Asakura (2011) also revealed wet deposition as the dominant deposition mechanism
for atmospheric pollutants, especially in monsoon areas of Asia. This shows that the
ratios of wet/dry deposition fluxes may vary at different locations around the globe.
The possible reason of variation in the ratios of wet/dry deposition fluxes can be due
to differences in climatic conditions at different locations or the type/size of
metal-PM. However, the phenomenon needs more clarity/research for conclusive
elucidation.
The average deposition of Cr, Cd, and Pb on soil was 0.96 Æ 0.48, 0.28 Æ 0.25,
and 1.90 Æ 1.54 mg/m
2 /year in China (Zhu et al. 2016a). The reported values of
heavy metal(loid)s in agricultural topsoil after atmospheric deposition of metal-PM
are 20,458, 688.90, 18.93, 19.88, 83.47, 0.49, 61.48, and 17.54 mg/kg for Fe, Mn,
Ni, Cu, Zn, Cd, Pb, and As, respectively (Rachwał et al. 2017a). Zaborska et al.
(2017) studied the spatial variation in metal concentration and their deposition rate in
sediments of Svalbard. The study indicated the concentration of heavy metal(loid)s
as 5.7–45.8 for Pb, 13.4–54.4 for Cu, 0.1–0.90 for Cd, and 55.6–130.4 mg/kg for
Zn. It was then indicated that the area received these pollutants from North American
sources through different possible transfer mechanism of metal-PM.
Different types of conventional devices are used for wet, dry, and bulk deposition
sampling. The devices used for atmospheric deposition sampling can be distinguished into different categories based on deposition type: (1) dry deposition
sampling when there is no precipitation, (2) wet deposition sampling only during
rain, and (3) bulk deposition sampling for both the dry and wet depositions (Amodio
et al. 2014). Recently, Wu et al. (2018) used Dustmate for collecting the dry
deposition PM concentration and rain collectors for the assessment of wet depositions. Different types of devices used in atmospheric deposition sampling of
PM-bound metal(loid)s include wet-dry deposimeter sampler, HDPE bucket
sampler, HDPE funnel-bottle sampler, HDPE automatic wet-dry sampler, HDPE
automatic wet-only sampler, water surface sampler, PVC dry deposition sampler,
high- and low-volume samplers, etc. (Amodio et al. 2014). Previously, Aas et al.
(2009) investigated the field intercomparison of three types of samplers to determine
the atmospheric deposition at different locations in Europe. The study revealed that
the samplers used showed efficient performance at different locations. They proposed that at industrial, rural, and urban locations, Bergerhoff samplers are necessary
to use.
Owing to the deposition of metal-PM, high concentrations of heavy metal(loid)s
were detected in the soil and sediments of mining area of Xikuangshan, China: 32.3,
399.98, 18.77, 17.86, 512.09, 40.46, 7.56, 45.43, and 273.67 mg/kg for Cr, Mn, Ni,
Cu, Zn, As, Cd, Pb, and Sb, respectively (Li et al. 2017a). They further reported that
windborne transport plays a significant role in the dispersal of the metal-PM. A
significant increase in annual dust (metal-PM) fall rate was measured in some areas
of India (Tiwari et al. 2008). Among heavy metals, the annual atmospheric deposition rate was Mn (387.3), Zn (336.6), Cr (124.4), Pb (71.0), Ni (51.2), Cu (39.8), and
Cd (6.93) g/h/year. The deposition of metal-PM was correlated with some meteorological factors such as wind velocity, humidity, and temperature (Tiwari et al. 2008).
78
M. Shahid et al.
for atmospheric pollutants, especially in monsoon areas of Asia. This shows that the
ratios of wet/dry deposition fluxes may vary at different locations around the globe.
The possible reason of variation in the ratios of wet/dry deposition fluxes can be due
to differences in climatic conditions at different locations or the type/size of
metal-PM. However, the phenomenon needs more clarity/research for conclusive
elucidation.
The average deposition of Cr, Cd, and Pb on soil was 0.96 Æ 0.48, 0.28 Æ 0.25,
and 1.90 Æ 1.54 mg/m
2 /year in China (Zhu et al. 2016a). The reported values of
heavy metal(loid)s in agricultural topsoil after atmospheric deposition of metal-PM
are 20,458, 688.90, 18.93, 19.88, 83.47, 0.49, 61.48, and 17.54 mg/kg for Fe, Mn,
Ni, Cu, Zn, Cd, Pb, and As, respectively (Rachwał et al. 2017a). Zaborska et al.
(2017) studied the spatial variation in metal concentration and their deposition rate in
sediments of Svalbard. The study indicated the concentration of heavy metal(loid)s
as 5.7–45.8 for Pb, 13.4–54.4 for Cu, 0.1–0.90 for Cd, and 55.6–130.4 mg/kg for
Zn. It was then indicated that the area received these pollutants from North American
sources through different possible transfer mechanism of metal-PM.
Different types of conventional devices are used for wet, dry, and bulk deposition
sampling. The devices used for atmospheric deposition sampling can be distinguished into different categories based on deposition type: (1) dry deposition
sampling when there is no precipitation, (2) wet deposition sampling only during
rain, and (3) bulk deposition sampling for both the dry and wet depositions (Amodio
et al. 2014). Recently, Wu et al. (2018) used Dustmate for collecting the dry
deposition PM concentration and rain collectors for the assessment of wet depositions. Different types of devices used in atmospheric deposition sampling of
PM-bound metal(loid)s include wet-dry deposimeter sampler, HDPE bucket
sampler, HDPE funnel-bottle sampler, HDPE automatic wet-dry sampler, HDPE
automatic wet-only sampler, water surface sampler, PVC dry deposition sampler,
high- and low-volume samplers, etc. (Amodio et al. 2014). Previously, Aas et al.
(2009) investigated the field intercomparison of three types of samplers to determine
the atmospheric deposition at different locations in Europe. The study revealed that
the samplers used showed efficient performance at different locations. They proposed that at industrial, rural, and urban locations, Bergerhoff samplers are necessary
to use.
Owing to the deposition of metal-PM, high concentrations of heavy metal(loid)s
were detected in the soil and sediments of mining area of Xikuangshan, China: 32.3,
399.98, 18.77, 17.86, 512.09, 40.46, 7.56, 45.43, and 273.67 mg/kg for Cr, Mn, Ni,
Cu, Zn, As, Cd, Pb, and Sb, respectively (Li et al. 2017a). They further reported that
windborne transport plays a significant role in the dispersal of the metal-PM. A
significant increase in annual dust (metal-PM) fall rate was measured in some areas
of India (Tiwari et al. 2008). Among heavy metals, the annual atmospheric deposition rate was Mn (387.3), Zn (336.6), Cr (124.4), Pb (71.0), Ni (51.2), Cu (39.8), and
Cd (6.93) g/h/year. The deposition of metal-PM was correlated with some meteorological factors such as wind velocity, humidity, and temperature (Tiwari et al. 2008).
78
M. Shahid et al.