Date of Award


Degree Type


Degree Name

Master of Science (MS)




Pharmaceutical compounds have been widely detected in surface waters but their effects on stream ecosystems are unknown. Cimetidine (Tagamet®), a widely used H2 histamine antagonist has been detected in surface waters. To measure chronic effects of cimetidine on stream invertebrates, I conducted a long-term (83d) artificial-stream experiment. A range of cimetidine concentrations (0.07 μg L-1 to 70.0 μg L-1) were added to streams supporting populations of the amphipod Gammarus fasciatus and beetle Psephenus herricki. P. herricki individual growth rates were reduced in the presence of cimetidine, but G. fasciatus individual growth rates were not different among treatments. G. fasciatus size distribution was significantly different in treatments with the lowest concentration of cimetidine 0.07 μg L-1 (ANOVA, p = 0.002) with no individuals in the three smallest size classes. Biomass and density of G. fasciatus were lower across all cimetidine treatments compared to the control and density was significantly lower than control when cimetidine concentrations were 0.7 μg L-1 (ANOVA, p = 0.035). Understanding effects of novel compounds currently detected in surface waters will require a substantial effort; the artificial stream approach can be useful in quantity effects of such compounds.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.