Chemistry Reference
In-Depth Information
CHAPTER
28
Germanium
OBAID M. FAROON, L. SAMUEL KEITH, HUGH HANSEN, AND BRUCE A. FOWLER
ABSTRACT
germanium hair level showed a variation of the fi ber
sizes of the skeletal muscles with dense cytoplasmic
bodies, reduction of cytochrome
c
oxidase activity,
mitochondrial myopathies, and vacuolar degenera-
tion; similar fi ndings were observed in rats treated
with germanium oxide.
High doses of germanium compounds (taken as
supplements) induced remarkable lactic acidosis,
hydropic degeneration of the proximal convoluted
tubules with presence of inclusion bodies, and some
cellular necrosis and subsequent renal failure; howev-
er, the renal glomeruli and the renal interstitial tissue
seemed normal. Neurological effects involved nega-
tive deep tendon refl exes in the lower extremities and
persistent tingling sensation of the palms and soles.
In addition to severe cardiac dilation, vacuolar degen-
eration of myocardial cells and interstitial edema were
observed.
Inhalation is the main route of exposure under
occupational conditions; the main source of germani-
um for the general population is food.
Short reviews of the toxicology of germanium and
its compounds have been published by Mogilevskaja
(1973), Underwood (1977), and Aldridge (1978). Recent
reviews on the adverse health effects were conducted
by Ohri
et al
. (1993) and Tao and Bolger (1997).
Animal experimental data show that germanium
compounds, both inorganic and organic, are rapidly
and almost completely absorbed from the lungs and
the gastrointestinal tract. The distribution among
the organs and tissues is fairly uniform, and there is
no evidence of preferential uptake or accumulation.
Absorbed germanium is rapidly excreted, mainly in
urine. Data on biological half-times are inadequate, but
for the rat the whole-body retention half-time has been
estimated at approximately 1.5 days.
Germanium tetrachloride is a strong irritant of
the respiratory system, skin, and the eye, possibly
because it is easily hydrolyzed producing hydrogen
chloride; in mice, high-level inhalation exposures
caused necrosis of the tracheal mucosa, bronchitis, and
interstitial pneumonia. Systemic toxicity of germa-
nium compounds is comparatively low. The specifi c
target or critical organs cannot be identifi ed, but ne-
phropathy, neuropathy, and hepatotoxicity are usu-
ally observed. Trialkylgermanium compounds are
less toxic than the corresponding lead or tin alkyls.
Germanium compounds do not seem to be carcino-
genic. Dimethylgermanium oxide is teratogenic in
chickens, but sodium germinate has not produced
malformations in hamsters.
There is little information on the toxicity of inor-
ganic germanium compounds to man, except that
germanium tetrachloride may produce skin irrita-
tion. In clinical trials, spirogermanium, an organo-
germanium antitumor agent, has been shown to be
neurotoxic. Recently, germanium was reported as
having anticancer effects. A patient with 175 ppm of
1 PHYSICAL AND CHEMICAL PROPERTIES
Germanium (Ge): atomic weight, 72.59; atomic number,
32; density, 5.32 (25°C); melting point, 937.4 °C; boiling
point, 2830°C; in elemental form it is a grey-white,
brittle solid; oxidation states +2 and +4. It belongs to
