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					Environmental
Effects of
Pesticides


Stephen J. Toth, Jr.              Wayne G. Buhler
Department of Entomology          Department of Horticultural Science
North Carolina State University   North Carolina State University

                                                  Photograph by Ken Hammond.
   What is the
  Environment?
• The “environment” is
  everything around us      Erwin W. Cole
  natural and manmade;
  not limited to the
  outdoors, but including
  indoor areas in which
  we live and work.

                            Ken Hammond
        How do Pesticides Effect
          the Environment?
• Point-Source Pollution: contamination that comes from
  a specific, identifiable place (a point)
• Includes pesticide
  spills, wash water
  from cleanup sites,
  leaks from storage
  sites, and improper
  disposal of pesticides
  and their containers
                                                Tim McCabe
        How do Pesticides Effect
          the Environment?
• Nonpoint-Source Pollution:
  contamination that comes
                                   Bob Nichols
  from a wide area
• Includes the drift of
  pesticides through
  the air, pesticide run-
  off into waterways,
  pesticide movement
  into ground water, etc.
 Environmentally-Sensitive Areas
Sensitive areas include sites or living things that are
easily injured by pesticides, including:

• areas where ground water
  is near surface or easily
  accessed through wells,
  sinkholes, etc.
• areas near surface waters
  (oceans, lakes, streams)
                                       NCSU Communication Services
 Environmentally-Sensitive Areas
Sensitive areas include sites or living things that are
easily injured by pesticides, including:

• areas heavily populated
  with people (schools,
  playgrounds, hospitals,
  nursing homes, etc.)
• areas populated with
  livestock and pets
                                                  Ken Hammond
 Environmentally-Sensitive Areas
Sensitive areas include sites or living things that are
easily injured by pesticides, including:

• areas near the habitats
  of endangered species
  and other wildlife
• areas near honey bees
• areas near food crops
  and ornamental plants

                                                  Steve Bambara
  Environmental Impact of Pesticides in Air
• The atmosphere is an important part of the hydrologic cycle
• Pesticides enter the
  atmosphere through
  drift, wind erosion
  and evaporation
• Pesticides can move
  great distances in the
  atmosphere
• Pesticides reach the
  earth’s surface via
  dry deposition and
  precipitation
                                                U. S Geological Survey
 Environmental Impact of Pesticides in Air
Long-range movement of long-lived pesticides documented:
• DDT and other organochlorine pesticides detected in Arctic
  and Antarctic fish and mammals; used in 1960s and 1970s
• Toxaphene is still transported
  into Great Lakes region by
  winds from the Gulf of
  Mexico; used on cotton in
  the South, banned in 1982


                                                     USDA/ARS
Environmental Impact of Pesticides in Air
 Pesticides frequently detected in the atmosphere:
 • Organochlorine insecticides (DDT, dieldrin and
   lindane): widespread use in 1960s and 1970s; resistant
   to environmental degradation
 • Organophosphate insecticides (chlorpyrifos, diazinon,
   malathion and methyl parathion): not long-lived in
   environment; used heavily in the past and at present
 • Triazine herbicides (atrazine): heavily-used herbicides,
   persistant in environment
 • Acetanilide herbicides (alachlor and metolachlor):
   used heavily, but not as persistant as triazine herbicides
Environmental Impact of Pesticides in Air




Number of pesticides detected in air, rain, snow and fog. U. S. Geologic Survey (1995).
 Environmental Impact of Pesticides in Air
Hazards of atmospheric pesticides to humans and environment:
• Source of exposure to pesticides
  through inhalation (lungs have
  surface area equal to tennis court)
• Source of contamination of surface               Gene Alexander
  waters and ground water through
  dry deposition and precipitation
• Transport of pesticides from
  application sites to sensitive areas
• Accumulation of pesticides in the
  environment (soil, wildlife, etc.)
 Environmental Impact of Pesticides in Soil
• Pesticides can move in the environment via the soil by two
  methods: erosion and leaching
• Erosion: soil particles
  which are transported
  by wind and water;
  pesticides attached
  to soil particles
• Leaching: downward
  movement of pesticides
  in the soil through
  cracks and pores
                                                   USDA Photograph
Environmental Impact of Pesticides in Soil
               Leaching          USDA Photograph

 • Soil normally filters water as
   it moves downward, removing
   contaminants such as pesticides
 • Soil and pesticide properties,
   geography and weather can
   influence the movement of
   pesticides (leaching)
 • Pesticides that leach through
   soils may reach ground water
 Environmental Impact of Pesticides in Soil
   Soil Properties That Affect Leaching
• Organic matter: plant and animal
  material decomposing in the soil;
  organic matter binds pesticides;
  the more organic matter in the
  soil, the less likely pesticides will
  leach
• Soil texture: determined by the
  percentage of sand, silt and clay;
  the higher percentage of sand, the
  more likely pesticides will leach
                                          USDA Photograph
Environmental Impact of Pesticides in Soil
  Soil Properties That Affect Leaching
• Soil acidity (pH): the acidity
  of the soil affects chemical
  properties of pesticides;
  as the soil pH decreases
  (becomes more acidic),
  pesticides bind more to
  the clay in the soil making
  the pesticides less likely to
  reach the ground water             Scott Bauer
Environmental Impact of Pesticides in Soil
Pesticide Properties That Affect Leaching
• Solubility: ability to dissolve in water; the more soluble
  the pesticide, the more likely it will leach
• Adsorption: the ability of the pesticide to bind tightly and
  quickly to organic matter in the soil affects leaching; the
  greater the ability to bind to organic matter, the less likely
  pesticides will leach
• Persistence: how long the pesticide remains in the soil;
  pesticides degraded primarily by sunlight, soil microbes
  and chemicals in the soil; the more persistent a pesticide,
  the more likely it will leach into ground water
Environmental Impact of Pesticides in Soil
Effects of Pesticide Application on Leaching

• Rate of application: the higher the rate (amount) of
  pesticide applied, the greater the chance the pesticides
  will leach
• Application method: pesticides applied to growing plants
  can be absorbed by the plants or broken down by sunlight
  before reaching soil; soil incorporated pesticides are not
  exposed to sunlight and have greatest chance of leaching
  into ground water
Environmental Impact of Pesticides in Soil
Effects of Geography & Weather on Leaching
• Geography: depth from soil surface to ground water (closer
  ground water is to soil surface, the more pesticide leaches
  into ground water)
• Weather: pesticides
  break down faster
  in warm, moist soil;
  therefore, less likely
  to leach

             Gene Alexander
Environmental Impact of Pesticides in Ground Water

 • Ground water is water
   located beneath the
   earth’s surface,
   usually in rock or soil
 • Ground water is the
   primary source of
   drinking water for
   50% of population,
   95% of rural residents
   in the United States

                         Ron Nichols
Environmental Impact of Pesticides in Ground Water
• At least 143 pesticides and 21 of their transformation
  products have been found in ground water, from every
  major chemical class
• Pesticides commonly
  found at low levels
  in agricultural areas
  (seldom exceed water-
  quality standards)
• Pesticides also found in
  non-agricultural setting
  such as golf courses and
  residential areas                                    Ken Hammond
Environmental Impact of Pesticides in Ground Water
Pesticides most frequently detected in ground water:
• Triazine (atrazine) and
  acetanilide (alachlor and
  metolachlor) herbicides:
  used extensively on corn
  and soybeans in Midwest
• Carbamate insecticide
  aldicarb (Temik): ground
  water contamination
  problems, sampled for
                                                       Bill Tarpenning
  extensively
Environmental Impact of Pesticides in Ground Water
Factors strongly associated with pesticide contamination of
of ground water are:
• High pesticide usage in
  the area
• High recharge of ground
  water by precipitation or
  irrigation
• High soil permeability
• Well contamination is
  greatest in shallow,
  inadequately sealed wells                             Tim McCabe
Environmental Impact of Pesticides in Surface Waters

• Surface waters include
  streams, rivers, lakes,
  reservoirs and oceans
• Streams and reservoirs
  supply approximately
  50% of the drinking
  water in United States

                                           Ken Hammond
Environmental Impact of Pesticides in Surface Waters

• Pesticides enter surface
  waters through run-off,
  wastewater discharges,
  atmospheric deposition
  (dry and precipitation),
  spills and ground water
• Pesticide concentrations
  in surface waters follow
  the seasonal patterns of
  pesticide application and
  run-off
                                        U. S Geological Survey
Environmental Impact of Pesticides in Surface Waters
 • Low levels of pesticides are widespread in surface waters in
   the United States
 • Herbicides are detected
   more frequently than
   insecticides, due to their
   greater use
 • Some pesticides exceed
   water-quality standards
   during certain seasons,
   but the annual average
   concentrations seldom
   exceed standards                                         Doug Wilson
Environmental Impact of Pesticides in Surface Waters
Pesticides most frequently detected in surface waters:
• Triazine (atrazine) and
  acetanilide (alachlor and
  metolachlor) and 2,4-D
  herbicides: widely used
  in agriculture
• Carbofuran and diazinon
  were the most frequently
  detected insecticides in
  current use
                                                         Bill Tarpenning
Environmental Impact
of Pesticides on Plants
 • Pesticides can move from
   the intended target and
   damage nearby plants,
   including crops, forests    Scott Bauer

   and ornamental plants
 • Phytotoxicity: plant
   injury resulting from
   contact with pesticides
   and/or inert ingredients
   in pesticide formulations
                               Bruce Fritz
Environmental Impact of Pesticides on Wildlife
Acute Poisoning: short exposures to some pesticides may kill or
sicken wildlife
• Fish kills caused by pesticide residues carried into waterways by
  run-off, drift, etc. (e.g., fish kills in Mississippi River resulting
  from Guthion use in Louisiana)
• Bird kills caused by birds
  consuming pesticide-treated
  vegetation/insects, pesticide
  granules, bait or treated seed
  (e.g., birds poisoned by eating
  granular carbofuran)

                                                              Ken Hammond
Environmental Impact of Pesticides on Wildlife
Chronic Poisoning: exposure to non-lethal levels of pesticides
over extended periods can cause reproductive effects, etc.
• Populations of bald eagles and other birds of prey were reduced
  by the widespread use of organochlorine insecticides (DDT) in
  1950s and 1960s
• These compounds and metabolites
  caused reproductive effects in birds
• Reduction in use of organochlorine
  insecticides in the 1970s and early
  1980s resulted in greatly improved
  reproduction and increasing bird
  populations                                                Tim McCabe
Environmental Impact of Pesticides on Wildlife
Secondary Poisoning: occurs when animals consume prey that
contain pesticide residues and concentrate the pesticide in their
bodies (i.e., bioaccumulation) resulting in their poisoning
• Predators become sick                               USDA Photograph

  after feeding on dead or
  dying animals poisoned
  by pesticides
• Pesticide residues move
  up the food chain (plants
  eaten by plant feeding
  animals which in turn are
  eaten by predators)
Environmental Impact of Pesticides on Wildlife
Indirect Effects: adverse effects caused by the modification or
elimination of wildlife habitat or food supply
• Herbicides can reduce
  food, cover and nesting                              Ken Hammond
  sites for wildlife
• Insecticides can reduce
  insects that serve as food
  supply for other animals
• Plant pollination can be
  effected by reductions in
  populations of bees and
  other plant pollinators
           Endangered and Threatened Species
                 of Plants and Animals
• Endangered species: “any
  species which is in danger of
  extinction throughout all or a
  significant portion of its range”
• Threatened species: “any
  species which is likely to
  become an endangered species
  within the foreseeable future”
• Endangered / threatened species
  of plants and animals protected              Tim McCabe

  by the U. S. EPA under the
  federal Endangered Species Act
Harmful Effects of Pesticides on Surfaces
• Pesticides can leave
  a visible deposit on
  surfaces (i.e., clothes,
  carpets, walls, etc.)
• Pesticides can corrode
  metal surfaces (i.e.,
  paint on automobiles)
• Pesticides can
  short-circuit electrical   N. C. Pesticide Applicator Training Program
  equipment
                           References
• Applying Pesticides Correctly: A Guide for Private and Commercial
  Applicators. Unit 4: Pesticides in the Environment. pp. 39-48.
• Applying Pesticides Correctly: A Guide for Private and Commercial
  Applicators. Unit 5: Special Environmental Concerns. pp. 49-59.
• McLaughlin, R. A., J. B. Weber, and R. L. Warren. 1994. Protecting
  Groundwater in North Carolina: A Pesticide and Soil Ranking System.
  AG-439-31. N. C. Cooperative Extension Service, Raleigh. 6 pp.
  (http://ces.soil.ncsu.edu/soilscience/publications/Soilfacts/AG-439-31/)
• U. S. Geologic Survey. 1995. Pesticides in the Atmosphere: Current
  Understanding of Distribution and Major Influences. Fact Sheet FS-
  152-95. U. S. Geologic Survey, U. S. Dept. of the Interior. 4 pp.
  (http://water.wr.usgs.gov/pnsp/atmos/)
                          References
• U. S. Geologic Survey. 1995. Pesticides in Ground Water: Current
  Understanding of Distribution and Major Influences. Fact Sheet FS-
  244-95. U. S. Geologic Survey, U. S. Dept. of the Interior. 4 pp.
  (http://water.wr.usgs.gov/pnsp/gw/)
• U. S. Geologic Survey. 1997. Pesticides in Surface Waters: Current
  Understanding of Distribution and Major Influences. Fact Sheet FS-
  039-97. U. S. Geologic Survey, U. S. Dept. of the Interior. 4 pp.
  (http://water.wr.usgs.gov/pnsp/gw/)
• Whitford, F., Miller, B., Bennett, R., Jones, M., and Blesoe, L. 1994.
  Pesticides and Wildlife: An Introduction to Testing, Registration, and
  Risk Management. Publication PP-30. Purdue University
  Cooperative Extension Service, West Lafayette, Indiana. pp. 6-7.
  (http://www.agcom.purdue.edu/AgCom/Pubs/PPP/PPP-30.html)

				
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