| Donnerstag, 14. Oktober 2010 um 00:04 Uhr |
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TOPIC:
Mechanistic modelling of reprotoxic effects of pesticides in populations of the freshwater gastropod Lymnaea stagnalis.
This PhD position is part of the European Initial Training Network CREAM: Mechanistic Effect Models for Ecological Risk Assessment of Chemicals. Please see www.cream-itn.eu
SUMMARY:
Obtaining more realistic risk forecasts of pesticides on populations of non-target species requires to improve current knowledge, toxicity test methods and data analysis tools. Approaches based on the Dynamic Energy Budget theory seem promising in this context. Indeed, DEB theory provides a physiology-based conceptual framework where effects on survival, growth and reproduction can be simultaneously investigated. Moreover, predicted individual responses to toxicants can directly be used as input data for population effect models. Yet, some ecotoxicological issues remains to be tackled in the DEB framework e.g. how to assess effects of time-varying concentrations and low doses of toxicants, which generate complex response pattern? How to explain patterns of individual recovery after exposure ceases?
This PhD project thus aims at exploring how the DEB theory could be used as a basis to improve existing mechanistic models for the analysis of biological responses to toxicants, focusing on three key issues for refined risk assessment practices: how to deal with complex exposure profiles, how to deal with complex responses to toxicants that are active at low doses and how to account for recovery.
Studies will be based on the coupling of experimental and modelling approaches in the pond snail. Snail¡¦s responses to pesticide exposure will be quantified through lab toxicity tests, focusing on the study of reproductive responses to low doses of toxicants. Observed exposure, effect and recovery patterns will be interpreted and modelled within the DEB framework. This may require adapting the physiological/ toxicological assumptions underlying the currently available models. Finally, effects modelled at the individual level will be extrapolated to the population level.
PhD objectives are to:
- identify from literature chemicals that generate reprotoxicity at low doses in non-target aquatic molluscs- design and implement laboratory toxicity tests in order to investigate effects and recovery patterns of snails exposed to the selected chemicals
- gain experience with current DEB models on toxicity data, and modify them when necessary in order to ensure that they can adequately explain patterns of effects and recovery in exposed snails
- upscale from individual to population-level effects of toxicants based on existing population models.
Expected outputs are validated/documented test methods and comprehensive effect models. Results will contribute to consolidate the basis of forthcoming standardized toxicity test methods and models to evaluate population effects of pesticides.
REQUIRED BACKGROUND KNOWLEDGE AND SKILLS:
S Master degree in Ecotoxicology (Biology or Ecology)
S An aptitude for modelling and mathematics would be advantageous
S Mobility, ability to cooperate in a research consortium and a good level in English are required
Please note that French citizens are not eligible (unless they have been living outside the country for the previous 3 years).
HOST RESEARCH GROUP:
INRA www.inra.fr
Research Center: Rennes (Brittany)
Research Group: Ecotoxicology and quality of Aquatic
Address: 65 rue de Saint Brieuc, CS 84215, 35042 Rennes Cedex
- CONTACT FOR APPLICATION -
Virginie Ducrot: +33 223 485 625, Diese E-Mail-Adresse ist gegen Spambots geschützt! Sie müssen JavaScript aktivieren, damit Sie sie sehen können.
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Von:
Virginie Ducrot
Diese E-Mail-Adresse ist gegen Spambots geschützt! Sie müssen JavaScript aktivieren, damit Sie sie sehen können.
INRA
France
Ansprechpartner: Virginie Ducrot, Diese E-Mail-Adresse ist gegen Spambots geschützt! Sie müssen JavaScript aktivieren, damit Sie sie sehen können.
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