Published on the Web 7/29/2009.
Comparative aquatic toxicity of propranolol and its photodegraded mixtures: Algae and rotifer screening†
Article first published online: 6 JAN 2010
Copyright © 2009 SETAC
Environmental Toxicology and Chemistry
Volume 28, Issue 12, pages 2622–2631, December 2009
How to Cite
Liu, Q.-T., Williams, T. D., Cumming, R. I., Holm, G., Hetheridge, M. J. and Murray-Smith, R. (2009), Comparative aquatic toxicity of propranolol and its photodegraded mixtures: Algae and rotifer screening. Environmental Toxicology and Chemistry, 28: 2622–2631. doi: 10.1897/09-071.1
- Issue published online: 6 JAN 2010
- Article first published online: 6 JAN 2010
- Manuscript Accepted: 2 JUL 2009
- Manuscript Received: 21 JAN 2009
- Transformation products;
- Environmental depletion;
Transformation products of pharmaceuticals formed by human metabolism within sewage treatment plant or receiving waters are predicted, in most cases, to be less toxic than the parent compound to common aquatic species. However, there is little available data to demonstrate whether this is generally the case. In the present study, a framework was developed to guide testing of transformation products using phototransformation of the β-blocker propranolol to test the hypothesis for this particular transformation route. Phototransformation is an important depletion mechanism of some pharmaceuticals in surface waters with fast reaction rate constants at environmentally relevant conditions. Samples of propranolol in deionized water (DIW) and river water (RW) were exposed to a solar simulator (λ: 295–800 nm) and comparative toxicity of propranolol and its degraded mixtures measured using algal (Pseudokirchneriella subcapitata) and rotifer (Brachionus calyciflorus) screening tests. Results suggested a reduction of toxicity in photodegraded mixtures compared to the parent active pharmaceutical ingredient in all samples tested. Chemical analysis of effect test solutions supported the hypothesis that propranolol was transformed into compounds that appear to be less toxic to the organisms tested under the study conditions. Although the reactions were much faster in RW than in DIW, profiles of transformation products were similar in both matrices at two starting concentrations (1 and 10 mg/L). Results for propranolol implied that the reduction of toxicity using algal and rotifer screening tests was probably due to the production of more hydrophilic and more polar transformation products. Such results will provide useful insights into the environmental risk assessment of pharmaceuticals by taking into account their transformation products.