Current toxicity tests have high monetary costs, efficiency issues and ethical concerns.New approach methodologies, such as transcriptomic dose response modelling (TDRM), are increasingly being used to address these issues. This thesis aimed to combine the TDRM method with an acute zebrafish embryo model exposure to determine effective concentrations for chemicals of concern (plasticizers and plastic monomers). We hypothesized that the TDRM methodology would be more sensitive and informative than traditional apical endpoints derived from acute fish exposures. We found that transcriptomic endpoints were more sensitive than apical endpoints for the majority of chemicals tested. However, several challenges related to experimental design and RNA sequencing were encountered and recommendations were given for future studies to address these challenges. Overall, the TDRM methodology, when combined with the zebrafish embryo model, shows promise as an effective tool for screening and prioritizing chemicals of concern. Research Centre (NWRC). I've had the pleasure to work on many amazing projects, meet amazing people and have had countless amazing experiences both inside and outside the lab all thanks to them. Their unique skills sets, and decades of combined experience helped me broaden my horizons and shaped me to be the researcher and person that I am today.