MEMOCTR

"Mechanistic modelling of Critical Target Tissue Residues based on substance properties, species characteristics and external effect concentrations"

 Partecipanti

Mappa

 Word cloud

Esplora la "nuvola delle parole (Word Cloud) per avere un'idea di massima del progetto.

 Obiettivo del progetto (Objective)

'A key challenge facing environmental risk assessors is the need to assess the risk of thousands of chemicals, for a wide range of species, with increased accuracy and ecological relevance, while using fewer resources and experimental animals. Traditional external toxicity metrics, such as the lethal aqueous concentration (LC50), are not sufficiently sophisticated to accomplish this task, and “new” approaches are emerging. This includes the tissue residue approach (TRA), which is advocated as a powerful tool to aid and improve ecological risk assessment. Claimed advantages include, a.o., a likely reduction in use of experimental animals, an improved ability to address mixture toxicity, and an improved ability to link laboratory measurements of exposure and effects to the field. Nevertheless, the application of the tissue-residue approach remains limited. This is mainly because internal target site concentrations are difficult to measure. Mechanistic models that enable the conversion of existing external effect data to critical target concentrations are therefore urgently needed. At present, such in silico tools are well-established for persistent organic chemicals acting via polar or non-polar narcosis. Reliable mechanistic models are however scarce for other modes of action. Therefore, we propose to develop mechanistic models that can reliably predict critical target residues from external effect concentrations for other chemicals, including reactive organic chemicals and metals.'

Introduzione (Teaser)

A recently completed research project has developed models to help estimate whether a substance will be toxic to a wide range of animals.

Descrizione progetto (Article)

Environmental risk assessment for potentially toxic chemicals is an increasingly difficult task in the face of new regulations, demands for greater accuracy and ethical considerations. Modelling the behaviour of potentially toxic compounds could address these issues, but the models need to be more accurate before they can be widely used.

The EU-funded MEMOCTR project endeavoured to improve the parameters for these toxic behaviour models. Specifically, they used metal toxicity in marine animals to enhance accuracy and broaden applicability.

Researchers gathered data on metal toxicity from marine animals such as the rainbow trout and the pond snail. They related this data to various physical characteristics of the organisms so as to make existing models suited to a wider range of species.

They found that acute toxicity in animals was directly linked to a property of chemicals called the covalent index. Another major finding was that metal toxicity (copper and silver in this case) is closely linked to species weight. Using this data, MEMOCTR developed refined models for copper and silver toxicity.

Metal toxicity has also been linked to loss of sodium. Survival rates of organisms have been linked to total loss of sodium, but further work is required to incorporate this information into models.

Predicting toxicity in animals is a complex and daunting task, but MEMOCTR has taken steps to change this. Soon, toxicokinetic/toxicodynamic models will be sophisticated enough to do away with expensive and unethical animal testing and to streamline environmental risk assessments.