Pesticide Residues in Vegetation - Pesticides: Evaluation of Environmental Pollution - page 313

plant species with a wide distribution in the study area to obtain representative results.
However, it must be considered that vegetation is a problematic tool for monitoring pollut-
ants, since there may be differences in the accumulation of the compounds between plant
species, for example, between conifers, deciduous trees, and herbaceous species (Vighi
2006). To consider the use of vegetation as an environmental indicator, the collection,
extraction, and analysis of the samples should be standardized.
It is important to study the presence of pesticides in the vegetation in areas located far
from the sources of pollution (reference areas) when conducting studies on regional and
global scales, to know the levels of “background pollution.”
The HCH and HCB organochlorine pesticides, which are more volatile, are concen-
trated mainly in cold areas and high mountain areas around the world (Barber et al. 2005;
Krauthacker et al. 2001), although mainly in the Northern Hemisphere. However, DDT has
higher levels of pollution in tropical areas, confirming the results obtained in the previous
studies (Calamari et al. 1991).
Although the results show the general trends of decreasing levels of DDT along the
years in plant samples, the concentrations of other organochlorine pesticides, such as lin-
dane, show that people are still using these compounds in some places around the world,
despite them being banned in most countries (Wang et al. 2007).
It would be interesting to carry out studies about the presence of other persistent pesticides,
such as chlorpyrifos, chlorfenvinphos, and others, which are widely used and which appear
in significant concentrations in freshwater, marine water, wastewater, sediments, and soils.
Acknowledgment
The authors gratefully acknowledge the Consejería de Innovación Ciencia y Empresa de la
Junta de Andalucía-FEDER (P05-FQM-0202) for the financial support.
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