Pesticide Residues in Vegetation - Pesticides: Evaluation of Environmental Pollution - page 307

Italy and Czech Republic (average concentrations above 10 μg/kg) are outstanding. In gen-
eral, as Calamari et al. showed in 1991, DDT contamination is more important in tropical
zones, contrary to what happens to other compounds, such as HCB. The HCH compound
has been studied in a total of 35 countries around the world. Most of the zones where HCH
has been studied in vegetation samples are in the Northern Hemisphere, mainly in the
European continent, where 68% of the total studies have been performed.
In most of the studies, the analyzed congeners were α- and γ-HCH (lindane), although,
in some cases, the congeners β- and δ-HCH have been also included (Barriada-Pereira et al.
2005; Krauthacker et al. 2001). In 49% of the analyzed samples, the average concentrations
of this contaminant were below 1 μg/kg (in dry weight of the analyzed species). In 33%
of the cases, the detected concentrations were between 1 and 10 μg/kg. Only in 18% of the
cases, average concentrations of HCH above 10 μg/kg were obtained.
In Europe, high average concentrations, in general, of HCH were found in Pinus spp.
and lichens/mosses (Figure 10.2). Also, the average concentrations obtained in the areas of
the Amazon, India, and Nepal are outstanding. The highest value of the concentration of
HCH, concretely of α-HCH, was found in New Delhi (India), in mango ( M. indica ) leaves:
a concentration of 106.9 μg/kg (Krauthacker et al. 2001). Significant concentrations of HCH
have been found in samples from high mountains characterized by low temperatures, in
areas such as Antarctica, Iceland, Nepal and Kenya. That confirms the processes of large-
scale transport of this contaminant and its higher accumulation in cold places. In that
sense, high mountain areas, such as cold zones, act like condensers for HCH (Barber et al.
2005; Calamari et al. 1991).
< 0.1-0.5 µ g/kg
0.6-1.0 µ g/kg
1.1-10.0 µ g/kg
> 10.1 µ g/kg
FIGURE 10.2
Distribution of HCH (mean concentrations) in Pinus spp. (triangle), Magnifera indica (circle) and lichen/moss
(square) around the world. The size of the symbol indicates different mean concentration of HCH (see legend).