Utility of Ecological Models

 

The lack of ecological realism is a widely recognised limitation in current regulatory practice for chemical risk assessment. The conventional risk assessment paradigm based on the ratio between predicted environmental concentrations (PECs), representative of simplistic, worst-case local or regional exposure scenarios, and predicted no effect concentrations (PNECs), extrapolated from laboratory studies on few tested species, does not provide sufficient evidence on the expected ecological impact of chemicals on ecosystems. The use of ecological models can improve our mechanistic understanding of the chain of key events from individual organism’s effects to effects on populations and even on communities.

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We are currently exploring new approaches in ecological modelling for use in higher tier environmental risk assessment of key ingredients in home and personal care consumer products. These include the development of organism level Dynamic Energy Budget (DEB) models, individual based models (IBMs) of population dynamics and food web models of aquatic ecosystems.

DEB models are based on energy flow, and calculate the amount of energy an individual allocates to reproduction, maintenance, and growth. These models have been used to explore the physiological modes of action based on measured organism responses to chemical exposure, but when coupled to population models (e.g IBMs) DEB also has the potential to predict chemical impact of population dynamics over time in different ecological scenarios (see Figure 1).

Food web models such as the US EPA sponsored AQUATOX predict how chemicals affect aquatic ecosystem dynamics by considering chemical fate and effects (direct and indirect) based on a detailed characterization of species composition and trophic interactions within a defined ecosystem.

The ultimate goal of this research area is to enable addressing ecologically relevant endpoints that are closer to specific protection goals.

Latest Presentation

Food web modelling of river ecosystems for risk assessment of down the drain chemicals

Latest Publication

Andrea Lombardo, Antonio Franco, Alberto Pivato, Alberto Barausse, Food web modeling of a river ecosystem for risk assessment of down-the-drain chemicals: A case study with AQUATOX, Science of The Total Environment, Volume 508, 1 March 2015, Pages 214-227, ISSN 0048-9697

http://www.sciencedirect.com/science/article/pii/S0048969714016209

Antonio Franco