers,
groundwater, to rivers & oceans, to plants
Surface WaterSurface water is
water that is above ground in lakes, rivers, ponds, and streams
A watershed is the entire area of land that is drained by a river
Fig. 14-3, p. 308
Unconfined Aquifer Recharge Area
Precipitation Evaporation and transpirationEvaporation
Confined Recharge Area
Runoff
Flowing artesian well
Recharge Unconfined Aquifer
Stream Well requiring a pump
Infiltration Water table Lak
eInfiltrationUnconfined aquiferConfined aquiferConfining impermeable rock layer
Less permeable material such as clay
Groundwater and Aquifers
Groundwater – water that seeps down into the soil and is stored underground
Aquifers – large amounts of water in underground rock formationsEx. Edward’s Aquifer (TX)
AquifersAquifers are running low – people are
pumping too much out!It can take millions of years to formRecharge zone: area of land from
which groundwater originates
Freshwater Pollutionthe introduction of chemical,
physical, or biological material into water that degrades the quality of the water and affects the organisms that drink it and live in it.
Major Water Pollutants and Their Sources
Common Diseases Transmitted to Humans through Contaminated
Drinking Water
Point Pollutionpollution that is
discharged from a single source, such as a factory, a wastewater treatment plant, or an oil tanker
Point Pollution Fairly easy to
identify, regulate, and control
Ex: septic tanks, storage lagoons for polluted waste, landfills, underground gasoline storage tanks, wastewater treatment plants, industrial plants
Nonpoint PollutionPollution that comes from many
sourcesReaches bodies of water via
streets and sewersAccumulation of small amounts
of pollution adds up to huge problems
Hard to regulate and control – mostly public awareness is only help
Nonpoint PollutionEx: highway
construction and maintenance; oil, gasoline, dog feces, litter from storm drain runoff; pesticides and fertilizer; dry salt (for snow and ice on roads)
Major kinds of water pollution
Pathogens – disease causing organisms such as bacteria; caused by untreated human sewage entering water
Organic matter – biodegradable remains of animals and plants, including feces; mainly nonpoint sources
Water PollutionOrganic
chemicals – pesticides, fertilizers, plastics, detergents, gasoline and oil, and other fossil fuel materials (hydrocarbons); nonpoint pollution
Water PollutionInorganic
chemicals – acids, salts, toxic metals; point and nonpoint
Toxic chemicals – poisonous chemicals, incl. heavy metals (lead, mercury, cadmium); industrial and household chemicals
Water PollutionPhysical
agents – heat and suspended solids such as soil
Radioactive waste – from power plants or nuclear processing and defense facilities
Wastewater Treatment Plants
Pipes lead from residential and industrial areas to wastewater treatment plants for treatment before being returned to lakes and rivers
Not 100% effective, especially with industrial wastewater
Sludge – product of treatment – can be used as fertilizer or bricks
Primary Sewage Treatment
One settling tank
Secondary Sewage Treatment
Two settling tanks
Other Treatment Uses
Solutions: Primary and Secondary Sewage
Treatment
Solutions: Septic Tank System
PathogensDisease-causing
microorganismsEnter water
through untreated wastewater/animal feces
Cholera, hepatitis, typhoid
E. coli checked using “fecal coliform test”
BioaccumulationOr biomagnificationBuild up of toxic pesticides in
animals through the food chain
EutrophicationEutrophication – build-up of
abundance of nutrients in lakes and streams over time
uses up large amounts of oxygen dissolved in water
Artificial eutrophicationEutrophication caused by
humansNormal process which has been
acceleratedInorganic plant nutrients
(phosphorous and nitrogen) enter water through sewage and fertilizer runoff
EutrophicationPhosphorous –
contained in detergents, animal wastes
- causes excessive algal growth
Algae BloomsLarge mats of
algae which float on the water
As algae die and decompose, large amts of dissolved oxygen are used
Fish suffocate
Water Quality as Measured by Dissolved Oxygen Content in Parts per Million
Dilution and Decay of Degradable, Oxygen-Demanding Wastes in a Stream
Thermal PollutionExcessive amounts of heat
added to a body of waterFrom power plants and other
industries -use water as a cooling
system -hot water returned to
stream/river -can cause massive fish kills
(suffocate) -hot water does not hold as
much dissolved oxygen as cold water
Clean Water Act“to restore and maintain the
chemical, physical, and biological integrity of the nation’s waters”
To make all surface water clean enough for fishing and swimming
Groundwater PollutionPesticides, fertilizers, agricultural
chemicals that seep into groundwater
EPA has detected at least 200 hazardous chemicals that can seep through the soil and into groundwater
Porosity vs. Permeability
Principal Sources of Groundwater Contamination in the U.S.
Groundwater Contamination from a Leaking Gasoline Tank
Solutions: Groundwater Pollution, Prevention and Cleanup
Ocean Pollution
RunoffAt least 85% of ocean pollution
comes from the landRiver runoff
Dumped directly in the ocean
Sludge from wastewater treatment
Ships dump directly into ocean
Residential Areas, Factories, and Farms Contribute to Pollution of Coastal Waters
A Large Zone of Oxygen-Depleted Water in the Gulf of Mexico Due to Algal Blooms
Oil SpillsLarge
disasters: ex. Exxon Valdez - 1989 only about 5% of oil pollution
Most oil is from tankers slowly leaking (706 Million Gallons of oil per year!!!)100 Million in
the USOil spilled
when loading and offloading tankers
Offshore oil rigs
Plastic
Plastic fishing lines - strangulation, trapped animals
Clear plastic bags - block digestive systems in turtles
Six-pack rings - around necks
The North Pacific Gyre
The world’s largest “landfill”: 100 Million tons of floating plastic, stretching for 500 nautical miles!
PreventionMARPOL - International
Convention for the Prevention of Pollution From Ships
prohibits discharge of oil and plastics in oceans and coastal waters
Marine Protection, Research, and Sanctuaries Act - double hulls on tankers
Solutions: Coastal Water Pollution, Prevention and Cleanup
Ocean OwnershipJurisdiction problemsLaw of the Sea Treaty - 22 km
(12 nautical miles) = exclusive economic zone