Structure and mode of action of organochlorines, organophophate and carbamates

1. STRUCTURE AND MODE OF
ACTION OF ORAGANOCHLORINES,
ORGANOPHOSPHATE AND
CARBAMATE GROUP PESTICIDES
Jagmeet Singh
M.Sc Entomology

3. INTRODUCTION
• Organochlorine (OC) pesticides are synthetic
pesticides widely used all over the world.
• They belong to the group of chlorinated hydrocarbon
derivatives, which have vast application in the
chemical industry and in agriculture.
• These compounds are known for their high toxicity,
slow degradation and bioaccumulation.
• Even though many of the compounds which belong to
OC were banned in developed countries.

4. HISTORY
• Organochlorine pesticides are chlorinated
hydrocarbons used extensively from the 1940s
through the 1960s in agriculture and mosquito
control.
• DDT was first commercially produced insecticide
(1940’s)
banned in the US in the 1970’s but is still
manufactured and exported (1 ton/day)

5. MODE OF ACTION
• Two types :-
1. DDT-type
2. Chlorinated type
• Organochlorine compounds work on insects by
opening what's known as the sodium ion channel in
the neurons or nerve cells of insects, causing them to
fire spontaneously.
• The insect will go into spasms and eventually die.

7. STRUCTURE

8. COMMONLY USED
• Lindane
• Methoxychlor
• Aldrin
• Dieldrin
• Chlordane
• Benzene hexachloride

9. BANNED PESTICIDES
• DDT
• Aldrin
• Chlordane
• Heptachlor
• Dieldrine

10. TOXICITY SYMPTOMS
• Cough
• Shortness of breath
• vomiting
• Diarrhea or abdominal pain
• Skin rash
• Headache
• Dizziness
• Ear, nose, and throat irritation
• Blurred vision

11. TREATMENT
• Lorazepam (Ativan)
• Activated Charcoal

13. INTRODUCTION
• Organophosphorus (OP) compounds are organic
derivatives of phosphorus that have largely been used
as pesticides and nerve agents, several of which are
highly toxic.
• Organophosphate pesticides are used in commercial
agriculture to control pests on fruit and vegetable
crops.
• They are also used in home gardens, for flea control
on pets, and in some no-pest strips.
• The main mechanism is blocking the
enzyme acetylcholinesterase causing nervous and
respiratory damages that result in the insects death,
but they are also hazardous to humans.

14. HISTORY
• In 1837, Von Hofmann synthesized methyl phosphor
chloride as an OP compound.
• Clermont produced tetraethylpyrophosphate (TEPP)
in 1854. Although TEPP was not the first synthesized
OP, it was the first OP cholinesterase inhibitor.
• In 1934, Dr. Gerhard Schrader, a German chemist at
I. G. Farbenindustrie synthesized hundreds of OPs
including parathion as a pesticide and tabun (dimethyl
phosphoroamidocyanidate), sarin (isopropyl
methylphosphonofluoridate), and soman (O-Pinacolyl
methylphosphonofluoridate).

15. • After World War II, American companies began
synthesizing organophosphate pesticides in large
quantities.
• Parathion was among the first marketed, followed
by malathion and azinphosmethyl.
• The popularity of these insecticides increased after
many of the organochlorine insecticides such
as DDT, dieldrin, and heptachlor were banned in the
1970s because of their long-life persistence in the
environment.

16. MODE OF ACTION
• Organophosphates interfere with the enzymes
acetylcholinesterase and other cholinesterases, disrupting
nerve impulses and killing or disabling the insect.
• Normally, nerve cells in the brains or muscles of humans or
insects send tiny electrical pulses down tendril to the end ot the
cell where the pulse has to jump across a gap – known as a
synapse – to another nerve cell.
• A chemicals known as ACh moves from one cell to the other
and binds with the new cell, sending the electrical pulse down
the new cell.
• These insecticides – and nerve gas agents that are closely
related – prevent the ACh from coming loose from the new
cell, so it can't receive any more impulses. The insects can't
function and die.

18. STRUCTURE

19. COMMONLY USED OP
• MONOCROTOPHOS
• PARATHION
• MALATHION
• CHOLOPYRIPHOS
• PHOSMET
• DIAZINON
• DICHLORVOS
• FENITROTHION
• METHYL PARATHION

20. BANNED OP
• Chlorpyrifos : banned in most of the countries still
used in India.
• Diazinon : banned for use in agriculture except for
household use.
• Fenitrothion : banned in Agriculture except for locust
control in scheduled desert area and public health.
• Parathion : Methyl Parathion 50 % EC and 2% DP
formulations are banned for use on fruits and
vegetables.
• Monocrotophos : banned on vegetables due to
persistance nature

21. TOXICITY SYMPTOMS
• Hypotension
• cough
• severe respiratory distress
• Blurred vision
• Hypersalivation
• Nausea
• Vomiting
• Abdominal pain
• Diarrhea
• Coma
• Death

22. TREATMENT
• Activated charcoal
• Breathing support
• Atropine used as an antidote ( 2 to 5 mg/kg)
• 2- PAM (1 to 2 g in adults; 20 to 40 mg/kg in
children).

24. INTRODUCTION
• Carbamates are organic compounds derived from
carbamic acid.
• they are more degradable than organophosphates.
• they have lower dermal toxicities.

25. HISTORY
• Carbaryl, the first successful carbamate, was
introduced in 1956. First, it has very low mammalian,
oral and dermal toxicity. Secondly, it has a rather
broad spectrum of insect control.

26. MODE OF ACTION
• Carbamates have similar properties to the
organophosphates, but last in the environment
for a much shorter time period. They are
thought to be less toxic.

27. STRUCTURE

28. COMMONLY USED CARBAMATES
• Carbaryl
• Methiocarb
• Thiodicarb
• Methomyl
• Carbofuran
• propoxur
• Aldicarb

29. BANNED
• Aldicarb