pollution – water and land nutrient oversupply solid wastes toxic chemicals pesticides/herbicides...
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Pollution – Water and Land
• Nutrient oversupply
• Solid wastes
• Toxic chemicals
• Pesticides/herbicides
• Nuclear waste
Human Impacts on Air and Water Quality
Pathogens Carried by Sewage
• Disease-causing agents• Safety measures
– Purification of public water supply– Sanitary collection/treatment of sewage– Sanitary practices when processing food
Chemical Pollutants
• Inorganic chemicals
– Heavy metals, acids, road salts
• Organic chemicals
– Petroleum, pesticides, detergents
Upper Hudson River
• Over 200 miles of river polluted– Polychlorinated biphenyls (PCB’s)– Mercury– Chlordane– Dioxins– DDT– Cesium– Lead
• Longest Superfund Site
PCB’s in Hudson River
• General Electric Factories– 1944-1977
• 1.3 million pounds of PCB’s dumped into Hudson River
• EPA steps in…– Evidence– Dumping of PCB stopped– Hudson river declared a Superfund Site– 2002 – GE must dredge river and remove
PCB’s
Problem…
• To dredge or not to dredge… that is the question!– GE – leave it alone
• Low level of PCB’s not harmful
• Disrupting sediment will release large quantities of PCB’s
– EPA – dredge and remove• Low levels over time will cause health problems
• With proper care discharge will be minimal
More Problems…
• How much PCB exposure is safe?– 100 ppm increases cancer rates in rats– Guesstimate of 1 ppb considered safe
• When do you stop dredging?
• 90% of material can be removed easily
• Last 10% very difficult
Effect of Sediments on Stream Ecology
• Loss of hiding/resting places for small fish
• Attached aquatic organisms scoured from the rocks and sand
• Poor light penetration
Organic Wastes
• Dissolved oxygen (DO) in the water is depleted during decomposition of organic wastes.
• Water quality test– Biochemical oxygen demand (BOD):
measure of the amount of organic material
Aquatic Plants
• Benthic plants– Emergent vegetation– Submerged aquatic vegetation (SAV)
• Floating Plants– Duck weed
• Phytoplankton– Green filamentous and single cell– Blue-green single cell– Diatoms single cell
Eutrophication
• As nutrients are added from pollution, an oligotrophic condition rapidly becomes eutrophic.
Natural and Cultural Eutrophication
• Natural eutrophication– aquatic succession– occurs over several hundreds of years
• Cultural eutrophication– driven by human activities– occurs rapidly
Controlling Point Sources
• Ban phosphate detergents– Suffolk county banned phosphate detergents in
1970
• Sewage-treatment improvements
Controlling Non-point Sources
• Runoff pollutants– Agricultural fields
– Deforested woodlands
– Overgrazed pastures
• Those damn ducks and geese!!!
Sometimes Solutions are Simple
Development of Sewage Collection and Treatment Systems
• Through the 1970s sewage was discharged directly into waterways
• Clean Water Act of 1972
Pollution – Air
• Particulates
• Acid-forming compounds
• Photochemical smog
• CO2
• CFCs
Chlorofluorocarbons (CFCs)
• Organic molecules in which both chlorine and fluorine atoms replace some of the hydrogen atoms
• Sources:– refrigerators and air conditioners– production of plastic foam– cleaner for electronic parts– pressurizing agent in aerosol cans
Health Effects of increased UV Radiation
• skin damage (skin cancers and premature aging),
• eye damage (including cataracts)
• suppression of the immune system
• adverse effects on some animal and plant life and some plastic materials
1987 Montreal Protocol
• 191 countries (including US) recognized the threats posed by ozone depletion
• 1987 – formed treaty to scale back CFC production/use by 50% by 2000
• 1990 – amendment to completely phase out ozone-destroying chemicals by 2000
• 1992 – amendment to completely phase out ozone-destroying chemicals by 1996
Depletion of stratospheric ozone levels over Antarctica
October 18, 2009
Is the south pole ozone hole getting smaller?
Stratospheric Ozone: Current Status and Future Plans
• Ozone layer is the same size since 1998; expected to return to normal levels ~2075. • Sustaining ozone recovery requires a worldwide phase-out of ozone-depleting substances. •
Air Pollution4 major air pollutants regulated by the Clean Air Act:
– particle pollution – carbon monoxide – sulfur dioxide– nitrogen dioxide
Air Quality Index– Calculated by EPA– ‘Good’, ‘Moderate’, ‘Unhealthy for sensitive individuals’,
‘Unhealthy’– Released to media daily
Air Quality Index• Today's Hourly AQI
Ground-level ozone• tropospheric (ground-level) ozone • formed through the interactions of man-made
(and natural) emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx) in the presence of heat and sunlight (UV)
• High dependence on weather conditions (hot, sunny, calm)
• typically a summertime pollutant, chief component of summertime smog
Sources of VOCs– Cars and gasoline-burning engines
– paints, insecticides, cleaners, industrial solvents, chemical manufacturing
US EPA
Sources of NOx – fossil fuels combustion (primarily from motor vehicles and
power plants) US EPA
Health effects of Ground level ozone (smog)
• constriction of the bronchial airways – (coughing, sore throat, ear aches, wheezing, chest
discomfort, uncomfortable breathing)• increases sensitivity to allergens • can be involved in the development of asthma. • weakens the immune system and facilitates the
development of lung infections. • Higher death rates due to lung and heart problems at
elevated ozone levels• Sensitive groups: asthmatics, children, elderly, people
with heart and lung disease, people who are active outdoors
Causes of Acid Rain
• Sulfur dioxide (SO2) + OH sulfuric acid (H2SO4)
• Nitrogen oxides (NOx)+ OH nitric acid (HNO3)
Acid Rain and the Clean Air Act
Anthropomorphic Sources of Acid Rain Pollution
pH Scale
• pH 1 2 3 4 5 6 7 8 9 10 11 12 13 14
• pH < 7 acidic
• pH 7 neutral
• pH < basic
Acidity of Precipitation
• Normal pH 5.6
• Anything less is acid rain
Acid Rain
Effects of Acid Rain
• Fresh Water– Decreased pH
• Die off of higher organisms
• Low reproductive rate in higher organism
• Example: Adirondacks– ~200 lakes are without complex life– Granite based watershed– Acid shock during spring thaw
Why are some lakes not effected?
• Buffering capacity– Limestone (CaCO3) reacts with H+ to form CO2
and water– Limestone is lost
Effects of Acid Rain
• Forests– Some trees are sensitive to acid– Example: Red Spruce in northeast– Replaced by acid tolerant Balsam Fir
Effects of Acid Rain
• Heavy metal leaching– Acidic pH causes normally insoluble heavy
metals to become soluble– Example: Mercury content of fish in Great
Lakes
Solutions
• Low sulfur coal
• Scrubber in smokestacks– Injects buffered or basic water into the exhaust
stream
• Use less fossil fuels
Water: Hydrologic Cycle and Human Use
Water: A Vital Resource
Polarity in H2O: The Water Molecule
O
H H+ +
--
covalent bond
CondensationO
H H+ +
--
O
H H+ +
--O
H H+ +
--
Evaporation and Condensation
• Evaporation – liquid gas– Purifies water
• Condensation – gas liquid– Forms precipitation and clouds
• The process of evaporation and condensation provides all the fresh water on the planet
Condensation
Relative Humidity
• Low temperature holds less water than high temperature– Winter air is drier
• Amount of humidity that air can hold is relative to temperature
Effects of Temperature on Water
• Temperature (kinetic energy) counteracts the effect of hydrogen bonds– Gas: steam, water vapor
• Individual water molecules
– Liquid: running water– Solid: ice
• 0°C , 32°F
• Why does ice float?
The Water Cycle
Precipitation
• Adiabatic cooling: warm air rises, expands and cools
• 100% relative humidity + cooling = clouds
• Increasing condensation = water droplets
Global Air Circulation
Rain Shadow Effect
Human Impacts on the Water Cycle
• Changing the Earth’s surface
• Floods
• Climate change
• Atmospheric pollution
• Withdrawing water supplies
Human Impacts on the Hydrologic Cycle
Surface Waters
• Dam impacts
• Ecological effects of changing salinity in estuaries– Increased salinity– Loss of native species– Invasive species increase
Dams
• Three Gorges Dam– Largest in world– Controls deadly floods– Displaced 1.2 million people including farms,
cities, homes, and factories– 370-mile-long reservoir
Dams: Disrupt Integrity of River System
• Above the dam– Flooding– Sediment deposition– Loss of functional floodplain
• Below the dam– Loss of normal river flow patterns– Loss of river biota– Loss of functional floodplain
Hoover DamAlong Colorado RiverBorder of Arizona and
Nevada
Aquifer Exploitation
• Groundwater use exceeds aquifer recharge
• Many remaining aquifers are heavily polluted
OgallalaAquifer
Grey Water Recycling
• Water NOT contaminated by sewage– Showers, tubs, sinks– Washing machines and dishwaters provided
biodegradable detergents are used
• Used for irrigation, watering lawns and gardens