Transcript Ch 21 Lecture - myersparkenvironmental

Chapter 21
WATER & SOIL
POLLUTION
YOUR responsibilities for Ch 21
 Read chapter opening (487-488)
 Enviro-breif
 Harmful algal blooms (pg 492)
 Something Fishy Near Sewage Treatment Plants (pg 505)
 Case in Point
 Water pollution in the Great Lakes (pg 507-508)
 Water pollution in other countries (pg 509- 511)
 Soil Pollution (pg 511-512)
 Meet the Challenge (pg 506)
Water pollution
 Water Pollution:
any physical or chemical change in water that
adversely affects the health of humans and other
organisms.

There are 8 categories
1.
2.
3.
4.
5.
6.
7.
8.
Sewage
Disease causing agents
Sediment pollution
Inorganic plant and algal nutrients
Organic compounds
Inorganic chemicals
Radioactive substances
Thermal pollution
1. Sewage
 Sewage is the release of waste water from drains or
sewers and includes human waste, soaps and
detergents.

Problems… What do you think???
Disease causing agents present
 Enrichment: Fertilization of a body of water by presence of high
level of nutrients such as nitrogen & phosphorous

 Sewage can be decomposed into CO2, water and
materials by microorganisms

Process of cellular respiration (oxygen is required)
Sewage cont…
 Oxygen has a limited ability to dissolve in water and
when sewage is present, the microorganisms that
break it down use up most of it

BIOCHEMICAL OXYGEN DEMAND (BOD)

The amount of oxygen needed by micoorganisms to decompose the
waste into CO2, water, and minerals

Expressed as milligrams of dissolved
O2 per liter of water (mg O2/L)

Large amounts of sewage  high BOD
 Robs the water of dissolved O2
 Anerobic miroorganisms produce
unpleasant odor..
bottom line…. High BOD =Poor water quality
2. Disease- Causing Agents
 Infectious organism that cause disease. They come
from the wastes of infected individuals.

Bacteria

Diseases:
Typhoid
Viruses
Cholera
Protozoa
Dysentery
Parasitic Worms
Polio
Hepatitis
 How are our water systems vulnerable to such disease
causing agents?

Milwaukee 1993
• Cryptosporidium contaminated the water supply
• 370,000 people developed diarrhea
• Several people died

Ontario, Canada 2000
• Escherichia coli
• Several killed, thousands sick
 Monitoring

Water sources are constantly monitored for contamination

E. choli is used as it is an indication of the amount of sewage present
 Fecal Coliform Test
• Water is filtered and the filter is put in a petri dish and incubated.
• Safe water should have no more that one coliform bacteria per 100 mL
• Most strains of coliform bacteria do not cause disease, but coliform test
is a reliable indication of the presence of pathogens or disease causing
agents in the water
3. Sediment Pollution
SEDIMENT POLLUTION:
Excessive amounts of
suspended soil particles
that settle out and
accumulate on the bottom
of a body of water due to
decrease in water velocity.
Causes:
Erosion of agricultural
lands, forest soils exposed
by logging, degraded
stream banks, overgrazed
rangelands, strip mines,
construction
Problems:
Reduces light penetration,
bring pollutants into the
water, reservoir filling,
channel changing
(shipping)
Solution:
Control of soil erosion
4. Inorganic Plant & Algal Nutrients
 Chemicals such as Nitrogen & Phosphorus that stimulate
the growth of plants and algae.

Necessary in small amounts, but overload is dangerous

Sources: Human & animal wastes, plant residues, atmospheric
deposition, fertilizer runoff from agricultural and residential areas

Problem: Excessive growth of algae and aquatic plants disrupting the
natural balance between producers and consumers. Also causes
enrichment, bad odors, and high BOD from excessive numbers of
algae dying and decomposition.

Dead Zone in the Gulf of Mexico
 Area the size of NJ is “dead” from the
seafloor up due to excess animal waste
moving downstream in spring & fall
HYPOXIA- oxygen free environment
5. Organic Compounds
 Chemicals that contain carbon atoms (mostly synthetic)
Study: Researchers from USGS collected samples from 139 waterways
- Water was tested for 95 organic compounds (antibiotics, caffeine, birth control pills etc.)
- Found: low levels of 82 chemicals found & 80% of streams had one organic compound
1/3 of all the streams tested had 10 or more organic compounds present
 What are they?
 pesticides, solvents, plastics,
industrial chemicals
DDT
 Where do they come from?
 Seeping landfills, leaching, runoff, dumping
Acetone
 How do we control organic compounds?
 Stewardship of our water sources, use of alternative
organic compounds, and tertiary water treatment.
Propane
6. Inorganic Chemicals
Contaminants that contain elements other than carbon:
Acids, Salts, Heavy Metals
1.
Lead
Sources: Paint, gas, incinerator ash dumped in ordinary
landfills, air pollution from factories, pesticides & fertilizer
residue on produce, food cans, serving plates & old pipes.
Medical Problems: Lead poisoning,
hypertension, miscarriages, stillbirths,
mental & physical impairments, hearing
loss, ADD, lowered IQ, learning
disabilities.
2.
Mercury

Vaporizes at room temperature DANGEROUS!

Once mercury settles into sediment, it is converted by bacteria to
methyl mercury compounds which are more toxic.
- Mercury accumulates in the muscles of tuna, swordfish, sharks
- Methyl mercury compounds remain in the environment for a
long time and are highly toxic to organisms
Sources: Coal burning power plants (33%), municipal waste
incinerators (18%), Medical waste incinerators (10%), smelting
metals (lead, copper, zinc), industrial waste water, household
trash (batteries, paints, plastics)
Medical Problems: mental retardation,
cerebral palsy, developmental delays in
children. Kidney disorders, damage
to the nervous and cardiovascular
systems, headaches,
depression
7. Radioactive Substances
 Contain atoms of unstable isotopes that emit radiation
 Sources: Mining & processing radioactive minerals, nuclear
plants, industries, medical & scientific facilities.
Indian Point Ground Water Contaminant Flows
(nuclear facility in NY)
8. Thermal Pollution
 Heated water produced during certain industrial
processes is released into waterways

Produces chemical & biological effects
Chemical: decomposition of waste occurs faster depleting water of
oxygen. Less oxygen dissolves in warm water
 Biological: less oxygen dissolved less animals or animal stress,
reproductive, digestion rates & respiration rates are affected

http://www.crocodile-clips.com/absorb/AC4/sample/LR1105_mg.html
Turkey Point
Nuclear Power plant
Thermal Pollution
How do NUTRIENTS affect water systems?
Oligotrophic Lake
Eutrophic lake
 Slow flowing streams with
 Enrichment of water nutrients
minimal nutrients
 Clear water
 Supports small populations
causing algal blooms
 High BOD
 Fish populations
(pike, sturgeon, whitefish cold )
(catfish, carp use less O2)
Types of Pollution
Point Source:
Pollution is discharged into the
environment through pipes, sewers
or ditches from specific sites
Non-Point Source:
Pollution caused by land pollutants
that enter bodies of water over large
areas rather than at a single point.
Agricultural runoff, mining wastes,
municipal wastes, construction sediments
Sources of Water Pollution
1. Agriculture
Discussed in chapter 13
2. Municipal:
Contains salts, asbestos, chlorides,
copper, cyanides, grease, lead, zinc,
hydrocarbons, motor oil, organic
wastes, phosphates, sulfuric acid
Combined Sewer System: Human and
industrial wastes are mixed with
urban runoff or snowmelts that
overpower the treatment plant & raw
sewage flows into waterways without
being treated
3. Industrial
- High BOD, toxic compounds, sludge
- Some industries are cleaning water
before they discharge it
Groundwater Pollution
Improving Water Quality
Purification of Drinking Water
 Water supplies include streams, rivers,
lakes, and reservoirs (dams)
1. Water is treated with aluminum sulfate
causing suspended particles to come out
2. Water is then filtered through sand
3. Some cities pump water through activated
carbon granules to remove organic cmpds.
4. Addition of chlorine to kill disease- causing
agents. Some cities use UV instead of Cl.
Should we use chlorine??
5. Fluoridation – adding fluoride to municipal
water sources to prevent tooth decay.
Municipal Sewage Treatment
Waste water undergoes several treatments at a
sewage treatment plant to prevent environmental
and public health problems. The treated water is
then discharged into rivers, lakes or the ocean.
Process:
Primary Treatment
1.
A.
B.
Removes suspended & floating particles
Screening & gravitational settling
1.
Solid material that settles out is known as primary sludge
2.
Does not eliminate the inorganic & organic compounds
remaining in the wastewater.
2.
Secondary Treatment
A.
Uses microorganisms to decompose the suspended
organic material
1.
Trickling filters: wastewater trickles through rock beds containing
bacterial which degrade the organic material
2. Activated sludge process: Wastewater is aerated and circulated
through bacteria rich particles.
3. Particles and microorganisms are allowed to settle out forming
Secondary Sludge
** Water is clear and free of organic wastes such as sewage**
Primary and Secondary Treatment
3.
Tertiary Treatment
A.
B.
C.
D.
Considered an advanced water treatment
Variety of biological, chemical & physical processes
Removes phosphorus & nitrogen
Can be used to purify wastewater so that it can be reused in
communities where water is scarce.
Question to think about-
What do we do with the
primary and secondary
sludge?
1. Anaerobic digestion
2. Fertilizer
3. Incineration
4. Ocean dumping
5. Sanitary landfill
Individual Septic Systems
 Many private residences use individual septic
systems instead of municipal sewage treatment.




Household sewage is piped into the septic tank
Particles settle to the bottom
Grease and oils form a scummy layer where bacteria
decomposes it
Waste water containing suspended organic and inorganic
material flows into the drain field through a network of
perforated pipes set in trenches of crushed stone
Purified wastewater then percolates into
the groundwater or evaporates from the soil

Do you see how there could be a
contamination problem here?
Septic Systems
The septic tank works
much like primary
treatment in municipal
sewage treatmentsewage from the house
is piped to the septic
tank, where particles
settle to the bottom
Wastewater containing
suspended organic and
inorganic material flows
into the drain field and
gradually seeps into the
soil
POLLUTION CONTROL THROUGH
LEGISLATION
The United States has attempted to control water
pollution through legislation since the passage of the
Refuse Act of 1899.
- intended to reduce the release of pollutants into
navigable rivers.
Governments control point source pollution by
1. Imposing penalties on polluters
2. Taxing polluters to pay for the cleanup
SAFE DRINKING WATER ACT
Prior to 1974, the states set their own
standards for safe drinking water
 SAFE DRINKING ACT



Set uniform federal standards
Required EPA to determine the maximum contaminant level
(MCL) which is the maximum permissible amount of any
pollutant that might adversely affect human health.
Amended in 1996- requires municipal water suppliers to tell
consumers what contaminants are present in their city’s water
and if those pose a health risk.
CLEAN WATER ACT
Controls the quality of rivers, lakes, aquifers, estuaries
and coastal water in the United States.
 Original name: Water Pollution Control Act of 1972
 Two basic goals:
 Eliminate discharge of pollutants in US waterways
 Attain water quality levels that make waterways safe to fish and
swim in.
 EPA is required to set up and monitor national
emission limitations

maximum permissible amount of water pollutants that can be discharged
from sewage treatment plants, factories and other point sources.
Clean Water Act continued….
 Results

Overall the CWA has been effective at improving the
quality of water from point sources.


Point sources must obtain permits from the National pollutant
Discharge Elimination System to discharge untreated water.
Non Point Source Pollution is more difficult and
expensive to control
CWA expanded in 1987 to allow National Pollutant Discharge
System to include non point sources such as sediment from
erosion from construction sites.
 NO real effective policy to address non-point source pollution.

Laws that Protect Groundwater
 Resource, Conservation and Recovery Act deals with
the storage and disposal of hazardous wastes and
helps prevent groundwater contamination.
 Safe Drinking Water Act contains provisions to
protect underground aquifers that are important
sources of drinking water.

Also regulates underground injection of wastes.
 Several laws related to pesticides, strip mining and
cleanup of abandoned hazardous waste sites
(brownfields) also indirectly protect groundwater.
Effects of Salinized Soil on Plants
Normally, the water
concentration inside
plant cells is lower than
that in the soil resulting
in a net movement of
water into the root cell.
When soil contains a
high amount of salt, its
relative water
concentration can be
lower than the water
concentration inside
cells. This causes water
to move out of the roots
into the soil, even when
the soil is wet.