Pesticide Residues in Vegetation - Pesticides: Evaluation of Environmental Pollution - page 301

10
Pesticide R esidues in Vegetation
Antonia Garrido Frenich, Isabel M a Campoy Jiménez,
M a del Mar Bayo Montoya, and José Luis Martínez Vidal
CONTENTS
10.1 Introduction ........................................................................................................................ 301
10.2 Methodology ...................................................................................................................... 303
10.3 Results and Discussion ..................................................................................................... 303
10.3.1 Spatial Distribution ............................................................................................... 306
10.3.2 Temporal Evolution ............................................................................................... 309
10.3.3 Distribution of Pesticides in Vegetation Species ............................................... 311
10.3.4 Distribution with Elevation.................................................................................. 312
10.4 Conclusions......................................................................................................................... 312
Acknowledgment........................................................................................................................ 313
References..................................................................................................................................... 313
10.1 Introduction
Pesticides have been used worldwide for pest control in crops, allowing the increase in
crop productivity and improved product quality. Their use has been considered a revo-
lution in agriculture, but, due to their high toxicity, many of them were included in the
Stockholm Convention (1972) and declared as persistent organic pollutants (POPs). From
1970s, many of these pesticides have been forbidden in most countries; however, in 1992,
approximately 2.5 million tons of pesticides were used around the world (Pimmentel et al.
1992). Although pesticide use has been controlled gradually, there may be more than 20,000
tons of obsolete pesticides in developing countries, and stocks are growing because a lot of
these countries do not have environmental policies in this regard (FAO 1997).
Pesticides are present in all environmental compartments; they can be transported
through great distances in the atmosphere before removal by deposition or degrada-
tion, depending on their residence time. Transport in ocean and atmosphere and fluxes
between these compartments are essential to understand global cycling of the contami-
nants (Stemmler and Lammel 2009). In the troposphere, they can be removed from the air
phase via atmospheric deposition to water and soil, and significant amounts of pesticides,
mainly persistent compounds, can be found in soils, water, groundwater, sediments, biota,
and vegetation (Barber et al. 2005).
In the aquatic ecosystems, there is a continuous exchange of pesticides among land,
sediment, sediment-water interface, interstitial waters, aquatic organisms, and air-water
interface. Absorption of lipophilic compounds by sediments plays an important role in
pesticide absorption by aquatic organisms, and this explains to a large degree why the
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