View source for 112. Occupational toxicology, chemical safety

* Occupational toxicology
** The maximum working time in occupational exposure to hazardous compounds is:
*** 8 hours per day, 5 days per week, 240 shifts per year
** Measurement of toxicity – by LD50 (the dose which kills 50%)
** Toxicity according to timeframe
*** Acute toxicity – within 24 hours
*** Subacute toxicity – between 24 hours and 90 days
*** Chronic toxicity – later than 90 days
** Elimination of organic toxic materials
*** Phase 1 of biotransformation – oxidation
**** By CYP450
*** Phase 2 of biotransformation – conjugation with glucuronic acid, acetyl, etc.
*** Phase 3 – excretion by kidney or liver
** Elimination of heavy metals
*** Phase 1 – expression of metallothionein genes
**** These genes code for proteins which bind to the heavy metals
*** Phase 2 – excretion or storage of the metal-protein complex
** Pesticides
*** Used in agriculture, wood preservation, pest control, over the counter, etc.
*** Occupational exposure
**** Pesticide synthesis workers
**** Agricultural workers
**** Pest control workers
*** Absorbed through skin, respiratory tract, <abbr>GI</abbr> tract
*** Persist for many months in the body
*** Examples
**** Organophosphates – Irreversibly inhibit acetylcholinesterase – cause cholinergic crisis
**** N-methyl carbamates – reversible inhibit acetylcholinesterase
**** DDT – a volatile organic compound (VOC)
* Chemical safety
** The CAS registry
*** A registry which contains every chemical substance known
*** Contains information about the substances
*** Currently contains more than 150 million
** Material safety data sheet
*** Follows all dangerous chemicals
*** Provides all relevant information, like possible hazards, how to handle safely, etc.
*** European hazard symbols
**** Used until 2015 – nowadays the Globally Harmonised System is used instead
**** E – explosive
**** F – highly flammable
**** O – oxidizing
**** T – toxic
**** Xn – harmful
**** Xi – irritating
**** C – corrosive
**** N – dangerous for the environment
** R phrases (risk phrases)
*** Codes which correspond to specific risks
*** R1 – explosive when dry
*** R45 – may cause cancer
*** etc.
** S phrases (safety phrases)
*** Codes which correspond to specific safety rules
*** S24 – avoid contact with skin
*** Etc.

[[Category:Public health 6 - Occupational hygiene and occupational medicine]]