| Summary: |
Rice is one of the major crops cultivated world wide. In Portugal, an area of about 30 000 ha, mainly distributed by Beira Litoral, Ribatejo and West, and Alentejo is dedicated to rice culture with annual productions reaching over 170 000 ton. As in other agricultural practices, pesticides are used in rice fields to control plagues, which permits to increase crops yields. In order to satisfy the phyto-pharmaceuticals demand, pesticide producing industries have been implemented around world. Several studies have been describing the environmental contamination with pesticides resultant from agricultural practices, accidental spillage or uncontrolled release of industrial effluents. The contamination of air, soils, surface and ground waters, and the throphic chain with pesticides has negative impacts on public health, and on biological diversity. Due to the unconfined application of pesticides, and the absence of effluent collectors, the implementation of agricultural treatment systems is difficult and expensive. However, due to metabolic diversity of the microbial communities of these habitats, it is expected that under favourable environmental conditions they could biodegrade the contaminating pesticides, minimising the harmful effects resultant from their dispersion. In this way, in situ bioremediation seems to be the best system to treat agricultural contaminated soils. However, the success of the treatment will depend on the knowledge of the genetic and metabolic diversity of the indigenous microbiota, and of the competition phenomena that might occur when the contaminated habitat is deliberately inoculated with degrading organisms.
This study will comprehend the following tasks i) the characterisation of the pedology and microbiota of rice fields soils with different histories of pesticide application; ii) the evaluation of the capacity of rice fields contaminated with different mixtures of pesticides of intrinsic remediation (natural attenuation); iii) the  |
Summary
Rice is one of the major crops cultivated world wide. In Portugal, an area of about 30 000 ha, mainly distributed by Beira Litoral, Ribatejo and West, and Alentejo is dedicated to rice culture with annual productions reaching over 170 000 ton. As in other agricultural practices, pesticides are used in rice fields to control plagues, which permits to increase crops yields. In order to satisfy the phyto-pharmaceuticals demand, pesticide producing industries have been implemented around world. Several studies have been describing the environmental contamination with pesticides resultant from agricultural practices, accidental spillage or uncontrolled release of industrial effluents. The contamination of air, soils, surface and ground waters, and the throphic chain with pesticides has negative impacts on public health, and on biological diversity. Due to the unconfined application of pesticides, and the absence of effluent collectors, the implementation of agricultural treatment systems is difficult and expensive. However, due to metabolic diversity of the microbial communities of these habitats, it is expected that under favourable environmental conditions they could biodegrade the contaminating pesticides, minimising the harmful effects resultant from their dispersion. In this way, in situ bioremediation seems to be the best system to treat agricultural contaminated soils. However, the success of the treatment will depend on the knowledge of the genetic and metabolic diversity of the indigenous microbiota, and of the competition phenomena that might occur when the contaminated habitat is deliberately inoculated with degrading organisms.
This study will comprehend the following tasks i) the characterisation of the pedology and microbiota of rice fields soils with different histories of pesticide application; ii) the evaluation of the capacity of rice fields contaminated with different mixtures of pesticides of intrinsic remediation (natural attenuation); iii) the influence of abiotic (biostimulation) and biotic (bioaugmentation) factors on soil remediation; iv) the isolation and characterisation of degradative microorganisms (that will be used in the bioaugmentation assays and in water treatment systems); v) development of a combined electrochemical/biodegradation system to cleanup soils; vi) development of a process for the treatment of effluents generated by pesticide producing industries (activated sludge or adsorption/biodegradation systems).
These different tasks will permit to achieve a global objective of the project that is to establish the methodologies necessary to implement pesticides contaminated soil in situ bioremediation, and the treatment of highly contaminated waters, as those resultant of washing of pesticide containers or industrial effluents. |