A Spanish-Moroccan research team has developed an ecological means of reducing pesticide-related water pollution by using natural organic waste materials, such as olive and date stones, and the leaves of plants such as the rock rose and radish. This new formula could help to reduce this problem that causes damage to health and the environment.
A group of experts in Analytical and Environmental Chemistry from the University of Seville (US), working with researchers from the University of Abdelmalek Essaadi in Morocco, has shown that date and olive stones, as well as the leaves of certain Mediterranean plants, can act to absorb pesticides.
The scientists studied the absorption of 22 different types of pesticides by 10 natural substances - five of which were organic waste materials (peanut shells, bamboo, and olive, avocado and date stones), and five of which were the leaves of plants (eucalyptus, radish, oregano, oleander and rock rose), which had been previously crushed.
The results of this study, published in the Journal of Hydrology, show that date and olive stones had the greatest absorption capacity, at 93% and 90% respectively, while the values for rock rose and radish leaves stood at 80%.
"Directly applying natural organic absorbents to cultivated soil not only helps to stop the pesticides leaching away and thus reduce their use, but also helps to improve soil fertility," Hicham El Bakouri, one of the study's co-authors and a researcher in the Department of Chemical and Environmental Engineering at the US, told SINC.
El Bakouri said that using this crushed organic matter on the soil also helps pollutants to biodegrade by increasing levels of microbiological activity and reducing the vertical movement of pesticides from the surface down into the groundwater - which is used for irrigation and human consumption.
Cooperation between Spain and Morocco
The analytical studies during this research project were carried out in the laboratories of the University of Abdelmalek Essaadi and the Higher School of Engineers of the US, and the samples were taken in Loukkos, in the north west of Morocco. The researchers tested the decontamination techniques in a number of fields throughout the region, and also carried out an information and awareness-raising campaign among the local population.
A large part of the groundwater in the Loukkos region suffers from pesticide pollution, with an average contaminant load per cultivated hectare of 6kg - a very similar figure to that in some Spanish autonomous regions, such as Extremadura, the Balearic Islands and Madrid.
El Bakouri stressed that the contamination of water resources by pesticides used in agriculture or harmful substances from industry is a problem worldwide.
"In many countries around the world, especially those with fewer resources, this type of water contamination represents a serious problem, and we need to find economical, environmentally-sustainable solutions, which are easy to put into use, such as the method we have proposed," said the researcher.
The project was financed by the Ministry of Science and Innovation (MICINN) and the Spanish Agency for International Development Cooperation (AECID).
- Elbakouri et al. Natural attenuation of pesticide water contamination by using ecological adsorbents: Application for chlorinated pesticides included in European Water Framework Directive. Journal of Hydrology, 2009; 364 (1-2): 175 DOI: 10.1016/j.jhydrol.2008.10.012
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