387
V. arsenica was 1877 mg kg
−1
and 2831 mg kg
−1
, for V. allchariensis 312 mg kg
−1
and 459 mg kg
−1
, and for V. macedonica 365 mg kg
−1
and 567 mg kg
−1
, respectively.
The appropriate mass fractions of Tl in roots and stems of V. arsenica were 10% and
15.5%, for V. allchariensis 7–18.7% and 9.4–12.2%, and for V. macedonica 4.7%
and 7.5%, respectively.
For animals and humans, the major pathway of exposure is the ingestion of plant
species that has grown on Tl-contaminated soils (Scheckel et al. 2004). When Tl is
present in soils, it may be easily taken up by plants because it is generally present as
thermodynamically stable Tl(I), an analogue of potassium (Madejon et al. 2007).
Thallium(I) has a very low stability that is constant with both organic and inorganic
ligands (Kaplan and Mattigod 1998; Nriagu 1998) and therefore should be easily
extractable from the leaves (Scheckel et al. 2004). However, transport of K and Tl
appeared to occur in different ways because Tremel et al. (1997) cannot find any
correlation between Tl and K in seeds and suggested that the explanation of the
behavior of Tl in the current study is probably similar to these indications.
From the results given in Table 13.1 and Fig. 13.5a–c, it can be seen that all of
the Viola species are able to accumulate toxic elements and distribute them into all
plant parts, especially with regard to the accumulation of As and Tl. The content of
As was significantly higher in the roots and seeds, but the content of Sb was considerably lower compared with the content of As and Tl. With no significant differences between the different parts of the plant, the content of Tl was significantly
higher in the leaves and flowers in all Viola species.
For the Viola endemic species, previous investigations were done, but only for
the accumulated As (not for Sb and Tl), and it was pointed out that the content of As
was significantly higher in the compared roots (Stevanović et al. 2010). It should be
emphasized that in the work of Stevanović et al. (2010) the plant species are divided
in roots and shoots and analyzed only for As.
All soil samples were collected from the same locations as the Viola species, and
they were also analyzed for the same elements (Table 13.2). It can be seen that all
three Viola species were exposed to the excess amount of As present in the soil, and
the accumulation of As in this endemic species is significantly high for that reason.
From the results given in Table 13.2, it can be noticed that the content of As in
soil samples was in the range from 86 to 12,775 mg kg
−1
with the median value of
5875 mg kg
−1
. The content of the Sb in the same soil samples ranged from 21 to
116 mg kg
−1
(median 37 mg kg
−1
), while the content of Tl ranged from 14 to
2140 mg kg
−1
with the median of 431 mg kg
−1
. Based on previous geological surveys of this locality, it may be concluded that such significantly high contents of
these elements are not related to any anthropogenic activities and that their sources
are mainly from natural phenomena (Volkov et al. 2006; Boev and Jelenkovic 2012).
Namely, it is known that the presence of Tl in the ore from this region (the northern
part of the locality of Allchar) ranges from 0.1 to 0.5%, with Sb up to 2.5% and As
level of about 1.5% (Volkov et al. 2006).
Different degrees of availability can be estimated depending on the extracting
power of the reagent that is used. We decided to investigate bioavailability of the
analyzed elements by the soil extraction with water, which only provides informa13 Accumulation Abilities of Endemic Plant Species from the Vicinity of an As-Sb-Tl…
V. arsenica was 1877 mg kg
−1
and 2831 mg kg
−1
, for V. allchariensis 312 mg kg
−1
and 459 mg kg
−1
, and for V. macedonica 365 mg kg
−1
and 567 mg kg
−1
, respectively.
The appropriate mass fractions of Tl in roots and stems of V. arsenica were 10% and
15.5%, for V. allchariensis 7–18.7% and 9.4–12.2%, and for V. macedonica 4.7%
and 7.5%, respectively.
For animals and humans, the major pathway of exposure is the ingestion of plant
species that has grown on Tl-contaminated soils (Scheckel et al. 2004). When Tl is
present in soils, it may be easily taken up by plants because it is generally present as
thermodynamically stable Tl(I), an analogue of potassium (Madejon et al. 2007).
Thallium(I) has a very low stability that is constant with both organic and inorganic
ligands (Kaplan and Mattigod 1998; Nriagu 1998) and therefore should be easily
extractable from the leaves (Scheckel et al. 2004). However, transport of K and Tl
appeared to occur in different ways because Tremel et al. (1997) cannot find any
correlation between Tl and K in seeds and suggested that the explanation of the
behavior of Tl in the current study is probably similar to these indications.
From the results given in Table 13.1 and Fig. 13.5a–c, it can be seen that all of
the Viola species are able to accumulate toxic elements and distribute them into all
plant parts, especially with regard to the accumulation of As and Tl. The content of
As was significantly higher in the roots and seeds, but the content of Sb was considerably lower compared with the content of As and Tl. With no significant differences between the different parts of the plant, the content of Tl was significantly
higher in the leaves and flowers in all Viola species.
For the Viola endemic species, previous investigations were done, but only for
the accumulated As (not for Sb and Tl), and it was pointed out that the content of As
was significantly higher in the compared roots (Stevanović et al. 2010). It should be
emphasized that in the work of Stevanović et al. (2010) the plant species are divided
in roots and shoots and analyzed only for As.
All soil samples were collected from the same locations as the Viola species, and
they were also analyzed for the same elements (Table 13.2). It can be seen that all
three Viola species were exposed to the excess amount of As present in the soil, and
the accumulation of As in this endemic species is significantly high for that reason.
From the results given in Table 13.2, it can be noticed that the content of As in
soil samples was in the range from 86 to 12,775 mg kg
−1
with the median value of
5875 mg kg
−1
. The content of the Sb in the same soil samples ranged from 21 to
116 mg kg
−1
(median 37 mg kg
−1
), while the content of Tl ranged from 14 to
2140 mg kg
−1
with the median of 431 mg kg
−1
. Based on previous geological surveys of this locality, it may be concluded that such significantly high contents of
these elements are not related to any anthropogenic activities and that their sources
are mainly from natural phenomena (Volkov et al. 2006; Boev and Jelenkovic 2012).
Namely, it is known that the presence of Tl in the ore from this region (the northern
part of the locality of Allchar) ranges from 0.1 to 0.5%, with Sb up to 2.5% and As
level of about 1.5% (Volkov et al. 2006).
Different degrees of availability can be estimated depending on the extracting
power of the reagent that is used. We decided to investigate bioavailability of the
analyzed elements by the soil extraction with water, which only provides informa13 Accumulation Abilities of Endemic Plant Species from the Vicinity of an As-Sb-Tl…