Vanadium - Toxicology of Metals - page 887

Roshchin et al . (1980) and Maroni et al . (1984) reported
a correlation between the concentrations of vanadium
in the urine of workers and the levels of exposure.
Vanadium concentrations in urine were measured
over an 8-day period in 20 boilermakers during the
cleaning of a large oil-fi red boiler (Hauser et al ., 1998).
Urine samples were collected in the morning (start of
shift) and at the end of shift, as well as on the following
Monday after a 38-hour time period without potential
exposure. Air vanadium concentrations, estimated with
personal sampling devices and work history diaries,
ranged from 0.36-32.19

solution of 5% VOSO 4 had a sensitizing effect on guinea
pigs' skin. Skin is, however, probably a minor route for
vanadium absorption in man (EPA, 1977). According
to IPCS (2001), there are no data relating to potential
systemic toxicity through dermal exposure.

5.2 Distribution
Absorbed vanadate (VO 4 2+ ) is converted to vanadyl
(VO 2+ ), although the vanadate form also exists (Fantus
et al ., 1995). Vanadate is transported in the serum mainly
bound to transferrin (Harris et al ., 1984; Sabbioni and
Marafante, 1981), whereas vanadyl is carried by albu-
min. Extracellular vanadium will be in the vanadate
(5+) state, and intracellular vanadium will most likely
be in the vanadyl (4+) state (Rubinson, 1981).
The total body pool of vanadium has been estimated
to be 100-200

g V/m 3 .
The authors found an increase in vanadium urine con-
centrations from 0.83 mg-1.52 V/g creatinine during the
fi rst working day. There was no signifi cant correla-
tion between the concentration of vanadium in the air
(as PM 10 ) and the concentration in urine. The authors
concluded that this might be due to a misclassifi cation
because of lack of information on the use of personal
protective devices, the use of spot urine samples versus
cumulative urine samples, and incomplete vanadium
clearance from each previous day's exposure.

µ g V/m 3 , with a median of 18.5 µ

g, depending on the content in the lungs
(Byrne and Kosta, 1978). Inhaled vanadium may con-
centrate in the lung tissue because of poor absorption,
because it is most often in an insoluble form (Schroeder,
1970). Tipton and Shafer (1964) have reported that the
vanadium content in the lungs seems to increase with
age. Brown and Taylor (1975) estimated the lung con-
centration to be 0.01-1 mg/kg; Byrne and Kosta in 1978
found levels to be 19-140 ng/g fresh weight (NAA).

µ

5.1.2 Ingestion

5.1.2.1 Animal Studies
The uptake of radioactive V 2 O 5 given orally to rats
was 2.6% (Conklin et al ., 1982). Parker and Sharma
(1978) and Roshchin et al . (1980) obtained similar
results. Later studies have confi rmed a poor gastroin-
testinal (GI) absorption (approximately 3% of admin-
istered dose; Ramanadham et al ., 1991). These authors
reported that absorption of vanadate (V 5+ ) was higher
than that of vanadyl (V 4+ ). Bismaltolato-oxovanadium
(IV) (BMOV), a synthetic organic vanadium compound
with insulin-mimetic action, was absorbed to a higher
extent than vanadyl sulfate in rats. Tissue uptake was
approximately 2-3 times higher after oral administra-
tion of BMOV than after vanadyl sulfate (Setyawati
et al ., 1998).

5.2.1 Animal Studies

The absorption, distribution, and retention of the
radioactive isotope 48 V 4+ administered by four differ-
ent routes were studied in albino rats by Roshchin et al .
(1980). There was a fast (30 minute) distribution to all
internal organs after intratracheal, subcutaneous, or
intraperitoneal administration. The greatest amount
of vanadium accumulated in bone tissues after intrat-
racheal administration (9.7% of administered dose),
and there was a delay in postexposure increases of the
kidney concentration of vanadium. The highest kid-
ney concentration was found on days 8-16 and was
approximately 4.5% of the dose given. Retention in the
lungs occurred mainly after IT instillation.
In a number of other reports from the 1980s that
were reviewed by the UK Health & Safety Executive
(HSE, 2002), the translocation and clearance of intrat-
racheally instilled vanadium compounds in rodents
were analyzed. Common fi ndings were an initial rapid
clearance from the lungs into blood, liver, and bone,
followed by a slower clearance. These studies also
indicated that there was a signifi cant absorption of
vanadium from the lungs. Cohen et al . (1996) reported
a tendency for vanadium to accumulate in the lung of
rats in a time-dependent manner. Similar fi ndings with
a proportional increase in the lung burden of vanadium
with time were reported by Dill et al . (2004).

5.1.2.2 Human Studies
The daily dietary intake of vanadium is in the range
of 10-60

g (Harland et al ., 1994). In general, ingested
vanadium compounds are poorly absorbed. Curran
et al . (1959) reported that approximately 0.1-1% of the
very soluble oxytartarovanadate was absorbed from
the human GI tract. The ICRP (1960) estimate for the
absorption of soluble vanadium compounds was 2%.

µ

5.1.3 Skin

According to Stokinger (1967), solutions of soluble
vanadium compounds may be absorbed through the
skin of rabbits. Roshchin et al . (1982) reported that a