Pesticide Residues in Vegetation - Pesticides: Evaluation of Environmental Pollution - page 309

The presence of endosulfan has been studied in a less number of occasions; only three
studies were compiled. In Spain, it was analyzed in eight different species of aquatic
plants, although contamination by this compound was found in only four of the target
species (Pérez-Ruzafa et al. 2000). The rest of the studies were carried out in high mountain
areas, in Canada (Davidson et al. 2003) and in the Mt. Qomolangma (Himalayas) (Wang
et al. 2007), and the presence of endosulfan was found in both the zones.
Regarding the endrin aldehyde, aldrin, dieldrin, and heptachlor pesticides, they have
been analyzed in a study performed on eight species of aquatic plants in Spain. Endrin
contamination was not found in this zone, but for the rest of the target compounds, the
results ranged between 3.40 μg/kg for aldrin and 1474.9 μg/kg for endrin aldehyde.
The PCP compound has also been studied in different zones of the European continent
(Sweden, Norway, Denmark, Germany, France, Switzerland, and Poland), in Pinus sylvestris
(Jensen et al. 1992). Values of the concentrations of this pollutant, which ranged between
0.29 μg/kg in Germany and 0.90 μg/kg in Sweden and Norway, have been recorded.

10.3.2 Temporal Evolution

The insecticide DDT was implemented in the late 1940s and was used until the 1970s in
large quantities in agricultural areas around the world. Although emissions of this com-
pound ceased in 1990, due to its persistence, DDT continues circulating among different
environmental compartments (Stemmler and Lammel 2009).
Concentrations of DDTs in plant samples have declined along the years, from 1988 to
2007 (Figure 10.4a), except for high concentration values found by Mahugija-Marco and

100

p-p´DDT
p-p´DDE

80

60

40

20

0

1985 1990 1995 2000 2005 2010

(a)

6

5

4

3

2

1

0

1988 1991 1994 2000 2001 2003 2007

(b)

FIGURE 10.4
(a) Temporal evolution of concentratrions of p-p´DDT and p-p´DDE in vegetation samples from 34 countries
around the world. (b) Temporal evolution of p-p´DDE / p-p´DDT ratio.