Environmental Risk of Groundwater Pollution by Pesticide Leaching through the Soil Profile

Abstract

Adsorption, degradation, and movement are the key processes conditioning the behavior and fate of pesticides in the soil. Six processes that can move pesticides are leaching, diffusion, volatilization, erosion and runoff , assimilation by microorganisms, and plant uptake. Leaching is the vertical downward displacement of pesticides through the soil profile and the unsaturated zone, and finally to groundwater, which is vulnerable to pollution. Pesticides are frequently leached through the soil by the effect of rain or irrigation water. Pesticide leaching is highest for weakly sorbing and/or persistent compounds, climates with high precipitation and low temperatures, and soils with low organic matter and sandy texture. On the contrary, for pesticides with a low persistence that disappear quickly, the risk of groundwater pollution considerably decreases. Different and varied factors such as physicalchemical properties of the pesticide, a permeability of the soil, texture and organic matter content of the soil, volatilization, crop-root uptake, and method and dose of pesticide application are responsible for the leaching rate of the pesticides. Soils that are high in clays and organic matter will slow the movement of water, attach easily to many pesticides, and generally have a higher diversity and population of soil organisms that can metabolize the pesticides.

Respuesta del cultivo de maíz a la bio-inoculación y fertilización química reducida en campo

“…También los niveles críticos o muy bajos de materia orgánica en el suelo (1.1%) pudieren haber influido sobre la escasa e incluso nula colonización de las raíces viable is decreasing the very harmful environmental threats that the excessive use of chemical supplies -pesticides and synthetic fertilizers -causes, of which those that stand out are soil compaction and degradation (Massah and Azadegan, 2016), fertility decline (Timsina, 2018), pollution of underground water, air, and soil (Pérez-Lucas et al, 2018;Zhang et al, 2018) and its acidif ication (Goulding, 2016) without excluding damage and harm caused to human health (Kumari et al, 2014;Silveira-Gramont et al, 2018).…”

“…Con base en los resultados obtenidos en este estudio, la propuesta metodológica implementada mediante la aplicación dual de estos microorganismos con dosis reducida de fertilización inorgánica podría ser una alternativa técnicamente factible de promover entre los productores, no solo por ser amigable con el ambiente, sino por tratarse de una práctica simple y barata que reduce el uso de agroquímicos y los altos costos de producción. Además, otra alternativa que pudiere ser viable es la disminución de las amenazas ambientales tan nocivas que ocasiona el uso excesivo de insumos químicos, como plaguicidas y fertilizantes sintéticos, entre los que se resaltan la degradación y compactación del suelo (Massah y Azadegan, 2016), el declive de su fertilidad (Timsina, 2018) la contaminación de las aguas subterráneas, aire y suelo (Pérez-Lucas et al, 2018;Zhang et al, 2018) y su acidif icación (Goulding, 2016), sin descartar los daños y perjuicios que ocasionan a la salud humana (Kumari et al, 2014;Silveira-Gramont et al, 2018).…”

Fate of Pyriproxyfen in Soils and Plants

“…Leaching is the vertical displacement of contaminants, such as water-soluble pesticides or fertilizers, carried by water downward through the soil profiles to the groundwater [31,32]. Soil texture and structure, organic matter and water content affect the leaching of pesticides in soil.…”

Assessment of Organophosphate and Carbamate Insecticides and Heavy Metal Contamination in Canal-Grown Water Morning Glory (Ipomoea aquatica Forssk) in Nakhon Nayok Province, Thailand

“…Pesticides can also be leached through the soil structure to groundwater, by flow or the infiltration process of rain water, but this depends on many factors (i.e. dose, method, application, and properties of the pesticide) [45]. Interestingly, it has been reported that several inorganic fertilizers and pesticides are important sources of heavy metals, such as Cd, Co, Cu, Zn, Pb, Fe, Mn, and Ni [10].…”