348
Trace Elements in Abiotic and Biotic Environments
53.4 AIR
Vanadium concentrations in the atmosphere vary broadly from <0.002 to 200 ng/m 3
in industrial/urban areas (Table 53.1). Air from Spitzbergen contains V within the
range of 0.4–2 ng/m 3 , and from the remote regions of the United Kingdom, it varies
from 5 to 10 ng/m 3 (Cawse vide Kabata-Pendias and Mukherjee 2007). Air in rural
regions of the United States contained V, during the period 1965–1969, from <1 to
64 ng/m 3 (ATSDR 2012d).
Vanadium input to the atmosphere from natural sources (soil dust, marine
aerosols) is estimated to be 65 kt/yr, and about the same amounts of V enter the
atmosphere from industrial sources (Anke 2004b).
Increased V concentrations in air during cold seasons, compared with warm seasons, indicate its sources from burning fossils fuels, coal, wood, and solid wastes
(ATSDR 2012d). Large amount of V-rich atmospheric particles and V dissolved in
rain are its significant sources in soils. The wet deposition of V in Sweden is estimated to be 5.7 g/ha/yr (Eriksson 2001a).
Mosses collected in Norway, during 1990–1995, contained V within <10–16,000
μg/kg, at an average value of 2,800 μg/kg, with the highest contents in samples from
the vicinity of the peat-fired plant (Berg and Steinnes 1997).
53.5 PLANTS
Phytoavailability of V is a function of its concentration in soil solution. Plants take
up V relatively easily, especially from acidic soils. This indicates that VO 2+ species, occurring under acidic conditions, are more easily absorbed by roots than
V and HV
3
4
2 species, which predominate in neutral and alkaline soils. In general,
cationic V species are more easily available to plants than anionic species. However,
both species may be biotransformed and chelated by some compounds, and thus
become more phytoavailable.
Vanadium is not yet considered to be an essential element for higher plants.
3−
2+
However, there are observations that vanadate (VO ) and vanadyl VO ) ions
4
(
form various complexes, which have both stimulating and inhibiting impacts on
several enzymes. The biotransformation of vanadate to vanadyl species may occur
during uptake by plants (Selim 2012). It is a specific catalyst that may substitute
Mo function in the N 2 fixation by some microorganisms, especially rhizobium
bacteria.
The contents of V in food plants vary broadly and are significantly elevated in
plants from V-contaminated regions. The highest V contents in the aboveground vegetables are reported to be in spinach, 533–840 μg/kg, and in lettuce, 280–710 μg/kg.
The elevated V contents, 50–2000  μg/kg, are also noticed in wild mushrooms
(ATSDR 2012d). The mean V contents of cereal grains are (in μg/kg) as follows:
wheat, 9; winter wheat, 2.2; and barley, 3.4 (Eriksson 2001a).
There is no much evidence for the V toxicity to plants, especially under field
conditions. Its increased levels, up to 3000 μg/L nutrient solution, under greenhouse
conditions, reduce the growth of collard (Brassica aleracea). The symptoms of V
toxicity (chlorosis and dwarfing) may appear at its content of 2000 μg/kg in some