Transcript Oct 30 - University of San Diego

Water Pollution – Sources and Effects
I.
B.
Sources
2.
Other factors
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a.
b.
c.
d.
e.
3.
Factors besides chemical pollutants can degrade water quality
Removal of adjacent vegetation
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Destabilization of shoreline
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Removal of shade  destabilizes temperatures
Siltation
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Increased turbidity  vision, photosynthesis
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Burial of organisms, filling of water body
Alteration of drainage patterns
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Damming, dredging, channelization
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Changes in vegetation cover in watershed
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Changes flow patterns, predictability, chemistry, sediment load
Leaching of chemicals from natural sources (geogenic, biogenic)
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Salts, metals (Ex: As), nutrients (Ex: P), acids (Ex: tannins)
Warm weather
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Raises temperatures, reduces oxygen solubility, may dry up
Interfere with designated beneficial uses
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Different beneficial uses for different water bodies  different factors of
interest, different methods for remediation
Water Pollution – Components
II.
A.
Oxygen-Depleting Substances
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Pollutants may lower O2 concentrations directly or
indirectly
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Usually biodegradable (organic wastes)
Reduced O2 levels can influence species composition in a
water body
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Ex: Salmon and trout sensitive to O2 levels
Low O2 levels also favor survival of anaerobic bacteria,
many of which produce noxious gases (H2S, CH4)
Examples
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2)
3)
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Sewage (including animal and plant materials)
Agricultural waste (leaves, plant debris, manure)
Food processing wastes
Toxic wastes can kill aquatic organisms, leading to O2
depletion by decomposing bacteria
Warm temperatures exacerbate O2 depletion
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Reduce solubility of oxygen
Accelerate bacterial decomposition rates
Water Pollution – Components
II.
B.
Infectious Agents
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Pathogenic bacteria
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Common components of animal wastes
Can produce outbreaks of typhoid, cholera, salmonellosis,
infectious hepatitis, dysentery (affect billions of people)
Examples
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Giardia causes swimmer’s itch by irritating skin but can cause
intestinal problems internally
Cryptosporidium contaminated Milwaukee water supply in 1993
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More than 400,000 people with symptoms and 100+ deaths
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Cysts passed through filtration in water treatment system
and went undetected
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Very difficult to scan water bodies for all potential
pathogens (problem: lag time b/w test & results)
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Use of indicator organisms (coliform bacteria, enterococci)
Possible sources (source identification challenging)
1)
2)
3)
4)
5)
Municipal sewage – Inadequately treated or spilled
Stormwater drains
Septic systems
Runoff from livestock pens
Sewage from recreational vehicles (boats, campers)
Water Pollution – Components
II.
C.
Toxic Organic Chemicals (TOCs)
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Usually synthetic chemicals
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Persistent organic pollutants (POPs)
Polychlorinated biphenyls (PCBs)
Polycyclic aromatic hydrocarbons (PAHs)
Dioxins
Herbicides, pesticides (Ex: chlordane, DDT)
Characteristics
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Bioavailable – readily assimilated
Lipid soluble – incorporated into lipid deposits
Bioaccumulate – concentrations increase with time and
exposure
Biomagnify – concentrations increase through food web
Tend to be resistant to degradation
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Facilitates wide dispersal
Long residence times (persistence)
Ex – DDT near White Point
Effects – Poorly understood for most compounds
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CNS damage
Liver damage
Birth defects
Time Magazine - 1947
Beach on Long Island, NY - 1945
Water Pollution – Components
II.
C.
Toxic Organic Chemicals (TOCs)
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Usually synthetic chemicals
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Persistent organic pollutants (POPs)
Polychlorinated biphenyls (PCBs)
Polycyclic aromatic hydrocarbons (PAHs)
Dioxins
Herbicides, pesticides (Ex: chlordane, DDT)
Characteristics
•
•
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•
•
Bioavailable – readily assimilated
Lipid soluble – incorporated into lipid deposits
Bioaccumulate – concentrations increase with time and
exposure
Biomagnify – concentrations increase through food web
Tend to be resistant to degradation
•
•
•
•
Facilitates wide dispersal
Long residence times (persistence)
Ex – DDT near White Point
Effects – Poorly understood for most compounds
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•
CNS damage
Liver damage
Birth defects
Water Pollution – Components
II.
C.
Toxic Organic Chemicals (TOCs)
•
Usually synthetic chemicals
•
•
•
•
•
•
Persistent organic pollutants (POPs)
Polychlorinated biphenyls (PCBs)
Polycyclic aromatic hydrocarbons (PAHs)
Dioxins
Herbicides, pesticides (Ex: chlordane, DDT)
Characteristics
•
•
•
•
•
Bioavailable – readily assimilated
Lipid soluble – incorporated into lipid deposits
Bioaccumulate – concentrations increase with time and
exposure
Biomagnify – concentrations increase through food web
Tend to be resistant to degradation
•
•
•
•
Facilitates wide dispersal
Long residence times (persistence)
Ex – DDT near White Point
Effects – Poorly understood for most compounds
•
•
•
CNS damage
Liver damage
Birth defects
http://www.epa.gov/region9/superfund/pvshelf/images/ddtconcbig.gif
Water Pollution – Components
II.
C.
Toxic Organic Chemicals (TOCs)
•
Usually synthetic chemicals
•
•
•
•
•
•
Persistent organic pollutants (POPs)
Polychlorinated biphenyls (PCBs)
Polycyclic aromatic hydrocarbons (PAHs)
Dioxins
Herbicides, pesticides (Ex: chlordane, DDT)
Characteristics
•
•
•
•
•
Bioavailable – readily assimilated
Lipid soluble – incorporated into lipid deposits
Bioaccumulate – concentrations increase with time and
exposure
Biomagnify – concentrations increase through food web
Tend to be resistant to degradation
•
•
•
•
Facilitates wide dispersal
Long residence times (persistence)
Ex – DDT near White Point
Effects – Poorly understood for most compounds
•
•
•
CNS damage
Liver damage
Birth defects