59
Nickel contents in moss samples ranged from 0.68 mg kg
−1
to 108 mg kg
−1
, with
an average concentration of 17.1 mg kg
−1
and a median of 0.57 mg kg
−1
. It shows a
high variation (CV% = 138%) followed by high positive values of skewness and
kurtosis (2.56 and 6.54, respectively) that indicate high disparity of the concentration data with a tendency of skewed right. Significant spatial variations are identified among different areas indicating the different levels of the Ni air pollution. The
spatial analysis of Ni concentration data (linear model) shows a high increase from
the south to the north direction of the country (Ni = 1.4 + 0.559 × n; n represents the
number sampling sites). By comparing the Ni spatial distributions obtained from the
spatial distributions of concentration data and the normalized Ni data, it was shown
that the positions of the anomalies of Ni concentration and normalized data lie in the
same positions (Fig. 2.14). It is clearly indicating that the anthropogenic emission
sources are predominant in Ni content in moss samples.
The anomalies with high Ni concentrations were found in the same sampling
sites as Cr normalized concentrations (St. 26, 30, 39, 40, 42–46, 54 and 55), positioned in the central (St. 22 and 24) and in the eastern parts of the country. The
highest Ni content was also found in Cr deposit areas (St. 42–46 and St. 54, 55).
High Ni contents in moss samples of these stations are strongly linked with anthropogenic sources of windblown dust particles sourced from the areas of chromite and
nickel silicate deposits and nickel-ferrous ores (Milushi 2015) indicating the high
effects of geogenic factors. Moss sample of St. 26 is also affected by Ni anthropogenic emission from metallurgical combine of Elbasani area, and St. 26 is affected
by Ni anthropogenic emission from the oil production industry of Kuçova area.
These findings showed that the distribution of Ni with relatively high contents is
mainly localized in the areas of Ni and Cr ores and mining industry which are highly
polluted by Ni sourced by windblown fine mineral dust particles. It indicates Ni
content in moss is probably derived mostly from local inputs of air pollution from
industry, mining activity and geogenic factors and long-range atmospheric transport. High median value of Ni in moss samples of Albania is higher than the median
value of European moss survey (Harmens et al. 2015).
Similar distribution patterns were observed from spatial analysis (linear model)
of 2015 and 2010 Ni concentration data that are characterized by high increase of
Ni content in S-N direction (Ni = 1.4 + 0.559 × n and Ni = −1.61 + 0.618 × n,
respectively). The changes observed in the spatial distribution plots of 2015 and
2010 were obtained as a result of a larger number of monitoring stations in 2015
(N = 55 sampling sites) compared with 2010 (N = 47 sampling sites). Substantial
changes have been identified in the Ni concentration levels of both monitoring periods. The content of Ni in the moss samples of 2015 was higher than those of 2010.
This is evidenced by changes in median values, 7568 mg kg
−1
and 5889 mg kg
−1
,
respectively. The Ni anomalies of 2015 and 2010 biomonitoring periods resulted in
the same monitoring areas. The same with other elements under investigation, the
differences observed on spatial distribution of Ni during 2015 and 2010 moss monitoring surveys are probably linked with the changes in the bioavailability of the
2 Spatial Series and Multivariate Analysis in Assessing the Essential (Cu and Zn…
Nickel contents in moss samples ranged from 0.68 mg kg
−1
to 108 mg kg
−1
, with
an average concentration of 17.1 mg kg
−1
and a median of 0.57 mg kg
−1
. It shows a
high variation (CV% = 138%) followed by high positive values of skewness and
kurtosis (2.56 and 6.54, respectively) that indicate high disparity of the concentration data with a tendency of skewed right. Significant spatial variations are identified among different areas indicating the different levels of the Ni air pollution. The
spatial analysis of Ni concentration data (linear model) shows a high increase from
the south to the north direction of the country (Ni = 1.4 + 0.559 × n; n represents the
number sampling sites). By comparing the Ni spatial distributions obtained from the
spatial distributions of concentration data and the normalized Ni data, it was shown
that the positions of the anomalies of Ni concentration and normalized data lie in the
same positions (Fig. 2.14). It is clearly indicating that the anthropogenic emission
sources are predominant in Ni content in moss samples.
The anomalies with high Ni concentrations were found in the same sampling
sites as Cr normalized concentrations (St. 26, 30, 39, 40, 42–46, 54 and 55), positioned in the central (St. 22 and 24) and in the eastern parts of the country. The
highest Ni content was also found in Cr deposit areas (St. 42–46 and St. 54, 55).
High Ni contents in moss samples of these stations are strongly linked with anthropogenic sources of windblown dust particles sourced from the areas of chromite and
nickel silicate deposits and nickel-ferrous ores (Milushi 2015) indicating the high
effects of geogenic factors. Moss sample of St. 26 is also affected by Ni anthropogenic emission from metallurgical combine of Elbasani area, and St. 26 is affected
by Ni anthropogenic emission from the oil production industry of Kuçova area.
These findings showed that the distribution of Ni with relatively high contents is
mainly localized in the areas of Ni and Cr ores and mining industry which are highly
polluted by Ni sourced by windblown fine mineral dust particles. It indicates Ni
content in moss is probably derived mostly from local inputs of air pollution from
industry, mining activity and geogenic factors and long-range atmospheric transport. High median value of Ni in moss samples of Albania is higher than the median
value of European moss survey (Harmens et al. 2015).
Similar distribution patterns were observed from spatial analysis (linear model)
of 2015 and 2010 Ni concentration data that are characterized by high increase of
Ni content in S-N direction (Ni = 1.4 + 0.559 × n and Ni = −1.61 + 0.618 × n,
respectively). The changes observed in the spatial distribution plots of 2015 and
2010 were obtained as a result of a larger number of monitoring stations in 2015
(N = 55 sampling sites) compared with 2010 (N = 47 sampling sites). Substantial
changes have been identified in the Ni concentration levels of both monitoring periods. The content of Ni in the moss samples of 2015 was higher than those of 2010.
This is evidenced by changes in median values, 7568 mg kg
−1
and 5889 mg kg
−1
,
respectively. The Ni anomalies of 2015 and 2010 biomonitoring periods resulted in
the same monitoring areas. The same with other elements under investigation, the
differences observed on spatial distribution of Ni during 2015 and 2010 moss monitoring surveys are probably linked with the changes in the bioavailability of the
2 Spatial Series and Multivariate Analysis in Assessing the Essential (Cu and Zn…