Notes Part 2
Core case study: Environmental Effects of Gold Mining
-
Gold producers
o South Africa
o Australia
o United States
o Canada
-
Cyanide heap leaching degrades rock and leaves you with gold
o Extremely toxic to birds and mammals
o 2000: collapse of a dam retaining a cyanide leach pond

Impact on organisms and the environment
What is geology?
-
Three major concentric zones of he earth
o Core –liquid/ semi-liquid
o Mantle – liquid/semi-liquid

Including the asthenosphere
o Crust

continental crust (thick)

oceanic crust: 71% of crust (thin in comparison)
The earth’s crust is made up of a mosaic of huge rigid plates: tectonic plates
The san andeas fault as it crosses part of the Carrizo plain in cali
Colcanoses release molten rock from the earth’s interior
-
Volcano
o Fissue
o Magma
o Lava
-
1980: eruption of mount St. Helens
-
1991: Eruption of Mount Pinatubo
-
Benefits of volcanic activity
Earthquakes are geological rock and roll events
-
Richter scale
There are three maor types of rockes
-
Earths crust
o Composed of minerals and rockes
-
Three broad classes of rockes, based on formaton
o Sedimentary

Sandstone (tar)

Shale (oil)

Dolomite

Limestone

Lignite

Bituminous coal
o Igneous

Granite

Lava rock
o Metamorphic

Anthracite

Slate

Marble
We use a variety of nonrenewable mineral resources
-
Mineral resource
o Fossil fuels
o Metallic minerals
o Nonmetallic minerals
-
Ore
o High-grade ore
o Low-grade ore
-
Importance and examples of nonrenewable metal and nonmetal mineral resources
Mineral use has advantages and disadvantages
-
Advantages of the processes of mining and converting minerals into useful
products
-
Disadvantages
Extraction, processing, using nonrenewable mineral and energy resources
-
mining
o exploration, extraction
o disturbed land, mining accident, health hazards, mine waste dumping, oil
spills and blowouts, noise, ugliness, heat
-
processing
o transportation, purification, manufacturing
o solid waste
o radioactive material
o air, water soil pollution
-
use
Ecological restoration of a mining site in new jersey, U.S.
Removing metals from ores has harmful environmental effects
Market prices affect supplies of nonrenewable minerals
-
subsidies and tax breaks to mining companies keep mineral prices artificially low
-
does this promote economic growth and national security/
-
scarce investment capital hinders the development of new supplies of mineral
resources
Case study: The U.S. general mining law of 1872
-
encouraged mineral exploration and mining of hard-rock minerals on U.S. public
lands
-
Developed to encourage settling the West (1800)
-
Until 1995, and could be bought for 1872 prices
-
Companies must pay for clean-up now
We can find substitutes for some scarce mineral resource
-
materials revolution
-
nanotechnology
-
silicon
-
high-strength plastics
o drawbacks?
Core case study: how long will supplies of conventional oil last?
-
Oil: energy supplier
-
How much is left? When will we run out
-
Three options
o Look for more
o Reduce oil use and waste
o Use other energy sources
-
no easy solutions
Fossil fuels supply most of our commercial energy
-
Solar energy
-
Indirect solar energy
o Wind
o Hydropower
o Biomass
-
Commercial energy
o nonrenewable energy resources, e.g. fossil diesel
o renewable energy resources
Natural capital: important nonrenewable energy resources
A brief history of human energy use
-
Muscle power: early humans
-
Discovery of fire
-
Agriculture
-
Use of wind and lowing water
-
Machines powered by wood, then coal
-
Internal combustion engine
-
Nuclear energy
-
Energy crisis
Open controls most of the world’s oil supplies
-
13 countries have at lest 60% of the world’s crude oil reserves
o Saudi Arabia 25%
o Canada 15%
-
Oil production peaks and flow rates to consumers
-
Possible effects of steeply rising oil prices
o Resuce energy waste
o Shift to non-carbon energy sources
o Higher prices for products made with petrochemicals
o Higher food prices; buy locally-produced food
o Airfares higher
o Smaller more fuel efficient cars
How energy is used
-
In the us
o Industry – 36.5%
o Residential and commercial buildings – 34%
o Transportation – 26%
Coal
-
Fossilized plant material
-
Most formed during Carboniferous period
o 286 million to 360 million years ago
-
World coal deposits 10x greater than conventional oil and gas
-
Under current consumption rates
o Several thousand years
-
Environmental Impact
o Air pollution

Radioactivity and toxic metals

25% of all atmospheric mercury

up to 10% sulfur by weight

sulfur is released and oxidizes to sulfur dioxide or sulfate
Oil
-
Organic material buried in sediment and subjected ot high pressure and
temperature
-
World supply = 4 trillion barrels
o 50% ultimately recoverable
o In 1999, proven reserves were estimated at 1 trillion barrels
-
Oil shales and tar sands
o Unconventional oil sources
o Could potentially double total reserve
o Lack technology to utilize them efficiently
Natural Gas
-
World’s third largest commercial fuel
o 23% of global energy consumption
o Produces hold as much CO2 as coal
o Most rapidly growing energy source

Difficulty to ship long distances and to store in large quantities
o Proven world reserves of natural gas

Roughly 60 year supply at present usage rates
Nuclear Power
-
President Dwight Eisenhower, 1954, “atoms for peace” speech
o Nuclear-powered electrical generators would provide power “too cheap to
meter.”

Between 1970 and 1974, American utilities ordered 140 new
reactors for power plants

After 1975, only 13 orders were placed for new nuclear reactors,
and all of those were subsequently cancelled
-
Currently, 103 nuclear reactors produce about 20% of all electricity consumed in
the U.S.
-
Nuclear fission
-
Radioactive waster management
o Until 1970, the US, Britain, France and Japan disposed of radioactive
waste in the ocean

1,000 tons if uranium of typically generates 100,000 tons of
tailings and 3.5 million liters of liquid waste
o About 100,000 tons of low-level waste (clothing) and about 15,000 tons of
high-level (spent-fuel) waste in the US.
Renewable Resources
(Sustainable Energy)
Conservation
-
Second Law of Thermodynamics
o When energy is converted from one form to another, some energy lot as
heat
o Energy conservation is the key
o In response to 1970’s oil prices, average US automobile gas-mileage
increased from 13 mpg in 1975 to 28.8 mpg in 1988
o Takes less fuel to heat a house today compared to 1974
Sustainable energy
-
Solar energy
-
Hydroelectric
-
Wind
-
Biomass
-
Hydrogen
-
Recycled buildings
Energy Conversion Efficiencies
-
Energy Efficiency
o Measure of energy produced compared to energy consumed
Tapping Solar Energy
-
A vast resource
o Average amount of solar energy arriving on top of the atmosphere is 1,330
watts per square meter
o 10,000 X other sources
-
Active solar
o Solar energy collected, pumped to storage facility to heat water
-
Photovoltaic Solar Energy
o Photovoltaic cells
o Capture solar energy
o Used in space
o Convert solar energy directly to electrical current
-
What is a fuel cell?
o Generator that chemically produces electricity from hydrogen and oxygen
o Produces direct current like a battery
o Unlike a battery, it never discharges; it continues to produce power as long
as fuel is supplied
Fuel cells
-
positive electrode (cathode) and negative electrode (anode)
-
separated by electrolyte
-
allows charged atoms to pass, not electrons
-
electrons pass through external circuit
-
generate electrical current
-
need H, O2
-
typical fuel cell efficiency is 40-45%
-
current is proportional to the size of electrodes
-
fuel cells can be stacked together until the desired power level is achieved
Fuel cell types
-
proton exchange membrane instead of electrolyte medium: cars
o Lightweight and operate at low temps
o efficiency typically less than 40%
-
phosphoric acid: most common fuel design for stationary electrical generation
Necar 4: diamlerChrysler
-
1999: first zero emission, fuel cell vehicle that has space or a driver and
passengers
-
top speed of 90 mph, 280 miles on a fill up
-
releases only water vapor into the air
-
production by 2004
FreedomCar and fuel cell initiative
-
2002: president bush announced a $1.2 billion freedom car and fuel initiative
-
development of technology needed for commercially viable hydrogen-powered
fuel cells
California fuel cell partnership, 2003
-
daimlerchryselr necar4a, necar5, fuel cell bus
-
Toyota FCHV-4
-
Hyundai santa fe FCV
-
Honda FCX
Energy from biomass
-
plants capture about 0.1% of all solar energy that reaches the earth’s surface
o about half the energy used in metabolism

useful biomass production estimated at 15-20 times the amount
currently obtained from all commercial energy sources
Burning biomass
-
wood provides less than 1% of US energy, but provides up to 95% in poorer
countries
o fine ash and soot and hazardous amounts of carbon monoxide (CO) and
hydrocarbons
-
40% of world population: firewood and charcoal are primary energy source
o Of these, ¾ do not have adequate supply
o 85% of fuel wood – developing countries
Dung and methane
-
Dung: not every efficient
-
Methane is main component of natural gas
o Produced y anaerobic decomposition
o Burning methane produced from manure

-
More heat than burning dung
Clear, efficient fuel
o Municipal landfills – 20% of annual output of methane to the atmosphere
Hydroelectric power
-
Hydroelectric production capacity has grown 15x
-
Energy derived from hydropower in 1994 was equivalent to 500 million tons of
oil
-
Much of recent hydropower development has been in very large dams
Dam drawbacks
-
human displacement
-
ecosystem destruction
-
wildlife losses
-
large-scale flooding due to dam failures
-
sedimentation
-
herbicide contamination
-
evaporative losses
-
nutrient flow retardation
Wind energy
-
Estimated 20 million megawatts of wind
o Commercially tapped worldwide
o Fifty times current nuclear generation
o When times current nuclear generation
o When conditions are favorable (min. 24 km/hr) electric prices typically
run as low as 3 cents/ KWH
Wind farms
-
large concentrations of wind generators producing commercial electricity
o negative impacts:

interrupt view in remote places

destroy sense of isolation

potential bird kills
Geothermal energy
-
high-pressure, high-temperature steam fields exist below the earth’s surface
-
benefits
o have long life span
o no mining needs
o little waste disposal
-
potential danger
o noxious gases
o noise problems from team valves
Tidal power station
-
Tide flows through turbines, creating electricity
-
Requires a high tide/low-tide diff
-
Problems:
o Saltwater flooding behind the dam
o Stormy coasts with strongest waves are far from major population centers
Toxicology
Toxins
-
60,000 chemicals sold commercially – US
o 8600 food additives
o 3400 cosmetics
o 35,000 pesticides
-
Only a small number of these are known to be harmful
Biological Effects
-
Immediate effects
o Mild-cough, headache
o Severe- convulsions, loss of breathing
-
Delayed effects
o Cancer, birth defects
o Low-level exposure over long-term
-
Local – site of contact
-
Systematic – affect organs and organ systems
How do toxins work?
-
Cellular level
o 1. Bind to enzyme – alter function of organ or tissue

Mercury, arsenic
o 2. Bind to non-enzymes: upset chemical balance

CO binds to hemoglobin
o 3. Mutations in genetic material
Factors related to toxin
-
1. Chemical composition
-
2. Physical characteristics: solubility
-
3. Pure or contaminated
-
4. Stability, storage
-
5. Availability of solvent to carry toxin
-
6. Movement of toxins through environment
o Through cells
Factors related to exposure
-
1. Dose: concentration and volume
-
2. Route, rate and site of exposure
-
3. Duration and frequency of exposure
-
4. Time of exposure: time of day, season, year
Factors related to organisms
-
1. Resistance to uptake, storage or cell permeability of toxin
-
2. Ability to detoxify
-
3. Other physical or chemical stress
-
4. Species and genetic characteristics
-
5. Nutritional status
-
6. Age, sex, body weight, maturity, immune system
Routes of exposure
-
Drinking
-
Breathing
-
Oral, dermal, inhalation
-
Eating
-
Medicinal drugs
-
Cosmetics, household accidents
Movement, Distribution and Fate of Toxins
-
Solubility – one of most important characteristics
-
Chemicals are divided into two major groups
o 1. Those that dissolve more readily in water

move rapidly through the environment

ready access to most human cells
o 2. Those that dissolve more readily in oil
Chemical interactions
-
Additive Reaction
o Effects of each chemical are added to one another
-
Synergistic Reaction
o One substance worsens the effect of the other
-
Potentiation
o Nontoxic chemical combines with toxin
o Makes even worse

Rubbing alcohol – no effect on liver

When combined with carbon tetrachloride, makes this chemical
worse
o Antagonistic Reaction

One material interferes with the effects, or stimulates the
breakdown, of other chemicals
Bioaccumulation
-
Bioaccumulation
o Selective absorption and storage
-
Biomagnification
o Toxins in lower trophic levels accumulate and concentrate up to the higher
levels
Persistence
-
Man chemicals – unstable
o Degrade rapidly
-
Others are more persistent
o POP’s: persistent organic pollutants
o Toxic effects may be stored for long period of time and spread to
unintended victims

DDT
DDT
-
1873: first synthesized
-
1939: rediscovered by Dr. Paul Meuller
o Nobel Prize in medicine: 1948
-
Effective January 1, 1973 EPA officially canceled all uses of DDT
o Not before more than 1 billion kg of DDT had been introduced into the US
-
DDT: disrupts the delicate balance of sodium and potassium within neurons
-
Broad spectrum insecticide
o Effective against mosquitoes that transmit malaria and yellow fever as
well as body live that carry typhus
Toxic Chemicals
-
Dangerous chemicals
o Hazardous: dangerous

Flammable, explosive, irritant acid caustic
o Toxic: Poisonous

Can be general or very specific

Often harmful even in dilute concentrations
o Allergens: substances that activate the immune system
o Antigens: Allergens that are recognized as foreign by white blood cells

Stimulate the production of specific antibodies
o Neurotoxins: attack nerve cells

Different types act in different ways

Heavy metals kill nerve cells

Anesthetics and chlorinated hydrocarbons disrupt nerve
cells membranes

Organophosphates and Carbonates inhibit signal
transmission between nerve cells
o Mutagens: damage or alter genetic material

1. Change DNA

2. Alter chromosomes

3. Missing or extra chromosomes

Includes:


Chemical: benzene

Physical: radiation
Cano occur in somatic or sex cells

Sex cells: passed on
Toxins
-
Teratogens: abnormalities during embryonic growth and development
o Known: Progesterone, thalidomide, rubella, alcohol, radiation
o Possible: aspirin, certain antibiotics, insulin, antihistamines, barbiturates,
iron, tobacco, antacids, insecticides, fungicides, herbicides, dioxin,
cortisone, lead, excess Vit. A, D.
-
Carcinogens: Cause cancers
o Toxic chemicals in the US cause the greatest risk to human ealth: benzene,
cadmium, carbon tetrachloride, chloroform, chromium, cyanides, lead,
mercury
o Case studies: Asbestos

Naturally occurring silicate mineral

Flexible, strong, resistant to heat, acid

Fibers easily dislodged and inhaled

Remain in lungs for life

Pulmonary fibrosis (asbestosis), lung cancer, mesothelioma
(cancer in lining of lungs)
Case Studies: Electromagnetic radiation
-
1079 – link between high-current power lines and childhood leukemia
-
EMF: electromagnetic fields
o Cancer, birth defects, miscarriage
-
Many problems with studies – weak correlations, no other factors considered
Natural and synthetic toxins
-
Many natural chemicals – very dangerous
o Arsenic and cyanide
-
many synthetic chemicals are relatively harmless
-
Both plants and animals produce chemicals similar to neurotransmitters,
hormones and regulatory molecules
Case studies: cyanide
-
Generation of cyanide waste
o Paint manufacture and sue
o Polymer production
o Chemical and pharmaceutical industry
o Steel industry
o Mining operations
o Coal manufacturing
o Electroplating wastes – contain .5% to 20% cyanide
Fraunhofer institute for interfacial engineering and biotechnology IGB
-
Scientists at the Fraunhofer IGB isolated a novel bacterium KS 7D
o Has cyanide hydrolyzing enzyme
-
Degradation of cyanide is catalyzed by a cyanide hydrolases that cleaves cyanide
and forms NH3 and formate in one step independently of oxygen and any cofactors
Case studies: mercury
-
Everglades
-
Mercury – atmospheric sources
-
Toxicity controlled by the relative rats of conversion to methylmercury
o Associated with other complex biogeochemical cycles particularly the
sulfur cycle
Tetrachloroethylene
-
Tetrachloroethylene (PCE) is a colorless organic liquid with a ild, chloroform-like
odor
-
Greatest use is in the textile industry, and as a component of aerosol dry-cleaning
products
Controlling toxic substances
-
US produces 125 million tons of synthetic chemicals
o 200 million tons of hazardous waste
-
1976 – toxic substances control act
o companies – 90 days to inform EPA that they will manufacture a
substance = testing
o EPA examines chemicals currently in use
o Control on chemical that are harmful (PCB’s)

Polychlorinated biphenyls

Insulating fluid in electrical transformers
Risk Assessment
-
1. Hazard identification
-
2. Estimation of risk
o probability of an event of occurrence
o severity of the event
-
3. Why is this difficult?
o Humans – not tested
o Testing is expensive, time consuming
o Animal testing – high concentrations
Measuring toxicity
-
Animal testing
o Most commonly used
o Exposure a population of laboratory animals to measured doses of specific
toxins

Dose response curves

LD50 - dose at which 50% of he test population is sensitive
Air pollution
Atmosphere
-
Composition
o 78% nitrogen
o 21% oxygen
o .01 – 4% water vapor
o <1% argon
o .037% co2
o Trace gases
-
Troposphere – weather breeder
-
Stratosphere
o Less water vapor
o More ozone – o3
o Ozone produced when UV interacts with O2
o Keeps 95% of harmful UV away
o Prevent rest of O2 from being converted to O3
Air pollution
-
Presence of 1 or more chemicals in sufficient quantities
o 1. Cause harm to life or materials
o 2. Alter climate
-
Naturally occurring – rarely enough to harm
o Sea spray – sulfur
o Vegetation - volatile organic compounds
o Bacterial metabolism – methane
o Viruses and bacteria
o Dust

Pollen
o Wildfires

Indonesia
o Volcanoes
-

Mt. Pinatubo

1994
Human induced
o Stationary sources (factories)
o Mobile sources (cars)
Outdoor Air
-
Primary pollutants: emitted directly into troposphere in harmful form or amount
-
Secondary pollutants: primary pollutants that react with one another or with basic
components of air
Pesticides
-
Chemical substances
o Natural or synthetic
-
Herbicides
-
Fungicides
-
Rodenticides
-
Insecticides
-
Antibiotics
Pesticides
-
Pesticide – chemical that kills (repels) pests
o Biocide – kills wide range of organisms
o Herbicide – kills plabts
o Insecticide – kill insects
o Fungiscide – fills fungi
o Acaricide – kills mites, ticks and spiders
o Nematicide – kills nematodes
o Rodenticide – kills rodents
o Avicide – kills birds
Earliest use of pesticides
-
Earliest pesticides – slat, sulfurous rock and extracts of tobacco, red pepper
arsenic
o 5,000 ya – Sumerians used sulfur
o 3,000 ya – Egyptians killed fleas
o 2,500 ya – Chinese = mercury and arsenic
o Romans burned fields and rotated crops to reduce crop disease
o Napoleonic army used crushed chrysanthemums to control lice
-
Petroleum oils, heavy metals and arsenic were used liberally – until 1940s
-
Replaced by organic synthetic pesticides, the most famous of which is DDT
Bioaccumulation
First Generation Pesticides
-
Natural, highly toxic
o Sulfur, arsenic, tobacco, lead, mercury
-
Simple preparations
o Hydrogen cyanide. ashes, caustic soda
-
Environmentally persistent
Second Generation Pesticides
-
Synthetic organic pesticides
-
939 – Paul Muller – DDT
o Dichlorodiphenyltrichloroethane
o Wide spectrum insecticide
o 1944 Nobel Prize
-
Today – 33,000 commercial pesticides
-
Chemical families
1. Chlorinated hydrocarbons

DDT, aldrin, dieldrin, chlordane, heptachlor, mirex, lindane,
toxaphene
-

Banned or restricted

Cancer, birth defects, environmental effects

Resistant – biomagnified
UN – “Dirty Dozen”
o ALDRIN

Soil application

Termites, grasshoppers and other insect pests

Kills birds, fish and humans

Aldrin-treated rice is thought to have killed hundreds of shorebirds
along Texas’s Gulf Coast
-
CHLORDANE
o Used extensively to control termites
o Stable in soil and relatively stable to ultraviolet radiation from sunlight
o May affect the human immune system
o Possible carcinogen
o Banned or restricted in many countries
-
CHLORDANE
o Eggshell thinning in birds
o Pesticide has been found I human milk, blood and semen
o Still pollutes aquatic ecosystems and drinking water supplies
o Continues to leach from foundations decades after application
-
DIELDRIN
o Control termites and textile pests
o Highly toxic to fish and other aquatic animals, especially frogs
o Dieldrin was the second most common pesticides found in pasteurized
milk
o Banned for use in 1974
-
ENDRIN
o Sprayed on the leaves of crops such as cotton and grains
o Control mice and other rodents
o Highly toxic to fish
-
HEPTACHLOR
o Kills soil insects and termites
o Responsible for the decline of may wild bird populations, including
Canada geese and American kestrels in the Columbia River basin
o High doses are also fatal to mink, rats and rabbits
o Possible human carcinogen
-
HEXACHLOROBENZENE (HCB)
o Treats weeds, kills fungi that affect food crops
o When people in eastern Turkey at HCB- treated seed grain between 1954
and 1959, they developed a variety of symptoms including colic
o Several thousand developed a metabolic disorder called porphyria turcica
14% died
o HCB is found in food of all types
-
MIREX
o Used to combat fire ants
o Fire retardant in plastics, rubber and electrical goods
o Possible human carcinogen
-
TOXAPHENE
o Used on cotton, cereal grains, fruits, nuts and vegetables
o Highly toxic to fish
o Possible cause for cancer among humans
o 37 countries have banned it
o 11 others have severely restricted its use
2 . Carbamates
-
Carbaryl (sevin)
-
Widely used
-
Breakdown more easily
-
Water soluble
-
Nerve poison
-
Birth defects, mutagens
-
CARBARYL
o 1956 – carbaryl was the first carbamate to be successful in the insecticide
industry

more of this pesticide has been used worldwide than all of the
other carbamates
o Low mammalian oral and dermal toxicity
o Broad spectrum of insect control
o Like the other carbamates, carbaryl antagonizes acetylcholine and
competes for binding sites on the enzyme cholinesterase
o Todd and Van Leeuwen (2002)
Organic phosphates
-
Malathion, parathion
-
Break down more rapidly than chlorinated hydrocarbons
-
Water soluble
-
Less likely to bioaccumulation
-
Serious health effects
West Nile
-
Flavivirus
-
Commonly found in Africa, West Asia and the Middle East
-
Closely related to St. Louis encephalitis virus found in the United States
-
Infect humans, birds, mosquitoes, horses and some other mammals
-
Thourhgt to be n the U.S. since 1999
-
Culex mosquito caries virus
-
Survives through the winter or “overwinter,” in the adult stage
West Nile Virus – larvicides
-
Methoprene
-
REsistered by EPA in 1975
-
Mimics the action of an insect growth-regulating hormone
-
Kill mosquito larvae
-
Altosid – trade name, applied as briquets
-
Breaks down quickly in water and soil and will not leach into ground water
-
Minimal risks to wildlife and humans
Mexican Pesticide Disaster
-
September 12, 2000
-
Salamanca, a city in the Mexican state of Guanajuato
-
Explosion followed by toxic cloud over city
Triazines
-
herbicides
-
less harmful
Pyrethroids
-
Natural and synthetic insecticides
-
Relatively harmless
Pyrethrin
-
Natural product- chrysanthemum flowers
o One of the ealiest pesticides
o Contact insecticide with quick “kock down”
o No evidence of harm to humans, dmestic aunals or wildlife when ued as
directed
o Bio-degradable
o Very light sensitive – used for quick kill
-
Permethrin is the manmade, synthetic pyrethrin
-
More stable than natural pyrethrins, more light tolerant and provides residual kill
of fleas and ticks
Use and abuse
-
Cheap to use
-
Kills pests quickly
-
DDT – used extensively in WWII
-
US – leading user of pesticides
o Mostly herbicides
o Farmers use more than 2x what they actually need
o Individual homes and gardens also overuse
o Do not take safety precautions
Biological effects
-
Non-target species
o Honeybees – pollinators
o Predators such as spiders
-
Creates genetically resistant pests
o Overuse
o Antibiotics
-
Damae to fishand wildlife
o DDT and raptorial birds
o Diazinon – gold courses
o Kills birds
o Carbofuran – lethal to songbirds
-
Human health effects
o FArmworkers exposed without safety equipment
Herbicides
-
46% of all pesticides
-
Atrazine, alachlor, butylate, 2, 4-D most widely used
-
POPs – increase metabolic rate of plants, plants “grow” to death
-
Mimic plant auxins (hormones
-
Agent Organge
o 50-50 mix of 2,4-D and 2,4,5-T
o Used as defoliant in Vietnam
o Serious medical problems in soldiers

Dioxins
-
Veterans children – birth defects
-
40,000 Vietnamese couples
o 3.5 more likely to miscarry or have children with birth defects
o High rate of cancers
Controlling Pesticides
-
Bans on production and use
o 1962 – Silent Spring
o Banned chemicals often used outside US
-
Registration
o 1972 Federal Insecticide, Fungicide and Rodenticide
-
Toelrance levels, montoring procedures
Integrated Pest Management
-
Environmental Contorls
o Alter biotic and biotic conditions in crops
o 1. Increasing crop diversity

Heteroculture

Crop Rotation
o 2. Altering time of planting
o 3. Altering plant and soil nutrients
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High nitrogen – not good for many pests
o Controlling adjacent crops and weeds
o Biological controls
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Predatory/Herbivorous Insects
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Genetics and Bioengineering
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Hormones
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Sex attractants
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Introducing predators, parasites, disease
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Cactus-eating moth – prickly pear
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