Insecticides: Agricultural Use and Human Health Implications

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Insecticides Agricultural Use and Human Health
Implications

• ?0601
• 40662021
• Zhou Wei

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Insectides

• Def pesticides that are used to kill insects
• Uses
• In the agriculture industry, they are used in
  combination with fungicides and herbicides
• Prevent insects from eating crops
• Control insect-borne disease

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Indoor Application

• Common insecticides flea powder and cockroach
  spray
• Can be tracked indoors (on shoes, gloves, pets,
  airborne dust)
• Indoor insecticides have longer half life than in
  the outdoor environment due to less water, UV and
  biological exposure and breakdown

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Classifications

• Organic synthetic chemicals that account for
  large number of pesticides
• Inorganic manufactured with metals
• Arsenates, sulfur, fluoride, and copper-compounds
• Contact toxic to insects by direct contact
• Aerosols
• Natural composed of plants to defend against
  insects
• Pyrethrum and nicotine
• Systemic incorporated with treated plants

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Agricultural Application

• Spray application most common method
• Applied manually by mounted tractor sprayers or
  hand held equipment
• Aerial application as well
• Targets insects that dwell on vegetation and soil

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Environmental Considerations

• Water pollution by various routes
• Pesticide drift
• VOC (volatile organic compounds)
• Soil contaminants
• Non-target organisms
• Pest resistance

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Environmental Considerations

• Prior to the use of a pesticide in the United
  States, the Environmental Protection Agency
  studies the ecological effects of a pesticide and
  its degradation products to various terrestrial
  and aquatic animals and plants.
• The EPA also studies the chemical fate and
  transport of a pesticide in soil, air, and water
  resources

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Organophosphorus Insecticides

• Class of chemicals composed of an organic radical
  bound to a phosphorus containing radical that
  kill insects.
• Classified as non-persistent because upon
  hydrolysis with air, soil, or sunlight, these
  compounds are rapidly degraded
• Widely used for agricultural, residential, and
  community health purposes
• Examples chlorpyrifos, diazinon, dichlorvos,
  fenthion, malathion, methyl-parathion
• Functions-
• Irreversibly inactivate acetylcholinesterase
• Disrupt insect nervous impulses which results in
  death or impairment of normal function
• Replaced organochlorine insecticides that were
  known to be persistent in the environment

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Adverse Health Effects

• Acute toxicity for mammals
• Pose as addictive toxic effects that are
  amplified by multiple exposures
• Metabolize quickly and excreted in urine
• Potential chronic health risks
• Respiratory depression, seizures, loss of
  consciousness
• Absorbed by inhalation, skin penetration, and
  ingestion

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Other Effects

• Psychiatric effects
• Cancer
• Eye defects
• Birth defects
• Cardiac effects
• Neurological

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Poisoning

• Signs and symptoms headache, nausea, muscle
  twitching, diarrhea, hypersecretion
• Treatment Clear airways to improve tissue
  oxygenation, administer atropine sulfate
  intravenously, decontaminate skin

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Alternatives and Considerations

• Methods of cultivation
• Other organisms to kill pests
• Genetic engineering
• Insect breeding interference

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Insecticide Summary

• Research safer ways to handle and apply
  insecticides
• Minimize human exposure by introducing new or
  improved personal protective equipment
• Investigate how home design and household
  cleaning practices affect indoor pesticide levels
• Implement simple preventative measures like
  removing shoes at the door or installing walk off
  mats
• Wash and peel food crops