Strategies to accelerate atrazine biodegradation in contaminated soils, waters or sediments and assessment of the ecotoxicity of this herbicide and its metabolites (ATRAZINEBIOREM)

Principal Investigator: Arsénio Mendes Fialho

Contract: POCI/AMB/56039/2004 – Ciências e Tecnologias do Ambiente

Start date: 01/09/2005

Duration: 36 months 

Atrazine is a member of the s-triazines herbicide family and is used extensively throughout the world as photosynthesis inhibitor of broad-leaf weeds in crops such as maize, sorghum and sugarcane. Due to its widespread use over the last thirty years, residues of atrazine and its derivatives have been frequently detected in soils, surface water and groundwater. The increasing concern about the toxicological properties of atrazine has boosted research direct toward bioremediation of atrazine-pollutes sites. By using microorganisms to clean up atrazine pollution, which has been done successfully, the level of contamination can be reduced to the point where the soil is no longer considered hazardous. However, to do so requires a complete understanding of how bacteria degrade this chemical in the environment, the assessment of the ecotoxicity of the herbicide and its metabolites and the development of analytical methods to accurately determine where the contaminants are located in the environment. The present project will exploit the use of a non-pathogenic bacterial strain (Pseudomonas sp ADP) to cleanup Portuguese soil, surface water and sediment samples contaminated with a range of atrazine concentrations chosen to simulate those arising from agricultural application or those relevant to an accidental spill situation. We intend to study: 1) the effect of biosurfactants on the solubility enhancement of atrazine in soil environments and clarify the potential of these molecules to enhance biodegradation rates of atrazine by the strain Pseudomonas sp ADP; 2) the ability of Pseudomonas sp ADP to cleanup sediment and water contaminated with atrazine and to identify some of the factors that influence bacterial performance; 3) the technology development of a open soil mesocosm for an accelerate bioremediation of soil contaminated with atrazine. Additionally, the project will focus on toxicological investigations of atrazine and their metabolites using soil, sediment and water organisms, and toxicity assessments developed for Saccharomyces cerevisiae as a eukaryotic model organism. The project will develop techniques which will allow an increased use of biological methods to remediate sites contaminated with atrazine, ultimately leading to the development of improved bioremediation strategies, with possible impact in the field of Environmental Sciences.