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PBT - Physiologically-Based Toxicity responses integrating metal speciation predictions from a biotic ligand model (BLM)
Coordinator - António José Arsénia Nogueira
Programme - POCI/PPCDT
Execution dates - 2005-09-15 - 2009-09-30 (49 Months)
Funding Entity - FCT
Funding for CESAM - 95.453 €
Total Funding - 95.453 €
Proponent Institution - Universidade de Aveiro

In this study we are planning to investigate and model the interactions between water chemistry and metals toxicity to freshwater organisms. The main objective of the study is to develop and validate a model to predict lethal and non-lethal toxicity of metals to freshwater species using characteristics of the water chemistry that are most determinant for them. Cladocerans will be used as the study object and model organisms. These organisms are representative of the lower trophic levels of a freshwater food web, making them ideal organism to assess the health of such systems. In the first stage of the project an extensive literature review will be conducted to produce a database of toxicity endpoints associated with copper and zinc in cladocerans. This database will be used as a reference to identify major experimental needs. In laboratory experiments, we will determine the functional relationships between food concentrations and several water chemistry parameters as conductivity, hardness, major cations and major anions in feeding and survival of individuals exposed to metals (copper and zinc). A modelling framework previously developed to describe Daphnia magna physiology will be refined to incorporate the biotic ligand model approach (BLM). These effects will be experimentally studied under controlled laboratory conditions for varying combinations of water chemistry parameters and metal concentrations. Once the physiological model incorporates the biotic ligand approach, using the relationships previously determined, it will be validated with an independent dataset. The applicability of the model will also be related with its ability of properly predict local species physiology and sensitivity. Thus, the physiological component of the model will be parameterised for Daphnia longispina and experiment will be carried out with several scenarios of exposure to copper and zinc. Full validation of the model will be evaluated according to its ability to predict relevant physiological and ecotoxicological endpoints (e.g. feeding, growth, reproduction, survival).

Members on this project

Susana Loureiro