3 The Evaluation of TM Atmospheric Deposition in Albania
37
3.4.6 Lanthanides
Lanthanides (Ln) are a group of 15 chemical elements from Lanthanum La (Z =
57) to Lutetium Lu (Z = 71). Due to the similar chemical-physical properties of Ln
with Yttrium, Y (Z = 39) and Scandium, Sc (Z = 21) they form the group of rare
earth elements (REE). REEs are typical representatives of the crustal elements. Due
to the similar chemical-physical properties of REEs these elements are geochemicaly associated and could be found together in the environment. They are also
naturally associated with minerals naturally containing radioactive elements, such
as uranium and thorium. REEs play an essential role in modern technology such
as metallurgical processing, alloying, electronics applications (e.g., hybrid vehicles,
wind turbines, cell phones, computer components, electric motors, specialty glass
and lenses) and military applications and products (EPA/600/R-12/572 2012). There
are limited toxicological or epidemiological data regarding the human health effects
of REEs (EPA/600/R-12/572 2012). The total REE content of soil surfaces is up
to 100–200 mg kg
−1 (Tyler 2004; Liang et al. 2005). Higher contents are mainly
derived by human activity, low mobility of REEs and their high adsorption to soils
(Cao et al. 2000; Li et al. 2013).
The REEs of present study show moderate variation (CV % < 70%, except Eu, Gd
and Tm which show high variations CV % ≥ 95%). High and significant correlations
(r > 0.6, p < 0.01) were mostly found between REEs, except Eu, Tb and Dy that show
moderate and significant correlations (r = 0.4 − 0.6, p < 0.01) with other REEs. Lu
did not show correlation with other REEs. It was probably due to the very low content
of Lu in moss samples, lower than the analytical LOQ of the method that leads to
the high uncertainty and high RSD% (RSD % > 32%) of concentration data of Lu.
The values of descriptive statistic parameters (mean, median, descriptive statistic,
CV %, skewness, kurtosis, minimum and maximum) of light (LREEs; the sum of
La to Eu content) and heavy (HREEs; the sum of Gd to Lu content) REEs in moss
samples are summarized in Table 3.1. The concentration data of RREs show moderate
variation among sampling sites suggesting consistent distributions in the all territory.
The abundance of REEs showed the following sequence in moss samples: Ce > La
> Nd > Gd > Dy > Yb > Eu > Tb > Tm > Lu by indicating higher content of LREEs
compared to HREEs. Due to the similar ionic radii and electron configurations, REEs
have very similar chemical characteristics and show similar associations or migrate
as a whole group of elements (Wang et al. 2019). Under natural conditions, the
behaviour and the content of REEs in environmental compartments is affected by
various factors such as pH, redox conditions and organic matters (Wang et al. 2019).
The spatial analysis plots of Sc, La, Ce and Yb (linear model) (Fig. 3.9) looks likely
homogenous throughout the country (Sc = 0.918 − 0.00121 × n, La = 2.165 −
0.0052 × n, Ce = 4.068 − 0.0106 × n, and Yb = 0.184 − 0.00053 × n, n represents
the number of sampling site).
The distribution pattern of La and Ce looks almost uniform over the country, with
the exception of some local variability with higher degree of selected REEs contents
37
3.4.6 Lanthanides
Lanthanides (Ln) are a group of 15 chemical elements from Lanthanum La (Z =
57) to Lutetium Lu (Z = 71). Due to the similar chemical-physical properties of Ln
with Yttrium, Y (Z = 39) and Scandium, Sc (Z = 21) they form the group of rare
earth elements (REE). REEs are typical representatives of the crustal elements. Due
to the similar chemical-physical properties of REEs these elements are geochemicaly associated and could be found together in the environment. They are also
naturally associated with minerals naturally containing radioactive elements, such
as uranium and thorium. REEs play an essential role in modern technology such
as metallurgical processing, alloying, electronics applications (e.g., hybrid vehicles,
wind turbines, cell phones, computer components, electric motors, specialty glass
and lenses) and military applications and products (EPA/600/R-12/572 2012). There
are limited toxicological or epidemiological data regarding the human health effects
of REEs (EPA/600/R-12/572 2012). The total REE content of soil surfaces is up
to 100–200 mg kg
−1 (Tyler 2004; Liang et al. 2005). Higher contents are mainly
derived by human activity, low mobility of REEs and their high adsorption to soils
(Cao et al. 2000; Li et al. 2013).
The REEs of present study show moderate variation (CV % < 70%, except Eu, Gd
and Tm which show high variations CV % ≥ 95%). High and significant correlations
(r > 0.6, p < 0.01) were mostly found between REEs, except Eu, Tb and Dy that show
moderate and significant correlations (r = 0.4 − 0.6, p < 0.01) with other REEs. Lu
did not show correlation with other REEs. It was probably due to the very low content
of Lu in moss samples, lower than the analytical LOQ of the method that leads to
the high uncertainty and high RSD% (RSD % > 32%) of concentration data of Lu.
The values of descriptive statistic parameters (mean, median, descriptive statistic,
CV %, skewness, kurtosis, minimum and maximum) of light (LREEs; the sum of
La to Eu content) and heavy (HREEs; the sum of Gd to Lu content) REEs in moss
samples are summarized in Table 3.1. The concentration data of RREs show moderate
variation among sampling sites suggesting consistent distributions in the all territory.
The abundance of REEs showed the following sequence in moss samples: Ce > La
> Nd > Gd > Dy > Yb > Eu > Tb > Tm > Lu by indicating higher content of LREEs
compared to HREEs. Due to the similar ionic radii and electron configurations, REEs
have very similar chemical characteristics and show similar associations or migrate
as a whole group of elements (Wang et al. 2019). Under natural conditions, the
behaviour and the content of REEs in environmental compartments is affected by
various factors such as pH, redox conditions and organic matters (Wang et al. 2019).
The spatial analysis plots of Sc, La, Ce and Yb (linear model) (Fig. 3.9) looks likely
homogenous throughout the country (Sc = 0.918 − 0.00121 × n, La = 2.165 −
0.0052 × n, Ce = 4.068 − 0.0106 × n, and Yb = 0.184 − 0.00053 × n, n represents
the number of sampling site).
The distribution pattern of La and Ce looks almost uniform over the country, with
the exception of some local variability with higher degree of selected REEs contents