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5B a - RA/ Ranking and Chemical Specific (TUP/212) Derivation of Sediment Quality Guidelines for chironomids by translation of effects from individual to population. PERY, Alexandre1, BABUT, Marc1, GARRIC, Jeanne1, 1 Cemagref, Freshwater Ecosystems Biology Div., Ecotoxicology Lab., LYON, none, FRANCE ABSTRACT- Effects of toxicants are commonly assessed at individual level, whereas the ultimate goal of ecotoxicology is to protect ecosystems. We built recently energy-based models to describe and predict growth, emergence and reproduction of the midge Chironomus riparius. We propose to use these models for determining effects at population level from effects at individual levels, the latter being obtained from standardized tests. Starting from conventional endpoints, i.e. 10 days survival or 28 days emergence, it is indeed possible to predict effects on populations, and consequently to derive sediment guidelines directly related to these effects. The main predicted effect on population is the density at equilibrium, of which the study is allowed by our models which account for energy transfers. apply this approach to (a) spiked sediments, and (b) a range of contaminated field sediments. According to the role of chironomids in aquatic ecosystems, this approach could lead to ecologically relevant guidelines, avoiding at least some of the biases of the current existing derivation methods. It could also help to derive site-specific, or branch specific guidelines within regulatory applications. Key words: chironomus, sediment quality guideline, population, model |
