(Mohanraj et al. 2004). The atmospheric concentration of metal-PM may vary over
different seasons (Li et al. 2017b; Zhang et al. 2016). For example, WHO (1987a)
reported airborne As concentration 450 ng/m
3 in winter and 70 ng/m
3 in summer for
the same geographic location.
The abovementioned studies showed that the atmospheric concentration of metalPM may rise beyond the toxic/threshold levels (reported by EU regulated levels,
WHO guidelines, or EPA’s RfCs) in different regions of the world. However, their
levels greatly vary in rural, urban, and industrial areas. In contrast to soil heavy
metal(loid) contamination, atmospheric contamination does not remain constant
and varies greatly with their intensity of emission from the source. Moreover, the
climatic conditions (wind, temperature, rainfall, etc.) also affect atmospheric level of
metal-PM. Therefore, it is of great importance to identify their possible sources of
emission from different natural and anthropogenic sources. Moreover, the atmospheric contamination of metal-PM by different sources requires constant monitoring compared to soil contamination.
2.3 Speciation of PM-Bound Metal(loid)s
Nowadays, metal speciation is highly topical, because the biogeochemical behavior
of a metal is highly dependent on its speciation in addition to total metal content
(Rafiq et al. 2017; Shahid et al. 2012a, b). Fine and coarse PMs are also reported to
contain different chemical forms of a metal (Anake et al. 2017; Helali et al. 2016;
Osán et al. 2010). Heavy metal(loid)s attached with atmospheric PM have different
species or fractions which show different bioavailability and potential risk to living
beings (Feng et al. 2009; Huang et al. 2018). Heavy metal(loid)s associated with PM
varies with the type of metal and particulate (Helali et al. 2016; Kang et al. 2017).
Various studies have been conducted for the assessment of heavy metal(loid)
speciation and their spatial and temporal variation with PM (Jia et al. 2018; Kang
et al. 2017; Pattanaik et al. 2016). Most of the heavy metal(loid)s are associated with
PM 10 and PM 2.5 , which can penetrate the respiratory tract and pulmonary region
causing adverse health effects (Krzemińska-Flowers et al. 2006).
Donnelly (1993) reported that incineration of solid waste emits toxic heavy
metal(loid)s into the atmosphere like As, Pb, Cr, Cd, Hg, Ag, and Be. These
heavy metal(loid)s upon incineration are generally converted into their respective
oxides and chlorides and are therefore released into the atmosphere in oxide or
chloride forms along with fine PM. Goix et al. (2014) carried out Raman microspectrometry of atmospheric fallouts of a Pb recycling factory. They reported that
xPbO.PbSO 4 , PbCO 3 , α-PbO, Na 2 SO 4 , PbSO 4 , and ZnSO 4 were identified in both
PM 2.5 and PM 10 samples as major species. Similarly, Uzu et al. (2011a) reported Pb,
PbS, PbO, PbSO 4 , and PbOÁPbSO 4 as the major species of Pb from a lead recycling
factory. They reported that the differences observed in chemical composition and
Ecotoxicology of Heavy Metal(loid)-Enriched Particulate Matter: Foliar. . .
73
different seasons (Li et al. 2017b; Zhang et al. 2016). For example, WHO (1987a)
reported airborne As concentration 450 ng/m
3 in winter and 70 ng/m
3 in summer for
the same geographic location.
The abovementioned studies showed that the atmospheric concentration of metalPM may rise beyond the toxic/threshold levels (reported by EU regulated levels,
WHO guidelines, or EPA’s RfCs) in different regions of the world. However, their
levels greatly vary in rural, urban, and industrial areas. In contrast to soil heavy
metal(loid) contamination, atmospheric contamination does not remain constant
and varies greatly with their intensity of emission from the source. Moreover, the
climatic conditions (wind, temperature, rainfall, etc.) also affect atmospheric level of
metal-PM. Therefore, it is of great importance to identify their possible sources of
emission from different natural and anthropogenic sources. Moreover, the atmospheric contamination of metal-PM by different sources requires constant monitoring compared to soil contamination.
2.3 Speciation of PM-Bound Metal(loid)s
Nowadays, metal speciation is highly topical, because the biogeochemical behavior
of a metal is highly dependent on its speciation in addition to total metal content
(Rafiq et al. 2017; Shahid et al. 2012a, b). Fine and coarse PMs are also reported to
contain different chemical forms of a metal (Anake et al. 2017; Helali et al. 2016;
Osán et al. 2010). Heavy metal(loid)s attached with atmospheric PM have different
species or fractions which show different bioavailability and potential risk to living
beings (Feng et al. 2009; Huang et al. 2018). Heavy metal(loid)s associated with PM
varies with the type of metal and particulate (Helali et al. 2016; Kang et al. 2017).
Various studies have been conducted for the assessment of heavy metal(loid)
speciation and their spatial and temporal variation with PM (Jia et al. 2018; Kang
et al. 2017; Pattanaik et al. 2016). Most of the heavy metal(loid)s are associated with
PM 10 and PM 2.5 , which can penetrate the respiratory tract and pulmonary region
causing adverse health effects (Krzemińska-Flowers et al. 2006).
Donnelly (1993) reported that incineration of solid waste emits toxic heavy
metal(loid)s into the atmosphere like As, Pb, Cr, Cd, Hg, Ag, and Be. These
heavy metal(loid)s upon incineration are generally converted into their respective
oxides and chlorides and are therefore released into the atmosphere in oxide or
chloride forms along with fine PM. Goix et al. (2014) carried out Raman microspectrometry of atmospheric fallouts of a Pb recycling factory. They reported that
xPbO.PbSO 4 , PbCO 3 , α-PbO, Na 2 SO 4 , PbSO 4 , and ZnSO 4 were identified in both
PM 2.5 and PM 10 samples as major species. Similarly, Uzu et al. (2011a) reported Pb,
PbS, PbO, PbSO 4 , and PbOÁPbSO 4 as the major species of Pb from a lead recycling
factory. They reported that the differences observed in chemical composition and
Ecotoxicology of Heavy Metal(loid)-Enriched Particulate Matter: Foliar. . .
73