New online tool to improve the environmental risk assessment of chemicals
JRC scientists have contributed to an international project to improve the environmental risk assessment of chemicals which has built a high quality ecotoxicological database called EnviroTox and developed new methodology for identifying chemicals that may pose a threat to the aquatic environment.
Environmental risk assessment of chemicals typically requires toxicity data for fish, algae and crustaceans.
A credible way of filling data gaps
To carry out more rigorous assessments additional data are often needed. However It is not practically possible to test all chemicals for effects on all wildlife species and it is even more challenging to assess risks posed by combined exposure to multiple chemicals, such as chemical mixtures.
A pragmatic and scientifically credible way of filling data gaps is to assign chemicals to groups and examine the distribution of toxicological effects across chemicals in the group. The groups can be composed in various ways, for example based on species, chemical class or mode of toxicological action.
Since the chemicals within each group usually have a range of toxic potencies, the most toxic values can be used to derive a safe concentration, known as the ecological Threshold of Toxicological Concern (eco-TTC). The ecoTTC approach can be used to fill data gaps while reducing the need for additional animal testing.
Case study published
A recently published case study demonstrated that eco-TTC values can facilitate a screening level mixture assessment if data are missing for a limited number of chemicals. Additional case studies are ongoing to better understand how the safe exposure levels derived by the ecoTTC approach compare with regulatory threshold values based on experimental data.
A valuable resource produced by this international collaborative project, led by the Health and Environmental Sciences Institute (HESI, USA), is a new public database of ecotoxicological data, the EnviroTox database, which brings together more than 91,000 curated records for more than 4000 chemicals across 1500 species.