Pesticides (vvimp)
Definition:- As per US Federal Insecticide, Fungicide & Rodontiside Act (FIFRA) defined Pesticide
as any substance or mixture of substances intended for the use as Plant Regulator, Defoliant or
Desiccant.
Types:-I) Inorganic & II) Organic
I) Inorganic:- 10% of total pesticides
a) Calcium Arsenite b) Lead Arsenite
c) Arsenic Acid
II) Organic:- Also known as Synthetic Pesticides
1) Chlorinated Hydrocarbons:a) DDT b) Benzene Hexa Chloride (BHC)
c) Endosulfan
2) Organic Phosphorus Compounds:- a) Malathion b) Parathion c) Dimethoate
d) Ethion f) Acephate
3) Carbamate Group:- a) Carbafuran b) Aldicarb c) Methomoil
Fumigants:- a) Cyanides b) Halogens c) Phosphorus
Herbicides (Weed Killers):- a) Endothal b) Diqat c) Paraquat d) Organic Acid Derivatives:- i)
Cacodylic Acid ii) 2,4 D (2,4 Dichloro Phenoxy Acetic Acid)
Rhondanticides:- a) Diphecinone b) Fumarine
Fungicides:- a) Disulpheram b) Penta Chloro Phenol c) Copper Compounds
Naturally occurring insecticides are a) Nicotine b) Pyrethrum
Organo Phosphorous Pesticides
This group of insecticides is classified according to a common mode of toxic action related to
inhibition of enzyme Cholinestrase. Therefore, they are known as Cholinestrase Inhibitors. They
are rapidly absorbed even though intact skin toxicity occurs during 1) Manufacture 2) Packaging
3) Handling 4) Storage & formulation
Route of Absorption:- All 3.
Mechanism of Action:- They cause inactivation or inhibition of the enzyme Cholinestrase resulting
in an accumulation of Acetyl Choline at synapses in Peripheral Nervous Syatem. This compound
most irreversibly phosphorylates the Acetyl Cholinestrase.
The effect depends upon the route of entry although acute toxicity usually rapid in onset but
symptoms may be delayed upto 12 hours.
Toxicity:- I) Acute Exposure:- A) General Symptoms:- 1) Nasal Hyperemia 2) Watery Discharge
3) Cough 4) Chest Discomfort 5) Dyspnoea 6) Wheezing
B) When it is Absorbed in the System:1) Pallor 2) Nausea 3) Vomitting
4) Diarrhea 5) Abdominal Pain & Cramps 6) Headache 7) Dizziness
8) Ocular Pain 9) Blurred Vision 10) Meosis 11) Lacrimtion 12) Salivation
13) Sweating 14) Confusion
C) Neuromuscular Symptoms:- 1) Ataxia 2) Slurred Speech 3) Weakness 4) Fatigue
5) Fasciculations 6) Twitching 7) Tremors of Tongue & Eyelids 8) Paralysis of
Extremities & Respiratory Muscles
D) In Severe Cases:- 1) Involuntary Defecation & Urination due to loss of sphincter control
2) Cyanosis 3) Psychosis 4) Hyperglycemia 5) Acute Pancreatitis
6) Convulsions 7) Coma
E) CVS:- 1) Fall of BP 2) Cardiac Arrest
F) Death is due to Respiratory Failure & Cardiac Arrest
II) Chronic Toxicity:- 1) Impaired Memory & Consciousness 2) Delayed Neuropathy 3) Psychosis
4) Severe Depression 5) Irritability 6) Confusion 7) Apathy 8) Social
Withdrawal 9) Speech Difficulty 10) Delayed Reaction Time 11) Nightmares
Difference between Organo Phosphorus Poisoning & Carbamate Poisoning:- Both are Cholinestrase Inhibitors
Diagnosis of OPP Poisoning:- By Cholinestrase Activity Measurement. Cholinestrases are of 2
types 1) Acetyl Cholinestrases & 2) Pseudo or Butyryl Cholinestrases
1) Acetyl Cholinestrase:- Primarily found in CNS & RBCs.
2) Pseudo or Butyryl Cholinestrases:- Found in Plasma, Liver & CNS
Both of these are inhibited by Organo Phospherous compounds. But those who retain the
level in RBCs are measured. 1) Michael Method 2) Rapid Filled Determination
Michel’s Method is very difficult to diagnose, so Rapid Filled Method is used. The
Cholinestrase Activity in blood is expressed as % of Activity. This is done with the help of
Cholinestrase Measuring Kit, through Colorimetric Chemical Analytic Process. Depending
upon following actions are recommended:% Cholinestrase Activity
1) 100 to 75%
(i.e. 25% is lacking)
2) 75 to 50%
3) 50 to 25%
4) 25 to 0%
Action Recommended
No action but retest in near future
Over Exposure is possible. Repeat test. If confirmed in second
test, Remove from further work for 2 weeks, & then retest to
assess the recovery.
Serious overexposure. Repeat Test. If confirmed remove from
all work with insecticide.
Very Serious & Dangerous Overexposure. Repeat Test. If
confirmed, remove from all pending pesticide work & arrange
Medical Examination & Treatment.
Carbafuran (Furadane)
It is a Carbamate group of Pesticides. It is a derivative of Carbamic Acid, deferring from
Cholorinated Hydrocarbons & Organo Phosphorus Pesticides, by absence of Cl⁻ & PO4⁻⁻. Toxicity
resulting from inactivation of Acetyl Cholinestrase, which allows accumulation of excessive Acetyl
Choline at number of sites like CNS, Parasympathetic Nervous System, Nerve Endings etc. It is
treated as Anticholinestrese Agent with toxicity having Rapid Reversibility.
Treatment of Organo Phosphorus Poisoning:1) Maintaining of Patent Airways
2) Removal of Contaminated Cloathing
3) Appropriate Antidote:IV 2 to 4 Mg of Atropine Sulphate &
1to 2 Gm of Soluble Salt of Pralidoxin every 6 hourly
OR 250 Mg. Obidoxin Chloride 6 hourly.
In Severe Cases 4-6 Mg. of Atropine can be used with
repeated dose of 2Mg. every 5-10 minutes till full
Atropinization is achieved.
Diazepam is used in mild cases but need to watch Respiratory
Paralysis.
Carbamate:- Atropine remains treatment of choice. Oximes are contraindicated in Carbamate
Poisoning. Carbamate is rapidly reversible while OPC are not Rapidly reversible.