New publication on TKTD modeling of sublethal endpoints for time‐variable toxicant exposure of Ceriodaphnia

Toxicokinetic-toxicodynamic (TKTD) modeling can integrate all available data from individual‐level bioassays into a single framework and enable refined risk assessments by extrapolating from laboratory results to time‐variable exposure scenarios. Dynamic energy budget (DEB) models coupled with TKTD modules (DEB-TKTD) are an approach to assess and predict sublethal effects of chemicals on individual organisms. However, thorough case studies are rare. A state‐of‐the‐art example is provided with the standard aquatic test species Ceriodaphnia dubia and the fungicide azoxystrobin, including laboratory toxicity tests, model calibration and validation, and environmental risk assessment. ECT’s contribution was the performance of GLP-compliant pulse-exposure calibration and validation experiments with C. dubia, which provided the required high-quality data to the modelling team. Once validated, the developed model was used to perform predictions for a time‐variable exposure scenario. A moving time‐window approach was used to perform the environmental risk assessment. This assessment method reduces uncertainty in the risk assessment while maintaining consistency with the traditional measures of risk.

For further information, see the open access publication in Environmental Toxicology and Chemistry :

Romoli, C., Trijau, M., Muller, E.B., Zakharova, L., Kuhl, R., Coors, A., Sherborne, N., Goussen, B., Ashauer, R. (2024). Environmental risk assessment of time-variable toxicant exposure with toxicokinetic-toxicodynamic modeling of sublethal endpoints and moving time windows: a case study with Ceriodaphnia dubia. Environmental Toxicology and Chemistry 43, 2409-2421.

For additional new publications, see ECT’s publication list.