Sex and age dependent mortality of Gammarus pulex in pesticide exposure (Switzerland)

Methods for assessing the toxicity of pesticides to aquatic invertebrates currently do not account for important organism characteristics. For example, the sensitivity to pesticides might be influenced by age and sex. Regarding the population level effects of pesticides, it matters whether the individuals who die are young or old - the young ones have more potential to contribute to the population abundance than old individuals. Equally, if males are more sensitive than females (or vice versa) the chemical disturbs the optimal sex ratio and thus reduces reproductive success of a population. Altogether, sex and age dependent mortality might influence the population abundance to a greater degree than current toxicity test methods would predict.

The offered Master thesis topic is about investigating whether mortality of Gammarus pulex under exposure to pesticides is influenced by sex and age. Approximately 15 pesticides (e.g. diazinon, propiconazole, imidacloprid, aldicarb, malathion, carbofuran) will be studied and the selection covers various modes of toxic action. Standard acute toxicity test designs will be modified to determine the G. pulex age, size and sex distributions before and after the test. The student will learn how to conduct laboratory experiments with G. pulex, carry out experiments with radiolabelled xenobiotics and statistical analysis of toxicity data.

The research will be carried out at the Swiss Federal Institute of Aquatic Science and Technology (Eawag) in the Department of Environmental Toxicology. The institute is a world leader in the field of water sciences. The project will start as soon as a suitable candidate is found (latest in spring 2012) and lasts approximately six months. Day to day supervision will be provided by Anna-Maija Nyman and Dr. Roman Ashauer.

More information:
Anna-Maija Nyman (in English or Finnish), e-mail: anna-maija.nyman@eawag.ch

More information on the department and the research group:
www.eawag.ch/forschung/utox/index_EN
www.ecotoxmodels.org