Transcript Fresh Water Pollution - Alabama School of Fine Arts

Fresh Water Pollution
{
Types, Effects, and Sources of Water
Pollution
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Infection Agents
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Acids, lead, arsenic, salts,
fluorides
Source: surface runoff, industrial
effluents, cleansers
Organic Chemicals
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Oil, gasoline, pesticides,
detergents
Source: industrial effluents,
solvents, runoff from farms
Soil, silt
Source: land erosion
Radioactive Materials
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Nitrate, phosphate, ammonium
Source: sewage, manure,
fertilizers
Sediment
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Inorganic Chemicals
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plant matter)
Source: human sewage, feedlots,
paper mills
Plant Nutrients
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Oxygen-Demanding Wastes
 Organic waste (animal manure,
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Bacteria, viruses, protozoa, and
parasitic worms
Source: human and animal
wastes
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Iodine, radon, uranium, cesium,
and thorium
Source: Nuclear and coal power
plants, mining, nuclear weapons
production
Heat (Thermal Pollution)
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Excessive heat
Source: Water cooling of electric
and industrial plants
Major Categories of Water Pollutants
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Fecal Coliform Test: measure number of
colonies of coliform bacteria present in a 100
mL sample of water
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BOD Test: the amount of oxygen demanding
wastes in water
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Safe drinking water contains no colonies
Safe swimming water contains a maximum of
200 colonies
The amount of dissolved oxygen needed by
aerobic decomposers to break down organic
materials in a certain volume of water
Chemical Analysis: determines the presence
and concentrations of inorganic and organic
chemicals
Indicator Species: can analyze tissues of
organisms found in water, or do a biodiversity
count
Measuring Water Quality
Water
Quality
DO (ppm) at 20˚C
Good
8-9
Slightly
polluted
6.7-8
Moderately
polluted
Heavily
polluted
Gravely
polluted
4.5-6.7
Below 4.5
Below 4
Dissolved Oxygen Content
{
Point Sources
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Discharge pollutants
at specific locations
through drain pipes,
ditches, or sewer lines
into surface water
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Factories
Sewage treatment
plants
Underground mines
Oil tankers
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Nonpoint Sources
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Scattered and diffuse
and hard to trace to a
specific site of
discharge
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Acid deposition
Runoff
Logged forests
Urban streets
Lawns and parking lots
Sources of Water Pollution
Which is easier to monitor and control?
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Water that flows recovers rapidly from degradable oxygendemanding wastes and thermal pollution (dilution)
This works as long as the stream is not overloaded with
pollutants and something does not reduce the flow of the stream
(damming, drought, etc.)
Oxygen Sag Curve
Freshwater
Streams and
Rivers
Types of
organisms
Clean Zone
Normal clean water
organisms
(trout, perch, bass,
mayfly, stonefly)
Concentration
Dissolved oxygen
8 ppm
Decomposition Septic Zone
Zone
Trash fish
(carp, gar,
leeches)
Fish absent,
fungi,
sludge
worms,
bacteria
(anaerobic)
Recovery Zone
Trash fish
(carp, gar,
leeches)
Oxygen sag
Biological oxygen
demand
2 ppm
Direction of flow
Point of waste or
heat discharge
Time or distance downstream
Clean Zone
Normal clean water
organisms
(trout, perch, bass,
mayfly, stonefly)
8 ppm
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Water Pollution Control
laws (1970s)
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Increased the number
and quality of wastewater plants in US and
most other developed
countries
Require industries to
reduce or eliminate
point-source discharges
Problem: the developing
world
Problem: “accidents”
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2014 Elk River chemical
spill of MCHM
What has been done?
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Dilution does not work as well as
in running water
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Often contain stratified layers that
do not mix
Have little flow
Ponds contain small volumes of
water
Much more vulnerable to pollution
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Plant nutrients, oil, pesticides, and
heavy metals
Can kill benthic life, fish, and birds
Cultural eutrophication
Freshwater Lakes
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Very vulnerable because it
cannot effectively cleanse itself
and dilute and disperse
contaminants
Clean up is also almost
impossible
Sources: storage lagoons, septic
tanks, landfills, hazardous
waste dumps, deep injection
wells
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We store gasoline, oil, solvents,
and hazardous wastes in metal
underground tanks that can
leak over time
High health risks in drinking
water
Groundwater Pollution