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BIOCIDES Powered By Docstoc
             What is a Pest?
• A pest is any species that
  competes with US for food
  (rabbits), invade gardens
  (aphids, caterpillars) and
  lawns (grubs, snails, slugs),
  destroys wood in houses
  (carpenter ants, termites),
  spreads disease (fleas,
  cockroaches, mosquitoes,
  ticks), or is a nuisance
  (raccoons, squirrels, Canada
         Biocides “Pesticides”
•   Insecticide – kills insects
•   Herbicide – kills weeds
•   Fungicides – kill fungi
•   Nematocides – kill roundworm
•   Rodenticide – kill rodents
•   Algicide – kills algae
•   Larvicide – kills larvae
• Over 3 million metric tons of biocides are
  used annually on Earth (1 lb. per person)
• Approximately 25% of the biocides used in
  the USA are used to rid houses, gardens,
  lawns, parks, playing fields, swimming
  pools, and golf courses of unwanted pests.
• The average USA homeowner applies 2-6
  times more biocides per acre than farmers
         Biocide Definitions
• Broad-spectrum agents: toxic to many
• Narrow-spectrum agents: effective against
  a narrowly defined group of organisms.
• Persistence – the length of time the
  biocide remains deadly in the
           Biocide History
• Until the 1950’s, farmers had two weapons
  to use against crop pests; natural
  pesticides found in plants such as
  pyrethrum and minerals containing
  arsenic, lead, and mercury (heavy metals!)
          Biocide History (1st & 2nd
           Generation Pesticides)
                   1800’s Botanicals
 As, Pb, Hg
                   Pyrethrum (rotenone)
                   From flower heads of
                   chrysanthemum flower and tropical
 highly toxic)
                   legumes (pyrethroids)

500 BC           1600’s                                1900’s Second
Sulfur                                                 Generation Pesticides
                 Nicotine                              = synthhetic organic
                 (SiO4) from                           chemicals (SOC’s)
              Biocide History
• Homeowners used natural defenses that few people use
  today because of the easy access and affordability of
• Ants – cayenne pepper, crushed mint leaves, or boric
  acid, vinegar.
• Mosquitoes – basil plants or rubbing basil oil, lime juice,
  or mugwort (weed) oil on bare skin.
• Cockroaches – boric acid, or establishing banana spider
  populations (not recommended, one of the deadliest
  spiders from Australia)
• Fleas – feed pets brewer’s yeast or use flea repellent
• Garden pests – introduce natural predators.
• Ex. Ladybugs LOVE aphids!
Also introduce insect-eating birds, toads
and frogs, fish, and snakes.
 Biocide History – Development of
  Synthetic Organic Compounds
• The use of SOC’s has revolutionized
  modern agriculture by allowing food
  production to more than double in
  developed countries and increase by
  120% in developing countries!
• SOC’s include pesticides, herbicides, and
  chemical fertilizers.
         Argument for Biocides
1. Pesticides increase food supplies and lower food costs
    for consumers.
2. Pesticides increase profits for farmers.
3. Pesticides work faster and better than natural
    alternatives as effective killers of pests.
4. The pesticide industry declares that the health risk of
    pesticides in insignificant compared with their benefits
    for food resources and boost to general health.
5. Many “new” pesticides are used at very low rates per
    unit area compared to “old” pesticides
  Argument Against Pesticides
1. Pests develop genetic resistance. The first
   generation breeds and as r-strategists, some
   of the DNA will not copy itself well and make a
   small group genetically resistant. They will
   survive and breed and make a second
   generation more resistant. Must increase
   concentration or combination of chemicals to
   be effective. “evolutionary arms race”
   Becomes a “Pesticide Treadmill”; a situation
   where farmers pay ,ore and more for pest
   control that are less and less effective due to
   insects development of genetic resistance.
     Argument Against Pesticides
2.  Broad-spectrum pesticides kill natural predators and
    parasites that may have been maintaining a pest
    species population at a reasonable level.
The “ideal” pesticide would:
•   Kill only the target pest and harm no other species.
•   Disappear quickly and breakdown into something
    harmless in the environment.
•   Not cause genetic resistance to target organisms.
•   Be cheap when true costing occurs (internalities +
    Argument Against Pesticides
• Pesticides bioaccumulate and biomagnify
  in the environment and in food webs.
• A compound is toxic to a wide range of
  organisms and is persistent in the
• Example DDT (dichloro-diphenyl-
  trichloroethane )
   Major Classes of Pesticides
1. Insecticides – DDT; high persistence,
    biologically magnified, broad-spectrum
2. Herbicides – paraquat; low persistence (days
    to weeks), not biologically magnified, narrow
3. Fungicides – captan; lowest persistence
    (several days), not biologically magnified,
    narrow spectrum
4. Fumigants – carbon tetrachloride (CCl4); high
    persistence, biologically magnified, broad
           DDT Case Study
• DDT is a chlorinated hydrocarbon and is used
  as an insecticide.
• DDT was first synthesized in 1874 but was
  forgotten until 1939 when Swiss chemist Paul
  Mueller found that DDT was highly toxic to
• The Swiss government immediately began to
  use DDT against a major pest, the Colorado
  potato beetle.
• DDT was highly effective against the Colorado
  potato beetle.
           DDT continued
• For two decades DDT was used in
  agriculture against insect pests and by
  medical workers against disease-carrying
• Malaria is a mosquito-transmitted
  disease (Anopholese mosquito is the
  vector species) causing fever, headache,
  vomitting, etc… and can become life-
  threatening if not treated.
          Endemic in more than 100 countries.
          Caused by four protozoa species.
          270–500 million new cases and
Malaria   1 million deaths per year.
                            Figure 19-14
                  Anopheles mosquito (vector)
                    in aquatic breeding area

                             Page 425

                                          1. Female
                                          mosquito bites
                                          infected human,
                                                                            of Malaria
                                          ingesting blood
                                          that contains

4. Parasite invades
blood cells, causing
malaria and making                                          2. Plasmodium
infected person                                             develops in
a new reservoir                                             mosquito
                         3. Mosquito injects Plasmodium
                         sporozoites into human host
          Problems with DDT
• DDT is toxic ( toxicity = the measure of how
  harmful a substance can be to organisms)
• DDT is persistent in the environment. The half -
  life of DDT ranges from 3-10 years in soil (half-
  life = the time it takes for the concentration of
  that substance to be reduced by half in a
  biological system)
• DDT breaks down to DDE which is persistent in
  the environment for 200 years and is more toxic
  than DDT!
        Problems with DDT
• DDT is soluble in fats; when organisms
  digest DDT, the pesticide concentrates in
  fatty parts of the body.
• This allows DDT to be passed along in the
  food web (bioaccumulate) and since
  organisms higher in higher trophic levels
  require more food to obtain their energy,
  DDT is biomagnified.
DDT in fish-eating
 birds (ospreys)
     25 ppm

                     DDT in large
                     fish (needle fish)
                     2 ppm

               DDT in small
               fish (minnows)
               0.5 ppm

               DDT in
               0.04 ppm

               DDT in water
               0.000003 ppm,
               Or 3 ppt

            Problems with DDT
• Scientists noticed that some animals no longer
  reproduce normally when exposed to DDT (endocrine
  blockers in higher organisms).
• Predatory birds at the top of the food chain lay eggs with
  unusually thin shells so that when hens sit on the nest,
  the eggs break and no offspring are born. DDE blocks
  the formation of calcium in egg production in the female.
  The eggs are formed from calcium carbonate in the
  female. Without the correct production of calcium
  carbonate, the eggs are produced too thinly. This caused
  the near extinction of the American bald eagle, osprey,
  and peregrine falcon.
       Rachel Carson and DDT
• Rachel Carson – biologist for
  Bureau of US Fisheries (later
  USFWS), became Editor in
  Chief for bureau’s publications
  in 1949.
• 1951 – wrote “The Sea Around
  Us” about the natural history of
  the oceans and anthropogenic
• Book was on the best seller list
  for 86 weeks, sold 2 million
  copies, was translated in 32
  languages, and won a National
  Book Award.
              Rachel Carson
• In 1958 DDT was sprayed to control mosquitoes
  near the home and private bird sanctuary of one
  of Rachel’s friends (Olga Huckins).
• After the sprayings, many of the birds died
  horrible deaths, so she asked Carson to
  investigate the effects of pesticides on birds and
  other wildlife.
• Initially, she found there was no independent
  critical research on environmental effects of
              Rachel Carson
• Carson surveyed the scientific
  literature and methodically built her
  case against the widespread use of
• 1962 she published “Silent Spring”;
  an allusion to the silencing of robins,
  catbirds, doves, jays, and wrens and
  scores of other bird voices because of
  their exposure to pesticides.
• She pointed out that “for the first time
  in the history of the world, every
  human being is now subjected to
  dangerous chemicals, from the
  moment of conception until death.”
       Opposition to Silent Spring
• Although the public embraced her book, the chemical industry viewed
  the book as a serious threat to booming pesticide sales.
• The chemical industry mounted a $250,000 campaign to discredit
• Chemical Industry scientists claimed that her book was full of
  inaccuracies, made selective use of research findings, and failed to
  give a balanced account of the benefits of pesticides.
• Critics claimed that “as a woman, she was incapable of
  understanding the highly scientific and technical subject of
• Others claimed she was a hysterical woman and a radical nature
  lover trying to scare the American public in order to sell books.
• 18 months after Silent Spring was published, Rachel Carson died
  from terminal cancer.

Silent Spring became one of the driving forces for the Environmental
   Movement in the United States!
        DDT Banned in USA
• 1973 The Environmental Protection Agency
  (EPA) banned the use of DDT in the USA.

• 1986 – a study on humans showed that an
  average level of 1.67 ppm of DDT was retained
  in fatty tissue, more than 10 years after the
  compound had been banned. The acceptable
  limit for DDT in human tissue is 0.2 ppm!
     DDT in Breast Milk Around the
• DDT is found to be
  significantly high in
  developing nations who still
  continue spraying DDT for
  malaria control.

• The USA is still the largest
  manufacturer of DDT in the

• DDT travels through the
  wind belts around the world.
•   Insecticides are chlorinated
    hydrocarbons and include:
•   DDT
•   Aldrin and dieldrin;
    organochlorine pesticides to treat
    termites, grasshoppers,                       Dieldrin
    woodborers, beetles – impacts to     Aldrin
    central nervous system. Dieldrin
    was used to control tse-tse fly to
    prevent tropical diseases.
    Causes tremors, disorientation
    and liver problems.
•   Chlordane – banned in 1990.
    Used to treat lawn, turf and
    ornamentals. Affects lungs,
    nervous system, and liver.
•   Organophosphates – (parathion
    and malathion) Spray for West
    Nile Virus on Long Island
West Nile Virus
                  West Nile Virus
• West Nile Virus (WNV) is a mosquito-borne virus that can cause
  encephalitis or meningitis-- an inflammation of the brain -- in humans
  and other animals. People get West Nile from the bite of a mosquito
  that is infected with West Nile virus. Mosquitoes become infected
  with West Nile virus when they feed on infected birds that carry the
  virus in their blood. West Nile virus is NOT transmitted from person
  to person. For example, you cannot get West Nile virus from
  touching or kissing a person who has the infection.

• West Nile virus is closely related to two other mosquito-borne
  encephalitis viruses in the United States : St. Louis Encephalitis
  (SLE) and Eastern Equine Encephalitis (EEE). These viruses have
  been responsible for illnesses requiring hospitalization of over a
  hundred people in Michigan , with several deaths. Some of these
  viruses have also caused equine illness with over 200 horse deaths
How Did West Nile Virus Get Here?
Hypothesis 1: Avian migratory pathways. First outbreaks
  in USA were in Queens Long Island, 1999. North Atlantic
  Flyway is the first western flyway for neotropical birds
  flown off course during storms from Black Sea
  Mediterranean Flyway (Nile River Region).

Hypothesis 2: First terror attack on USA was biological.
  Evidence that in 1996 Sadaam Hussein made a very
  large purchase of West Nile Virus from US Biological
  Supply Companies (traced through chain of custody) and
  that Queens, New York was the release point. Easy to
  do by releasing into ponds where mosquitoes breed and
  larvae develop, become infected and females spread the
• Carbamates replaced
  many of the halogenated
  hydrocarbons (Aldicarb)
  and is used primarily as a
  molluscicide for areas
  invaded by Quagga and        Aldicarb
  zebra mussels and as a
• Carbon tetrachloride, ethelyne dibromide,
  and methylbromide.
• The chemicals used for fumigants are also
  used in dry cleaning agents and freon
• Rotenone and pyrethrum – also used on Long
  Island to spray for West Nile Virus.
• Persistence – low (days to weeks), EPA claims
  they are not biologically magnified in the
• Sprayed at “unnatural” concentrations
 How Dangerous Are Biocides?
• 50,000 different pesticides are used in the USA!
• Hazardous risk to humans depends on:
  a. Concentration of pesticide in environment or
  inhaled or ingested.
  b. How much is absorbed and retained in
  drinking water or crop. (The higher the solubility,
  the more dangerous the compound will be.)
  c. The duration of exposure to the chemical.
  d. How quickly the compound is metabolized
  and excreted from the body.
    How Dangerous Are Pesticides?
• Halogenated hydrocarbons like DDT and Chlordane are the MOST
  dangerous to humans and ARE carcinogenic.
• Organophosphates (parathion and malathion, pyrethroids) generally
  break down “rapidly” in the environment and to date have been rarely
  found in groundwater on Long Island. Continued use to combat
  West Nile Virus is likely to increase the presence of these
  substances in the environment. We really don’t know the long-term
  impacts to human health since we do not have a long history of
  spraying them at the frequency they are being sprayed and at the
  concentration they are being sprayed.

• Peconic Bay Keeper, Kevin McAllister has filed a lawsuit against
  Suffolk County Department of Health Service, Vector Control Unit
  (2005) and all spraying has ceased in Suffolk County EXCEPT for
  Fire Island National Seashore.

• SCDHS now proposes to construct large ponded areas in wetlands
  to attract and kill mosquitoes (large-scale mosquito ditching projects
  which convey pollutants to Great South Bay Estuary. Ducks
  Unlimited to aid in construction efforts. Council just recently formed
  to scientifically review EACH project to prevent total destruction of
  wetland ecosystems in Suffolk County.
 How Dangerous Are Carbamates?
• Aldicarb, carbofuran, and oxamyl are the most
  commonly used carbamates on Long Island.
• Aldicarb has been detected in 2000 groundwater wells in
  Suffolk County where soils are sandy, the water table is
  shallow and agriculture is extensive.
• EPA defines “acceptable risk” of biocides in our drinking
  water to be “one that causes no more than one
  additional case of cancer in a population of a million
  people who drink the water over the course of a lifetime”
• How can we determine if a person’s cancer has been
  directly caused by ingestion of contaminated drinking
  water when all of the foods we eat are loaded with
  carcinogens and when the air we breathe are loaded
  with hydrocarbons and other toxins from burning fossil
  fuels, smelting ores, and industrial production of goods?
  How Dangerous Are Fumigants?
• Fumigants are released
  through gas cartridges
  (gases) that infiltrate
  every crack and space
  in a room or below
• When released, the
  area must be well
  ventilated and humans
  and domestic animals
  may not re-enter for 6 –
  8 hours after treatment.
• What do you think?
  Fumigants in the Atmosphere
• Carbon tetrachloride and chlorides used in
  refrigeration processes (freon) are the
  direct cause to the thinning of the ozone
Ozone (O3) in the stratosphere forms when HQE UV photons break
apart diatomic O2(g) molecules forming reactive free radicals O. The
free radicals combine with other diatomic molecules of O2 to from
Importance: Each ozone molecule in the stratosphere can absorb a
UV photon with a wavelength less than 320 nm. This energy
absorption prevents potentially harmful UV rays from reaching the
earth’s surface.
Chlorine from chlorofluorocarbons (CFC’s) emitted from refrigerators,
and air conditioners and include freons are highly stable molecules in the
Chlorine atoms emitted from fumigants migrate upward in the
HQE UV photons in the stratosphere split chlorine radicals from CFC’s
by breaking the C-Cl bond.
The Cl radicals are very reactive and can participate in a series of
photochemical reactions that destroy O3 by converting it to O2. When free
radicals of O combine to form diatomic molecules of oxygen they prevent
additional atoms of O3 from forming.
Every Cl radical can destroy on average 100,000 O3 molecules!
         LAYER THIN?
 Winter at the poles is sunless with steady winds that
  blow in a circular pattern forming a huge swirling mass of
  very cold air “polar vortex winds”.
 When sun appears on the horizon, droplets of water form
  ice crystals that collect CFC’s and form Cl and ClO
  molecules that combine to form Cl2O2 molecules that
  store up in vortex. The spring sunlight breaks these up
  and releases large numbers of Cl molecules that begin
  to attack O3 molecules.
 Ozone thinning is worse over south pole than north pole.
As O3 layer in stratosphere continues to thin, more UV-B
radiation will pass through the stratosphere into the troposphere
and cause squamous cell cancer and cataracts in humans.
Other human health issues include suppression of the immune
system,, lower yields of key crops, serious decline in
phytoplankton and forest productivity, and deeper penetration of
UV radiation into lakes disrupting ecosystem structure and
 It will take 50-60 years to return to 1975 levels and 100-200 years to
  return to 1950 levels.
 Use substitutes such as hydrochloroflurocarbons (HCFC’s); less Cl
  molecules and have shorter lifespan in stratosphere. Can still
  cause O3 depletion. Other substitutes are hydrofluorocarbons
  (HJFC’s), propane, and butane.
 Developing nations can us HC technology to leap ahead of
  Industrialized nations. HC’s cannot be patented!
 Implement plans and policies to deter CFC useage.

1987 – 36 nations met in Montreal to develop a treaty to cut emissions of
CFC’s by 35% between 1989 and 2000.
1990 – 93 countries met in London
1992 - 92 nations met in Copenhagen
1997 – 92 nations met in Montreal once again and adopted a protocol
accelerating the phase out of key ozone-depleting chemicals.
BEST EXAMPLE – global cooperation in response to serious threats to
global environmental security. Developing nations set up over $250 million
fund to help developing nations not use CFC’s and phase it out early in their
transition to a developing nation.
• Synergistic effects – when low or acceptable
  concentrations of hazardous materials or toxins exist in
  the environment (air, water or soil), the combined effect
  of ALL of them often prove EXTREMELY harmful to
  human health and the overall health of ecosystems.
• Example – Lobster population declines in Long Island
  Sound – now believed to be synergistic effects of
  pesticide runoff, poor overall water quality, and
  increased water temperature from global warming.
  Conditions now are optimum for a parasitic protozoan to
  attack lobsters increasing mortality rates each year.
  Long Island’s Lobster Industry is losing approximately 16
  million dollars a year in revenue. Blue crabs and sea
  urchins are also experiencing large population die offs.
             Parkinson’s Disease
• Researchers have found a link to Parkinson’s Disease (a
  neurodegenerative disorder) and the botanical pesticide rotenone.
• When Michael J. Fox was diagnosed with Parkinson’s Disease, he
  promoted the need for research and a tremendous amount of money
  has bee targeted toward identifying causes and promoting research
  to find cures for this disease.

• Parkinsons’ Disease was first described by James Parkinson in
  1817. The condition kills the nerve cells in the brain that release
  dopamine, a chemical necessary for controlling body movements.

• To reduce the risk of Parkinson’s Disease, Consumers must reduce
  their exposure to pesticides by washing residue off of foods, not
  using sanitizers and mildew removers which contain pesticides, and
  not applying them on their lawns or in their gardens.
                   Chaos in Borneo to Borneo to
    World Health Organization (WHO) sent supplies of DDT
    combat malaria and kill mosquitoes.
•   It was very successful and wiped out the mosquito population quickly.
•   The billions of cockroaches that lived in the village stored the DDT in
    their tissue.
•   Small lizards fed on the roaches who became weakened by the DDT
    and slowed down.
•   Cats were able to catch the lizards more easily (favorite food).
•   Since the cats ate a lot of lizards and the DDT biomagnified through
    the food web, the cats began to die.
•   Once the cat population decreased, the rats moved in (no natural
•   The lizard population declined because of the cats predating on them
    and a caterpillar population that used to be maintained by the lizards
    was now increasing and feeding on the roof material of the homes of
    the villagers.
•   The homes began to collapse.
•   Emergency workers sent emergency calls for more cats!
•   Cats were parachuted in to Borneo to kill the rats who were spreading
    disease (plague)!
              Earth Summit
     Rio Di Janeiro, Brazil June 1992
•    Issues:
1.   Climate Change – a treaty to curb CO2 emissions to
     reduce the Greenhouse Effect.
2.   Biological Diversity – a treaty to decrease the rate of
     extinction of the world’s endangered species.
3.   Deforestation – A statement of principles regarding
     deforestation and destruction of the world’s forests.
4.   Agenda 21 – Complex Action Plan for the 21st Centruy
     in which developed nations would provide money to
     help developing nations become industrialized without
     harming the environment.
5.   Earth Charter (The Rio Declaration) – a philosophical
     statement about sustainable development.
              Earth Summit
     Rio Di Janeiro, Brazil June 1992
•    Outcome:
1.   Climate Change Treaty – More than 165 nations signed the treaty and it
     is now considered legally binding. The USA and other large CO2
     emitters did not meet the 2000 emission targets. Worldwide emissions
     continue to increase by 20%/year.
2.   Biological Diversity Treaty – More than 165 nations signed the treaty
     and it is now considered legally binding. President Clinton signed in
     June, 1993. Congress failed to approve it and it has not been ratified by
     the US since.
3.   Agenda 21 – offers more than 2500 actions to deal with urgent
     environmental, health, and social issues worldwide. It does not offer a
     firm commitment for financial assistance by developed nations to aid in
     sustainable development of developing nations. 53 members including
     the US meet annually to monitor implementation of Agenda 21.
4.   Earth Charter – on-going process for development of a comprehensive
     philosophical statement.
5.   Treaty on Desertification – This treaty has not yet gone into effect.
            MARGARET MEAD

“The atmosphere is the key
symbol of global
interdependence. If we
can’t solve some of our
problems in the face of
threats to this global
common, then I can’t be
very optimistic about the
future world!”
1.   Cultivation Practices
2.   Biological Control – release natural predators
3.   Biopesticides
4.   Insect Birth Control (Asian Long-horned Beetle)
5.   Pheremones (insect sex attractants)
6.   Hot water zapping
7.   Gamma radiation (zapping foods)
8.   IPM’s
       Integrated Pest Management
•    Aim: Reduction of crop damage to economically tolerable levels and NOT
     eradication of pests!
•    Ecosystem Approach using biological, chemical, and cultivation
     (mechanical) methods.
•    How Can This Be Achieved?
a.   Add sales tax to pesticides (subsidy to gain $ to promote sustainable
     agricultural methods)
b.   Set up demonstration sites and educational seminars, not only for farmers
     but for homeowners.
c.   Provide training for homeowners.
d.   Create federal and state subsidies to promote sustainability and deter
     environmentally degrading practices. Reward those who practice
     sustainable methods!
         The Good News Is…
• Between 1972 and 1996, the EPA banned 55
  active pesticide ingredients known to be
  carcinogenic or biomagnify in the environment.
• 1996 Food Quality Protection Act – EPA set
  new standards for pesticide tolerance levels in
• Manufacturers of pesticides must demonstrate
  active ingredients are safe for infants, children,
• EPA must develop new screening for
  active/inactive ingredients to protect human
  health risk.
• FIFRA = Federal Insecticide, Fungicide,
  and Rodenticide Act
• It requires ALL commercial pesticides to
  be approved by the EPA (sets tolerance
  levels) for general and/or restricted use.
              What Can You Do?
• 1. Build healthy soil – Add 2-3 inches of compost each year to
  improve the organic content of your soil.
• 2. Grow plants native to the northeast – they will be tolerant of
  climactic conditions and possess genetic resistance to many pests
  through natural selection.
• 3. Create diverse gardens to attract local wildlife –
  butterfly/hummingbird gardens, seed-producing perennials that
  provide nutrients during avian migratory seasons. Include trees and
  shrubs with berries.
• 4. Manage plant problems with safe, nontoxic solutions by
  introducing natural predators, using herbs and spices that naturally
  deter pests, and interplanting marigolds and chrysanthemum within
  your garden (strong chemical defense against pests).
• 5. Improve your lawn by adding compost, introducing earthworms
  (aeration, pulling weeds). Reduce the size of your lawn by
  increasing xerophytic gardens around your property.