Vanadium - Toxicology of Metals - page 884

commonly used for measuring vanadium in environ-
mental and biological samples (Begerov et al ., 2000).
Pyrzyn'ska and Wierzbicki (2004) reviewed problems
that may occur in ET-AAS, such as tailing of the absorb-
ance signal, carbide formation, and acid interferences.
However, if vanadium levels are to be monitored in
unpolluted areas or in nonexposed people, the detec-
tion levels of GF-AAS may not be suffi ciently low. Nei-
ther are direct spectrophotometric methods sensitive
and/or selective enough without sample pretreatment
(Pyrzyn'ska and Wierzbicki, 2004). Solid-phase spec-
trometry has higher sensitivity and lower detection
limits than direct methods.
As is the case with other trace metals, reliable anal-
yses of low vanadium contents require good quality
control programs, including careful contamination-
free sample collecting and processing as well as a sen-
sitive method of analyzing (Cornelis et al ., 1980; 1981;
Sabbioni et al ., 1996).

The aerospace market is a big user. Vanadium pen-
toxide and metavanadates are important catalysts in
inorganic and organic chemical industries (e.g., in sul-
furic acid and plastics production). Although catalytic
uses of vanadium are of great technological value, they
account for <1% of the vanadium consumption (e.g.,
approximately 0.3% of the vanadium consumption in
the United States (Fisher, 1975; U.S. Bureau of Mines,
1994). Vanadium pentoxide is also used in some pig-
ments and inks in the ceramic industry (IPCS, 2001).

4 ENVIRONMENTAL LEVELS
AND EXPOSURES

4.1 General Environment

4.1.1 Food

Food is the major source of exposure of vanadium
for the general population. Vanadium levels in the
diet from fi ve regions in the United States ranged from
30.9 ± 1.5 in the Southeast to 50.5 ± 1.5

3 PRODUCTION AND USES

g/kg dry weight
in the West (Harland and Harden-Williams, 1994).
WHO (1996) reported daily intakes between 6 and 30
µ

µ

3.1 Production
There are approximately 65 vanadium minerals, but
commercial mining is restricted to carnotite (potas-
sium uranyl vanadate), vanadinite, roscoelite, and
patronite (ATSDR, 1997). Most vanadium is, however,
produced from residues of iron and titanium extraction
(Heslop and Jones, 1976). A signifi cant source of vana-
dium is the extraction from the furnace (boiler) ash of
power plants that are fueled with residual oils (Exley
et al ., 1966). The world production of vanadium has
increased from approximately 29,000 tons in 1978 (U.S.
Bureau of Mines, 1979) to 44,000 tons in 2004 (US Geo-
logical Mineral Survey Resources Program, 2004). The
major producers are China, South Africa, and Russia.
The technology of vanadium production involves
roasting of vanadium-bearing ores with a sodium salt,
water extraction of the resulting sodium metavanadate
(NaVO 3 ), and precipitation to obtain sodium hexavana-
date, which on fusion yields technical grade vanadium
pentoxide. Reduction of V 2 O 5 with calcium or alumo-
thermic reduction combined with electron-beam melt-
ing is used to obtain vanadium metal (Fisher, 1975).

g. Myron et al . (1977), Byrne and Kosta (1978), and
Evans et al . (1985) reported vanadium concentrations
in food ranging from 1-30 g/kg fresh weight. Bev-

erages, fats and oils, milk, fresh fruits, and vegetables
had the lowest levels, ranging from 1-7

µ

µ g/kg. Higher

levels, 7-30 g/kg, were found in whole grains, sea-

food, and meats. The highest concentrations of vana-
dium were recorded in parsley, dry mushrooms, and
oysters. Vanadium concentrations in French and Cali-
fornian wines were reported to range from 7.0-90.0
µ

µ

g/L in red, and from 6.6-43.9 µ g/L in white wines

(Teissedre et al ., 1998).

4.1.2 Air

Combustion of fossil fuels, especially of crude oils,
is the most dominant source of emissions of vanadium
into the atmosphere (Mamane and Pirrone, 1998). The
emissions from oil combustion are estimated to be
58,500 tons per year, which accounts for 91% of the total
global emissions from both natural and anthropogenic
sources (IPCS, 2001). The EPA (1977) and Schroeder
et al . (1987) have reviewed vanadium concentrations in
air up to the early 1980s. The range of concentrations
was great and varied from 0.4-1460 ng V/m 3 in urban
air in the United States and 11-73 ng/m 3 in Europe.
The concentrations were lower in rural areas.
There is still a wide concentration range of levels
of vanadium reported in air from 0.5-1230 ng/m 3 in
urban locations worldwide (Mamane and Pirrone,

3.2 Uses
Approximately 85% of vanadium is used in the
production of special steels and alloys, some of which
have a potential application for fuel cladding in nuclear
power production. There is an increasing demand for
vanadium in high-strength low-alloy (HSLA) steels.