Is NMR metabolomics in fish a useful tool for evaluating advanced sewage treatment technologies?

Dr Linda Samuelsson^a, L. Gunnarsson^a, L. Förlin^b and D. G. J. Larsson^a

^aInstitute of Neuroscience and Physiology, Department of Physiology, Division for Endocrinology, University of Gothenburg, Göteborg, Sweden.

^bDepartment of Zoology/Zoophysiology, University of Gothenburg, Göteborg, Sweden.

Pharmaceuticals reach the aquatic environment from a number of sources, of which treated sewage effluent is a major contributor. Since pharmaceuticals are designed to be biologically active, they have the potential to affect wildlife even at low concentrations. It adds to the risks that many pharmaceuticals are not easily degraded and are used continuously and in increasing amounts worldwide. One possible way to reduce pharmaceutical discharges to the aquatic environment is by introducing more efficient sewage treatment technologies. Sewage treatment plants are not designed to remove small organic compounds (such as pharmaceuticals), but additional treatment using advanced technologies may prove to be useful for this purpose.

The presentation will cover a recent study at Sjöstadsverket, an experimental sewage treatment plant in Stockholm, Sweden (in collaboration with Stockholm Water). Six parallel sewage treatment lines, including traditional and more advanced treatment methods such as ozonation and a membrane bioreactor, were evaluated for the ability to remove around 70 pharmaceuticals from the household sewage (Björlenius et al, in prep.). Biological effect studies were carried out by exposing rainbow trout to the treated effluents for two weeks. Exploratory effect analyses (metabolomics) were included primarily as a method to indirectly detect the potential generation of unknown and unwanted chemicals during the secondary treatment with a potential to disturb the physiology of exposed aquatic organisms. Blood plasma was analysed using ¹H NMR metabolomics. The results indicate differences in plasma metabolite profiles between several of the treatments. Additional analyses of hepatic gene expression indicated a marked difference in the ability of different secondary treatments to remove estrogenic compounds. Taken together, this study shows that metabolomics can be a complementary tool for evaluating biological effects of sewage treatment techniques.