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Date of Award

Spring 5-6-2011

Degree Name

Bachelor of Science


Environmental Science

First Advisor

Dr. Alison Draper

Second Advisor

Dr. Joan Morrison

Third Advisor

Dr. Maria Krisch


With increasing frequency and concentration pharmaceuticals have been identified in surface waters across the world. They enter the environment through improper disposal, incomplete metabolism and in run-off from production sites. Diuretics are drugs that aid in the treatment of numerous diseases by increasing urinary excretion. Due to their frequency of use and their documented environmental presence this subclass was selected as the focus for this study. Diuretics can be divided into four main groups by their mechanism of action: carbonic anhydrase inhibitors, loop diuretics, thiazides, and potassium sparing diuretics. Due to their common prescription rates and varying mechanisms of action the following drugs were tested: acetazolamide, amiloride, bendroflumethiazide, bumetanide, chlorothiazide, ethacrynic acid, furosemide, hydrochlorothiazide, indapamide, spironolactone, triamterene and trichlormethiazide. A 48-hour exposure of each drug to

Daphnia magna was used to examine the drugs‟ toxicity, using survival as an indicator of effect. Each drug was examined initially at the environmentally relevant concentration of 10ppb and then at the greater concentrations of 100ppb, 1ppm and 10ppm. Because toxicity data for these diuretics in aquatic environments are mostly lacking, the LC50 values were determined in the one case for which it was possible. Overall, the drugs had little effect on the survival of Daphnia magna even at concentrations well above reported environmental concentrations. Spironolactone was the only drug that resulted in significant mortality to Daphnia and the LC50 value was determined to be approximately 5.5ppm. However, conclusions on these drugs‟ overall toxicity will be dependent on further studies that can examine toxicity in combination with other pollutants, the toxicity to algae and other organisms, and the 2 impact of prolonged exposure on not only on mortality but on physiology, metabolism, reproduction, behavior and overall health.


Senior thesis completed at Trinity College for the degree of Bachelor of Science in Environmental Science. Accessible to members of the Trinity community only.