Process Safety Flashcards
Toxicology
What is a toxicant?
chemical or physical agent - includes dust, fibres, noise and radiation
what is toxicity
property of the agent describing its effect on biological organisms
what is a toxic hazard
likelihood of damage to biological organisms based on exposure resulting from transport and other factors of usage.
what is the difference between toxicity and a toxic hazard
the toxic hazard that is presented by a substance can be reduced using appropriate hygiene techniques.
Toxicity cannot be changed
what are the four entry routes of a toxicant
- ingestion
- inhalation
- injection
- dermal absorption
which allows for absorption into blood fastest (give fastest to slowest)
- injection
- inhalation
- ingestion
- dermal
What are the effects of a toxicant on the GI tract
toxicants have biggest effect on area when ingested. Airborne particles lodge in mucous of upper respiratory tract.
What are rate and selectivity of absorption dependent on
type of chemical, molecular weight, molecule size, shape, acidity, susceptibility to attack intestinal flora, rate of movement through tract
how does the skin play a part in toxicants entering organisms
dermal absorption and injection
how can absorption through the skin occur
through hair folicles and sweat glands
how does skin change in absorption capabilities around the body
skin on palm- thicker than elsewhere, but has increased porosity and absorbs toxicant more highly
what does increased presence of water in the skin do
increased permeability and absorption.
what are the two areas where toxicants can impact the respiratory system
- upper respiratory system: nose, sinuses, mouth, pharynx, larynx, trachea
- lower respiratory: lungs and smaller structures - bronchi and alveoli
how are toxicants eliminated from biological organisms
- excretion: through kidneys, liver, lungs, other
- detoxification: changing chemical into something less harmful (bio transformation)
- storage: in fatty tissue
what are irreversible affects of toxicants
- carcinogen (cancer)
- mutagen (chromosomal damage)
- reproductive hazard (reproductive system damage)
- teratogen (birth defects)
Possibly reversible effects
- Dermatoxic - skin
- hemotoxic - blood
- haptoxic - liver
- nephrotoxic - kidneys
- neurotoxic - nervous system
- pulmonotoxic - lungs
what affects the response of a biological organism to a toxicant
age, sex, weight, diet, general health, other
how is a dose vs response curve generated
- toxicological test run on large number of individuals, each exposed to same does, response recorded.
- fraction or percentage of individuals experiencing specific response plotted.
- experiment repeated for different doses
- mean and standard deviation determined for each does
- complete dose-response curve prepared - selecting response being tested, determining cumulative mean for response at each dose, plot vs dose
how do names for dose vs response curves differ
- death or lethality - lethal dose curve
- minor and reversible - effective dose curve
- response is toxic, not lethal, irreversible - toxic dose
- response is death or lethality - lethal dose
what is additive interaction for dose vs response curve
for several chemicals -combined effect, the sum of individual effects
what is synergistic interaction for dose vs response curve
for several chemicals -combined effect more than individual effects
what is potentiate interaction for dose vs response
for several chemicals -presence of one increases effect of the other
what is antagonistic interaction for dose vs response
for several chemicals -both counteract each other
