The increasing use of drugs and their subsequent discharge into the aquatic environment is a growing concern due to the threat they pose to non-target organisms and the link between environmental health and human health. Since the major route of entry of these drugs is through the sewage treatment plants, aquatic organisms are exposed to them throughout their whole life span. The majority of studies of the adverse effects of pharmaceuticals on the aquatic ecosystem have been focused on acute effects and the use of mortality as the toxicological endpoint. Not much is known about the long term effects of these drugs on the aquatic environment.
This PhD study, which builds on the success of the PILLS project, investigates the toxic effects of human drugs using sublethal endpoints as well as adopting a more holistic approach by looking at effects at different levels of biological organization (Molecular to Cellular to Organismal) using aquatic organisms belonging to different trophic levels namely: (1) green algae, primary producers, vital for the sustenance of the aquatic food chain; and (2) zebrafish embryos, excellent models for toxicological assessments due to optical clarity and exhibition of similar cardiovascular functional characteristics as humans.
This study aims to assess the environmental risk associated with pharmaceuticals using the endpoints of growth and photosynthesis in microalgae and embryonic development in zebrafish with the aim of associating these with effects at lower levels of biological organisation using molecular and biochemical biomarkers indicative of oxidative, photosynthetic and energy stress in biological cells.