Aug. 9, 2018 — Using high performance computing resources, a team of researchers from Laboratoire de Chimie et Physique Quantiques de Toulouse aimed to understand the interactions between pesticides and a soil component. The results help users track pesticide levels in watercourses.

Agriculture is the principal source of livelihood in many regions of the developing world, and the future of our world depends on sustainable agriculture on a global level. HPC is becoming critical in agricultural activity, plague control, pesticide design and monitoring the effects of pesticides. Climate data is used to understand the impact of climate change on water and agriculture in the Middle East and North Africa, help local authorities in the management of water and agricultural resources, and assist vulnerable communities in the region through improved drought management and response.

The French agricultural sector uses just over 500 organic synthesis molecules in the around 2 900 commercially available pesticide products that have been approved for sale. There is a risk that active ingredients in the pesticides could find their way into the environment as well as into the food chain.

These represent a potential danger to people and to ecosystems with immediate and/or long-term effects. Therefore, pesticides’ presence in watercourses and in ground water has been checked more and more often since the turn of the century. These tests highlight the widespread occurrence of pesticides in aquatic milieus, mostly in very small amounts. The results of the analyses make it possible to check that standards are being complied with. These standards, defined at the European level per ingredient, are included in the quality objectives of the European Water Framework Directive.

At the Laboratoire de Chimie et Physique Quantiques de Toulouse (LCPQ), scientists led by Fabienne Bessac and Sophie Hoyau, lecturer researchers at Toulouse INP-PURPAN and Université Paul Sabatier, are conducting research aimed at improving our understanding of the interactions between the pesticide molecules and a type of clay, Montmorillonite. The pesticides being studied are atrazine (a herbicide banned since 2004 but still found in groundwater and surface water), metamitron (a herbicide), fenhexamide (a fungicide used most notably on vines), and subsequently glyphosate.

A multi-stage approach is being used: from the isolated pesticide to the hydrated pesticide adsorbed in the clay and including the complex between the pesticide and the ions presents in the soil. For these complex theoretical chemical computations, 1.4 million hours on EOS and 1 million hours on Occigen, GENCI’s supercomputer, were used. High performance computing resources enabled the researchers to trace how fenhexamide is desorbed (released) in the presence of water for Montmorillonite.

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Source: European Commission