Chemistry Reference
In-Depth Information
for blood (0.15-0.3
µ
g/L; van Montfort
et al
., 1979) and
organic tellurium compounds (e.g., dimethyl telluride)
may be responsible for the garlic-like odor to breath,
possible by inhibiting the enzyme squalene epoxidase
(Taylor, 1996).
urine (<0.1-10
g/L; Fodor and Barnes, 1983; Koba-
yashi and Imaizumi, 1991). Only few and incomplete
data are, however, available from the working environ-
ment and regarding the relationship between tellurium
in air, blood, and urine. Accordingly, it is not clarifi ed
whether these relationships are linear or nonlinear.
µ
7.2 Systemic Effects and Dose-Response
Relationships
7.2.1 Animals
6.3 Biomarkers of Effects
Quantitative data on the relationship between inter-
nal dose and adverse health effects are still lacking
and, thus, risk assessment cannot be carried out. More
studies are needed to produce data that can be used
for dose-effect and dose-response studies in humans.
An early and classical sign is the garlicky odor of the
breath, which may appear after ingestion of 40
Acute and subacute studies of systemic toxicity
of tellurium and tellurium compounds in rats show
a number of symptoms (e.g., listlessness, decreased
locomotor activity, somnolence, anorexia, weight loss,
gastrointestinal disturbances, changes in fur, and occa-
sionally epilation and hind leg paralysis) (Amdur, 1958;
DeMeio, 1946; DeMeio and Jetter, 1948; Sandrackaja,
1962a).
µ
g of
soluble tellurium.
7.2.1.1 Liver
Studies on rats, rabbits, and Peking ducks exposed
to different tellurium compounds (tellurium dioxide,
tellurium tetrachloride, sodium tellurite) showed
liver changes ranging from simple cellular swelling
to hydropic and fatty degeneration and cell necrosis
(Carlton and Kelly, 1967; DeMeio and Jetter, 1948;
Elnicnyh and Lencenko, 1969; Lencenko, 1967; San-
drackaja, 1962b). Other changes detected included
impairment of glycogen function, detoxifying func-
tions, and of protein metabolism as indicated by dose-
related reduction of galactose tolerance, hippuric
acid excretion, decrease of albumin/globulin ratio in
serum, urinary bilirubin excretion, and inhibition of
cholinesterase (Lencenko, 1967; Lencenko, and Plotko
1969; Sandrackaja, 1962b).
7 EFFECTS AND DOSE-RESPONSE
RELATIONSHIPS
Tellurium is not regarded as an essential trace ele-
ment. Thus, tellurium defi ciency is not a problem in
humans or animals.
7.1 Local Effects and Dose-Response
Relationships
7.1.1 Animals
Inhalation of elemental tellurium and tellurium
dioxide aerosols (10, 50, and 100 mg/m
3
; 2 hours daily;
13-15 weeks) caused desquamatory bronchitis and
lobar pneumonia in rats (Izrael'son, 1973; Sandrackaja,
1962a). Inhalation of high concentrations of tellurium
hexafl uoride (50 mg/m
3
; 1 hour) produced pulmonary
edema in rabbits, guinea pigs, rats, and mice (Kim-
merle, 1960). Decreased body weights and black depos-
its in lung tissue have been observed in male Harlan
Wistar albino rats 6 months after a single intratracheal
instillation of tellurium and tellurium-dioxide (Geary
et al
., 1978).
7.2.1.2 Kidney
Rats exposed to tellurium dioxide through inha-
lational exposure (condensation aerosol, 10 and
50 mg/m
3
, 2 hours daily, 13-15 weeks) showed signs
of focal vacuolization of cells and hemorrhage in the
glomeruli, followed by albuminuria and hematuria
(Sandrackaja, 1962a,b). In another study, rats were fed
tellurium dioxide (375-1500 mg Te/kg diet, 24-128
days; De Meio and Jetter, 1946). The treatment resulted
in changes ranging from cellular swelling to necrosis,
accompanied in some rats by oliguria and anuria. The
fi ndings indicated severe lesions in the proximal tubu-
lar epithelium (De Meio and Jetter, 1948).
7.1.2 Humans
Exposures to tellurium vapor and hydrogen tel-
luride may lead to irritation of the respiratory tract
(Izrael'son, 1973; Popova
et al
., 1965), leading to bron-
chitis and pneumonia (Lewis, 1996). Dermatitis and
blue-black skin discoloration may occur from exposure
to tellurium hexafl uoride. Ingestion of no more than
40
7.2.1.3 Blood
Rats exposed to tellurium dioxide and elemen-
tal tellurium aerosol (50-100 mg/m
3
, 2 hours daily,
13-15 weeks) developed a normochromic, possibly
g of soluble tellurium may lead to the unusual
breath odor. It has been suggested that the formation of
µ
