Toxicology 2017

Question 1

Define LD50

Answer 1

Lethal Dose 50
Concentration exposure (oral/dermal) at which 50% of tested population dies

Question 2

Define LC50

Answer 2

Concentration exposure (inhalation) at which 50% tested population dies

Question 3

Define TLV

Answer 3

Threshold Limit Values
Chemical concentrations to which workers may be exposed all day without adverse effects
ACGIH sets levels
Levels published by NIOSH
Toxicity exposure is function of time and does

Question 4

Define TWA

Answer 4

Time weighted average
Average concentration workers can be repeatedly exposed to during 8 hr day, 40 hr week without developing adverse chronic effects

Question 5

What is TLV-C?

Answer 5

TLV-C is a ceiling value
concentration that cannot be exceeded even instantaneously because of serious health effects

Question 6

What is TLV-STEL?

Answer 6

Short Term Exposure Limits
allowable exposure concentration for short time period
A 15 min avg exposure period no more than 4 times per day, with a min 1 hr between exposures, provided 8hr TWA not exceeded

Question 7

What are PEL’s?

Answer 7

Permissible Exposure Limits
Cal-OSHA mandated values to enforce workplace violations

Question 8

what is a ceiling in terms of toxicity?

Answer 8

Maximum exposure concentration at any time

Question 9

What is the standard for acute toxicity ratings?

Answer 9

Acute oral LD50<5000mg/kg single dose
Dermal LD50<4300 mg/kg in 4 hr period
Inhalation LC50<10000ppm gas vapor