Chemistry Reference
In-Depth Information
to appear in the nervous system, as described previ-
ously. An early and critical sign in peripheral neuropa-
thy is a block in the cholesterol biosynthesis pathway,
causing an accumulation of squalene within the nerve,
followed by the breakdown of myelin.
retrograde pyelography died (Keall
et al
., 1946). Acute
exposure to tellurium may cause acute respiratory irri-
tation followed by the development of garlicky odor
of the breath and sweat. Systemic effects may include
fatigue, headache, malaise, lassitude, weakness, diz-
ziness, somnolence, alopecia, and gastritis. Chronic
exposure may lead to garlic breath, metallic taste in
the mouth, decreased sweating, dryness in the mouth,
fatigue, anorexia, and nausea. The skin may develop
a blue-black discoloration after exposure to tellurium
hexafl uoride (Rumack, 2003; Yarema and Curry, 2005).
The garlicky odor of the breath and sweat is an early
classical sign and may also be found in urine and feces.
Ingestion of as little as 40
8 CARCINOGENICITY
AND MUTAGENICITY
Tellurium has not been reported as a human or
animal carcinogen. Mutagenicity studies are sparse,
and more information is needed before fi rm conclu-
sions can be made. In 1980, Kanematsu
et al
. carried
out rec assays on 127 metal compounds with
Bacillus
subtilis
to check their DNA-damaging capacity and
mutagenicity. Reverse mutation assays with
E. coli
and
Salmonella
strains showed that tellurium com-
pounds (Na
2
H
4
Te O
6
, Na
2
Te O
3
) were potent mutagens.
More recently Tiano
et al
. (2000) studied the ability of
three diaryl tellurides to protect trout (
Salmo irideus
)
erythrocytes against oxidative stress, induced ther-
mally and by variation of pH. At low concentrations
(<10
g of soluble tellurium may
be suffi cient to cause the garlic odor. Tellurium hex-
afl uoride is especially toxic by inhalation and may
produce respiratory depression, pulmonary edema,
cardiovascular collapse, and death in experimental
animals (Rumack, 2003).
After a signifi cant exposure to tellurium hexafl uo-
ride, chest X-ray, arterial blood gases, or pulse oxime-
try may be checked. Also hematological parameters
should be monitored.
For treatment of tellurium poisoning after oral expo-
sure, administration of activated charcoal as a slurry
(240 mL water/30 g charcoal) may be tried. The usual
dose is 25-100 g in adults, 25-50 g in children (1-12
years), and 1 g/kg in infants (<1 year old).
Most cases require no treatment after inhalational
exposure. As a fi rst step, the patient should be moved
to fresh air. If signs of cough or diffi culty in breath-
ing appear, check whether the patient has developed
respiratory tract irritation, bronchitis, or pneumoni-
tis. Oxygen supply and assisted ventilation may be
required. Bronchospasm can be treated with beta
2
ago-
nists and oral or parenteral corticosteroids (Rumack,
2003).
If the eyes have been exposed, they should be irri-
gated with copious amounts of room temperature
water for at least 15 minutes. If irritation, pain, swell-
ing, lacrimation, or photophobia persist, the patient
should be sent to a health care facility.
After dermal exposure, contaminated clothing
should be removed, and the exposed area should be
thoroughly washed with soap and water. If irritation
or pain persist, the patient should be sent to a health
care facility (Rumack, 2003).
µ
mol/L), all three tellurides had a protective
effect on DNA damage without altering the hemoly-
sis rate. In higher concentrations, they accelerated the
hemolysis rate and two of the diaryl tellurides were
strongly genotoxic.
There are also several experiments indicating an
anticarcinogenic effect of tellurium.
Bloomer
et al
. (1981) found in animal experiments
on mice that astatine-211-tellurium colloid (an alpha-
emitting radiocolloid) had a curative effect versus
experimental malignant ascites without causing undue
toxicity to normal tissue. Similarly,
in vivo
experiments
showed that Te signifi cantly prolonged the survival of
mice implanted with tumors (Sun
et al
., 1996).
Experiments on cancer cell lines have indicated a
protective effect by some organotellurium compounds
(e.g., diaryl telluride, alkyl aryl telluride, and dialkyl
telluride) (Engman
et al
., 1997; 2000; Powis
et al
., 1997;
Sun
et al
., 1996).
µ
9 DIAGNOSIS, PREVENTION,
AND TREATMENT OF TELLURIUM
POISONING
Tellurium intoxications are rare and almost exclu-
sively confi ned to occupationally exposed workers.
There have been no reports of workers dying from expo-
sure to tellurium or tellurium compounds. Accidental
deaths have occurred, however. Two of three patients
given sodium tellurite instead of sodium iodide during
10 STANDARDS—THRESHOLD
LIMIT VALUES
Elemental tellurium, Te dioxide and Te chloride, has
a TWA of 0.1 mg/m
3
(ACGIH TLV, 2006; OSHA PEL,
