Toxicity Flashcards
what is hygienic limit assessment?
The highest acceptable average content level of a contaminant in air which is to be inhaled, calculated as a time weighted average.
Level limit value or ceiling value
Explain AEGL
Acute Exposure Guideline Levels
Estimate the concentration at which most people will begin to experience health effects when exposed to chemicals for a specific length of time
Explain ERPG
Emergency Response Planning Guidelines
Estimate the concentration at which most people will begin to experience health effects if they are exposed to a hazardous airborne chemical for 1 hour
Explain TEEL
Temporary Emergency Exposure Limits
Estimate the concentrations at which most people will begin to experience health effects if they are exposed to a hazardous airborne chemical for a given duration
Explain IDLH
Immediately Dangerous to Life and Health
Exposure is likely to cause death or immediate or delayed permanent adverse health effects or prevent escape
Maximum concentration above which only a highly reliable breathing apparatus providing maximum worker protection is permitted
what kind of response could one get from toxicity?
Combination of psychological and pathological response
Physiological
During the fire (short term)
Smoke
Irritants
Asphyxiants
Pathological
Post-exposure
Neuropathological effects
Cardiovascular effects
Carcinogenic effects
Sensitization
Pulminary
Give examples of different pathways for exposure
Inhalation
Dermal
Oral
Eyes
What is a dose?
A well defined amount that an individual is exposed to
ie Mg species / kg body weight
What is concentration?
Used often for exposure to gases and aerosoles
Typically mg species/m3 air. Alt PPM
Explain dose-response relationship
Lethal Dose and Lethal Concentration
LDx LCx resulting in lethal outcome for X% of population
Lethality is not the only outcome of interest and other outcomes can be specified Effective dose or effective concentration
Ex sensation, impaired reactions, medical attention needed, injury
What is there to consider for a toxicity assessment?
Smoke particles
Asphyxiants
Irritant gases
Heat
Sensitisers
FED
FEC
What is FED and FEC?
FED – Fractional effective dose
* FEC – Fractional effective concentration
* Can be applied for visibility, species, temperature, radiation
Important to assess whether physical effects of exposure is immediate or depends on accumulated dose
- Irritant immediately can cause pain, concentration dependent
- Asphyxiant can depend on dose inhaled
When using the FED model, we can refer to:
Lethal doses FLD
Incapacitating doses FID
Threshold concentration FIC
What is LC50?
The volume fraction of toxit gas or smoke to produce lethality in 50 % of test animals within a specified exposure and post-exposure
IC50 is similarly defined for incapacitation
