Document Type

Theses, Masters

Rights

Available under a Creative Commons Attribution Non-Commercial Share Alike 4.0 International Licence

Publication Details

Successfully submitted for the award of Master of Philosophy (M.Phil) to the Technological University Dublin in 2008.

Abstract

Currently interest in pharmaceuticals as potential environmental contaminants has increases significantly. This is due to the awareness of the possible adverse effects to human health and the environment caused by such contaminants. Within the past few years, the highly prescribed antidepressants, selective serotonin reuptake inhibitors (SSRI), have received attention as their occurrence in the environment has been recently documented. Prior to this, there was very little known about the ecotoxicity of SSRIs, and in particular sertraline hydrochloride. Similarly the cholesterol-lowering drugs, known as statins are among the most frequently prescribed agents in Ireland and worldwide for the treatment of coronary heart disease. There is also a current lack of information about the adverse effects of pravastatin sodium on aquatic organisms. In ecotoxicology, a ‘battery’ of test systems are used to investigate the effects and mechanisms of action of an environmental contaminant as it is generally accepted that no single bioassay will have a universal sensitivity to all contaminants. The use of more than one test system (incorporating several trophic levels where possible) therefore increases the likelihood of detecting a test substance’s potential toxicity. The aim of the present study was to test two ecologically relevant potential classes of aquatic contaminants namely sertraline hydrochloride and pravastatin sodium on a battery of freshwater species. In addition to the standardized methods, both compounds were also tested on fish cell culture and their cytotoxicity and genotoxicity was assessed. The most sensitive test system found was the D. magna 21 day test several orders of magnitude more sensitive than the other bioassys in both of our studies. The cell lines PLHC-1 and RTG-2 did not display significant differences from each other in terms of sensitivity to sertraline or pravastatin. Also the analysis of DNA alterations in aquatic organisms has been shown to be a highly successful method for evaluating the genotoxic contamination of the environment, being able to detect exposure to low concentration of contaminants in a wide range of species. Even though no significant DNA damage was observed for either pharmaceutical tested, the comet essay can still be considered a valuable tool in ecotoxicity test, however further validation is required for its use with fish cell lines. These results show the advantages of having a tiered approach within a test battery. The presented results indicate that both sertraline hydrochloride and pravastatin sodium adversely affect aquatic organisms at levels several orders of magnitude higher than that reported in municipal effluent concentrations; however as chronic exposure effects may result from lower concentration exposures further research into chronic toxicity is needed. In addition as aquatic species are not exposed to just single contaminants in real exposure scenarios, but rather to mixture of chemicals, combined effects will be a focus of future research.

DOI

https://doi.org/10.21427/D7D893

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