Skip to Main content Skip to Navigation
Conference papers

Proposition d’une démarche intégrative de confrontation entre valeurs d’indicateurs pesticides, valeurs estimées par la modélisation agro-hydrologique et descripteurs écotoxicologiques dans un processus de validation d’indicateurs. Application à l’IFT Substance Active potentiel de transfert

Abstract : Since 2007, pesticide indicators have been used by French agro-environmental public institutions so as to evaluate and limit the impact of agricultural practices on surface water quality, in accordance with the WFD requirements. A methodological work as been led, including the whole chain of causality (chemical pressure, transfer, state, impact), so as to test the coherence of various tools classically used to assess pesticide impact (an indicator of pesticide potential of transfer to waters, agro-hydrological models, chemical and biological measurements of pesticide impact in water courses). An integrative approach has been implemented so as to confront (i) indicators versus models results, (ii) models results versus chemical observations and (iii) chemical versus biological observations. The tested indicator (IFT SA Potentiel de Transfert) has been developped by INRA and it integrates an estimation of pesticide active ingredient frequency of treatment as well as its mobilily characteristics. Two case studies has been chosen : a mixed farming (cereals, vine, oleaginous plants) agricultural cathment (Ruiné in Charente, 413 ha of arable land) and a vine growing catchment (La Morcille in Beaujolais, 175 ha of arable land). In La Morcille the model MACRO has been used at the field scale while the SWAT model has been used in Ruiné at the sub-catchment scale. The calculations have been achieved at the crop season scale. Chemical monitoring has been achieved according to grab or passive sampling strategies and biological impact has been assessed on diatoms submitted to one month of exposure in each water course of Ruiné (2 observation sites) and La Morcille (3 observation sites). A specific environmental information system using data-warehousing has been used to help the gathering and agregation of data at the sub-catchment scale. Even if the results should be confirmed with complementary tests, a global coherence between the indicator and the results of the model MACRO at the field scale has been highlighted. It was much more difficult to highlight correlations in that way at the sub-catchment scale, probably because of the interference of a combination of factors (different soils, slopes, soil covers) which contribute, as well as agricultural practices, to pesticides transfer. The results permitted to highlight some points of attention so as to consolidate the approach and first conclusions. In particular, one has to grant a special attention to the quality and coherence of the data used for the different levels of confrontations. Obviously, the space and time scales of data acquisition must be compatible, which, in fact, is not so common, data being acquired through different programmes. It is also recommanded to display of a long enough set of meteorological data permitting to take into account the influence of inter-annual rainfall patterns on pesticide modelled transfer and then to provid more robust mean results to confront to the indicator, which, for its part, does not integrate the climat influence. Observation data highlighted the importance of better take into account pesticides degradation products in pesticide indicators and models, as some may be widely detected in surface waters and ecotoxic. Besides, models validity should be verified in more agro-predo-climatical situations so as to improve the consistence of their results before the confrotation with indicators.
Document type :
Conference papers
Complete list of metadata

https://hal.inrae.fr/hal-02604280
Contributor : Migration Irstea Publications <>
Submitted on : Saturday, May 16, 2020 - 9:20:45 AM
Last modification on : Friday, June 4, 2021 - 2:28:12 PM

Identifiers

  • HAL Id : hal-02604280, version 1
  • IRSTEA : PUB00050193

Citation

Frédéric Zahm, Véronique Gouy, Soizic Morin, V. Kuentz Simonet, Odile Leccia-Phelpin, et al.. Proposition d’une démarche intégrative de confrontation entre valeurs d’indicateurs pesticides, valeurs estimées par la modélisation agro-hydrologique et descripteurs écotoxicologiques dans un processus de validation d’indicateurs. Application à l’IFT Substance Active potentiel de transfert. 46ème congrès du Groupe Français des Pesticides, May 2016, Bordeaux, France. pp.6. ⟨hal-02604280⟩

Share

Metrics

Record views

81