Chemistry Reference
In-Depth Information
the more than 100 minerals of antimony that are found
in nature, the predominant one is stibnite (Sb
2
S
3
). The
principal world resources of antimony are Bolivia,
China, Mexico, Russia, and South Africa. The global
mine production of antimony in 2003 was 81,600 metric
tons and in 2004 it was 112,000 metric tons (estimated)
(U.S. Geological Survey, 2005).
4 ENVIRONMENTAL LEVELS AND
EXPOSURES
4.1 General Environment
4.1.1 Food and Daily Intake
Meat, freshwater fi sh, poultry, cereal, fruit, and veg-
etables contain about 1-10 ng/g wet weight (Health
Canada, 1997). A study of 12 table-ready foods showed
antimony content to range from 0.22-2.81
3.3 Uses
Antimony is a common constituent of metal alloys
(e.g., with lead and copper). In fact, the most important
use of antimony metal is as a hardener in lead stor-
age batteries (U.S. Geological Survey, 2005). Antimony
trioxide is used in fi re retardants formulations for plas-
tics, rubbers, textiles, paper, and paints; as an addi-
tive in glass and ceramic products; and as a catalyst in
the chemical industry. Antimony trisulfi de is used in
explosives, pigments, antimony salts, and ruby glass
(IARC, 1989). Antimony is a component of important
thermoelectric materials, which are being synthesized
and studied in the form of nanoparticles (Quarez
et al
.,
2005; Schlecht
et al
., 2006; Xie
et al
., 2004).
Pentavalent antimony has been used for more than 50
years to treat both visceral and cutaneous leishmaniasis,
parasitic diseases. One proposed mode of action is the
inhibition of energy metabolism and macromolecular
biosynthesis by means of inhibition of glycolysis and
fatty acid
g/kg
(Cunningham, 1987). Other reports on antimony lev-
els in food include pooled human milk, 13
µ
g/kg
(Iyengar
et al
., 1982); dorsal muscle of white suckers
and brown bullheads (fi sh) from two acidifi ed Adiron-
dack, New York, lakes, <0.014-0.20
µ
g/g, and <0.04-
<3.0 (dry wt.), respectively (Heit and Klusek, 1985);
crayfi sh, redbreast sunfi sh, stonerollers from a stream
in Tennessee that receives effl uent from a U.S. Depart-
ment of Energy facility, 20.24
µ
µ
g/kg, 8.73
µ
g/kg, and
18.51
g/kg, respectively (Rao
et al
., 1996); bivalves
from the Gulf of Mexico, <0.05
µ
g/g (wet wt.) (Reish,
et al
., 1983); mollusk tissue, crustacean tissue, and fi sh
tissue, 0.031-0.060, 0.018-0.116, and <0.009-0.010
µ
µ
g/g
(dry wt.) (Maher, 1986).
A study of nutrients in the diet conducted by the U.S.
Food and Drug Administration estimated the average
daily intake of antimony from food and water to be
4.6
g/day (Iyengar
et al
., 1987). Using data on levels
of antimony in the United States, Health Canada esti-
mated a daily intake for adults of 7.44
µ
-oxidation (Berman
et al
., 1985; 1987). Wyllie
et al
. (2004) demonstrated that antimony affects both
the thiol-buffering capacity and the thio redox poten-
tial within the cells of
Leishmania donovani
. The authors
suggest that Sb(V) in pentavalent antimonial drugs is
reduced to Sb(III), which is the biologically active form.
A major problem with pentavalent antimony drug
therapy is that increasingly larger doses for longer
durations are needed to be effective. In India, where
more than half the cases of leishmaniasis occur, large-
scale unresponsiveness to antimony treatment is occur-
ring (Murray, 2000; Thakur
et al
., 2004). In addition,
treatment is limited because of the toxicity of the drugs.
The results of one study suggest that residual Sb (III) in
the pentavalent meglumine antimonate drug is respon-
sible for the cytotoxicity of the drug, and the multi-
ple resistance-associated protein 1 (MRP-1)-mediated
resistance (Dzamitika
et al
., 2006). Although alternative
therapies have become available (Blum
et al
., 2004;
Murray, 2000; 2004; Sundar 2002), treatment with pen-
tavalent antimony compounds is still an accepted form
of therapy (Laguna, 2003; MMWR, 2003; 2004). Uzun
et
al
. (2004) described a technique of intralesional appli-
cation of meglumine antimonate solution to treat 890
patients with cutaneous leishmaniasis and reported an
effi cacy of 97.2% with no serious adverse side effects.
β
g of antimony
per day, with about 38% coming from drinking water
(Health Canada, 1997).
µ
4.1.2 Air, Soil, and Water
Antimony is present in the earth's crust at a con-
centration of about 0.2-0.5 mg/kg (McCutcheon
et al
.,
1995) and is released naturally into the atmosphere in
the form of particulate matter or adsorbed to particu-
late matter. It is estimated that 41% of antimony present
in air is due to natural sources, including wind-borne
soil particulates (32.5%), volcanoes (29.6%), sea salt
spray (23.3%), forest fi res (9.2%), and biogenic sources
(12.1%) (Nriagu, 1989). Anthropogenic sources include
nonferrous metal mining, nonferrous metal primary
and secondary smelting and refi ning (Crecelius
et al
.,
1974, Pacyna
et al
., 1984; Shotyk
et al
., 2005b), coal com-
bustion (Gladney
et al
., 1978), and refuse and sludge
combustion (Greenberg
et al
., 1978). Data regarding lev-
els of antimony in ambient air are insuffi cient to report
mean or median levels (ATSDR, 1992). The EPA (1992
revised 2000) has established a respiratory benchmark
dose (BMD) for antimony of 0.087 mg/m
3
and an RfC
for antimony trioxide of 0.0002 mg/m
3
.
