Lead (Pb), cobalt (Co) and chromium (Cr)
In the vineyard soils studied, lead (Pb) has average values (Table 3) of
21.9 mg·kg–1 in topsoil and 20.2
mg·kg–1 in subsoil. In some cases moderately high Pb
levels (31.6 mg·kg–1) are detected in some soils when
compared to the pedogeochemical baseline levels for Castilla-La Mancha
(19.3 mg·kg–1, Jiménez Ballesta et al. 2010). This
level is probably caused by the mechanized equipment used for works
carried out in the vineyard. However, these values are still far below
the total mean contents of other regions. For example, the lead content
in Castellon, Spain, is 56.1 mg·kg–1 (Peris et al.
2007), in the Champagne region of France Pb ranges from 76 (deep
horizon) to 141 mg·kg–1 (topsoil) (Chopin et al.
2008) and, in the case of the soils from Brestnik village, (Bulgaria),
values range from 72.6 mg·kg–1 for a depth of 0–10
cm to 61.4 mg·kg–1 (Huzum et al. 2012).
In the present study, the chromium (Cr) content is in the range between
71.0 and 29.9 mg·kg–1 (Table 3), with an average of
51.4 mg·kg–1, in top horizons, whereas in the subsoil
the values range between 70.9 and 25.5 mg·kg–1, with
an average of 50.0 mg·kg–1. The chromium contents in
soils worldwide differ greatly, i.e., in the range from 7 to 2221
mg·kg–1 (McBride 1994), and this depends mostly on
the parent material and soil mineralogy. Mîrlean et al. (2007) suggested
a variation between 8.2 (young plantation) and 77.9
mg·kg–1. In Portugal the Cr content has an average of
31 mg·kg–1 (from a minimum of 3 to a maximum value of
243 mg·kg–1) (Reis et al. 2007), while the values for
some areas in Spain are quite similar, with a total mean content of 32.2
mg·kg–1 (Peris et al. 2007). With some exceptions,
the chromium concentrations did not exceed the pedogeochemical baseline
value for soils of Castilla-La Mancha (Jiménez Ballesta et al. 2010).
The average cobalt (Co) content is near to 10.5
mg·kg–1 (Table 3) for both topsoil and subsoil, with
values slightly higher than for the soils of Castilla-La Mancha (5.8
mg·kg–1, Jiménez Ballesta et al. 2010). Cobalt is an
element that is essential to human health but excess amounts can cause
detrimental effects (ATSDR 2004). The transfer potential from soil to
the edible parts of plants is rather low (Luo et al. 2010).
The total average nickel (Ni) contents (Table 3) in the topsoil and
subsoil of Alcubillas are similar (34.7 vs 33.9
mg·kg–1, respectively). In terms of Ni values, a
total mean content of 19.9 mg·kg–1 was reported for
the Castellon area of Spain (Peris et al. 2007) and a mean value of 28
mg·kg–1 (with a minimum of 2
mg·kg–1 and a maximum of 539
mg·kg–1) was found in the Douro basin, Portugal (Reis
et al. 2007). The levels of Ni in Alcubillas are slightly higher than
the current Castilla-La Mancha pedogeochemical reference value (16.9
mg·kg–1).