Conceptual, mathematical and simulation models are important and exciting, because they capture general principles of a scientific area and because they can make
predictions.This website is about the development of ecotoxicological models, the research focus of my
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The Environment Department at the University of York is working with Unilever’s Safety & Environmental Assurance Centre (SEAC) in Colworth to develop capability in the development and application of ecological models to support risk-based decision making and we are seeking an Ecological Modeller/Ecotoxicologist.
You will be based primarily at Unilever on Colworth Science Park in Bedfordshire, working alongside a team of ecotoxicologists and modelers but you will also spend a significant amount of time (ca. 20%) at the University of York to facilitate knowledge integration and transfer. The specific aim is to develop a modelling framework for environmental risk assessment of down-the-drain chemicals that integrates toxicokinetics, toxicodynamics and population dynamics with environmental stress.
A first degree in a biological, chemical or environmental science (or similar) and a postgraduate professional qualification (PhD) are essential. You will also have experience of ecological effects modelling or toxicokinetic-toxicodynamic modelling and be able to understand testing requirements, experimental design and interpretation of results.
Interspecies variation in sensitivity to synthetic chemicals can be orders of magnitude large. Species traits causing the variation can be related to toxicokinetics (uptake, distribution, biotransformation, elimination) or toxicodynamics (interaction with biological target sites). We present an approach to systematically measure and model the contribution of uptake, biotransformation, internal distribution, and elimination kinetics toward species sensitivity differences. The aim is to express sensitivity as target tissue specific, internal lethal concentrations. A case study with the pesticides diazinon, imidacloprid, and propiconazole and the aquatic invertebrates Gammarus pulex, Gammarus fossarum, and Lymnaea stagnalis illustrates the approach. L. stagnalis accumulates more pesticides than Gammaridae when measured in whole organisms but less in target tissues such as the nervous system. Toxicokinetics, i.e. biotransformation and distribution, explain the higher tolerance of L. stagnalis to the insecticide diazinon when compared to Gammaridae. L. stagnalis was again more tolerant to the other neurotoxicant imidacloprid; however, the difference in sensitivity could not be explained by toxicokinetics alone, indicating the importance of toxicodynamic differences. Sensitivity to propiconazole was comparable among all species and, when expressed as internal lethal concentrations, falls in the range of baseline toxicity. (published in Environmental Science & Technology)