WP8 Beyond Occurrence: Fate and Effects of Pharmaceutical and Other Emerging Wastewater Contaminants in Aquatic Systems
Wednesday, 16 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(RIC-1117-753776) Effects of Statins and Selective Serotonin Reuptake Inhibitors (SSRI) on Chitobiase Expression of Zooplankton.

Belka, M¹, Kelly, S¹, Symes, S¹, Zoerb, M¹, Hanson, M², Richards, S¹, ¹ Department of Biological and Environmental Sciences, The University of Tennessee at Chattanooga, Chattanooga, TN, USA² Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, Canada

ABSTRACT- Pharmaceuticals are being introduced into surface waters via raw sewage and treated sewage effluent. This widespread release has become an imperative issue problematic to global aquatic ecosystems. Since pharmaceuticals are designed to alter physiological mechanisms including hormonal regulation, concern about endocrine controlled development in organisms of surface waters receiving sewage effluent is warranted. The enzyme chitobiase is associated with development of aquatic invertebrates as it facilitates molting and subsequent growth. The aim of the present research is to assess the suitability of the chitobiase assay for use as a rapid, inexpensive, non-lethal screen of pharmaceutical effects on aquatic invertebrates, specifically Daphnia magna. Reduction in enzyme activity should be linked to reduced growth, survivorship and reproduction. This approach was used to further investigate the effects of statins and SSRIs on Daphnia magna which have been shown in our lab to affect reproduction at 1.0 g/L in 21-d life cycle tests. Consistent chitobiase results were obtained by testing as few as three organisms (in triplicate) per test solution. Initial results indicate that exposure to a statin and a SSRI individually affect Daphnia neonatal chitobiase expression at concentrations of 1.0 g/L in 48-h tests. Thus, 48-h Daphnia chitobiase expression appears to correlate with 21-d reproductive effects. Based on our findings, the chitobiase assay has the potential to be an efficient non-lethal assay that may be used to screen for potential reproductive effects in aquatic invertebrates. This threshold at which change in chitobiase activity occurs approaches that of pharmaceutical concentrations currently found in North American surface waters. The potential for the use of chitobiase as a non-lethal screening tool and the ecological relevance of our findings will be further discussed.

Key words: pharmaceutical, chitobiase, Daphnia magna, aquatic