organochlorines

1. Organochlorines pesticides

2. • Organochlorines pesticides are organic compounds with five or more
chlorine atoms.
• Organochlorines were the first synthetic organic pesticides to be used
in agriculture and in public health.
• Most of them were widely used as insecticides for the control of a wide
range of insects, and they have a long-term residual effect in the
environment since they are resistant to most chemical and microbial
degradations.
• Organochlorine insecticides act as nervous system disruptors leading
to convulsions and paralysis of the insect and its eventual death.
• Some of the commonly used representative examples of
organochlorine pesticides are DDT, lindane, endosulfan, aldrin, dieldrin
and chlordane and their chemical structures are presented hereunder.

4. General Properties
- Are highly persistent chemicals that are chemically inert and photostable
- are lipophilic, so get absorbed on lipid tissues of living organisms and soil
particles
- they tend to build up in food chains
- They have a high oral toxicity and long residual activity. High persistence
makes them ideal for soil application
- have low mammalian toxicity, low vapor pressure and low aqueous solubility
- They have low solubility in water
- They also have a wide spectrum of activity: tend to kill even natural enemies
leading to the build-up of secondary enemies, hence some like DDT have been
banned
- Some members have both nematicidal and acaricidal effect

5. PRACTICAL USES
CHEMICAL PESTS CONTROLLED
Endosulfan Ants, grasshoppers, lepidopteran larva
Chlordane Aphids, grasshoppers. Used in homes to control
household insects, termites, wireworms and other soil
insects
Toxaphene Boll weevils on cotton
Dieldrin Surface treatment of soil, seed dressing, root dipping.
Also used in public health to control cockroaches, fleas
and tsetse
DDT Bollworms and aphids on cotton
Also control mosquitoes
Methoxychlor Flea beetles Colorado beetle
HCH Seed dressing, armyworm, grain weevils, grasshoppers,
apple sawflies, cockroaches
Aldrin Bollworms, cutworms, dipteran larva, mealybug,
Ceratitis capitata, white grubs, termites

6. Mode of Action
- they generally destabilize the nervous system
- exposure leads to headache, dizziness, nausea, weakness in lungs
-When dosages are light, even in the case of frequent or continuous
exposure, the pesticides do not often cause visible symptoms of
poisoning, but residues tend to accumulate in the body (tend to be
deposited in the fatty tissues of organisms)

7. SECONDARY AND ENVIRONMENTAL EFFECTS
-Organochlorines can persist in the soil for months or years of high doses are
applied to clay or soils rich in organic matter
-Predators which feed on earthworms are threatened because organochlorines
tend to get biologically magnified
-In plants, organochlorines can be translocated to edible parts. Grazing animals can
get the chemical residues in the grass. This ends up in meat, milk or eggs.

8. END
PRESENTED BY
WALTER MWANUNURA
ZAYNE BOI
28/03/17