pollution – water and land nutrient oversupply solid wastes toxic chemicals pesticides/herbicides...

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