17. Acute toxicity: depends on concentration of COHb in blood.
<10% No symptoms
At 10% Headache
10-20% Headache, tinnitus, dyspnea
20-30% As above + nausea, vomiting
30-45% As above + confusion, coma
> 50% Respiratory center depression & death
23. Solvent: degreasing, paint stripping
Absorption through respiratory route or through skin
Metabolized in bloodstream to …… CO
24. May elevate COHb to 10% or more especially in poorly ventilated
space
Probably not significant to healthy person; may become mildly
symptomatic
Cigarette smokers, those with angina or current CHD a concern:
excess CO may trigger symptoms
25. Methylene Chloride
OSHA Standard: 25 ppm/ TWA8: STEL 125 ppm
NIOSH: As low as can be achieved (carcinogen)
Because of metabolic conversion to CO, the
biological life of COHb from methylene chloride
is longer than that from direct CO exposure
34. Cyanide is a rapidly
acting, potentially
deadly chemical that
can exist in various
forms: a colorless gas
(hydrogen cyanide), a
colorless liquid, or in
form of crystals,
powder or pellets
(cyanide salts such as
sodium cyanide).
Cyanide is sometimes
described as having a
bitter almond smell,
but it does not always
give an odor, nor can
everybody detect it.
Cyanide is a naturally
occurring chemical
compound & is found
in several plants (e.g.
cassava roots,
almonds) and in
cigarette smoke.
35.
36.
37.
38. Uses:
1- Fumigant (rodenticide, insecticide).
2- Extraction of silver & gold.
Mechanism of action:
- HCN absorbed through the lung.
- Excreted in urine & feces as thiocyanates.
- It inhibits cytochrome oxidase enzymes.
39. With a gold recovery rate of around 60-90%, its
performance is superior to mercury with a recovery
rate of 20-50%, depending on the processing
system. Sometimes, cyanide is used to capture
residual gold by leaching ore and tailings to which
mercury has previously been added – i.e. mercury
contaminated materials.
55. SEWER GAS
Sewer gasis a combination of non-toxic and toxic gases
that are present in sanitary and combined sewer collection
systems at varying levels depending on the source.
Elements of sewer gases include hydrogen sulfide,
methane, ammonia, carbon dioxide, sulfur dioxide and
nitrogen oxides, as well as biological organisms (bacteria,
viruses, etc.). Other components in sewer gas may include
substances that are improperly disposed of in sanitary
sewer systems, such as gasoline or solvents.