Post on 14-Jan-2016
Pollution – Air
• Particulates
• Acid-forming compounds
• Photochemical smog
• CO2
• CFCs
Pollution – Water and Land
• Nutrient oversupply
• Solid wastes
• Toxic chemicals
• Pesticides/herbicides
• Nuclear waste
Water Pollution Source
Pathogens Carried by Sewage
• Disease-causing agents• Safety measures
– Purification of public water supply– Sanitary collection/treatment of sewage– Sanitary practices when processing food
Testing Water for SewageFecal Coliform Test
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 – we survived!!!
• 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
Sewage Treatment – Methane Gas Production
• Biogas
• Fermentation byproduct
• Can be used as fuel to generate electricity
Atmospheric Structure
Formation of the Ozone Shield
UV light + O2 O + O
Free O + O2 O3
Free O + O3 O2 + O2
UV light + O3O + O2
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
Breakdown of Ozone Shield
CFCl3 + UV Cl + CFCl2
Cl + O3 ClO + O2
ClO + ClO 2 Cl + O2
Chlorine is a catalyst that destroys the production of ozone.
Montreal Protocol
• 1987 – scale back CFC production 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
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
pH
• Negative log of H+ concentration
• pH 1 = 10-1 grams/Liter = 0.1 grams/Liter
• As pH increases OH- (hydroxide ions) decreases
• pH 7 neutral = equal amount of H+ and OH- ions
Acidity of Precipitation
• Normal pH 5.6
• Anything less is acid rain
Acid Rain
Causes of Acid Rain
• Sulfur dioxide (SO2) + OH sulfuric acid (H2SO4)
• Nitrogen oxides (NOx)+ OH nitric acid (HNO3)
Hydroxide Radicals
• O3 + UV light O2 + O
• O + H2O 2OH
Sources
• Natural– Sulfur dioxide
• 50-70
– Nitrogen oxides• 30-40
• Anthropogenic– Sulfur dioxide
• 100-130
– Nitrogen oxides• 60-70
Anthropomorphic Sources of Acid Rain Pollution
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