Water Pollution
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Any change in water quality that has a harmful effect on
living organisms
Any change that makes the water unsuitable for the use
intended
Chemical
Biological
Physical
Thermal
Safe Drinking Water
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95% in developed countries have safe drinking water
74% in developing countries
1.4 billion lack safe water
9,300 die/day: contaminated water or lack of adequate
hygiene
Water Quality
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Tests and analyses of water samples
Fecal coliform test
Coliforms inhabit intestines of human and other animals
Presence indicates water has been exposed to wastes that
may carry pathogens
Fecal Coliforms
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Not all coliforms cause disease
Pass water through filter
Place filter on culture medium
Grow out bacteria for 24 hours
Safe for drinking—no colonies in sample size of 100 ml
Fecal Coliforms
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Safe for swimming ≤ 200 colonies/ 100 ml
Raw sewage—several million colonies/100 ml
High readings—determine source
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Look at different strains
Identify source—humans, pets, livestock
Dissolved Oxygen
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Related to amount of oxygen-demanding wastes
Organic materials that are usually biodegradable by
aerobic bacteria if there is enough dissolved oxygen in the
water
Biological Oxygen Demand
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Amount of dissolved oxygen consumed by aquatic
decomposers
Given volume of water at a certain temperature over a
specific time period
Chemical Analyses
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Presence and concentration of organic and inorganic
chemicals that pollute water
Various methods, various machines
Sediment content—measure weight of sediment
Suspended sediment—measure turbidity of sample
Living organisms
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Indicator species: cattail, mussels, rockfish
Plants and bottom dwellers or filter feeders
Biosensors: bioengineered bacteria or fungi glow in
presence of specific pollutant
Sources
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Single source—point source
Release at specific locations
Drain pipes, sewage lines
Easier to identify, monitor, regulate sources
Sources
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Nonpoint sources—scattered and diffuse
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Not traced to single discharge site
Acid deposition (rain), runoff of agricultural chemicals,
urban runoff, lawns, golf courses
Difficult to identify and control source
Activities Producing Pollution
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Food production
Sediment from cropland and rangelands
 Fertilizers
 Pesticides
 Bacteria from livestock
 Food processing wastes
 Excess salts
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Activities Producing Pollution
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Making things—industrial facilities and mining
Industrial wastewater
 Acid deposition
 Sediments toxic chemical runoff
 Acid drainage
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Infectious Agents
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Typhoid, cholera, bacterial and amoebic dysentery, polio,
hepatitis A, schistosomiasis—contaminated water
Malaria, yellow fever, dengue fever, filariaisis—insects with
aquatic larvae
Infectious Waste
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Sewage treatment facilities—treat human waste
Water treatment—chlorination and filtration
Keep two streams separate
Rehydration cocktail—clean water, sugar, salt
Oxygen-Demanding Waste
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Oxygen content above 6 ppm supports game fish
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< 2ppm—worms, bacteria, fungi
Add O2—turbulence and diffusion
Deplete O2—respiration and chemical processes
Oxygen-demanding Waste
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BOD
COD
DO—more related to organism survival, measures
pollutants, but is also function of temperature and aeration
Fresh Water Streams &
OD Waste
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Effects on streams depends on volume, flow and
temperature
Combination of dilution and biodegradation—natural
processes help
Moderate pollution loads
Fresh Water Streams &
OD waste
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Oxygen sag curve—oxygen depleted as bacteria breaks
pollutants down
Hits populations with high O demands
Recover downstream
Factors include—waste volume, stream volume, flow rate,
turbulence, temperature, pH
Lakes and OD Wastes
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OD wastes more problematic
Layers of lake allow little mixing
Little flow
Little discharge
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Agricultural chemicals, oils, lead, mercury, selenium
Biomagnification
Water Quality
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Oligotrophic—clear water, low biological activity
Eutrophic—rich in organisms and organic materials
Eutrophication
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Natural nutrient enrichment of lakes, nitrates and
phosphates
Increase phytoplankton -> increase fish
Cultural eutrophication—increase from human activities
Blooms of plant and bacterial growth
May reduce productivity
Cultural Eutrophication
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Decaying organisms depletes O
If continuous, aerobic organisms die
Anerobics take over
Produce methane and hydrogen sulfide
Eutrophication and Marine Systems
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Nearshore waters, bays, estuaries
Dead zones—Mississippi River and Gulf of Mexico, Nile
River and Meditteranian Sea
Toxic tides—red tides, dinoflagellates, Pfiesteria piscisida
Water-soluble
Inorganic Chemicals
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Acids, toxic metals (lead, arsenic, selenium), salts (sodium
chloride) and flourides
Inorganic Chemicals
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Make fresh water unusable
Skin cancers, spine and neck damage
Nervous system damage
Harm fish and aquatic life
Lower crop yields
Accelerate metal corrosion
Inorganic Pollutants
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Weathering of rocks
Industrial activities
Metals—lead, mercury
Non-metallic salts—selenium, arsenic
Acids and bases—acid deposition
Alkaline soils (with limestone)—help to neutralize
Organic Chemicals
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Chemical, pharmaceuticals and plastics
Oil, gasoline, cleaning solvents, detergents
Nervous system damage
Cancers
Harm fish and wildlife
Thermal Pollution
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Temperature change (+ or - ) alters water quality and
ability to support life
Water temperature changes alter ability to hold O
Warmer temperature, less O
Industrial and power plants use water to cool
Thermal Pollution
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Restrictions on how much temperature change is allowed
Animals attracted to warmth and food source
Alter plant life
Sediment
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Erosion rates increase as result of human activities
Sediments fill lakes, alter shipping channels
Cover eggs and bottom dwelling animals
Blocked sunlight
Sediment
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Rebuild wetlands
Deposit nutrient laden silt
Build land
Groundwater Pollution
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So far, “easy”
Groundwater—invisible but valuable
Major source of drinking water
Once contaminated, pollutants hard to remove
Groundwater
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Pollution moves from site of introduction
Forms plume
Contaminated water may be used for drinking or
agricultural water
Groundwater
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Degradable waste not degraded
Slow flow—no dilution or dispersion
Lower dissolved O
Lower numbers of aerobic decomposing bacteria
Lower temperature
Nondegradable waste not degraded
Groundwater Pollution
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Identification, monitoring, remediation—expensive
Municipal groundwater supplies contaminated—45% in U.
S.
Industrial waste ponds and lagoons leak
Acids, wood preservatives, fuels
Groundwater Pollution
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Leaking Underground Storage Tanks
Historically 85% leakage
Silicon Valley
Leaking gasoline storage
Cleanup costs--$10,000 to $250,000 per tank
Groundwater Pollution
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Military facilities
Wash facilities
Fuel dumps
Explosive washouts
Etc.
Groundwater Pollution
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Leaking landfills
No liner or cracked liner
Deep well injection
Should not have migrated into groundwater
Ocean Pollution
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Materials on land end up in ocean
Oils, metals, solvents, sediments
Solid waste—ends up in ocean
After storm—mountains of waste end up in LA and San
Gabriel Rivers, transported to ocean and beaches
Ocean Pollution
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Federal law requires clean up before solid waste hits ocean
Temporary dams, barricades
Stay out of water for three days minimum before
swimming
Ocean Pollution—Oil
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Oil tanker spills—dramatic, ship impaled on rocks
Intensive clean-up efforts and costs
Greater impact overall—land-based activities, waste oil,
washing and loading oil tankers & ships
Ocean Pollution—Oil
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Effects depend on
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Type of oil: crude or refined
Type of system: open ocean, bay, estuary
Amount released
Distance from shore
Time of year
Weather conditions
Average water temperature
Ocean currents
Oil Pollution
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VOCs—immediately kill several types of organisms
Tar-like globs float and cover ocean and shore birds
Heavy oil sinks to bottom—smothers bottom-dwelling
organisms
Oil Pollution
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Rule of thumb for recovery time from exposure to large
exposures—
Crude oil—3 years
 Refined oil—10-15 years
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Water Pollution Control
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Source Reduction
Don’t produce
 Don’t release
 Alter agriculture practice
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Nonpoint Source
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Agriculture—erosion, agriculture chemicals, animal waste
Urban runoff—salts, oil rubber metals, fertilizer
Construction sites—sediment, barriers and filters on catch
basins
Land disposal—leaking liners