pesticide Flashcards
define pesticide
kills or harm some form of life. any substance or mixture for preventing, destroying, repelling, or mitigating any pest.
what was historically used as a fumigant to kill bacteria and fungi?
sulfur and it is widely used today
true or false? there is no such thing as a safe pesticide?
True
what are insecticides?
neurotoxicants that poison the nervous system
what are organochlorine insecticides?
organochlorine (chlorinated hydrocarbon) insecticides are a diverse group of agents
what makes organchlorine good insecticides?
low votality
chemical stability
lipid solubility
slow rate of biotransformation and degradation
what makes organochlorine bad insecticides?
persists in the environment
bioaccumulates
is biomagnified through food chains
what are ways of pesticide exposure?
General population - food, water, air
Bystander exposure - home(families) and serial drift
occupational exposure- manufacturing, greenhouse workers, mixer-loaders, applicators, harvesting, handling
Poisonings - accidental or suicidal
how does dosage increase for pesticide exposure?
From low to high mg/kg body weight?
- general population
- bystander effect
- occupational exposure
- poisonings
what are the classes of insecticides?
organochlorine insecticides
organophosphate/carbamate insecticides
pyrethroid insecticides
mechanism of action of organophosphate and carbamates?
excess acetylcholine
mechanism of action of organochlorines and pyrethroids
enzymes and axonal membranes
chronic signs of Organochlorine insecticides?
EEG pattern changes
anxiety
hyperexcitability
acute sings of organochlorine insecticides?
dizziness
headache
nausea
vomiting
how does the patch test show exposure to organochlorines dienochlor?
hyperpigmentation occurs
mechanism of action for DDT type of pesticides?
repetitive discharges in neurons result inh intermittent tremoring/convulsive seizures
nerve membrance is sensitive to very small stimuli
what type of pesticide causes prolonged repolarization
DDT and K+ is critical for repolarization
what type of pesticide causes negative afterpotential?
DDT
where do chlorinated cyclodiene, benzene, and cyclohexane type insecticides act on?
In CNS
what is picrotoxin?
nerve excitant and antagonist of neurotransmitter GABA in the CNS
what is DDT broken down to?
DDE
biotransformation for cyclodiene type of insecticides is ?
slow
how is poisoing of insecticides life threating?
causes tremors and motor seizures
how do you treat or decontaminate insecticides?
administer diazepam or phenobarbital to control convulsions
what do organophosphate and carbamate have in common?
similar mechanism of action
both inhibit actionof acetylcholinesterase at the synapse btw 2 neurons or motor neuron or muscle
how is cholinesterase inhibited?
activity of end organ does not cease and OP binds to cholinesterase preventing regeneration
whats acetylcholinesterase (AchEase)?
enzyme that breaks down neurotransmitter acetylcholine
which insecticide are irreversible and reversible inhibitors of Acetylcholinesterase?
organophosphate compounds are irreversible inhibitors of acetylcholinesterase
carbamate compounds are reversible inhibitors of AChEase
what is the acronym for cholinesterase inhibition syndrome?
DUMBELS Diarrhea Urination Miosis Bronchorrhea Emesis Lacrimation Salivation
what are common clinical presentations with cholinesterase inhibitors?
nausea vomiting miosis sweating, urinary frequency non specific constitutional symptoms
what are management for cholinesterase inhibitor poisoning?
collection of serume, urine, and clothing samples
hospitalize for severe symptoms
treat with atropine or pralidoxime
workplace restrictions
the treatment of atropine for cholinesterase inhibitor does what?
reverses DUMBELS syndrome
what does treatement of pralidoxime for cholinesterase inhibitor poisoning do?
2 PAM reactivates cholinesterase
cholinesterase levels rise
what are pyrethroid insecticides?
synthetic chemicals similar to insecticides extracted from pyrethrum or chrysanthemum flowers.
health effects of pyrethrins?
low systemic toxicity
respiratory sensitization (asthma)
skin reactions
whats the pyrethrins and pyrethroids mechanism of toxicity?
prolonged inactivation of nerve membrane sodium channels
Type I - shorter inactivation
Type II - longer inactivation
what do Type I and Type II pyrethrins and pyrethoids both inhibit?
both inhibit Ca/Mg ATpase which increases Ca2+ levels and neurotransmitter release
how to treat pyrethrin and pyrethroid illness?
decontaminate
vitamin E cream
symptomatic therapy
remove from further exposure
dipyridyl compounds are found in?
herbicides
what are the dipyridyl compounds found in herbicides?
paraquat
diquat
paraquat toxicity through ingestioin causes?
GI tract edema, ulcers hepatocellular injury acute tubular necrosis pulmonary fibrosis lung liver kidney damage
what are the outcomes of different paraquat levels?
survival likely in less than 1 urine and less than 20 blood
pulmonary fibrosis in 1-1000 in urine and 20-40 in blood
death w/in 24 hrs if 10-10,000 urine and greater than 40 in blood.
the herbicide glyphosate causes?
skin and eye irritation
death if large amound ingested
what are fumigants?
halogenated hydrocarbons
inorganic compounds
pro-fumigants
metal phosphides
methyl bromide acute toxicity
blisters delayed pulmonary edema CNS depressant (usual cause of death)
list of fumigants
sulfurlyl flouride
methyl bromide (blistering)
metam sodium (cough)
phosphide compounds
list of fungicides
thiocarbamates (skin rash, pear picker) phalimide derivatives substituted aromatics inorganic captan (dermititis)
health effects of fungicides?
dermatitis
possible carcinogen
what causes ashy dermatitis?
chlorothalonil
characteristics of rodenticides?
no bait shyness makes animal continue to eat it
causes non suspicous death
makes intoxicated animal go out to the open to die
species specific by being low toxic to other animals
What are chronic illnesses of organochlorines
Impairment of spermatogenesis
Hesperexcitability
EEG pattern changes
Anxiety
What are the 3 types of herbicides?
Dipyridal compounds which are parquet and diquat
Glyphosate
Phenoxy compounds
