Dublin PP Symposium 2024 – Application of TKTD Models in Ecotoxicological Risk Assessments

Dublin PP Symposium 2024 – Application of TKTD Models in Ecotoxicological Risk Assessments

During Kerona Scientific’s annual Dublin Plant Protection Symposium, Dr. Dirk Nickisch and Dr. Oliver Jakoby, from Rifcon, gave a very interesting presentation on “Application of TKTD Models in Ecotoxicological Risk Assessments”.  

Unlike traditional laboratory studies that rely on fixed conditions, Toxicokinetic-Toxicodynamic (TKTD) models can predict outcomes under dynamic and realistic environmental scenarios, allowing for the extrapolation of data beyond laboratory conditions. For example, the models can predict exposure concentration thresholds that cause specific mortality rates or estimate exposure concentrations for different time spans. This is particularly relevant as regulatory frameworks evolve, requiring more complex risk assessments beyond conventional methods. 

The reliability of TKTD models is dependent on the quality of input data. As an example, chronic studies typically designed to avoid showing effects can leave gaps in data needed to calibrate models effectively. Addressing these gaps may require extending study durations or designing experiments specifically for model validation, such as measuring recovery effects. 

Despite their promise, TKTD models face challenges, including the lack of user-friendly interfaces and limited case studies for validation. However, already available tools like openGUTS and BeeGUTS, along with EFSA’s peer review group for model evaluation, represent progress. 

Dr. Nickisch and Dr. Jakoby also discussed emerging tools like DeEP for aquatic invertebrates and cvasi for primary producers which reflect the growing diversification of these models. Although many variants of TKTD models and implementations are available, the basic concepts (calibration – validation – predictions/safety margins) are the same.  

As regulations tighten and environmental concerns grow, modelling will play an increasingly important role in the regulatory process in ecotoxicology and should be kept in mind when conducting new studies.  

If you missed the Dublin Plant Protection Symposium, please contact Kerona if you wish to purchase a copy of the presentations. For assistance with the Regulation of PPP in the EU and UK the Kerona Regulatory team can be contacted at info@kerona.ie