Organochlorines Flashcards
What is the source?
Naturally through biological, physical, and chemical processes
-oceans are the main source, followed by soil
Ingestion of contaminated feeds, sprayed foliage or pesticide containers (Shokry)
May be absorbed through the skin, MM, or inhaled when applied topically
Synthetically chlorination process modifies the physical properties of hydrocarbons in several ways resulting in wide structural variety and divergent chemical properties that leads to a broad range of names and applications
List chemical properties of organochlorines
Persistent in the environment
-Chlorination of organic compounds reduces reactivity
-stability is manifested as environmental persistence (more Cl, more persistent)
Lipophilic (fat soluble)
What are the two main groups of organochlorine pesticides?
Dichlorodiphenyltrichloroethane (DDT)- type compounds
Chlorinated alicyclics (open and closed chains)
Why can DDT have an environmental impact?
It can be bioaccumulated in earthworms and biomagnified in robins
These are endocrine disrupters
What is bioaccumulation?
DDT/DDE have relatively long 1/2 lives of up to 15 years– this allows for the small organisms to have a lot of time to take up and accumulate DDT/DDE in fatty tissue
- this can eventually lead to toxic levels and death
What is biomagnification?
When the organisms higher in the food chain eat the smaller organisms lower in the food chains such that the concentrations of DDT/DDE could be magnified
What is egg shell thinning?
DDT/DDE (estrogen like activity) impairs the shell glands ability to excrete calcium carbonate to harden the egg shell- soft eggs do not survive
How are these absorbed?
Dermal- most common, MM, or inhaled when applied topically
What is the mode of action of DDT?
Axonal Na+ channels remain open and K+ channels don’t open completely; thus repolarization is inhibited
What is the MOA of Chlorinated alicyclic type?
Binds to but does not activate GABA receptor (blocks the action of GABA)
Since GABA can’t bind receptor, then the Cl- upon Chanel’s don’t open
What is the main storage tissue?
Fat
What is the major route for decontamination?
Biliary excretion
-metabolites can enter enterohepatic recycling, be reabsorbed, and result in toxicity
What happens if the organochlories are excreted in milk?
Neonatal exposure
What are the main CS+?
CNS Hyperstimulation
-salivation, nausea, vomiting, apprehension, tremors, hyperthermia, incoordination, intermittent clonic-tonic seizures and OPISTHOTONOS
What is the diagnosis?
No specific pathological lesions (acute)
