Effects of Pesticide Chemicals on the Human Body

Chemical Family

Type of Pesticide

Action on Human System

Symptoms Internal Exposure

Symptoms External Exposure

Symptoms Chronic Exposure

Organo- phosphates diazinonC SpectracideT

Insecticides, acaricides

Inhibits acetylcholi- nesterase (an enzyme) in the tissues

Headache, dizziness, weak- ness, shaking, nausea, stomach cramps, diarrhea, sweating

Minimal rashes but readily ab- sorbed through the skin

Loss of appetite, weakness, weight loss, and general feeling of sickness

Carbamates carbaryl C 

Sevin T

Insecticides acaricides

Reversible changes in acetylcholines- terase enzyme of tissues

Headache, dizziness, weak- ness, shaking, nausea, stomach cramps, diarrhea, sweating

Minimal rashes but readily ab- sorbed through the skin

Loss of appetite weakness, weight loss, and general feeling of sickness

Organo- chlorines (Chlorinated Hydrocarbons) 

methoxychlor C 

Marlate T

Insecticides, acaricides (HCB is a fungicide)

Disrupt function of nervous system, mainly the brain

Headache, dizziness, weak- ness, shaking, nausea, excita- bility, disor- ientation

Minimal rashes but readily ab- sorbed through the skin

Some buildup in the fat tissues. May cause nerv- ousness, weak- ness, and shaking

Pentachlo- rophenol penta C 

Pentacon T

Herbicides, defoliants, molluscicides, germ- icides,fungi- cides, and wood preservatives

Toxic to liver, kidneys, and nervous system

Headache, weakness, nausea, excessive sweating

Highly irritating to skin, eyes, nose, and throat

Weight loss, weakness, anemia

Chloro- phenoxy Pesticides 2,4-D C 

Weed-B-Gon T

Herbicides Irritant to lung, stomach and in- testinal linings. Injure liver, kidney, and nervous system

Prompt vomit- ing, burning sensation in stomach, dia- rrhea, muscle twitching

Moderately irritating to eyes, skin, and lungs

Do not remain in body; passed out within hours or days

Paraquat and Diquat

Herbicides Injure skin, nails, cornea, liver, kidney, linings of stomach and intes- tine, and respiratory system

Burning pain, nausea, vomiting, and diarrhea

Irritates and injures skin and nails

Thiocarbamates and DithiocarbamatesZineb T

Fungicides Low human toxicity

Nausea, vomiting, diarrhea, weak-ness, and nasal stuffiness

Irritating to skin, eyes, nose, and throat

Pyrethrins and Pyreth- roids Prentox T 

Ectiban T

Very low human toxicity

Slight toxic reaction

Arsenical Pesticides

Rodenticides, insecticides, acaricides, marine anti- fouling com- pounds, desi- ccants, herbi- cides, fungicides

Toxic to liver, kidney, brain, bone marrow, and nervous system

Headache, burning stomach pain, vomiting, diarrhea, dizzi- ness. Garlic odor on breath and feces

Swelling of mouth and throat, irritating to nose, throat, and eyes

Accumulates in body. Chronic headaches, dizzi- ness, stomach- aches, salivation, low fever, garlic breath

Coumarins, Indandiones, and other Anti-coagulants warfarinC

Prevents blood from clotting

Reaction if low accidental dose ingested

Sodium Fluoroacetate Compound 1080 T

Rodenticides Extremely toxic. Affects heart tissue and brain

Stomach pain, vomiting, hallucination, nervousness

Minimal

Zinc Phosphide Phosdrin T

Rodenticides Highly toxic; severe intestinal irritation; severe injury to liver, kidneys, nervous system and heart

Intense nausea stomach pain, excitement, chills, cough

Minimal

Yellow phosphorus

Rodenticides Highly toxic; blood system injury; injury to liver, nervous system, heart, and kidneys

Breath has garlic odor; feces may glow and smoke from phosphorus fumes; vomiting and diarrhea; burning pain in throat, stomach, and intestines

Dermal exposure usually low; irritates nose and throat

Strychnine and Crimidine

Rodenticides Acts directly on cells in the brain and spinal cord to cause convulsions

Blue skin color; violent convulsions

Minimal

Red Squill Dethdiet T

Rodenticides Low toxicity Prompt vomit- ing and nausea

Minimal Excreted rapidly; not retained in body

ANTU and Norbormide

Rodenticides Selectively toxic to rats; toxic to humans only in huge suicidal

Blue skin, labored breathing

Minimal

doses

Sulfur Dioxide, For- maldehyde, Chloropicrin, and Acrolein

Fumigants Strong irritant of lungs and throat

Headache, dizzi- ness, nausea, wheezing, cough

Severe irritation of eyes, nose, andthroat. Blisters on skin

 

Methyl Bromide, Ethylene Oxide and Propylene Oxide

Fumigants Serious injury to lungs; injures nervous system

Coughing of frothy fluid; severe shortness of breath, drowsiness, shaking, weakness

Irritates eyes, nose, and throat

Lack of coordination

Halocarbons ethylene dibromideC

Fumigants Injures heart muscles; also injures lungs, brain, liver and kidneys

Shock, drowsi- ness, shaking weakness

Irritates eyes, nose, throat. Blisters and redness on the skin

Liver damage, weight loss, and jaundice

Carbon disulfide

Fumigants Injury to nervous system

Headache, dizzi- ness, nausea, and disorientation

Irritates eyes, nose, and throat. Blisters and red- ness on skin

Pain, tingling and weakness of arms and legs; loss of mental functions

Phosphine Fumigants Injures lungs, liver, kidneys, and nervous system

Weakness, shaking, vomit- ing, cough, diffi- culty in breathing, intense thirst

Irritates eyes, nose, and throat

Pain in eyes and nose; nosebleeds; abdominal pain

Metal Phosphides aluminum 

phosphideC PhostoxinT

Fumigants Injures lungs, liver, kidneys, heart and nervous system

Nausea and vomiting followed by weakness, shaking, and dizziness

Irritants  

Sulfuryl Flouride VikaneT

Fumigants Injures lungs and kidneys

Muscle twitching, convulsions

Irritant Injury to kidneys and lungs

Hydrogen Cyanide, Acrylonitrile, and Sodium Cyanide

Fumigants, rodenticides

Injury to brain and heart tissues

Headache, nausea nausea, constric- tion of throat, dizziness, nervous- ness. Sudden un- consciousness

Irritant  

4-Amino pyridine AvitrolT

Avicides Disrupts nervous system functions

Thirst, nausea, dizziness, weakness, excessive sweating

Chlordi- meform acaron C

Insecticides, miticides

Bladder injury Abdominal and back pain; pain- ful urination; blood in urine

Skin rash; sweet taste in mouth

Copper salts and Organic Complexes copper sulfateC

Fungicides Injures intestinal lining, brain, liver, kidneys, and blood

Prompt vomiting; burning pain in chest; diarrhea, headache, sweating

Irritates skin and eyes; damages mucous membranes

Cyclohexi- mide Acti-dioneT

Fungicides Irritates stomach and intestine; injury to kidneys, brain lining, and nervous system

Excitement, tremors, sali- vation, diarrhea

Minimal

Endothall Herbicides, algicides

Damages heart, blood vessels, nervous system, and intestional lining.

Convulsions, shock, lack of coordination

Irritating to eyes, skin, and mucous membranes

Nicotine Sulfate Black Leaf 40 T

Insecticides Injures nervous system

Nausea, headache, diarrhea, dizzi- ness, shaking, ab- dominal pain, lack of coordination, sweating, sali- vation.

Minimal but readily absorbed through the skin

Phenylmercuric Salts phenylmercury acetateC 

Agrosan T

Fungicides Injures nervous system and kidneys

Delirium, muscle weakness,lack of coordination

Minimal Weakness and lack of coordination in arms and legs; difficulty in talking and swallowing

Sodium Chlorate Atratol T

Herbicides, defoliants

Injury to intestines; restlessness tinal lining, nervous system, and kidneys

Swelling of mouth and throat; pain in esophagus, stomach, and intes-

Irritant

Acetamides butachlor C MacheteT

Herbicides Irritants Moderately irritating to skin and eyes

Acetanilides alachlorC LassoT

Herbicides Irritant Mild irritants; propa- chlor is a skin irritant and sensitizer

Alumino Flouride Salt cryoliteC 

Insecticide Irritant Slight irritant of eyes, nose, and skin

KryocideT

Bensoic and and Benzilic Derivatives chlorambenC 

AmibenT

Insecticides, herbicides

Irritant Irritating to skin and respiratory tract

Benzonit- riles bromoxynilC 

BuctrilT

Fungicides, Herbicides

Irritant Moderately irritating to lungs

Moderately irritating to skin

Dithiocar- bamates mancozebC 

Dithane M-45T

Herbicides, fungicides

Do not inhibit cholinesterase; mild irritants.

Mild irritant to skin, eyes, nose, and throat

Carbanilate prophamC 

Chem-HoeT

Herbicides Irritant Irritant and skin sensitizer

Dicarboxi- mides captanC

Fungicides Irritant Skin irritant

Dinitroani- line Com- pounds trifluralinC 

TreflanT

Herbicides Irritant Slightly to moder- ately irritating to skin, eyes, nose, and throat

Oxadiazola oxadiazonC 

RonstarT

Herbicides Irritant Irritating to skin and eyes

Picolinic Acid triclopyrC 

GarlonT

Herbicides Irritant Irritates lungs Irritating to skin, eyes, nose, and and throat

Pyridazi- none maleic hydrazide C 

RetardT

Growth retardant

Irritant Slightly irritating.

Phosphonomethyl Glycine 

Herbicides Irritant Irritates lungs Irritates eyes

glyphosate C Roundup T

Thiadiazin(ol) betazonC BasagranT

Herbicides, fungicides

Irritant Vomiting, diarrhea, shaking, and weak- ness caused by bentazon herbicides

Moderately irritating to skin, eyes, nose, and throat

Triazines atrazineC 

AAtrexT

Herbicides Irritant Mildly irritating to skin, eyes, nose, and throat

Uracils bromacilC Hyvar T

Herbicides Irritant Irritating to lungs

Irritating to skin, eyes, nose, and throat

Urea 

diuronC Karmex T

Herbicides, insecticides

Irritant Moderately irritating to skin, eyes, nose, and throat

C = Common name T = Trade name

Table 1. Insecticide types and their modes of action [from Radcliffe et al. (2009)].

Insecticide Type Mode of Action

Organochlorine Most act on neurons by causing a sodium/potassium imbalance preventing

normal transmission of nerve impulses, while some act on the GABA (γ-

aminobutyric acid) receptor preventing chloride ions from entering the neurons

causing a hyperexcitable state characterized by tremors and convulsions;

usually broad-spectrum insecticides that have been taken out of use.

Organophosphate Cause acetylcholinesterase (AChE) inhibition and accumulation of acetylcholine

at neuromuscular junctions causing rapid twitching of voluntary muscles and

eventually paralysis; broad-range insecticide, generally the most toxic of all

pesticides to vertebrates.

Organosulfur Exhibit ovicidal activity (i.e., they kill the egg stage); used only against mites

with very low toxicity to other organisms.

Carbamates Cause acetylcholinesterase (AChE) inhibition causing central nervous system

effects (i.e. rapid twitching of voluntary muscles and eventually paralysis); very

broad spectrum toxicity and highly toxic to fish.

Formamidines Inhibit the enzyme monoamine oxidase that degrades neurotransmitters causing

an accumulation of these compounds; affected insects become quiescent and

die; used in the control of OP and carbamate-resistant pests.

Dinitrophenols Act by uncoupling or inhibiting oxidative phosphorylation preventing the

formation of adenosine triphosphate (ATP); All types have been withdrawn from

use.

Organotins Inhibit phosphorylation at the site of dinitrophenol uncoupling, preventing the

formation of ATP; used extensively against mites on fruit trees, formerly used as

an antifouling agent and molluscacide; very toxic to aquatic life.

Pyrethroids Acts by keeping open the sodium channels in neuronal membranes affecting

both the peripheral and central nervous systems causing a hyper-excitable state

causing such symptoms as tremors, incoordination, hyperactivity and paralysis;

effective against most agricultural insect pests; extremely toxic to fish.

Nicotinoids Act on the central nervous system causing irreversible blockage of the

postsynaptic nicotinergic acetylcholine receptors; used in the control of sucking

insects, soil insects, whiteflies, termites, turf insects, and the Colorado potato

beetle; have generally low toxicity to mammals, birds and fish. 

Spinosyns Acts by disrupting binding of acetylcholine in nicotinic acetylcholine receptors at

the postsynaptic cell; effective against caterpillars, lepidopteran larvae, leaf

miners, thrips, and termites; regarded for its high level of specificity.

Pyrazoles Inhibits mitochondrial electron transport at the NADH-CoQ reductase site leading

to disruption of ATP formation; effective against psylla, aphids, whitefly and

thrips; results of testing on one type (fipronil) indicate no effects on the clams,

Table 1. Insecticide types and their modes of action [from Radcliffe et al. (2009)].

Insecticide Type Mode of Action

oysters, or fish, with marginal effects on shrimp.

Pyridazinones Interrupt mitochondrial electron transport at Site 1; mainly used as a miticide;

display toxicity to aquatic arthropods and fish.

Quinazolines Acts on the larval stages of most insect by inhibiting or blocking the synthesis of

chitin in the exoskeleton; developing larvae exhibit rupture of the malformed

cuticle or death by starvation; not registered in U.S.

Botanicals Depending upon the type can have various effects: 

Pyrethrum – affects both the central and peripheral nervous systems, stimulating

nerve cells to produce repetitive discharges and eventually leading to paralysis;

commonly used to control lice. 

Nicotine – mimics acetylcholine (Ach) in the central nervous system ganglia,

causing twitching, convulsions and death; used most to control aphids and

caterpillars. 

Rotenone – acts as a respiratory enzyme inhibitor; used as a piscicide that kills

all fish at doses non-toxic to fish food organisms. 

Limonene – affects the sensory nerves of the peripheral nervous system; used to

control fleas, lice, mites, and ticks, while remaining virtually non-toxic to warm-

blooded animals and only slightly toxic to fish. 

Neem – reduces feeding and disrupts molting by inhibiting biosynthesis or

metabolism of ecdysone, the juvenile molting hormone; commonly used against

moth and butterfly larvae.

Synergists/

Activators

Inhibit cytochrome P-450 dependent polysubstrate monooxygenases (PSMOs)

preventing the degradation of toxicants, enhancing the activity of insecticides

when used in concert; synergists and activators are not in themselves

considered toxic or insecticidal.

Antibiotics Act by blocking the neurotransmitter GABA at the neuromuscular junction;

feeding and egg laying stop shortly after exposure while death may take several

days; most promising use of these materials is the control of spider mites,

leafminers and other difficult to control greenhouse pests. 

Fumigants Act as narcotics that lodge in lipid-containing tissues inducing narcosis, sleep or

unconsciousness; pest affected depends on particular compound.

Inorganics Mode of action is dependent upon type of inorganic: may uncouple oxidative

phosphorylation (arsenicals), inhibit enzymes involved in energy production, or

act as desiccants; pest group depends on compound (e.g., sulfur for mites, boric

acid for cockroaches).  

Biorational Grouped as biochemicals (hormones, enzymes, pheromones natural agents such

as growth regulators) or microbials (viruses, bacteria, fungi, protozoa and

nematodes), acting as either attractants, growth regulators or endotoxins;

Table 1. Insecticide types and their modes of action [from Radcliffe et al. (2009)].

Insecticide Type Mode of Action

known for very low toxicity to non-target species.

Benzoylureas Act as insect growth regulators by interfering with chitin synthesis; greatest

value is in the control of caterpillars and beetle larvae but is also registered for

gypsy moth and mushroom fly; some types are known for their impacts on

invertebrates (reduced emergent species) and early life stages of sunfish

(reduced weight) (Boyle et al. 1996).