38
2.2.2 Sampling
Sampling was performed during a relatively dry season of August–September 2015,
according to the guidelines of the LRTAP Convention-ICP Vegetation protocol and
sampling strategy of the European Programme on Biomonitoring of Heavy Metal
Atmospheric Deposition (Frontasyeva and Harmens 2015). Moss samples were collected at a total of 55 sampling sites. A systematic sampling scheme was applied
(EPA QA/G-5S 2002) with a homogeneous distribution of more or less equal densities (≈2 moss samples/1000 km
2
). One of the recommended moss species, H. cupressiforme, widely spread in Albania, was used in this study as an air pollution
bioindicator. The sampling locations were situated at least 300 m away from main
roads or buildings and 100 m from small roads and single houses. Most of the
samples were collected in open areas. Composite moss samples were formed by five
to ten sub-samples collected within an area of 50 × 50 m
2
. The sampling sites in
mountain areas were positioned in deep valleys by keeping the altitude lower than
1000 m. Only five samples in the southeast (Korça-Pogradec region) were collected
from the plateau region with an elevation lower than 1300 m. To prevent any contamination of the samples, sampling and sample handling were performed using
disposable polyethylene gloves. The distribution of the sampling sites is shown in
Fig. 2.1.
2.2.3 Sample Preparation and Chemical Analysis
Unwashed green and greenish-brown parts of moss leaves that represent 3–5 years
of plant growth were cleaned from the foreign materials that adhered to the surface
of the samples such as tree bark, lichens, soil dust and the dead materials. The
samples were dried to constant weight for 48 h at 30–35 °C. To reduce the particle
size and satisfy the conditions for homogeneity of the sample, the samples were
ground and homogenized prior to the analysis using a plastic mortar and pestle.
Moss samples were totally digested using a microwave digestion system (Mars,
CEM, USA) according to the method presented by Stafilov et al. (2018). The instrumental parameters of both methods are published at Stafilov et al. (2018) and
Balabanova et al. (2010). The content of Co, Cu, Ni and Zn in the moss samples was
determined by inductively coupled plasma atomic emission spectrometric (ICPAES) (Varian, 715ES). As and Cd were determined by electrothermal atomic
absorption spectrometry (ETAAS) (Varian, SpectrAA 640Z). ICP-AES and ETAAS
analysis were performed at the Institute of Chemistry, Faculty of Science, Ss. Cyril
and Methodius University, Skopje, North Macedonia.
Mercury was determined by cold vapour atomic absorption spectrometry
(CVAAS) (Varian 10+ equipped with a homemade cold vapour system) as described
by Lazo and Cullaj (2002). Wet digestion of homogeneous sub-sample (0.5 g
S. Allajbeu et al.
2.2.2 Sampling
Sampling was performed during a relatively dry season of August–September 2015,
according to the guidelines of the LRTAP Convention-ICP Vegetation protocol and
sampling strategy of the European Programme on Biomonitoring of Heavy Metal
Atmospheric Deposition (Frontasyeva and Harmens 2015). Moss samples were collected at a total of 55 sampling sites. A systematic sampling scheme was applied
(EPA QA/G-5S 2002) with a homogeneous distribution of more or less equal densities (≈2 moss samples/1000 km
2
). One of the recommended moss species, H. cupressiforme, widely spread in Albania, was used in this study as an air pollution
bioindicator. The sampling locations were situated at least 300 m away from main
roads or buildings and 100 m from small roads and single houses. Most of the
samples were collected in open areas. Composite moss samples were formed by five
to ten sub-samples collected within an area of 50 × 50 m
2
. The sampling sites in
mountain areas were positioned in deep valleys by keeping the altitude lower than
1000 m. Only five samples in the southeast (Korça-Pogradec region) were collected
from the plateau region with an elevation lower than 1300 m. To prevent any contamination of the samples, sampling and sample handling were performed using
disposable polyethylene gloves. The distribution of the sampling sites is shown in
Fig. 2.1.
2.2.3 Sample Preparation and Chemical Analysis
Unwashed green and greenish-brown parts of moss leaves that represent 3–5 years
of plant growth were cleaned from the foreign materials that adhered to the surface
of the samples such as tree bark, lichens, soil dust and the dead materials. The
samples were dried to constant weight for 48 h at 30–35 °C. To reduce the particle
size and satisfy the conditions for homogeneity of the sample, the samples were
ground and homogenized prior to the analysis using a plastic mortar and pestle.
Moss samples were totally digested using a microwave digestion system (Mars,
CEM, USA) according to the method presented by Stafilov et al. (2018). The instrumental parameters of both methods are published at Stafilov et al. (2018) and
Balabanova et al. (2010). The content of Co, Cu, Ni and Zn in the moss samples was
determined by inductively coupled plasma atomic emission spectrometric (ICPAES) (Varian, 715ES). As and Cd were determined by electrothermal atomic
absorption spectrometry (ETAAS) (Varian, SpectrAA 640Z). ICP-AES and ETAAS
analysis were performed at the Institute of Chemistry, Faculty of Science, Ss. Cyril
and Methodius University, Skopje, North Macedonia.
Mercury was determined by cold vapour atomic absorption spectrometry
(CVAAS) (Varian 10+ equipped with a homemade cold vapour system) as described
by Lazo and Cullaj (2002). Wet digestion of homogeneous sub-sample (0.5 g
S. Allajbeu et al.