Entry into the marine environment
Vanadium (V) is a greyish metal that occurs in
the form of two natural isotopes 50V and 51V. It
forms oxidation states of -1, 0, +2, +3, +4, and
+5, the oxidation states +3, +4, and +5 being the
most common. Oxidation state +4 is the most stable.
Metallic vanadium does not occur in nature. Over
70 vanadium minerals are known, carnatite and vanadinite
being the most important from the point of view
of mining. Vanadium is mainly (75 - 85%) used in
ferrous metallurgy as an alloy additive in various
types of steel. Its use in non-ferrous metals is
important for the atomic energy industry, aircraft
construction, and space technology. Vanadium is
also widely used as a catalyst in the chemical industry,
where vanadium pentoxide and metavanadates are especially
important for the production of sulfuric acid and
plastics. Small quantities of vanadium are used
in a variety of other applications (WHO 1988).
Power- and heat-producing plants using fossil fuels
(petroleum, coal, oil) cause the most widespread
discharge of vanadium into the environment. Burning
of coal wastes or dumps of coal dust in mining areas
are other sources of vanadium discharge into the
atmosphere. In the distillation and purification
of crude oil, most of the vanadium remains in the
residues. Burning of distilled petroleum fuels contributes
less vanadium to the atmosphere (WHO 1988).
Recorded levels in the marine
Vanadium is not commonly monitored for in UK marine
waters and was not included in the National Monitoring
Programme (MPMMG 1998). Grimwood and Dixon (1997)
reported some values for total vanadium at two sites
in the North East region of the Environment Agency
(ranging from an annual average of 1mg
l-1 to <20mg
Fate and behaviour in the marine
Most of the vanadium entering sea water is in suspension
or adsorbed on colloids. It does not react chemically
with sea water but passes mechanically through it.
This is reflected in its distribution on the sea
bed in the form of silt. Only about 10% of the vanadium
is present in a soluble form. The very low concentrations
of vanadium in sea water indicate that vanadium
is continuously removed from sea water, but the
actual mechanisms are largely unknown. Vanadium
that accumulates in ascidians, holothurians, and
in marine algae will end up in the silt (WHO 1988).
Effects on the marine environment
Toxicity to marine organisms
An exhaustive literature review on the toxicity
of vanadium to marine organisms has not been carried
out for the purposes of this profile. The information
provided in this section is taken from existing
review documents (Mance et al 1984 and Grimwood
and Dixon 1997). The most sensitive groups of organisms
have been identified.
The current EQS adopted in UK legislation (HMSO
1989) is a value of 100 mg l-1, expressed as a total annual average
concentration which Mance et al proposed
in 1988. They found few data and these only related
to acute toxicity. Too few data were available to
assess which group of organisms exhibited greatest
sensitivity. The EQS was derived by applying a safety
factor of 100 to the lowest, most reliable LC50
of 10,000 mg
l-1, reported for the annelid
Nereis diversicolor following 9 days exposure.
It was recommended that the EQS should be reviewed
once a larger dataset became available.
More recently, Grimwood and Dixon (1997) reviewed
data on the saltwater toxicity of vanadium since
the report by Mance et al (1984). They found
no reliable toxicity data that indicated higher
sensitivity of saltwater organisms had been reported
for vanadium. They recommended that the EQS of 100
(total annual average) was appropriate for the protection
of all saltwater life, although where there was
concern that the health of communities in sites
of nature conservation importance may be compromised
as a result of the presence of particularly sensitive
species, a lower value may be used as a guideline.
However, in the absence of any new toxicity data,
it was not possible to make any recommendations
on such a value.
Mance et al (1988) reviewed the limited
information on the bioaccumulation of vanadium and
reported the majority of BCFs below 100, indicating
that bioaccumulation of vanadium is not likely to
be a problem.
Potential effects on European
Potential effects include:
- acute toxic effects on marine organisms at concentrations
above the EQS of 100 mg l-1 (annual average) of dissolved
vanadium in the water column.