Evaluación de compuestos tóxicos: plaguicidas órganoclorados y metales pesados en suelos agrícolas del distrito de riego de Repelón - Atlántico
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Cervantes Fuentes, Duvan Salomón | 2017-11-27
During the second half of twentieth century, Repelón was known as the main agricultural
source in the Atlántico department. A town, which like most of the country at that time, had
cultivation as the motor of its development, standing out the cotton, tomato and fruit crops in
general, as well as having an irrigation district that supplied the fields of water throughout the
year.
Several factors slowly undermined the agricultural production on region, increasing the use of
fertilizers to maintain the production level and pesticides to keep out plagues in order to ensure
food security. These, caused the deposition of toxic compounds such as organochlorides in
Repelon soils, which at that time they were used freely on cotton crops and poorly regulated. The
presence of these noxious compounds on soils might become a serious risk for the productive
purpose of soil, from economic, sanitary and environmental perspective.
Considering the above, concentrations of toxic compounds such as organochlorine pesticides,
(Heptachlor Benzene, Aldrin, Endosulfan, Dieldrin, Endrin) were analyzed by Gas
Chromatography. Otherwise, concentrations of heavy metals (Mercury, Lead, Nickel, Zinc,
Copper, Chrome and Cadmium), were analyzed by Inductively Coupled Plasma Emission Mass
Spectroscopy (ICP-MS). Samples were taken from agricultural soils belonging to the irrigation
district of Repelon, at the south region of Atlantico department, in Colombia. Through this study
area, it was used a random sampling in zigzag which started with the location of ten sampling
points with historical intensive agricultural production. For every heavy metal that was analyzed, excluding Cadmium, they were found analytically
detectable concentrations (greater than the detection limit of 0.01 mg/kg). However, pesticides
concentrations found were not quantitative values, because they were below the detection rate of
analytical technique (2 .
The pollution degree of heavy metals was established through the Geoaccumulation Index
(Igeo) and Enrichment Factors (EF). In the case of Copper, moderate enrichment was found in
all points, whereas Chromium showed a minimal enrichment in points 5, 7 and 8, and moderate
enrichment in the other analyzed points, while other metals presented minimal enrichment at all
points.
On the other hand, the Geoaccumulation Index showed that the soil was moderately polluted
with Copper at all points as well as with Chromium excepting points 3 and 4. For Zinc, just
point 9 is moderately polluted and rest of the samples are little polluted. In the case of Nickel,
only point 3 is not polluted, while the others are little polluted. Surprisingly, the soils are not
polluted either with Mercury, Lead or Cadmium.
Finally, presented results prove that heavy metals requiring more attention in Repelón
irrigation district are Chromium and Copper due to their irregular concentrations in some zones,
deducing a common source of pollution which requires further studies to establish its causes.
Additionally, although the concentration from the other metals was low, it must be correlated
with environmental factors and physicochemical characteristics of the soil to define its potential
toxicity as well as the impacts on human health.
LEER