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Toxicology Exam II
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Chemicals may cause harm via
inhalation
ingestion
absorbsorption through the skin
Industrial workers are exposed to chemical solvents and vapors during
synthesis
manufacturing
packaging
use in an occupational setting
Guidelines are set to establish
safe ambient air concentrations for many chemicals found in the workplace
Workplace exposure guidelines established by the American Conference of Governmental Industrial Hygienists (ACGIH)
Threshold limit values
ACGIH has no
regulatory authority
Toxicologic basis for each TLV are based on
respiratory sensitization
sensory irritation
odor
narcosis
asphyxia
TLV is not
a relative index of toxicity
a fine line separating safe from dangerous
Common units for TLV
parts per million (ppm)
parts per billion (ppb)
chemical per cubic meter of air (mg/m
3
)
Conversion of ppm to mg/m
3
mg/m
3
= (ppm x mw)/22.4
Threshold limit value-time weighted average (TLV-TWA)
concentration for a normal 8hr work day or 40hr work week for which
nearly all
workers may be repeatedly exposed without adverse effect.
Threshold limit value-short term exposure limit (TLV-STEL)
max concentration (larger than TLV-TWA)
should not be exceeded during a 15 min exposure
Threshold limit value-ceiling (TLV-C)
concentration that should not be exceded when exposure is instantaneous
compounds designated "S"
skin contact is the significant route of exposure
potential corrosive effects
systemic toxicity due to absorption
ACGIH classifies carcinogens as
A1 = confirmed in humans
A2 = suspected in humans
A3 = animal carcinogens
TLVs are heavily based on
workplace exposures
conditions occuring w/in the US
OSHA regulation
standards for exposure to airborne contaminants
agency of the federal government
OSHA's version of TLV-TWA
permissible exposure limit
Substances that are specifically regulated as carcinogens by OSHA are indicated by
OSHA-CA
additional regulation applies
Some states operate their own occupational health programs in cooperation with OSHA. In these states ______ standards may apply.
more strict
OSHA defines Immediately dangerous to life or health (IDLH) as
a max concentration from which one could escape within 30 minutes without any symptoms or irreversible health affects
Warning properties that are valuable indicators of exposure
odor
sensory irritation
Sense of smell may be unreliable for detecting compounds because of
olfactoy fatigue
individual differences in odor thresholds
no correlation between odor quality and toxicity
pleasant smelling compounds are not less toxic
Most common routes of exposure
skin contact
inhalation
Chemicals which may come in contact with skin or be inhaled
gasses/vapors/aerosols
volatile liquids
other liquids
dusts and fibers
Organs most commonly affected by industrial chemicals
respiratory system
skin
most prevalent occupational disesase that accouts for more work days lost than all prescribed industrial diseases together
dermatitis
Chemical agents may cause
irritation
sensitization
inflammation
Primary irritants
acids
alkalis
metals
solvents
organic/inorganic chemicals
Solvents will
degrease skin
Acids and alkalis will
denature skin proteins
Skin sensitizers act via _____ mechanisms to cause ____.
immunological
contact dermatitis
Re-exposure to a previous sensitizer will cause
allergic reaction
Example of skin sensitizers
nickel and its salts
Sensitization following inhalation exposure may lead to
asthma
Toluene-diisocyanate
pulmonary sensitizer used in many compounds
Causes occupational acne
chlorinated hydrocarbons
Halogenated aliphatic hydrocarbons are used for
degreasing & clensing agents
Halogenated Aliphatic Hydrocarbon compounds
CCL
4
CHCL
3
trichloroethylene
tetrachloroethylene (perchloroethylene)
1,2-dichloroethrane
1,1,1 - trichlorethane (methylchloroform)
Clinical side effects of halogenated aliphatic hydrocarbons
CNS depression
liver injury
kidney injury
cardio-toxicity (sensitization to norepinephrine)
Most potent CNS depressant halogenated aliphatic hydrocarbon
Chloroform
Chronic exposure to tetrachloroethylene can
impair memory
induce peripheral neuropathy
1,1,1-trichlorethene (HAH) is associated with
peripheral neuropathy
Most potent HAH in regards to hepatotoxicity
CCL
4
HAH's that may cause nephrotoxicity
CCL
4
CHCL
3
trichlorothylene
tetrachloroethylene
HAH's have shown _____ in life time exposure studies in rats or mice
carcinogenicity
Treatments for exposure to HAHs
no specific treatment
depends on organ system involved
Used for CCL
4
toxicity
L-Acetylcyst
e
ine
Products used widely in plastic, agriculture and chemical industries as solvents degreasers and fuel
petroleum and solvent distillates
Excessive inhalation or ingestion of petroleum products causes
n/v
pulmonary irritation
CNS and respiratory depression
cardiac sensitization to catacholamines
Chemical pneumonia
direct injury from pulmonary aspiration of petroleum distillates
Treatment for petroleum and solvent distillates
administration of charcoal (if ingested not if inhaled)
gastric lavage
artificial respiration
Author
Rx2013
ID
67007
Card Set
Toxicology Exam II
Description
Industrial Solvents I
Updated
2011-02-17T13:04:06Z
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