ECETOC scientists investigate feasibility of including georeferenced data to improve ecological relevance of chemical risk assessments

The Centre for chemical safety assessment (ECETOC) has carried out a study into the feasibility of using georeferenced data to improve the ecological relevance of risk assessments.

For several decades, chemical safety assessments have followed a generic approach of comparing estimated reasonably worst-case chemical exposure concentrations to toxic thresholds designed to protect all species.

This approach, however, does not recognise the spatial and temporal variations in species distribution. Whilst the approach aims to be protective, a more precise understanding of where and when exposure and species co-occur enables chemical safety assessments to be better tailored.

In addition, environmental management practices can result in heavily modified ecosystems. For example, intensively farmed land is managed for crop production, so will not support the same diversity of species that could be sustained under different land uses.

Today, georeferenced ecological data are becoming increasingly available in enough detail to be useful for chemical risk assessments, potentially improving their environmental relevance. Spatially explicit chemical exposure estimation tools are also available.

The ECETOC Task Force (TF) analysed two aquatic case studies that explore how such data and tools could be applied to chemical safety assessment.

For each case study, the TF first estimated the distribution of chemical exposure by combining local emission and environmental information with models of what happens to the chemicals after they enter the environment. The TF then looked at the toxicity thresholds of different sorts of species present and their distribution along with local exposure estimates (i.e. the potential risk). Finally, they overlaid the risk data with the ecological status of biomonitoring sites to determine if any relationships existed.

The aim of the study was not to carry out a risk assessment of any specific chemical, but rather to demonstrate whether the integration of relevant data and potential approaches was feasible.

The TF concluded that deriving georeferenced exposure concentrations and ecological data on species distribution in the landscape was technically feasible, but that the assessment of risk is less well resolved because of the limited range of ecotoxicity data. In addition, there are not many comprehensive and consistent ecological data sets that span large geographic areas.

The challenges of adopting georeferenced environmental risk assessments over continental scales could potentially be addressed by developing and applying spatially explicit ecological effects models. Further increasing the efficiency and simplicity of assessment and interpretation methods would also be needed, including the development of guidance on how to assess spatial and temporal distributions of risk for decision making.

The Task Force’s full study has been published in the scientific journal ‘Ecotoxicology and Environmental Safety’. The full paper can be found here.